Carbon footprint accounting method for producing products using residues from low-yield camellia oil forest transformation

Abstract

The present invention discloses a carbon footprint accounting method for producing products using residues from the transformation of low-yield camellia oil forests, comprising the following steps: S1. defining objectives and scope; S2. data collection; S3. determining carbon footprint accounting indicators; S4. carbon footprint calculation; S5. impact assessment; S6. sensitivity analysis; S7. result interpretation and decision support. The present invention uses a carbon footprint accounting method and a method of use for producing boards, pulp and biomass energy products using residues from the transformation of low-yield camellia oil forests to solve the problem of lack of accurate quantification and resource utilization of a large amount of residues generated by the transformation of low-yield camellia oil forests in my country, reduce emission hotspots in the production process, and promote the realization of carbon neutrality goals.

Description

Technical Field

[0001] The patent of this invention specifically relates to a carbon footprint accounting method for producing products using the residues from the transformation of low-yield camellia oleifera forests. Background Art

[0002] Camellia oleifera Abel. is a woody oil-bearing tree species unique to my country, mainly distributed in Hunan, Jiangxi, Guangxi, Fujian, Guangdong and other provinces. The existing methods for accurately improving the quality of oil-tea economic forests mainly include renewal and transformation, renovation and reconstruction, water and fertilizer management, high-grafting and crown replacement, density adjustment, etc. Among them, the solutions adopted for structural transformation of forest stands such as renewal and transformation, renovation and reconstruction, and density adjustment are thinning, pruning and complete felling of old forests, which will produce a considerable amount of underutilized oil-tea timber. If such a huge area of ​​existing inefficient and low-yield oil-tea forests is transformed, rich and sustainable timber resources can be generated, and their existing production potential can be fully utilized. Patent 202410153089.9 discloses a carbon footprint accounting method and system for the breeding stage of economic forest varieties. It divides the economic forest breeding stage into the breeding stage of improved varieties, the greenhouse cultivation stage and the field seedling and rejuvenation stage, and divides the input categories into eight sub-stages: energy, fertilizer, pesticide, reagent, consumables, labor, transportation and waste treatment, but does not mention the accounting method for low-yield and low-efficiency oil-tea forests; Patent CN101927515A discloses a new type of board manufacturing method, which uses crop straw, bison plant straw, vines, herbaceous plants, shrubs and tree branches as the main raw materials, and removes rotten wood. The rotten raw materials are simply processed by removing sand and gravel, etc. to make new boards, but the carbon footprint accounting of the boards is not involved; Patent CN105010083A discloses a method for transforming low-yield tea forests, which greatly increases the tea oil production of tea forests by pruning, reclamation, fertilization and other operations on old tea forests, but does not involve the carbon footprint accounting of the transformed forests; Existing patent searches have found that there is no carbon footprint accounting method for using the residues from the transformation of low-yield tea forests to produce boards, pulp and biomass energy products, so this patent will fill the gap in this field. In recent years, with the rapid development of agriculture and forestry, the planting area of ​​economic crops such as tea, walnuts, and chestnuts has continued to expand. During the production and processing process, a large amount of residues, such as shells, pomace, and pruned branches and leaves, are produced. The annual output of tea, walnut, and chestnut shells alone is as high as 29.3 million tons.

[0003] As global forest resources gradually decrease, major timber exporting countries have begun to strictly control their own timber resources. At the same time, due to the limitations of my country's natural conditions, the area suitable for the growth of arbor forests only accounts for about 50% of the country's land area. In areas suitable for the growth of arbor forests, planting and cultivation have been basically completed, but most forests are of low quality, and the forest volume per unit area is only about 80% of the world average. With the advancement of my country's environmental protection strategy, my country's timber output has been showing a downward trend. While the supply of timber is in short supply, the demand for timber continues to grow. As the contradiction between supply and demand in the upstream timber market further increases, the first to bear the brunt are domestic panels, floor materials, construction and other industries. In particular, as a natural carbon storage reservoir, wood panels have important ecological benefits. Nearly 80% of the wood used in the panel industry relies on imports. In the future, it will be more and more difficult to import wood, and the cost will be higher and higher. The issue of wood safety has become increasingly prominent and has become one of the hot issues that directly affect the country's economic development. Therefore, seeking sustainable, sufficient supply, environmentally friendly alternative wood resources has become an important development trend, and oil tea wood has thus appeared in the public's field of vision.

[0004] Boards refer to the remaining wood materials such as trunks and twigs left over from the structural forest transformation of some low-quality and low-efficiency forest land in the oil-tea economic forest land used for the production of oil-tea oil. The wood products obtained by processing the boards as raw materials are made into boards, pulp, and biomass energy products to achieve efficient biological recycling of oil-tea forests, fill the gap in the carbon footprint accounting of boards, pulp, and biomass energy products produced from the residual materials of economic forests, and promote the sustainable development and utilization of resources; at the same time, boards are made into wooden boards and wooden pulp. Biomass energy fixes carbon in organisms and reduces carbon emissions. Existing research on oil-tea wood, pulp, and biomass has found that oil-tea wood is a high-quality timber species with high density, rich in fiber, bio-oil and biochar, and is a high-quality raw material for making boards, pulp, and biomass energy products. The study found that the fiber length and strength of camellia oleifera shells were improved after steam explosion treatment, and the paper produced after mixing with softwood pulp had good tensile strength and water resistance. In addition, COS after pyrolysis treatment can produce high calorific value biomass fuels, such as bio-oil and biochar, showing its great potential in pulp and biomass energy production; pyrolysis characteristics and thermodynamic analysis of camellia oleifera seed residue (COSR), these residues can produce high-quality bio-oil and biochar during pyrolysis, showing its potential in biomass energy production. In addition, camellia oleifera shells are rich in cellulose, hemicellulose and lignin, and are ideal raw materials for pulp preparation. Its utilization rate can be greatly improved through proper treatment, but there is a lack of carbon footprint accounting for the residues used in pulping.

[0005] The main technologies in the existing oil tea economic forest quality improvement project include variety improvement, cultivation technology improvement, comprehensive utilization of economic forests, and pest and disease control. There is no quantification and evaluation method for the ecological advantages of boards, but how to quantify and evaluate the ecological advantages of boards, pulp, and biomass energy. In the existing technical field, the carbon footprint accounting method is generally adopted. Carbon footprint refers to the total amount of carbon released or absorbed in the entire life cycle from raw material collection, processing, manufacturing, transportation, to product use and disposal; through the existing technology and literature search of carbon footprint, it is found that the existing carbon footprint accounting involves agriculture, industry, construction and energy, but there is no accurate carbon footprint accounting method for wood products in the forestry industry; and the research on existing wood products is in the application of wood modification technology, new wood composite materials, wood structure and construction applications, biomass energy utilization and other technical applications, but there is little research on its carbon footprint accounting, especially the carbon footprint accounting research of boards is blank. In addition, the existing document "Design Research on Carbon Emission Reduction of Wood-Based Boards Based on the Whole Life Cycle" mentions that the carbon emission research on wood-based boards based on the whole life cycle starts from the production of boards to their use and scrapping, lacks the accounting of the raw material acquisition and production stages of wood products, and the definition of the accounting scope of the carbon footprint of wood-based boards throughout their life cycle is not accurate, and the accounting results are not accurate enough; based on the accounting boundaries determined in "A Brief Analysis of Greenhouse Gas Emission Accounting Standards and Methods in the Pulp and Paper Industry", including emissions caused by fossil fuel combustion, emissions during the production process, carbon emissions generated by the company's net purchase of electricity and heat, and carbon emissions generated by wastewater treatment, there is a lack of carbon accounting content for the raw material collection and transportation stages; based on the mention in "Vigorously Developing Forestry Biomass Energy Industry" that China vigorously develops forestry biomass energy, the industrial chain is gradually improved, and the focus is on the development of molded fuels, biomass power generation, heating and polygeneration, but the carbon footprint accounting process of biomass energy products is not involved.

[0006] In summary, existing research and inventions tend to focus on the processing methods of board residues, while the field of carbon footprint accounting for the production of board, pulp, and biomass products from board residues is still relatively neglected. At present, there is no method that can clearly calculate the carbon footprint of board residues from the forest farm gate to the wood processing plant gate. Therefore, this study is based on the evaluation of the ecological costs and benefits of the entire life cycle of board raw material acquisition, wood product processing, board production, and use and scrap disposal, and designs a "gate-to-gate" carbon footprint accounting method to accurately evaluate the carbon emissions during its life cycle, provide a more comprehensive and accurate carbon footprint assessment result, alleviate the dilemma of low-quality and inefficient transformation of existing oil tea forests, improve land utilization, and fill the current huge gap between supply and demand of wood. Summary of the invention

[0007] In response to the problems in the prior art, the present invention provides a carbon footprint accounting method for producing products using residues from the transformation of low-yield camellia oil forests, and a carbon footprint accounting method and a use method for producing boards, pulp and biomass energy products using residues from the transformation of low-yield camellia oil forests, so as to solve the problem of lack of accurate quantification and resource utilization of a large amount of residues generated by the transformation of low-yield camellia oil forests in my country, and reduce emission hotspots in the production process.

[0008] To achieve the above-mentioned purpose, the present invention provides a carbon footprint accounting method for producing products using residues from low-yield camellia oleifera forest transformation, comprising the following steps:

[0009] S1. Define the objectives and scope: (1) Determine the classification of board residues into boards, pulp, and biomass energy; (2) Determine the functional units; (3) Determine the system boundaries, including the five process units of oil tea wood harvesting, wood product manufacturing and processing, board manufacturing and processing, product use, and disposal and scrapping, as well as the corresponding inputs and outputs; (4) Determine the selection criteria;

[0010] S2. Data collection: (1) Collect and record the on-site data list of each process unit, specifically determine the allocation procedures, calculation methods, data requirements and emission factors in each sub-stage, and obtain data; (2) Collect the emission factor list of the entire life cycle, specifically: determine the carbon emission inventory of each stage based on the production information of board, pulp and biomass energy products, analyze the carbon emission inventory of the residual products in the life cycle, and determine the input and output lists of each stage;

[0011] S3. Determine the carbon footprint accounting indicators: Use the emission factor method to build a carbon emission accounting model. The carbon footprint accounting indicators are the greenhouse gases emitted from energy consumption, material input and disposal during the entire life cycle. Greenhouse gases include CO2 and CH4N2O.

[0012] S4. Carbon footprint calculation: After collecting and collating the on-site activity data at each stage, use the corresponding emission factors to estimate the amount of greenhouse gas emitted by each activity in the process unit, and use the carbon emission accounting model of each stage to obtain the carbon footprint of economic forest products; that is, multiply the on-site activity data by the corresponding emission factor and divide it by the functional unit to calculate the unit carbon emissions of the process unit; for different carbon footprint calculation indicators, convert the emissions into carbon dioxide equivalents, and sum up the carbon emissions of each process unit based on the functional units of board residues as boards, pulp, and biomass energy, and obtain the unit total carbon footprint of board residues as boards, pulp, and biomass products "from gate to gate";

[0013] S5. Impact assessment: Identify the influencing factors, classify the influencing factors and collect relevant data, and use statistical and analytical methods to process and analyze the data to assess the specific impact of each influencing factor on the assessment results;

[0014] S6. Sensitivity analysis: Identify the key parameters that are most likely to have a significant impact on the impact assessment, set ranges for the key parameters, select appropriate analysis methods, use different parameter values ​​within the parameter range for multiple assessments, and observe the magnitude and trend of the results; conduct uncertainty and sensitivity analysis, and analyze the emission share and data quality;

[0015] S7. Result interpretation and decision support: Based on the analysis results, compare significant differences and trends, and explain the cause-effect relationship of the results. Based on the evaluation results and interpretation, formulate sustainable decision support measures, consider key indicators in terms of environmental impact, carbon emissions, resource utilization, etc., identify potential opportunities for improvement and optimization, and formulate specific action plans; the tracking unit is capable of calculating, storing and tracking the artificial forest "plot" activities and implementation imprint information, activity energy consumption information, activity GHG emission information, and carbon credit information of the operation process related to each of the at least two forest farms, locations or "plots".

[0016] Preferably, the specific content of step S1 is:

[0017] Each sub-stage of the life cycle is divided into three sub-systems: producing boards, pulp and biomass energy products from the residues of low-yield camellia forests, and the system boundaries, functional units and selection criteria of the carbon footprint of each part are determined; among which:

[0018] (a) The low-yield oil-tea forest refers to the forest whose production potential has not been fully utilized due to factors such as complex varieties, extensive planting, aging trees, poor soil conditions, and serious pests and diseases, with an annual oil production of 150 kg / hm2. 2 The following oil tea trees have grown into forests;

[0019] (b) The transformation of low-yield forests refers to the use of modern production and management technologies to improve varieties, shape and prune, fertilize, and control pests and diseases on low-yield and low-efficiency forest land, aiming to change the current low-yield status of tea oil trees, increase tea oil output, and increase economic benefits;

[0020] (c) The residuals from the transformation of low-yield camellia oil forests refer to the woody residues of felled camellia oil trees, branches and trunks remaining in the forest land when measures such as variety improvement, transformation of inferior plants and density adjustment are adopted for the transformation of low-yield camellia oil forests;

[0021] (d) The board production subsystem refers to wooden boards made from the trunk parts of the residues from the transformation of low-yield tea-oil forests, including solid wood boards and artificial boards; solid wood boards are made directly from the trunk sawn timber of the residues from the transformation of low-yield tea-oil forests, while artificial boards are made from the twigs of the residues from the transformation of low-yield tea-oil forests after processing and pressing;

[0022] (e) The pulp production subsystem refers to a pulp made by chemically or mechanically treating the fiber part of the residue, which is used to produce pulp products;

[0023] (f) The biomass energy production subsystem refers to the energy products produced by utilizing the residues from the transformation of low-yield tea oil forests through various biomass energy conversion technologies, including physical conversion, chemical conversion and biological conversion. These residues include the trunks, twigs and leaves of tea oil trees. Through the efficient use of these biomass resources, they are converted into renewable energy to replace traditional fossil energy.

[0024] Preferably, the board production subsystem includes felling and on-site transportation, off-site transportation to a wood processing plant, and production at the wood processing plant, specifically:

[0025] (a) The felling and on-site transportation refers to the process from felling of low-yield oil-tea tree forests to transportation to the forest farm, mainly including felling, logging, log collection, on-site transportation and loading;

[0026] (i) Harvesting of low-yield conversion residues refers to the harvesting of the trunks, branches, leaves and other residues cut down during the conversion of low-yield oil-tea forests from the forest land, carried out manually or mechanically;

[0027] (ii) Low-resource logging refers to the collection of felled tea tree residues to a specific location by manual or mechanical means, usually by hauling them to the side of a forest road or to a logging yard;

[0028] (iii) The sorting of the residues after logging refers to the stacking of the residues after logging in accordance with certain specifications and requirements to facilitate subsequent transportation and processing. This step usually involves sorting, cleaning and stacking the residues;

[0029] (iv) On-site transportation and loading of low-carbon waste residues refers to the transportation of waste residues from the forest land to the forest farm gate by means of tractors or trucks, and loading them onto trucks for off-site transportation. This process may require multiple loading and unloading and transportation operations;

[0030] (b) The off-site transportation to the wood processing plant refers to the process of transporting the residues at the forest gate to the wood processing plant by means of transportation such as roads or railways, which usually involves long-distance transportation and needs to consider the economy and efficiency of transportation;

[0031] (c) The processing and production stage in the wood processing plant refers to the process of subjecting the residues from the transformation of low-yield tea oil forest to a series of processing and production processes in the wood processing plant, mainly including peeling, sawing, planing, drying and chemical treatment processes in the lumberyard. These processes are aimed at processing the residues into wood products with economic value, such as boards, pulp and biomass energy products.

[0032] (i) Debarking at the lumberyard involves transporting logs from the lumberyard to the sawmill feeder and log resaw or debarker after logs have been sorted and stored;

[0033] (ii) sawing consists essentially of the processing of long sawn timber into short sawn timber and the breaking up or sawing of logs into rough raw timber and residues, which include boards, offcuts, sawdust and ground offcuts;

[0034] (iii) trimmings, planks and strips are processed on chippers, where the chips are transported to a nearby pulp mill;

[0035] (iv) Drying mainly involves drying, leveling and conditioning the wood in a kiln; Planing steps include: splitting, grading and sorting the wood; Planing or fine planing the wood;

[0036] (v) Chemical treatment mainly involves treating the produced boards with insect and moisture proofing and applying paint.

[0037] Preferably, the pulp production subsystem includes a wood processing plant processing stage, a transportation stage and a pulp processing plant production stage, specifically:

[0038] (a) The processing stage of the wood processing plant includes the debarking, sawing and planing process at the lumberyard, and the wood chips and other scraps produced are transported to the pulp processing plant for processing;

[0039] (i) Lumberyard debarking means the removal of the bark from logs to facilitate subsequent sawing and planing;

[0040] (ii) Sawing means the processing of logs into sawn timber of specified dimensions and the collection of the resulting scraps and sawdust;

[0041] (iii) Planing means further processing of sawn timber to smooth its surface and produce scraps such as wood chips;

[0042] (b) The production stages of the pulp processing plant are divided into pulping, bleaching, drying and packaging processes;

[0043] (i) The pulping process mainly uses physical methods (such as chopping and grinding) and chemical methods (such as chemical soaking) to separate the fibers from the raw materials;

[0044] (ii) bleaching is usually achieved by using chemicals (such as chlorine or oxides) to make the fibers whiter;

[0045] (iii) Drying, which mainly includes kiln drying, air heat drying or drying drums, improves the quality of pulp by reducing the moisture content in the fibers;

[0046] (iv) Packaging mainly includes the process units of cutting the dried pulp into appropriate sizes, stacking, bundling and packaging.

[0047] 1. Preferably, the biomass energy product subsystem includes a raw material collection stage, a raw material transportation stage and a biomass energy production stage, specifically:

[0048] (a) The raw material collection stage includes the collection, sorting and loading of the forest residues (tea tree leaves, taproots, lateral roots, etc.) after the low-yield oil-tea plantation is transformed, as well as the collection of the scraps (wood chips, ground edges, etc.) generated during the processing of the wood processing plant;

[0049] (i) Skidding means the collection of the remaining materials scattered on the forest land into piles for subsequent processing;

[0050] (ii) Sorting means arranging the collected piles of residues into regular strips for easy loading;

[0051] (iii) Loading means loading the sorted residues onto the transport vehicle;

[0052] (b) The raw material transportation stage refers to the transportation of forest residues to biomass processing plants and the transportation of scraps generated by wood processing plants to biomass processing plants;

[0053] (c) The biomass energy production stage includes chipping, wood pellet production and cogeneration processes;

[0054] (i) Slicing means cutting larger wood scraps into smaller pieces for subsequent processing;

[0055] (ii) The wood pellet production process usually includes crushing, drying and pelletizing process units;

[0056] (iii) Cogeneration refers to the efficient use of energy by burning biomass to produce heat and electricity.

[0057] Preferably, the system boundary refers to the scope of the board, pulp and biomass production system from "gate to gate", and determines the input and output of the system. The system production includes material and chemical inputs, electricity and fuel use, and the inputs of their suppliers and product transportation consumption. The output includes the emission of various greenhouse gases, specifically:

[0058] (a) The boundary of the board production system is “from the forest gate to the wood processing factory gate”, from the logging and on-site transportation of low-yield camellia forest land to the off-site transportation and board processing and production life cycle stages;

[0059] The inputs to the system include forest road construction and labor, material inputs, and energy and fuel inputs;

[0060] The output of the system is greenhouse gases, and the greenhouse gases selected for this study are carbon dioxide, methane, and nitrous oxide;

[0061] (b) The boundary of the pulp production system is “from the wood processing plant gate to the pulp processing plant gate”, which includes the life cycle stages from the transportation of wood chips and scraps from the wood processing plant to the pulp processing plant and pulp processing production;

[0062] The input of the system includes material input, energy and fuel input, and the output of the system is greenhouse gas. The greenhouse gases selected in this study are carbon dioxide, methane and nitrous oxide;

[0063] (c) The boundary of the biomass energy production system is “from the forest gate to the biomass energy processing plant gate”. The system boundary starts from the life cycle stage of collecting forest residues from low-yield camellia oil forests, transporting forest residues off-site to the biomass energy processing plant and biomass energy processing production;

[0064] The inputs of the system include forest roads, labor inputs, energy inputs and fuel inputs;

[0065] The output of the system is greenhouse gases, and the greenhouse gases selected for this study are carbon dioxide, methane, and nitrous oxide.

[0066] Preferably, the step S1 further comprises the step of determining a unified calculation standard in the board, pulp and biomass energy production system, specifically:

[0067] (i) The functional unit of the board production is 1 cubic meter of finished board, which is used as the benchmark to measure the resources consumed and the environmental impact of the entire production process;

[0068] (ii) The functional unit of pulp production is 1 ton of finished pulp, which is used as the benchmark unit for assessing resource input and environmental emissions during pulp production;

[0069] (iii) The functional unit of biomass energy production is 1 kg of biomass energy product, which is used to calculate resource usage and environmental impact during the production process.

[0070] 2. Preferably, in step S2, determining the allocation procedure in each sub-stage refers to using a mass allocation method to allocate materials, energy, transportation, and output in the board, pulp, and biomass energy production system; specifically:

[0071] (a) Material allocation refers to the allocation of materials required for the production of board, pulp and biomass products;

[0072] (i) Material inputs in the production process of panel products include: lubricating oil used in the logging process of low-yield tea-oil forests, lubricating oil and hydraulic oil used in processing equipment in wood processing plants, and paint solvents used in chemical treatment;

[0073] (ii) Material inputs for pulp product production include: calcium oxide and sodium hydroxide used in the pulping process in the pulp mill, and hydrogen peroxide, sulfuric acid, ethanol and sodium chlorate used in the bleaching process;

[0074] (b) The energy distribution mentioned above refers to the distribution of energy required in the process of producing board, pulp and biomass products;

[0075] (i) Energy inputs in the production process of panel products include: diesel consumed by logging equipment (chain saws, loggers, etc.) during the logging process of low-yield camellia oil forests, propane consumed by propane equipment used for power generation or heating in wood processing plants, diesel and gasoline consumed by sawing machines and planing machines, power grid electricity consumed by on-site facilities, and electricity generated by kiln drying furnaces; natural gas consumed in the drying process;

[0076] (ii) Energy inputs in the pulp product production process include: grid electricity and on-site electricity consumed in pulping, bleaching and drying processes, and heat energy generated by on-site steam consumed in the drying process;

[0077] (iii) Energy inputs in the production of biomass products include: natural gas consumed in the production of chips and wood pellets, and liquefied petroleum gas and natural gas used in the cogeneration process;

[0078] (c) The transportation allocation mentioned above refers to the allocation of transportation activities involved in the production of board, pulp and biomass products;

[0079] (i) The transportation process of board product production includes: ① transportation within the oil tea forest, transportation from the forest to the forest gate, ② transportation from the forest gate to the railway freight station, and ③ transportation from the railway freight station to the wood processing plant;

[0080] (ii) The transportation process of pulp product production includes: ① transporting wood chips and other scraps from wood processing plants to pulp processing plants; ② materials in pulp processing plants are usually purchased from local suppliers and transported by gasoline trucks;

[0081] (iii) The transportation process of biomass energy product production includes: ① transportation of residues from the forest farm gate to the railway freight station, ② transportation from the railway freight station to the biomass energy processing plant;

[0082] (d) The output distribution refers to the distribution of various outputs in the process of producing boards, pulp and biomass energy products. Every 1,000 kg of low-reform residues can produce 219 kg of board products, 104 kg of pulp products and 677 kg of biomass energy products.

[0083] 3. Preferably, in step S2, data acquisition refers to acquiring the production input data and output data required for each stage according to the allocation process and system boundaries of the board, pulp and biomass energy production system, including the following:

[0084] (a) Data on the collection of raw materials: including the quantity, type and biomass of felled residues, obtained through on-site measurement and statistics;

[0085] (b) The production process data: including fuel consumption and transportation distance during transportation, energy and water usage during processing, obtained by recording the operating time and efficiency of production equipment;

[0086] (c) Emission data: including the quantity and composition of waste gas, wastewater and solid waste, especially greenhouse gas emissions, obtained through online monitoring equipment and regular sampling and analysis.

[0087] Specifically, perform the following operations:

[0088] (1) Acquisition and classification of residues from low-yield camellia forest transformation:

[0089] (a) the logging information records include the logging location, logging method, logging quantity and logging tool types;

[0090] (i) The felling site records include specific latitude and longitude coordinates to ensure the accurate location of the felling site;

[0091] (ii) The felling method must be clearly stated whether it is manual or mechanical, and the use time and work efficiency of the mechanical equipment must be recorded;

[0092] (iii) The number of trees felled includes the number of trees felled each time and the total number of trees felled cumulatively, so as to facilitate comprehensive statistics of felling activities;

[0093] (iv) Types of harvesting tools: List all types of tools used for harvesting and record the specific model and specifications of each tool to facilitate tool management and use evaluation;

[0094] (b) the transportation information records include records of the transportation distance, transportation vehicle and fuel type from the felling site to the processing plant;

[0095] (i) Transport distance: Record the transport route and total distance from the felling site to the processing plant to facilitate optimization of transport routes and accurate measurement of distances;

[0096] (ii) Transport vehicles and fuel types: Record the types of transport vehicles used for transportation, their specific models and fuel types, as well as the amount of fuel consumed for each transport and the load of the transport vehicles, to ensure comprehensive monitoring of the transportation process and rationalization of fuel use;

[0097] (c) the records of timber characteristics include records of timber mass, density, volume, moisture content and carbon content;

[0098] (i) The mass of the timber is measured using standard methods to ensure the accuracy of the data and recorded as weight;

[0099] (ii) The density of wood is recorded as kg / m3. 3 ) to facilitate a comprehensive understanding of wood properties;

[0100] (iii) Volume is measured in cubic metres (m 3 ) as the unit to ensure the accuracy of volume data;

[0101] (iv) Humidity is measured using a hygrometer and expressed as a percentage (%) to ensure the accuracy of humidity data;

[0102] (v) Carbon content is expressed as a percentage (%) to facilitate accurate assessment of wood carbon storage.

[0103] (2) Plate manufacturing and processing:

[0104] (a) the records of the sawn timber production process include the machine model, power, usage time, energy consumption, sawn timber drying method and related consumption;

[0105] (i) record the model and power of the machines used, including peelers, trimmers, sawmills, conveyors, drills, planers, sanders, etc.;

[0106] (ii) record the usage time of each machine to facilitate equipment management and maintenance;

[0107] (iii) record the energy consumption of each machine, including electricity and fuel consumption, to monitor energy use in the production process;

[0108] (iv) record the method of timber drying, such as kiln, boiler, etc., and record the related timber scraps, natural gas, coal consumption and water consumption to ensure the rational use of energy and resources in the drying process;

[0109] (b) the board production process records include the machine model, power, usage time, energy consumption, board drying method and related consumption records;

[0110] (i) record the model and power of the machines used, including cutters, crushers, cookers, hot presses, planers, sanders, trimmers, mixing equipment, etc.;

[0111] (ii) record the usage time of each machine to ensure efficient use of equipment;

[0112] (iii) record the energy consumption of each machine, including electricity and fuel consumption, to facilitate optimal management of energy use;

[0113] (iv) record the method of drying the boards, such as kiln, boiler, etc., and record the related wood scraps, natural gas, coal consumption and water consumption;

[0114] (3) Pulp manufacturing and processing:

[0115] (a) the raw material preparation equipment records include the model, power and usage time of chippers, peelers and screeners;

[0116] (b) the cooking equipment record includes the specific type of cooker (e.g., continuous cooker or batch cooker), operating parameters and electricity consumption;

[0117] (c) the washing equipment records include the model, power and usage time of the pulp washer and bleaching machine;

[0118] (d) the pulping equipment records include the model, power and power consumption of the pulper and refiner;

[0119] (e) the bleaching equipment records include the model, power and usage time of the bleaching tower and bleaching agent storage equipment;

[0120] (f) the concentration equipment records include operating parameters and power consumption of vacuum concentrators and filter presses;

[0121] (g) the drying equipment records include the model, power and usage time of the drum dryer and belt dryer;

[0122] (h) the forming equipment records include the model, power and operating parameters of the cylinder forming machine and the Fourdrinier paper making machine;

[0123] (i) The auxiliary equipment records include the model, quantity, power and usage time of conveyors, pumps, pipelines and control systems;

[0124] (4) Manufacturing and processing of biomass energy products:

[0125] (a) the raw material preparation equipment records include the model, power and usage time of chippers, crushers and screeners;

[0126] (b) the drying equipment records include operating parameters and power consumption of specific types (e.g. drum dryers and belt dryers);

[0127] (c) the pelletizing equipment records include the model, power and usage time of the ring die pelletizer and the flat die pelletizer;

[0128] (d) the cooling equipment records include the model, operating parameters and power consumption of cooling towers and chillers;

[0129] (e) The packaging equipment records include the model, power and usage time of the automatic packaging machine and semi-automatic packaging machine;

[0130] (f) The auxiliary equipment records include the model, quantity, power and usage time of conveyors, pumps, pipelines and control systems to comprehensively assess the energy consumption and environmental impact of the manufacturing and processing of biomass energy products;

[0131] (g) the fuel characteristics record includes the type, calorific value, moisture content and ash content of the biomass particles;

[0132] (h) Records of energy use in the process, including the amount and source of electricity, natural gas or other auxiliary fuels consumed.

[0133] Preferably, in step S2, the emission factor refers to the emission coefficient of collected input data to calculate its carbon footprint, and the collected databases include: Ecoinvent database, ELCD database, CLCD database, CPCD database, GaBi database, BUWAL250 database IDEMAT 2001 database, VTT / KCL-eco database, CPMLCA database, USA InputOutput Industry Dala database, which collect emission factors of raw materials, energy, and transportation.

[0134] Preferably, in step S3, the carbon footprint accounting indicators include carbon footprint accounting of board production, carbon footprint accounting of pulp production, and carbon footprint accounting of biomass energy production:

[0135] (i) The carbon footprint accounting of board production includes three stages: felling and on-site transportation, off-site transportation, and wood processing. In the felling and on-site transportation stage, the fuel consumption and emissions of felling equipment are calculated; in the off-site transportation stage, the fuel consumption and emissions of transportation vehicles are calculated; in the wood processing stage, the energy consumption and emissions of sawing, planing and drying are calculated;

[0136] (ii) The carbon footprint accounting of pulp production includes five stages: transportation of processing residues, pulping, bleaching, drying and packaging. In the stage of transportation of processing residues, the fuel consumption and emissions of transportation vehicles are accounted for; in the stage of pulping, the energy and chemical consumption and emissions of the physical and chemical pulping process are accounted for; in the stage of bleaching, the use of bleaching agents and the emissions generated are accounted for; in the stage of drying, the energy consumption and emissions of drying equipment are accounted for; in the stage of packaging, the energy consumption and emissions of packaging materials and equipment are accounted for;

[0137] (iii) Carbon footprint accounting for biomass energy production includes three stages: raw material collection, raw material transportation, and biomass energy production. In the raw material collection stage, the fuel consumption and emissions of the collection equipment are accounted for; in the raw material transportation stage, the fuel consumption and emissions of the transportation vehicles are accounted for; in the biomass energy production stage, the energy consumption and emissions in the production of chips, wood pellets and cogeneration are accounted for.

[0138] Preferably, the specific content of step S4 is:

[0139] Calculate total carbon footprint:

[0140]

[0141] Wherein, is the total carbon footprint of products produced from the residues of low-yield camellia oil forest transformation, i is the carbon emission type, and Ci is the carbon emission of different types; specifically, it includes the following steps:

[0142] (a) Material use emissions include chemical inputs during the product life cycle; the chemicals include paint solvents, calcium oxide, sodium hydroxide, sodium chlorate, hydrogen peroxide, ethanol, sulfuric acid; lubricating oil and hydraulic oil consumed by equipment and greenhouse gas emissions generated by water used in the production process. The calculation formula is as follows:

[0143]

[0144] Among them, C1 represents the greenhouse gas emissions from the use of materials for the production of wood products from the residues of low-yield camellia forest transformation, i represents the material use category, Pi represents the total amount of material use, and EFi is the corresponding greenhouse gas emission coefficient;

[0145] (b) Energy use emissions include greenhouse gas emissions from grid electricity, on-site electricity consumed by equipment during the product life cycle, diesel consumed by diesel equipment, propane consumed by propane equipment, natural gas consumed by cogeneration, and coal and liquefied petroleum gas consumed by drying furnaces. The calculation formula is as follows:

[0146]

[0147] Among them, C2 represents the greenhouse gas emissions from the energy use of producing wood products from the residues of low-yield camellia forest transformation, i represents the type of energy used, and Pi Indicates energy consumption, EF i is the corresponding emission factor;

[0148] (c) Transportation emissions include greenhouse gas emissions from road transportation of upstream raw material supply, on-site transportation of low-yield tea-oil forests, and off-site transportation of residual materials during the product life cycle. The calculation formula is as follows:

[0149]

[0150] Among them, C3 represents the greenhouse gas emissions generated by the transportation of wood products produced from the residues of low-yield camellia forest transformation, i represents the type of energy consumed in the transportation process, and P i Represents the energy consumption of the transportation process, M i Indicates the load during transportation, D i Indicates the transport distance, EF i is the corresponding emission factor;

[0151] (d) Due to the steep terrain and heterogeneous distribution of low-yield forests, the felling and on-site transportation process in the transformation of low-yield oil-tea forests requires a lot of manpower. The calculation formula for manual greenhouse gas emissions is as follows:

[0152] C4=P i ×EF labor ;

[0153] Among them, C4 represents the greenhouse gas emissions from the production of wood products from the residues of low-yield camellia forest transformation, P i Indicates the number of man-days of labor input, EF labor is the artificial greenhouse gas emission factor;

[0154] (e) Infrastructure emissions are greenhouse gas emissions related to infrastructure construction, operation and maintenance; the calculation formula is as follows:

[0155] C5=L×EF load ;

[0156] Among them, C5 represents the greenhouse gas emissions from the construction and maintenance of forest roads for the production of wood products from the residues of low-yield tea-oil forests, L represents the length of forest road construction and maintenance, and EF load Indicates the greenhouse gas emission factor of forest road construction and maintenance;

[0157] (f) The total carbon footprint of the life cycle of board products, pulp products and biomass products produced from the residues of low-yield camellia forest transformation is the sum of emissions from material use, energy use, transportation, labor and infrastructure. The calculation formula is as follows:

[0158]

[0159] Where, is the total carbon footprint of products produced from the residues of low-yield camellia forest transformation, i is the carbon emission type, C i For different types of carbon emissions.

[0160] The carbon footprint impact of using the residues from low-yield tea tree forests to produce panels, pulp and biomass energy products includes:

[0161] (i) The carbon footprint assessment of panel production mainly considers the impact of energy use on carbon emissions, focusing on the consumption of diesel and electricity in the production process;

[0162] (ii) The carbon footprint assessment of pulp production mainly considers the impact of material use and energy consumption, with a focus on the use of chemicals in the pulping and bleaching processes and their contribution to carbon emissions;

[0163] (iii) Carbon footprint assessment of biomass energy product production mainly considers carbon emissions during raw material collection and processing, with a focus on assessing the impact of forest road construction and fuel consumption on carbon emissions;

[0164] Preferably, the specific content of step S5 is:

[0165] The impact assessment steps include:

[0166] (1) Identify the key factors that may have a significant impact on the results of the life cycle assessment. These factors may include raw material selection, production process, transportation method, energy consumption, waste disposal method, etc.;

[0167] (2) Classify the identified influencing factors according to their nature and stage of action. For example, the influencing factors can be divided into the raw material acquisition stage, the manufacturing process stage, the transportation stage, the use stage, and the waste disposal stage;

[0168] (3) Collect relevant data for each influencing factor and combine it with the life cycle assessment model or tool. Use statistical and analytical methods to process and analyze the data to evaluate the specific impact of each influencing factor on the assessment results.

[0169] 4. Preferably, the specific content of step S6 is:

[0170] The sensitivity analysis included:

[0171] (1) Identify the key parameters that are most likely to have a significant impact on the results of the life cycle assessment. These parameters may include the carbon emission coefficient of raw material collection, energy consumption data of the manufacturing process, transportation distance, energy consumption during the product use phase, etc.;

[0172] (2) For each key parameter, determine a reasonable parameter range. These ranges can be minimum and maximum values, or different values ​​or distributions. Considering the uncertainty, use probability distribution to describe the range of parameter variation;

[0173] (3) According to the specific situation, select appropriate sensitivity analysis methods, including univariate sensitivity analysis, multivariate sensitivity analysis, single factor sensitivity analysis, and Monte Carlo simulation;

[0174] (4) Based on the selected sensitivity analysis method, sensitivity analysis is performed on each key parameter, which usually involves multiple evaluations within the parameter range, using different parameter values. For each parameter value, the evaluation results are calculated and compared, and the change range and trend of the evaluation results are observed to determine the degree of influence of the key parameters on the results.

[0175] 5. Preferably, the sensitivity analysis specifically comprises the following steps:

[0176] (i) Evaluate the impact of raw material supply fluctuations on the carbon footprint of board, pulp and biomass production by simulating different raw material supply levels;

[0177] (ii) assess the impact of energy price changes on production costs and carbon emissions by analyzing fluctuations in diesel, electricity and other energy prices;

[0178] (iii) Evaluate the impact of technical efficiency fluctuations on carbon footprint by simulating changes in production efficiency of board, pulp and biomass products under different technical levels;

[0179] (i) Determine the factors of change: The factors of change include transformation mode, production process, energy use, material use, region, etc.

[0180] (ii) Design experimental plan: Design life cycle assessment experiments based on the transformation model and production process, covering all combinations of change factors.

[0181] (iii) Determine activity data and carbon emission factors: Collect activity data for each transformation model and production process, and determine the carbon emission factors based on the life cycle assessment standard.

[0182] (iv) Run experiments: Record activity data in a lab or real production environment to ensure accuracy and repeatability.

[0183] (v) Analyze the results: Statistically analyze the experimental data, calculate the life cycle carbon footprint, identify the main emission hotspots, and evaluate the sensitivity of the changing factors.

[0184] (vi) Explain the results: Explain the impact of changing factors on carbon emissions, determine the optimal emission reduction conditions, and put forward improvement suggestions.

[0185] (vii) Conclusion: The best transformation model and production process were obtained, which could significantly reduce carbon emissions and improve resource utilization efficiency through optimization, thus providing scientific basis and technical support for the transformation of low-yield oil tea forests.

[0186] 6. The specific content of step S7 is:

[0187] The results interpretation and decision support include:

[0188] (1) Compare the results of different stages, find significant differences and trends, explain the causal relationship of the results, such as the contribution of specific life cycle stages, the impact of key links, etc., to ensure the comprehensibility and accuracy of the results so as to effectively communicate with board manufacturers and wood processing plants;

[0189] (2) Based on the evaluation results and interpretations, develop sustainable decision support measures, taking into account key indicators in terms of environmental impact, carbon emissions, resource utilization, etc., identify potential opportunities for improvement and optimization, and develop specific action plans, including measures to improve product design, manufacturing process optimization, supply chain improvement, energy management, etc., to ensure that the decision support measures are relevant and feasible to the evaluation results and are consistent with the sustainable development goals.

[0190] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0191] 1. The present invention first proposed the definition and efficient utilization of the boards produced by low-quality and low-yield transformation, released the huge production potential of the boards, provided the possibility for maximizing the bioeconomic value and land utilization efficiency of the low-quality and low-yield transformation residues of oil tea forests, and provided the most effective technical support for the comprehensive implementation of the low-quality and low-efficiency transformation policy of oil tea forests;

[0192] 2. The present invention accurately quantifies the carbon emissions of boards, pulp, and biomass energy products at each life cycle stage and evaluates their impact on the environment. In addition, by using the wood produced from the transformation residues for boards, pulp, and biomass energy products, it further realizes resource recycling, improves the comprehensive utilization rate and product added value of the wood products left over from economic forest transformation, and enhances the comprehensive benefits of the oil-tea plantation industry, creating a precedent for the realization of the value of the oil-tea plantation ecosystem;

[0193] 3. The present invention helps to achieve efficient utilization of oil tea forest resources, effectively alleviates the contradiction between wood supply and demand in my country, ensures wood safety, food and oil safety and ecological safety; thereby reducing further destruction of natural forests and protecting species diversity;

[0194] 4. The present invention helps to achieve efficient utilization of tea oil forest resources, effectively alleviates the contradiction between supply and demand of pulp in my country, and ensures pulp safety, food and oil safety, and ecological safety; by utilizing the residues from the transformation of low-yield tea oil forests to produce pulp, it not only reduces dependence on natural forest resources, avoids excessive felling of natural forests, and thus reduces the risk of further destruction of natural forests, but also effectively maintains the stability of the ecosystem.

[0195] 5. The present invention helps to achieve efficient utilization of oil-tea camellia forest resources, effectively alleviates the contradiction between supply and demand of biomass energy in my country, ensures biomass safety, food and oil safety and ecological safety; by using the residues of low-yield oil-tea camellia forest transformation to produce biomass energy, it reduces dependence on fossil fuels, reduces greenhouse gas emissions, and further promotes the development of a low-carbon economy. At the same time, using the transformation residues as biomass energy raw materials avoids the incineration or disposal of agricultural and forestry wastes, and promotes a virtuous cycle of the ecological environment.

[0196] 6. This invention provides oil tea forest operators with a highly cost-effective, natural-based "plot" level solution, which can effectively fill the existing technical gaps in the precision quality improvement project of economic forests.

[0197] 7. The present invention fully taps the carbon emission reduction potential of board residues by calculating and quantifying the carbon footprint of boards, pulp and biomass energy products. By utilizing the residues from the transformation of low-yield camellia oleifera forests to produce boards, greenhouse gas emissions can be reduced and the efficiency of wood resource utilization can be improved; utilizing board residues to produce pulp can alleviate the contradiction between pulp supply and demand and reduce dependence on natural forests; utilizing board residues to produce biomass energy can reduce the use of fossil fuels and reduce carbon emissions. These measures not only tap into the ecological benefits and product added value of boards, but also fully tap the carbon sequestration potential of boards, providing new impetus for the sustainable development of board-related industries and making important contributions to addressing climate change;

[0198] 8. This method considers the classification and utilization of different parts of the board to make different types of boards, pulp and biomass energy products. According to different production and processing methods, the carbon footprint accounting is carried out in a refined and step-by-step manner. Compared with the existing technology, the granularity of the accounting is finer, the results are more accurate and reliable, and the adaptability is stronger; at the same time, in the three stages of wood product production and board manufacturing, pulp production, and biomass energy conversion, multiple functional units are used to divide into multiple parts for accounting, and the conversion coefficient is further set according to the utilization ratio of different types of products to the board, so as to obtain the total carbon footprint of the board, pulp and biomass energy products. Compared with the existing technology, it is convenient to compare with other similar forest products, and the calculation results are more comparable and consistent. In addition, the present invention fully utilizes the carbon emission reduction potential by producing boards, pulp and biomass energy from board residues. Through the classification accounting method, it not only realizes the maximization of the ecological benefits and product added value of the board, but also provides new impetus for the sustainable development of board-related industries;

[0199] 9. The present invention uses a cross-industry emission factor library to comprehensively consider the carbon emissions of board residues in the production of boards, pulp and biomass energy products to ensure the comprehensiveness and accuracy of the accounting. Through this emission factor library, the carbon emissions of each link are accurately measured and recorded. Compared with the existing technology, it has a wider scope of application, richer data and more reliable accounting results. The use of this library for comprehensive evaluation promotes comparative analysis between different forest products and improves the consistency and comparability of accounting results.

[0200] 10. The present invention provides data support for the green and efficient use of board materials, considers the use of board processing scraps in the accounting to reduce emissions from the consumption of other energy sources, accurately quantifies this part of emission reduction, encourages wood-related industries to make full use of scraps and other by-products, improves the comprehensive utilization rate of wood resources, and reduces resource waste and energy emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0201] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0202] Figure 1 It is a flow chart of the carbon footprint accounting method of the present invention for producing boards, pulp and biomass energy products by utilizing the residues from the transformation of low-yield camellia oil forests.

[0203] Figure 2 This is a schematic diagram of the carbon footprint accounting system of the present invention for producing boards, pulp and biomass energy products using residues from the transformation of low-yield camellia oil forests.

[0204] Figure 3 It is a schematic diagram of the system boundary of the present invention for producing boards using the residues from the transformation of low-yield camellia oil forests.

[0205] Figure 4 It is a schematic diagram of the system boundary for producing pulp from the residues of low-yield camellia oil forest transformation according to the present invention.

[0206] Figure 5 It is a schematic diagram of the system boundary of the present invention for producing biomass energy products by utilizing the residues from the transformation of low-yield camellia oleifera forests.

[0207] Figure 6 It is a list of emission factors for the entire life cycle stage of the present invention using the residues from the transformation of low-yield camellia oleifera forests to produce boards, pulp and biomass energy products. DETAILED DESCRIPTION

[0208] The features of the present invention are further described below by implementing examples. The implementation examples are only used to explain the present invention and are not used to limit the scope of the present invention.

[0209] The patent of this invention uses the Guangxi Zhuang Autonomous Region State-owned Weld Forest Farm as an example to calculate the carbon footprint of the residues from the transformation of low-yield camellia forests to produce boards, pulp, and biomass energy products; the invention is described in detail below in conjunction with the accompanying drawings and implementation cases. The accompanying drawings constitute a part of this application and together with the implementation cases illustrate the invention. However, those skilled in the art should know that the following embodiments are not the only limitation on the technical solution of the present invention, and any equivalent changes or modifications made under the spirit of the technical solution of the present invention should be deemed to fall within the scope of protection of the present invention;

[0210] like Figure 1 , Figure 2 As shown, the embodiment of the present invention discloses a carbon footprint accounting method for producing board materials, pulp and biomass energy products using the residues of low-yield camellia oleifera forest transformation, comprising the following steps:

[0211] S1. Define the objectives and scope: (1) Determine the classification of boards: Boards are divided into two categories: plate-type boards and solid wood boards. Solid wood boards are boards based on sawn timber from tea oil trees, which are usually obtained by processing the main trunk of tea oil logs, while plate-type boards are boards based on artificial boards made of boards, which are wood products made by chopping and processing the twigs of tea oil logs, of which tea oil sawn timber accounts for 60% of the total volume of tea oil logs, artificial boards made of tea oil account for 30% of the total volume of tea oil logs, and scraps and bark from the processing process account for 10% of the total volume of tea oil logs;

[0212] (2) Functional units include: from the stage of oil tea wood harvesting to the stage of wood product processing, each cubic meter of logs is used as the functional unit; from the stage of board production to the stage of use and scrap disposal, each cubic meter of board is used as the functional unit; from the stage of pulp production to the stage of use and scrap disposal, each ton of pulp is used as the functional unit; from the stage of biomass energy production to the stage of use and scrap disposal, each kilogram of biomass energy product is used as the functional unit;

[0213] (3) Determine the system boundaries: Figure 3 As shown, the board system boundary is: from the harvesting of tea oil wood to the manufacturing and processing of wood products; from the manufacturing and processing of boards to the use of products; from the use of products to the disposal and scrapping stage; in detail, the process of wood product manufacturing and processing includes sawn wood processing and wood-based board processing, and board manufacturing and processing includes solid wood board manufacturing and processing and plate-type board manufacturing and processing. Input materials include tap water, natural gas, fuel oil, electricity, glue and other additives, and output materials include wastewater, waste gas and solid waste. Disposal and scrapping are usually disposed of by incineration;

[0214] like Figure 4 As shown in the figure, the boundaries of the pulp system are: from raw material acquisition to pulp production; from pulp production to product use; from product use to disposal and scrapping. Pulp production includes the entire process from raw material acquisition, pulping, bleaching to finished pulp. Input materials include tap water, natural gas, fuel oil, electricity, chemicals and other additives, and output materials include wastewater, waste gas and solid waste. Disposal and scrapping are usually disposed of by incineration, and the calculation of the recycled part is not considered;

[0215] like Figure 5 As shown in the figure, the boundaries of the biomass energy system are: from biomass collection to biomass energy product production; from biomass energy product production to product use; from product use to disposal and scrapping. In detail, biomass energy product production covers biomass collection, pretreatment, conversion and final product use, involving fuel conversion and energy output. Input materials include tap water, natural gas, fuel oil, electricity and other additives. Output materials include wastewater, waste gas and solid waste. Disposal and scrapping are usually carried out through incineration. The above system boundaries do not consider the calculation of the recycled part.

[0216] S2. Data collection: In a life cycle assessment of tea oil timber harvesting and processing in a forest farm: (1) Collect and record a list of on-site data for each process unit, including the type, power and usage time of harvesting equipment, diesel consumption, type of transport vehicles and fuel consumption, and equipment type, power, usage time, wood loss rate and glue consumption in sawn timber processing and wood-based panel processing; (2) Collect a list of emission factors for the entire life cycle, covering the specific values ​​of greenhouse gas emissions, energy consumption and waste emissions at each stage from harvesting, transportation, processing to waste treatment.

[0217] S3. Determine the carbon footprint accounting indicators: The carbon footprint accounting indicators cover the greenhouse gas emissions from energy consumption, material input and disposal of scrap throughout the entire life cycle, including the following specific contents: First, the emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) generated in the process of energy consumption. The rest are greenhouse gas emissions generated in the process of material input, including raw materials such as glue and chemicals used in the production process; greenhouse gas emissions generated in the process of disposal of scrap, mainly CO2, CH4 and N2O emissions generated by incineration. These indicators must be fully recorded.

[0218] S4. Carbon footprint calculation: After collecting and collating the on-site activity data at each stage, use the corresponding emission factor to estimate the amount of greenhouse gas emitted by each activity in the process unit, that is, multiply the on-site activity data by the corresponding emission factor to calculate the unit carbon emissions of the process unit; for different carbon footprint calculation indicators, convert the emissions into carbon dioxide equivalent. For boards, collect energy and material consumption data for each process unit from wood harvesting to product use and disposal, and calculate the unit carbon emissions. Finally, add up the carbon emissions of each stage according to the functional unit of each cubic meter of board to obtain the total carbon footprint of the board "from gate to gate"; for pulp production, collect energy and chemical consumption data for each process unit from raw material acquisition, pulping, bleaching to finished pulp, and add up the carbon emissions of each stage according to the functional unit of each ton of pulp; for biomass energy products, collect energy and material consumption data for each process unit from biomass collection, pretreatment, conversion to final product use, and add up the carbon emissions of each stage according to the functional unit of each kilogram of biomass energy product.

[0219] S5. Impact assessment: Identify the influencing factors, classify the influencing factors and collect relevant data, and use statistical and analytical methods to process and analyze the data to evaluate the specific impact of each influencing factor on the assessment results.

[0220] S6. Sensitivity analysis: Identify the key parameters that are most likely to have a significant impact on the impact assessment, set ranges for the key parameters, select appropriate analysis methods, use multiple assessments with different parameter values ​​within the parameter range, and observe the magnitude and trend of the results.

[0221] S7. Interpretation of results and decision support: Based on the analysis results, compare significant differences and trends, and explain the cause-effect relationship of the results. Based on the evaluation results and interpretation, formulate sustainable decision support measures, consider key indicators in terms of environmental impact, carbon emissions, resource utilization, etc., identify potential opportunities for improvement and optimization, and formulate specific action plans;

[0222] The specific content of step S1 is:

[0223] There are two types of boards: solid wood boards and plate-type boards. Solid wood boards are boards based on sawn timber from tea oil trees. Sawed timber is a wood product formed by sawing, drying and processing the trunk of tea oil logs, accounting for 6 / 10 of the total volume of tea oil logs; plate-type boards are boards based on artificial boards made from chopped twigs of tea oil logs. Artificial boards are wood products formed by chopped, glued and pressed twigs of tea oil logs, accounting for 3 / 10 of the total volume of tea oil logs, and the scraps and bark produced during the processing process each account for 1 / 20 of the total volume of tea oil logs; pulp is a cellulose material obtained by a series of treatments and processing of tea oil logs, specifically including the entire process of raw material acquisition, pulping, bleaching to finished pulp. The pulping process involves chopping, cooking and chemically treating wood materials such as twigs and bark of oil tea logs to remove non-cellulose materials and make cellulose pulp; the bleaching process further removes impurities and color to make the pulp reach the required whiteness and purity; Biomass energy: Biomass energy is a renewable energy product formed by collecting, pretreating and converting biomass residues from oil tea forests, covering the entire process from biomass collection to final product use. Biomass energy products include crushing, drying, gasifying or burning biomass materials such as branches, leaves, bark, and scraps of oil tea forests to convert them into heat energy, electricity or biofuels. The production process of biomass energy products involves energy conversion and utilization, generating heat or electricity through combustion or gasification, or producing liquid fuels through biochemical methods.

[0224] Functional units include: from the stage of harvesting tea wood to the processing of wood products, each cubic meter of logs is used as the functional unit; from the stage of board production to the stage of use and scrap disposal, each cubic meter of board is used as the functional unit; pulp production includes the whole process from raw material acquisition, pulping, bleaching to finished pulp, and all stages use each ton of pulp as the functional unit; biomass energy product production covers the whole process from biomass collection, pretreatment, conversion to the use of final products, and all stages use each kilogram of biomass energy product as the functional unit;

[0225] Determine the system boundary: The board system boundary is: from the harvesting of tea oil wood to the manufacturing and processing of wood products; from the manufacturing and processing of boards to the use of products; from the use of products to the disposal and scrapping stage; in detail, the process of wood product manufacturing and processing includes sawn wood processing and wood-based board processing, and board manufacturing and processing includes solid wood board manufacturing and processing and plate-type board manufacturing and processing. Input materials include tap water, natural gas, fuel oil, electricity, glue and other additives, and output materials include wastewater, waste gas and solid waste. Disposal and scrapping are usually disposed of by incineration;

[0226] The boundaries of the pulp system are: from raw material acquisition to pulp production; from pulp production to product use; from product use to disposal and scrapping. Pulp production includes the entire process from raw material acquisition, pulping, bleaching to finished pulp. Input materials include tap water, natural gas, fuel oil, electricity, chemicals and other additives, and output materials include wastewater, waste gas and solid waste. Disposal and scrapping are usually disposed of by incineration, and the calculation of the recycled part is not considered;

[0227] The boundaries of the biomass energy system are: from biomass collection to biomass energy product production; from biomass energy product production to product use; from product use to disposal and scrapping. In detail, biomass energy product production covers biomass collection, pretreatment, conversion and final product use, involving fuel conversion and energy output. Input materials include tap water, natural gas, fuel oil, electricity and other additives. Output materials include wastewater, waste gas and solid waste. Disposal and scrapping are usually disposed of by incineration. The above system boundaries do not consider the calculation of the recovery part.

[0228] The specific content of step S2 is:

[0229] Collect an inventory of field activity data for each process unit, including:

[0230] (1) Harvesting of oil tea timber: record the felling location, felling method (manual or mechanical), felling quantity, and felling tool type (chain saw, electric saw, etc.); record the transportation distance of the timber from the felling location to the processing plant, the means of transportation (such as trucks, ships, etc.) and the type of fuel (gasoline, diesel); record the characteristics of the timber: including timber quality, density, volume, moisture, carbon content and other related information.

[0231] (2) Board manufacturing and processing: record the transportation distance of boards from the wood processing plant to the board factory, the type of transportation tools (such as trucks, ships, etc.) and fuel (gasoline, diesel), and the total mass and total volume of the transported boards; record the model, power, usage time, power consumption, and type and amount of board glue used in the manufacturing and processing of solid wood boards (including upper axis milling machines, tenoning machines, cross-cutting saws, joinery band saws, routers, electronic cutting saws, and sliding table saws); record the type and amount of glue, coatings, paints and other chemicals used in the paint finishing stage, and the model, power and usage time of air compressors and spray boxes used for spraying; record the model, quantity, quality and type of hardware, sponge paper, and cartons used in the assembly and packaging stage of solid wood boards and panel boards.

[0232] (3) Pulp manufacturing and processing: For raw material preparation equipment, the model, power and usage time of chippers, peelers and screeners shall be recorded; for cooking equipment, the specific types of cookers, such as continuous cookers and batch cookers, the operating parameters and power consumption shall be recorded; for washing equipment, the model, power and usage time of pulp washers and bleaching machines shall be recorded; for pulping equipment, the model, power and usage time of pulp beaters and refiners shall be recorded; for bleaching equipment, the model, power and usage time of bleaching towers and bleaching agent storage equipment shall be recorded; for concentrating equipment, the operating parameters and power consumption of vacuum concentrators and filter presses shall be recorded; for drying equipment, the model, power and usage time of drum dryers and belt dryers shall be recorded; for forming equipment, the model, power and operating parameters of cage forming machines and fourdrinier papermaking machines shall be recorded; for auxiliary equipment, the model, quantity, power and usage time of conveyors, pumps, pipelines and control systems shall be recorded.

[0233] (4) Manufacturing and processing of biomass energy products: The data list of on-site activities in the manufacturing and processing of biomass energy products includes: raw material preparation equipment records the model, power and usage time of chippers, crushers and screeners; drying equipment records the specific types, such as the operating parameters and power consumption of drum dryers and belt dryers; pelletizing equipment records the model, power and usage time of ring die pelletizers and flat die pelletizers; cooling equipment records the model, operating parameters and power consumption of cooling towers and coolers; packaging equipment records the model, power and usage time of automatic packaging machines and semi-automatic packaging machines; auxiliary equipment records the model, quantity, power and usage time of conveyors, pumps, pipelines and control systems to comprehensively evaluate the energy consumption and environmental impact of the manufacturing and processing of biomass energy products; fuel characteristics record the type, calorific value, moisture content and ash content of biomass pellets; energy usage in the process flow records the consumption and source of electricity, natural gas or other auxiliary fuels.

[0234] (5) Product use: record the service life and location of board, pulp and biomass;

[0235] Background data collected (such as Figure 6 shown) include:

[0236] Collect emission factors of raw materials, energy, transportation, etc. from domestic and foreign databases such as Ecoinvent database, ELCD database, CLCD database, GaBi database, BUWAL250 database, IDEMAT 2001 database, VTT / KCL-eco database, CPMLCA database, USA Input Output IndustryDala database, etc., and organize and record emission factor lists including material input type, energy input type, emission factor parameters, and parameter sources;

[0237] The specific content of step S4 is:

[0238] Calculate total carbon footprint:

[0239]

[0240] Where, is the total carbon footprint of products produced from the residues of low-yield camellia forest transformation, i is the carbon emission type, C i for different types of carbon emissions;

[0241] (a) Material use emissions include greenhouse gas emissions from chemical inputs (such as paint solvents, calcium oxide, sodium hydroxide, sodium chlorate, hydrogen peroxide, ethanol, sulfuric acid) during the product life cycle, lubricating oil and hydraulic oil consumed by equipment, and water used in the production process. The calculation formula is as follows:

[0242]

[0243] Among them, C1 represents the greenhouse gas emissions from the use of materials for the production of wood products from the residues of low-yield camellia forest transformation, i represents the material use category, Pi represents the total amount of material use, and EFi is the corresponding greenhouse gas emission coefficient;

[0244] (b) Energy use emissions include greenhouse gas emissions from grid electricity, on-site electricity consumed by equipment during the product life cycle, diesel consumed by diesel equipment, propane consumed by propane equipment, natural gas consumed by cogeneration, and coal and liquefied petroleum gas consumed by drying furnaces. The calculation formula is as follows:

[0245]

[0246] Among them, C2 represents the greenhouse gas emissions from the energy use of producing wood products from the residues of low-yield camellia forest transformation, i represents the type of energy used, and P i Indicates energy consumption, EF i is the corresponding emission factor;

[0247] (c) Transportation emissions include greenhouse gas emissions from road transportation of upstream raw material supply, on-site transportation of low-yield tea-oil forests, and off-site transportation of residual materials during the product life cycle. The calculation formula is as follows:

[0248]

[0249] Among them, C3 represents the greenhouse gas emissions generated by the transportation of wood products produced from the residues of low-yield camellia forest transformation, i represents the type of energy consumed in the transportation process, and P i Represents the energy consumption of the transportation process, M i Indicates the load during transportation, D i Indicates the transport distance, EF i is the corresponding emission factor;

[0250] (d) Due to the steep terrain and heterogeneous distribution of low-yield forests, the felling and on-site transportation process in the transformation of low-yield oil-tea forests requires a lot of manpower. The calculation formula for manual greenhouse gas emissions is as follows:

[0251] C4=P i ×EF labor ;

[0252] Among them, C4 represents the greenhouse gas emissions from the production of wood products from the residues of low-yield camellia forest transformation, P i Indicates the number of man-days of labor input, EF labor is the artificial greenhouse gas emission factor;

[0253] (e) Calculation of carbon emissions during felling of oil tea wood:

[0254] (1) The calculation formula for the carbon emissions per cubic meter of logs (EA1) from the energy consumed in the process of felling logs at the felling site is:

[0255]

[0256] Where: i represents the different energy types used in the felling process (diesel, gasoline, electricity), M represents the total volume of logs (cubic meters), P i Indicates the total energy consumption of the felling process (liters or kilowatt-hours), E i Indicates the emission factor of the energy (carbon dioxide equivalent, CO2.eq);

[0257]

[0258] Where: i represents the different fuel types (diesel, gasoline) of the process, P i Indicates the fuel consumption per unit mass kilometer during transportation (liters per kilogram per kilometer), D it represents the transportation distance (km) of the fuel, M represents the total volume of logs (m3), Y represents the it Indicates the mass of logs transported by the fuel (kg), E i Indicates the emission factor of the energy (carbon dioxide equivalent, CO2.eq);

[0259] The specific content of step S5 is:

[0260] The impact assessment steps include:

[0261] (1) Identify the key factors that may have a significant impact on the results of the life cycle assessment. These factors may include raw material selection, production process, transportation method, energy consumption, waste disposal method, etc.;

[0262] (2) The identified environmental factors that affect the product life cycle are classified in detail. They can be classified according to their nature and performance in each stage of the life cycle. For example, these factors can be divided into the raw material acquisition stage, the manufacturing process stage, the transportation stage, the use stage and the waste treatment stage. In the raw material acquisition stage, the factors include the harvesting of camellia wood, the resources consumed during the primary processing, such as fuel and water, and the greenhouse gas emissions during the harvesting process. In the manufacturing process stage, the factors involve the energy (such as electricity and natural gas), materials (such as glue and chemicals) used in the production of wood products and panels, and the wastewater, waste gas and solid waste generated during the production process. In the transportation stage, the factors include the fuel consumption and greenhouse gas emissions during the transportation of raw materials and finished products between different production links. The factors in the use stage involve the performance of the product during its service life and the potential impact on the environment, such as the application of panels in furniture and construction, and the maintenance and repair needs generated during use. The factors in the waste treatment stage include the disposal methods at the end of the product life cycle, such as incineration, landfill or recycling, and their impact on the environment, including the emissions generated by waste treatment.

[0263] (3) Collect relevant data for each influencing factor and combine it with the life cycle assessment model or tool. Use statistical and analytical methods to process and analyze the data to evaluate the specific impact of each influencing factor on the assessment results.

[0264] The specific content of step S6 is:

[0265] (1) Identify the key parameters that are most likely to have a significant impact on the results of the life cycle assessment. These parameters may include the carbon emission coefficient of raw material collection, energy consumption data of the manufacturing process, transportation distance, energy consumption during the product use phase, etc.;

[0266] (2) For each key parameter, determine a reasonable parameter range. These ranges can be minimum and maximum values, or different values ​​or distributions. Considering the uncertainty, use probability distribution to describe the range of parameter variation;

[0267] (3) According to the specific situation, select the appropriate sensitivity analysis method. Commonly used methods include univariate sensitivity analysis, multivariate sensitivity analysis, single factor sensitivity analysis, Monte Carlo simulation, etc.

[0268] (4) Based on the selected method, a sensitivity analysis is performed on each key parameter, which usually involves multiple evaluations within the parameter range, using different parameter values. For each parameter value, the evaluation results are calculated and compared, and the change range and trend of the evaluation results are observed to determine the degree of influence of the key parameters on the results.

[0269] The specific content of step S7 is:

[0270] The results interpretation and decision support include:

[0271] (1) Compare the results of different stages, find significant differences and trends, explain the causal relationship of the results, such as the contribution of specific life cycle stages, the impact of key links, etc., to ensure the comprehensibility and accuracy of the results so as to effectively communicate with board manufacturers and wood processing plants;

[0272] (2) Based on the evaluation results and interpretations, develop sustainable decision support measures, taking into account key indicators in terms of environmental impact, carbon emissions, resource utilization, etc., identify potential opportunities for improvement and optimization, and develop specific action plans, including measures to improve product design, manufacturing process optimization, supply chain improvement, energy management, etc., to ensure that the decision support measures are relevant and feasible to the evaluation results and are consistent with the sustainable development goals.

[0273] The invention is not limited to the above-mentioned embodiments. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the technical principles of the invention. These improvements and modifications should also be regarded as the protection scope of the invention.

Claims

1. A carbon footprint accounting method for producing products using residues from low-yield camellia oleifera forest transformation, characterized in that: The following steps are involved: S1. Define the objectives and scope: (1) Determine the classification of board residues into boards, pulp, and biomass energy; (2) Determine the functional units; (3) Determine the system boundaries, including the five process units of oil tea wood harvesting, wood product manufacturing and processing, board manufacturing and processing, product use, and disposal and scrapping, as well as the corresponding inputs and outputs; (4) Determine the selection criteria; S2. Data collection: (1) Collect and record the on-site data list of each process unit, specifically determine the allocation procedures, calculation methods, data requirements and emission factors in each sub-stage, and obtain data; (2) Collect the emission factor list of the entire life cycle, specifically: determine the carbon emission inventory of each stage based on the production information of board, pulp and biomass energy products, analyze the carbon emission inventory of the residual products in the life cycle, and determine the input and output lists of each stage; S3. Determine the carbon footprint accounting indicators: Use the emission factor method to build a carbon emission accounting model. The carbon footprint accounting indicators are the greenhouse gases emitted from energy consumption, material input and disposal during the entire life cycle. Greenhouse gases include CO2 and CH4N2O. S4. Carbon footprint calculation: After collecting and collating the on-site activity data at each stage, use the corresponding emission factors to estimate the amount of greenhouse gas emitted by each activity in the process unit, and use the carbon emission accounting model of each stage to obtain the carbon footprint of economic forest products; that is, multiply the on-site activity data by the corresponding emission factor and divide it by the functional unit to calculate the unit carbon emissions of the process unit; for different carbon footprint calculation indicators, convert the emissions into carbon dioxide equivalents, and sum up the carbon emissions of each process unit based on the functional units of board residues as boards, pulp, and biomass energy, and obtain the unit total carbon footprint of board residues as boards, pulp, and biomass products "from gate to gate"; S5. Impact assessment: Identify the influencing factors, classify the influencing factors and collect relevant data, and use statistical and analytical methods to process and analyze the data to assess the specific impact of each influencing factor on the assessment results; S6. Sensitivity analysis: Identify the key parameters that have a significant impact on the impact assessment, set the range of the key parameters, select appropriate analysis methods, use different parameter values ​​within the parameter range for multiple assessments, and observe the magnitude and trend of the results; conduct uncertainty and sensitivity analysis, and analyze the emission share and data quality; S7. Result interpretation and decision support: Based on the analysis results, compare significant differences and trends, and explain the cause-effect relationship of the results. Based on the evaluation results and interpretation, formulate sustainable decision support measures, consider key indicators in terms of environmental impact, carbon emissions, and resource utilization, identify potential opportunities for improvement and optimization, and formulate specific action plans; the tracking unit can calculate, store and track the artificial forest "plot" activities and implementation imprint information, activity energy consumption information, activity GHG emission information and management process carbon credit information for each forest farm, location or "plot" in at least two forest farms, locations or "plots".

2. The carbon footprint calculation method for producing products using residues from low-yield camellia oleifera forest transformation according to claim 1 is characterized in that: The specific content of step S1 is: Each sub-stage of the life cycle is divided into three sub-systems: producing boards, pulp and biomass energy products from the residues of low-yield camellia forests, and the system boundaries, functional units and selection criteria of the carbon footprint of each part are determined; among which: (a) The low-yield oil-tea forest refers to the forest whose production potential has not been fully utilized due to factors such as complex varieties, extensive planting, aging trees, poor soil conditions and serious pests and diseases, and the annual oil production is less than 150kg / hm2. 2 The following oil tea trees have formed forests; (b) The transformation of low-yield forests refers to the use of modern production and management technologies to improve varieties, shape and prune, fertilize, and control pests and diseases on low-yield and low-efficiency forest land, aiming to change the current low-yield status of tea oil trees, increase tea oil output, and increase economic benefits; (c) The residuals from the transformation of low-yield camellia oil forests refer to the woody residues of felled camellia oil trees, branches and trunks remaining in the forest land when measures such as variety improvement, transformation of inferior trees and density adjustment are adopted for the transformation of low-yield camellia oil forests; (d) The board production subsystem refers to wooden boards made from the trunks of the residues from the transformation of low-yield tea-oil forests, including solid wood boards and artificial boards; solid wood boards are made directly from the sawn timber of the trunks of the residues from the transformation of low-yield tea-oil forests, while artificial boards are made from the twigs of the residues from the transformation of low-yield tea-oil forests after processing and pressing; (e) Pulp production subsystem means pulp obtained by chemical or mechanical treatment of the fiber fraction of the residue for the production of pulp products; (f) The biomass energy production subsystem refers to the energy products produced by utilizing the residues from the transformation of low-yield tea oil forests through various biomass conversion technologies, including physical conversion, chemical conversion and biological conversion. These residues include the trunks, twigs and leaves of tea oil trees. Through the efficient use of these biomass resources, they are converted into renewable energy to replace traditional fossil energy.

3. The carbon footprint calculation method for producing products using residues from low-yield camellia oleifera forest transformation according to claim 2 is characterized in that: The board production subsystem includes harvesting and on-site transportation, off-site transportation to the wood processing plant, and the production stage of the wood processing plant, specifically: (a) The felling and on-site transportation refers to the process from felling of low-yield oil-tea tree forests to transportation to the forest farm, including felling, logging, timber collection, on-site transportation and loading; (i) Harvesting of low-yield conversion residues refers to the harvesting of the trunks, branches and leaves left over from the low-yield oil-tea tree forests during the conversion process, either manually or mechanically; (ii) Logging of low-reform residues refers to the collection of felled tea oil tree residues by manual or mechanical means to a specific location, which is beside a forest road or in a logging yard; (iii) The sorting of the residues after logging refers to the stacking of the residues after logging according to certain specifications and requirements to facilitate subsequent transportation and processing. This step involves sorting, cleaning and stacking the residues; (iv) On-site transportation and loading of low-carbon waste residues refers to the transportation of waste residues from the forest land to the forest farm gate by means of transportation and loading for off-site transportation. This process requires multiple loading and unloading and transportation operations; (b) The off-site transportation to the wood processing plant refers to the process of transporting the residues at the forest gate to the wood processing plant by road or rail, which involves long-distance transportation and needs to consider the economy and efficiency of transportation; (c) The processing and production stage of the wood processing plant refers to the process of subjecting the residues of the low-yield camellia oil forest transformation to a series of processing and production processes in the wood processing plant, including debarking in the timber yard, sawing, planing, drying and chemical treatment processes, which are aimed at processing the residues into wood products with economic value, including boards, pulp and biomass energy products; (i) Debarking at the lumberyard: the transportation of logs from the lumberyard to the sawmill feeder and log resaw or debarker after sorting and storage; (ii) Sawing step: processing long sawn timber into short sawn timber and breaking down or sawing logs into rough green timber and residues, including boards, offcuts, sawdust and ground offcuts; (iii) trimmings, planks and strips are processed on chippers, where the chips are transported to a nearby pulp mill; (iv) Drying is the process of drying, leveling and conditioning the wood in a kiln; Planing steps include: splitting, grading and sorting the wood; Planing or fine planing the wood; (v) Chemical treatment involves treating the produced boards against insects and moisture and applying paint.

4. The carbon footprint calculation method for producing products using residues from low-yield camellia oleifera forest transformation according to claim 2 is characterized in that: The pulp production subsystem includes the wood processing plant processing stage, the transportation stage and the pulp processing plant production stage, specifically: (a) The processing stage of the wood processing plant includes the debarking, sawing and planing process at the lumberyard, and the scraps generated are transported to the pulp processing plant for processing; (i) Lumberyard debarking means the removal of the bark from logs to facilitate subsequent sawing and planing; (ii) Sawing means the processing of logs into sawn timber of specified dimensions and the collection of the resulting scraps and sawdust; (iii) Planing means further processing of sawn timber to smooth its surface and produce scraps; (b) The production stages of the pulp processing plant are divided into pulping, bleaching, drying and packaging processes; (i) The pulping process separates the fibers from the raw material by physical and chemical methods; (ii) Bleaching is achieved by using chemicals to make the fibers whiter; (iii) Drying including kiln drying, air heat drying or drying drums, which improves the quality of the pulp by reducing the moisture content of the fibers; (iv) The packaging process unit includes cutting the dried pulp into appropriate sizes, stacking, bundling and packaging.

5. The carbon footprint calculation method for producing products using residues from low-yield camellia oleifera forest transformation according to claim 2 is characterized in that: The biomass energy product subsystem includes a raw material collection stage, a raw material transportation stage and a biomass energy production stage, specifically: (a) The raw material collection stage includes the collection, sorting and loading of the remaining materials from the low-yield oil-tea tree forest after low-conversion, as well as the collection of the scraps generated during the processing of the wood processing plant; (i) Skidding means the collection of the remaining materials scattered on the forest land into piles for subsequent processing; (ii) Sorting means arranging the collected piles of residues into regular strips for easy loading; (iii) Loading means loading the sorted residues onto the transport vehicle; (b) The raw material transportation stage refers to the transportation of forest residues to biomass processing plants and the transportation of scraps generated by wood processing plants to biomass processing plants; (c) The biomass energy production stage includes chipping, wood pellet production and cogeneration processes; (i) Slicing means cutting larger wood scraps into smaller pieces for subsequent processing; (ii) The wood pellet production process includes crushing, drying and pelletizing process units; (iii) Cogeneration refers to the efficient use of energy by burning biomass to produce heat and electricity.

6. The carbon footprint calculation method for producing products using residues from low-yield camellia oleifera forest transformation according to claim 1 is characterized in that: The system boundary refers to the scope of the board, pulp and biomass production system from "gate to gate", and determines the input and output of the system. The system production includes material and chemical inputs, electricity and fuel use, and the inputs of their suppliers and product transportation consumption. The output includes the emissions of various greenhouse gases, specifically: (a) The boundary of the board production system is "from the forest gate to the wood processing factory gate", from the harvesting of low-yield tea-oil forest land and on-site transportation, through off-site transportation and board processing and production life cycle stages; The inputs to the system include forest road construction and labor, material inputs, and energy and fuel inputs; The output of the system is greenhouse gas, and the greenhouse gas is selected to be carbon dioxide, methane and nitrous oxide; (b) The boundary of the pulp production system is "from wood mill gate to pulp mill gate", which includes the life cycle stages from the transportation of wood chips and scraps from the wood mill to the pulp mill and pulp processing production; The input of the system includes material input, energy and fuel input, and the output of the system is greenhouse gas, wherein the greenhouse gas is selected to be carbon dioxide, methane and nitrous oxide; (c) The boundary of the biomass energy production system is "from the forest gate to the biomass energy processing plant gate", and the system boundary starts from the life cycle stage of collecting forest residues from low-yield tea-oil forest land, transporting forest residues off-site to the biomass energy processing plant and biomass energy processing production; The inputs of the system include forest roads, labor inputs, energy inputs and fuel inputs; The output of the system is greenhouse gases, which are selected to be carbon dioxide, methane and nitrous oxide.

7. According to the carbon footprint calculation method for producing products using residues from low-yield camellia forest transformation as claimed in claim 1, step S1 further comprises the step of determining a unified calculation standard in the board, pulp and biomass energy production system, specifically: (i) The functional unit of panel production is 1 cubic meter of finished panel, which is used as the benchmark to measure the resources consumed and environmental impact of the entire production process; (ii) The functional unit of pulp production is 1 ton of finished pulp, which is used as the benchmark unit for assessing resource input and environmental emissions in the pulp production process; (iii) The functional unit of biomass energy production is 1 kg of biomass energy product, which is used to calculate resource usage and environmental impact during the production process.

8. The carbon footprint calculation method for producing products using residues from low-yield camellia oleifera forest transformation according to claim 1 is characterized in that: In step S2, determining the allocation procedure in each sub-stage refers to using a mass allocation method to allocate materials, energy, transportation, and output in the board, pulp, and biomass energy production system; specifically: (a) Material allocation means the allocation of materials required for the production of board, pulp and biomass products; (i) Material inputs in the production process of panel products include: lubricating oil used in the logging process of low-yield tea-oil forests, lubricating oil and hydraulic oil used in processing equipment in wood processing plants, and paint solvents used in chemical treatment; (ii) Material inputs for pulp product production include: calcium oxide and sodium hydroxide used in the pulping process in the pulp mill, and hydrogen peroxide, sulfuric acid, ethanol and sodium chlorate used in the bleaching process; (b) Energy distribution means the distribution of energy required for the production of board, pulp and biomass products; (i) Energy inputs in the production process of panel products include: diesel consumed by logging equipment during the logging of low-yield tea-oil forests, propane consumed by propane equipment used for power generation or heating in wood processing plants, diesel and gasoline consumed by sawing and planing machines, power grid electricity consumed by on-site facilities, and electricity generated by kiln drying furnaces; natural gas consumed in the drying process; (ii) Energy inputs in the pulp product production process include: grid electricity and on-site electricity consumed in pulping, bleaching and drying processes, and heat energy generated by on-site steam consumed in the drying process; (iii) Energy inputs in the production of biomass products include: natural gas consumed in the production of chips and wood pellets, and liquefied petroleum gas and natural gas used in the cogeneration process; (c) Transportation allocation refers to the allocation of transportation activities involved in the production of board, pulp and biomass products; (i) The transportation process of board product production includes: ① transportation within the oil tea forest, transportation from the forest to the forest gate, ② transportation from the forest gate to the railway freight station, and ③ transportation from the railway freight station to the wood processing plant; (ii) The transportation process of pulp product production includes: ① transporting scraps to the pulp processing plant, ② purchasing materials in the pulp processing plant from local suppliers, and the means of transportation is gasoline trucks; (iii) The transportation process of biomass energy product production includes: ① transportation of residues from the forest farm gate to the railway freight station, ② transportation from the railway freight station to the biomass energy processing plant; (d) Output allocation refers to the distribution of various outputs in the process of producing boards, pulp and biomass energy products. Every 1,000 kg of low-reform residues can produce 219 kg of board products, 104 kg of pulp products and 677 kg of biomass energy products.

9. The carbon footprint accounting method for producing products using residues from low-yield camellia oleifera forest transformation according to claim 1, characterized in that: In step S2, the data acquisition refers to acquiring the production input data and output data required for each stage according to the allocation process and system boundaries of the board, pulp and biomass production system, including the following: (a) Raw material collection data: including the quantity, type and biomass of harvested residues, obtained through on-site measurement and statistics; (b) Production process data: covers fuel consumption during transportation, transportation distance, energy and water usage during processing, obtained by recording the operating time and efficiency of production equipment; (c) Emission data: including the quantity and composition of waste gas, wastewater and solid waste, obtained through online monitoring equipment and regular sampling and analysis.

10. The carbon footprint calculation method for producing products using residues from low-yield camellia oleifera forest transformation according to claim 1, characterized in that: In step S2, the emission factor refers to the emission coefficient of the collected input data to calculate its carbon footprint. The collected databases include: Ecoinvent database, ELCD database, CLCD database, CPCD database, GaBi database, BUWAL250 database, IDEMAT 2001 database, VTT / KCL-eco database, CPMLCA database, USA InputOutput Industry Dala database, which collects emission factors of raw materials, energy, and transportation.

11. The carbon footprint calculation method for producing products using residues from low-yield camellia oleifera forest transformation according to claim 1, characterized in that: In step S3, the carbon footprint accounting indicators include carbon footprint accounting for board production, carbon footprint accounting for pulp production, and carbon footprint accounting for biomass energy production: (i) The carbon footprint accounting of board production includes three stages: felling and on-site transportation, off-site transportation, and wood processing. In the felling and on-site transportation stage, the fuel consumption and emissions of felling equipment are calculated; in the off-site transportation stage, the fuel consumption and emissions of transportation vehicles are calculated; in the wood processing stage, the energy consumption and emissions of sawing, planing and drying are calculated; (ii) The carbon footprint accounting of pulp production includes five stages: transportation of processing residues, pulping, bleaching, drying and packaging. In the stage of transportation of processing residues, the fuel consumption and emissions of transportation vehicles are accounted for; in the stage of pulping, the energy and chemical consumption and emissions of the physical and chemical pulping process are accounted for; in the stage of bleaching, the use of bleaching agents and the emissions generated are accounted for; in the stage of drying, the energy consumption and emissions of drying equipment are accounted for; in the stage of packaging, the energy consumption and emissions of packaging materials and equipment are accounted for; (iii) Carbon footprint accounting for biomass energy production includes three stages: raw material collection, raw material transportation, and biomass energy production. In the raw material collection stage, the fuel consumption and emissions of the collection equipment are accounted for; in the raw material transportation stage, the fuel consumption and emissions of the transportation vehicles are accounted for; in the biomass energy production stage, the energy consumption and emissions in the production of chips, wood pellets and cogeneration are accounted for.

12. The carbon footprint calculation method for producing products using residues from low-yield camellia oleifera forest transformation according to claim 1, characterized in that: Step S4 includes the following specific steps: (a) Material use emissions include chemical inputs during the product life cycle; the chemicals include paint solvents, calcium oxide, sodium hydroxide, sodium chlorate, hydrogen peroxide, ethanol, sulfuric acid; lubricating oil and hydraulic oil consumed by equipment and greenhouse gas emissions generated by water used in the production process. The calculation formula is as follows: Among them, C1 represents the greenhouse gas emissions from the use of materials for the production of wood products from the residues of low-yield camellia forest transformation, i represents the material use category, Pi represents the total amount of material use, and EFi is the corresponding greenhouse gas emission coefficient; (b) Energy use emissions include greenhouse gas emissions from grid electricity, on-site electricity consumed by equipment during the product life cycle, diesel consumed by diesel equipment, propane consumed by propane equipment, natural gas consumed by cogeneration, and coal and liquefied petroleum gas consumed by drying furnaces. The calculation formula is as follows: Among them, C2 represents the greenhouse gas emissions from the energy used to produce wood products from the residues of low-yield camellia forest transformation, i represents the type of energy used, and P i Indicates energy consumption, EF i is the corresponding emission factor; (c) Transportation emissions include greenhouse gas emissions from road transportation of upstream raw material supply, on-site transportation of low-yield tea-oil forests, and off-site transportation of residual materials during the product life cycle. The calculation formula is as follows: Among them, C3 represents the greenhouse gas emissions generated by the transportation of wood products produced from the residues of low-yield camellia forest transformation, i represents the type of energy consumed in the transportation process, and P i Represents the energy consumption of the transportation process, M i Indicates the load during transportation, D i Indicates the transport distance, EF i is the corresponding emission factor; (d) Due to the steep terrain and heterogeneous distribution of low-yield forests, the felling and on-site transportation process in the transformation of low-yield oil-tea forests requires a lot of manpower. The calculation formula for manual greenhouse gas emissions is as follows: C4=P i ×EF labor ; Among them, C4 represents the greenhouse gas emissions from the production of wood products from the residues of low-yield camellia forest transformation, P i Indicates the number of man-days of labor input, EF labor is the artificial greenhouse gas emission factor; (e) Infrastructure emissions are greenhouse gas emissions related to infrastructure construction, operation and maintenance; the calculation formula is as follows: C5=L×EF load , Among them, C5 represents the greenhouse gas emissions from the construction and maintenance of forest roads for the production of wood products from the residues of low-yield tea-oil forests, L represents the length of forest road construction and maintenance, and EF load Indicates the greenhouse gas emission factor of forest road construction and maintenance; (f) The total carbon footprint of the life cycle of board products, pulp products and biomass products produced from the residues of low-yield camellia forest transformation is the sum of emissions from material use, energy use, transportation, labor and infrastructure. The calculation formula is as follows: Among them, C is the total carbon footprint of products produced from the residues of low-yield camellia forest transformation, i is the carbon emission type, and C i For different types of carbon emissions.

13. The carbon footprint calculation method for producing products using residues from low-yield camellia oleifera forest transformation according to claim 1 is characterized in that: The specific content of step S5 is: The impact assessment steps include: (1) Identify the key factors that have a significant impact on the results of the life cycle assessment, including raw material selection, production process, transportation method, energy consumption, and waste treatment method; (2) classifying the determined influencing factors according to their properties and action stages; the classification includes: dividing the influencing factors into raw material acquisition stage, manufacturing process stage, transportation stage, use stage and waste treatment stage; (3) Collect relevant data for each influencing factor and combine it with the life cycle assessment model or tool. Use statistical and analytical methods to process and analyze the data to evaluate the specific impact of each influencing factor on the assessment results.

14. The carbon footprint calculation method for producing products using residues from low-yield camellia oleifera forest transformation according to claim 1, characterized in that: The specific content of step S6 is: The sensitivity analysis included: (1) Identify key parameters that have a significant impact on the results of the life cycle assessment, including carbon emission coefficients for raw material collection, energy consumption data for the manufacturing process, transportation distance, and energy consumption during the product use phase; (2) for each key parameter, determine a reasonable parameter range, wherein the parameter range includes a minimum value and a maximum value or a probability distribution; (3) According to the specific situation, select appropriate sensitivity analysis methods, including univariate sensitivity analysis, multivariate sensitivity analysis, single factor sensitivity analysis, and Monte Carlo simulation; (4) Based on the selected sensitivity analysis method, sensitivity analysis is performed on each key parameter, which involves multiple evaluations within the parameter range, using different parameter values. For each parameter value, the evaluation results are calculated and compared, and the change range and trend of the evaluation results are observed to determine the degree of influence of the key parameters on the results.

15. The carbon footprint calculation method for producing products using residues from low-yield camellia oleifera forest transformation according to claim 14 is characterized in that: The sensitivity analysis specifically includes the following steps: (i) Evaluate the impact of raw material supply fluctuations on the carbon footprint of board, pulp and biomass production by simulating different raw material supply levels; (ii) assess the impact of energy price changes on production costs and carbon emissions by analyzing fluctuations in diesel, electricity and other energy prices; (iii) Evaluate the impact of technical efficiency fluctuations on carbon footprint by simulating changes in production efficiency of board, pulp and biomass products under different technical levels; (i) Determine the factors of change: The factors of change include transformation mode, production process, energy use, material use, and region; (ii) Design of experimental scheme: Design of life cycle assessment experiments based on transformation mode and production process, covering all combinations of change factors; (iii) Determine activity data and carbon emission factors: collect activity data for each transformation model and production process, and determine carbon emission factors based on life cycle assessment criteria; (iv) Run experiments: record activity data in a laboratory or actual production environment to ensure accuracy and repeatability; (v) Analyze the results: Statistically analyze the experimental data, calculate the life cycle carbon footprint, identify the main emission hotspots, and evaluate the sensitivity of the change factors; (vi) Explain the results: explain the impact of changing factors on carbon emissions, determine the optimal emission reduction conditions, and put forward improvement suggestions; (vii) Conclusion: The best transformation model and production process were obtained, which could significantly reduce carbon emissions and improve resource utilization efficiency through optimization, thus providing scientific basis and technical support for the transformation of low-yield oil tea forests.

16. The carbon footprint calculation method for producing products using residues from low-yield camellia oleifera forest transformation according to claim 1, characterized in that: The specific content of step S7 is: The results interpretation and decision support include: (1) Compare the results of different stages, find significant differences and trends, explain the cause and effect relationship of the results, including the contribution of specific life cycle stages and the impact of key links, and ensure the comprehensibility and accuracy of the results so as to effectively communicate with board manufacturers and wood processing plants; (2) Based on the assessment results and interpretations, develop sustainable decision support measures, taking into account key indicators in terms of environmental impact, carbon emissions and resource utilization, identify potential opportunities for improvement and optimization, and develop specific action plans, including measures to improve product design, optimize manufacturing processes, improve supply chains and optimize energy management, ensuring that the decision support measures are relevant and feasible to the assessment results and are consistent with sustainable development goals.

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