A classification method for high carbon sink plant species and a regional carbon sink evaluation method in karst areas

Abstract

The present invention provides a method for classifying high-carbon sequestration plant species in karst areas and a method for regional carbon sequestration assessment. The steps include: obtaining the instantaneous net photosynthetic rate of test plants in the target area, classifying the carbon sequestration capacity of the test plants, and the indicators include the daily assimilation amount per unit leaf area, the daily carbon fixation amount per unit leaf area, the daily oxygen release amount per unit leaf area, the daily assimilation amount per unit land area, the daily carbon fixation amount per unit land, the daily oxygen release amount per unit land, the daily assimilation amount of a single plant, the daily carbon fixation amount of a single plant, and the daily oxygen release amount of a single plant; classifying the carbon sequestration capacity of the target area and giving the carbon sequestration assessment result of the target area. The present invention maximally reflects the comprehensive carbon fixation capacity of plants, and realizes the carbon sequestration screening and classification of plant species, and determines the basic methods, processes and steps suitable for measuring the carbon sequestration capacity of plants in karst areas.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon sink assessment in karst areas, and specifically relates to a method for classifying high carbon sink plant species in karst areas and a method for regional carbon sink evaluation. Background Art

[0002] During the growth process, plants can absorb carbon dioxide in the atmosphere through photosynthesis and convert it into organic matter such as cellulose, which is fixed in the plants. The fixed carbon becomes the "carbon sink" of the trees. Selecting high carbon sink tree species in urban greening and improving the tree management level are important means to improve the carbon sink quality and thus achieve carbon sequestration and increment in cities. However, at present, the average biomass method is used to screen high carbon sink plants. This method consumes a large amount of manpower and material resources and has a narrow scope of application, only applicable to plant species with allometric growth equations. Some other studies have adopted the assimilation method. However, the selected measurement methods have not been standardized yet. Usually, only the single scale of leaves has been studied, lacking a technical method for systematic screening and evaluation of the carbon sequestration benefits of existing plant species at multiple scales.

[0003] In karst areas, plants mostly grow in areas with thin soil layers. Due to the complex terrain of the underlying surface and the poor water permeability of the rock layers, the water sources available to plants are relatively single, and the growth differences between plants are large. Compared with other vegetation types, there is a certain gap in the understanding of the carbon sequestration capacity of plants in karst areas. More importantly, there is a lack of a set of standardized carbon sink assessment and classification technologies. Therefore, it is necessary to develop a method for classifying high carbon sink plant species in karst areas and its carbon sink evaluation method.

[0004] When measuring the instantaneous net photosynthetic rate of plant leaves, according to relevant requirements, it is usually necessary to measure the sun-facing leaves at the top of the plant. For karst areas, currently, it is only possible to measure by using an excavator or a crane to carry a photosynthesis meter and extend it to the position of the measured leaves, which is very inconvenient to operate, and the plant individuals that can be covered are extremely limited, making it difficult to accurately evaluate the carbon sink in karst areas. Summary of the Invention

[0005] At least to solve the technical problems mentioned in the background art, the purpose of the present invention is to provide a method for classifying high carbon sink plant species in karst areas and a method for regional carbon sink evaluation.

[0006] The present invention adopts the following technical solutions.

[0007] A method for classifying high carbon sink plant species in karst areas, the steps include:

[0008] Step 1, at a set time point, obtain the instantaneous net photosynthetic rate of the test plants in the target area;

[0009] Step 2: Obtain the daily assimilation amount per unit leaf area of the test plant according to the following formula (1).

[0010]

[0011] In the formula: P—the total net assimilation amount from 8:00 to 18:00 on the measurement day (mmol·m -2 ),

[0012] P i —the instantaneous net photosynthetic rate at the initial measurement point (μmmol m -2 s -1 ),

[0013] P i+1 —the instantaneous net photosynthetic rate at the next measurement point (μmmol·m -2 s -1 ),

[0014] t i —the instantaneous time at the initial measurement point (h),

[0015] t i + 1—the time at the next measurement point (h),

[0016] i—the number of tests;

[0017] Step 3: Obtain the daily carbon fixation amount and daily oxygen release amount per unit leaf area of the test plant according to the following formula (2).

[0018]

[0019] In the formula: 44—the molar mass of carbon dioxide; 32—the molar mass of oxygen;

[0020] W CO2 —the mass of carbon dioxide fixed by the leaves per unit area (g m -2 d -1 ),

[0021] W O2 —the amount of oxygen released by the leaves per unit area (g m -2 d -1 );

[0022] Step 3: Obtain the daily assimilation amount, daily carbon fixation amount and daily oxygen release amount of a single plant according to the following formula (3).

[0023]

[0024] In the formula: P I is the daily assimilation amount of a single plant (mol d -2 ),

[0025] I CO2Daily carbon fixation per plant (g d -1 ), I O2 Daily oxygen release per plant (g d -1 ),

[0026] P - Daily assimilation per unit leaf area (mmol·m -2 ),

[0027] W co2 - Carbon fixation of leaves per unit area (g m -2 d -1 ),

[0028] W O2 - Daily oxygen release per unit area (g m -2 d -1 ),

[0029] S - Total leaf area of a single plant (m -2 );

[0030] Step 4, Obtain the daily assimilation, daily carbon fixation, and daily oxygen release of the test plant per unit land area according to the following formula (4),

[0031]

[0032] In the formula: P c Daily assimilation per unit land area (mmol m -2 d -1 ),

[0033] Cco2 - Daily carbon fixation per unit land area (g m -2 d -1 ),

[0034] C 02 - Daily oxygen release per unit land area (g m -2 d -1 ),

[0035] P - Daily assimilation per unit leaf area (mmol·m -2 ),

[0036] LAI - Leaf area index,

[0037] W CO2 - Carbon fixation of leaves per unit area (g m -2 d -1 ),

[0038] W O2 - Daily oxygen release per unit area (g m -2 d -1 ).

[0039] Step 5: Use the systematic clustering method to classify the carbon sequestration capabilities of the test plants. Among them, the indicators used to construct the carbon sequestration capacity classification system are the daily assimilation amount per unit leaf area, the daily carbon fixation amount per unit leaf area, the daily oxygen release amount per unit leaf area, the daily assimilation amount per unit land area, the daily carbon fixation amount per unit land, the daily oxygen release amount per unit land, the daily assimilation amount of a single plant, the daily carbon fixation amount of a single plant, and the daily oxygen release amount of a single plant, these 9 indicators;

[0040] Step 6: Output the classification results. Among them, level 1 is defined as the excellent level of the carbon sequestration capacity of the test plants, level 2 is defined as the good carbon sequestration capacity of the test plants, and level 3 is defined as the general carbon sequestration capacity of the test plants.

[0041] As an optimal solution, in step 1, when measuring, five plant individuals with the same size and growth vigor are selected as sample plant replicates for each plant species, and 3 sunny, intact and mature leaves located at the top of the plant are selected as leaf replicates for each plant; the net photosynthetic rate of the plant leaves is measured every 2 hours, and 5 instantaneous values of the same leaf are recorded each time.

[0042] Furthermore, a lifting system is used to load a portable photosynthesis meter to measure the instantaneous net photosynthetic rate of the test plants in the target area; the lifting system includes a first support frame located at the center of the target area and a second support frame located on the periphery of the target area. The second support frame is installed on a circular track, and the diameter of the circular track is greater than the maximum span of the target area. The first support frame and the second support frame are connected by a cableway, and a portable photosynthesis meter is placed on the hanging basket of the cableway; when the second support frame circles around the circular track, the cableway rotates around the first support frame, and the projection area of the cableway covers the entire target area. Adopting such a solution can not only achieve the measurement coverage of all plants in the target area in a clever way, but also measure the instantaneous net photosynthetic rate of plant leaves more conveniently and accurately, and can quickly and flexibly switch to different positions for measurement, especially suitable for karst areas with many stones and crisscrossed gullies.

[0043] As an optimal solution, the steps to obtain the instantaneous net photosynthetic rate of the test plants in the target area in step 1 include:

[0044] Step 11: Select the first test plant in the target area and mark the first coordinate position of the first test plant;

[0045] Step 12: Control the operation of the cableway to make the hanging basket of the cableway run directly above the first coordinate position;

[0046] Step 13: Adjust the height of the hanging basket so that the relative distance between the detection end of the portable photosynthesis meter on the hanging basket and the measured leaf meets the test requirements;

[0047] Step 14: Turn on the portable photosynthesis meter to obtain the instantaneous net photosynthetic rate of the leaves of the first test plant;

[0048] Step 15, when the selected second test plant in the target area is located on the side of the first test plant, first control the second support frame to move along the circular track. When the cableway is directly above the second test plant, control the second support frame to stop and fix. Then control the cableway to operate so that the hanging basket of the cableway runs directly above the second test plant. Then, refer to Step 13 and Step 14 to obtain the instantaneous net photosynthetic rate of the leaves of the second test plant.

[0049] A method for evaluating regional carbon sinks in karst areas, the steps include:

[0050] Step A, use the aforementioned method to obtain the classification of high carbon sink plant species in the target area;

[0051] Step B, divide the target area into several unit areas;

[0052] Step C, obtain the main plant species in each unit area;

[0053] Step D, obtain the carbon sink degree D of the unit area according to the following formula,

[0054] D = number of plant one X1 * corresponding classification result value H1 of plant one * R1% + number of plant two X2 * corresponding classification result value H2 of plant two * R2% +... + number of plant n X n * corresponding classification result value H of plant n n * R n %,

[0055] In the formula, X n represents the number of the nth plant, H n represents the classification result corresponding to the nth plant; R n represents the weight ratio of the classification result corresponding to the nth plant. When the classification result is level 1, R n takes 0.5, the corresponding classification result value when the classification result is level 1 is 3, when the classification result is level 2, R n takes 0.3, the corresponding classification result value when the classification result is level 2 is 2, when the classification result is level 3, R n takes 0.2, the corresponding classification result value when the classification result is level 3 is 1;

[0056] Step E, classify the carbon sink capacity of the target area and give the carbon sink evaluation result of the target area.

[0057] As an optimal solution, the length of the unit area is equal to the entire length or width of the karst area, and the width of the unit area is not less than the maximum plant diameter in the karst area.

[0058] Beneficial effects: When quantifying the plant carbon sequestration capacity, the present invention comprehensively considers evaluation indicators such as the daily assimilation amount per unit leaf area of plants, the daily carbon sequestration amount per unit leaf area, the daily oxygen release amount per unit leaf area, the daily assimilation amount per unit land area, the daily carbon sequestration amount per unit land, the daily oxygen release amount per unit land, the daily assimilation amount of a single plant, the daily carbon sequestration amount of a single plant, and the daily oxygen release amount of a single plant. This avoids the deviation in the accounting of the overall plant carbon sequestration capacity by a single scale, maximally reflects the comprehensive carbon sequestration capacity of plants, and realizes the carbon sequestration screening and classification of plant species; the present invention determines the basic methods, processes, and steps suitable for measuring the plant carbon sequestration capacity in karst areas, and clearly restricts and explains the selection of plant samples, the process steps of photosynthetic measurement, and carbon sequestration classification, facilitating popularization and utilization; the present invention achieves the measurement coverage of all plants in the target area with a clever scheme, can more conveniently measure the instantaneous net photosynthetic rate of plant leaves, can more accurately evaluate the carbon sequestration in karst areas, and can quickly and flexibly switch to different positions for measurement. Description of the Drawings

[0059] Figure 1 is the net photosynthetic rate of the plants measured in Example 1,

[0060] Figure 2 is the leaf area index of the plants measured in Example 1,

[0061] Figure 3 is the carbon sequestration capacity of shrub plants based on per unit leaf area in Example 1,

[0062] Figure 4 is the carbon sequestration capacity of shrub plants based on per single plant in Example 1,

[0063] Figure 5 is the carbon sequestration capacity of shrub plants based on per unit land area in Example 1,

[0064] Figure 6 is the downward view of the lifting system applied to the target area in Example 2. Detailed Embodiments

[0065] The technical solutions in the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0066] Example 1

[0067] A method for classifying high-carbon sequestration plant species in a karst area (Tongluo Mountain, Chongqing), the steps include:

[0068] Through preliminary field plant community surveys and data analysis, the following more than 11 common woody plants in the Tongluo Mountain area were determined. See Table 1 for details;

[0069] Table 1 Common Woody Plants in the Tongluo Mountain Area

[0070] Serial number Species name Family and genus 1 Viburnum odoratissimum Viburnum, family Caprifoliaceae 2 Coriaria nepalensis Coriaria, family Coriariaceae 3 Viburnum chinshanense Viburnum, family Caprifoliaceae 4 Photinia serratifolia Photinia, family Rosaceae 5 Bougainvillea spectabilis Bougainvillea, family Nyctaginaceae 6 Rhododendron simsii Rhododendron, family Ericaceae 7 Pittosporum tobira Pittosporum, family Pittosporaceae 8 Ligustrum lucidum Ligustrum, family Oleaceae 9 Pyracantha fortuneana Pyracantha, family Rosaceae 10 Vitex negundo Vitex, family Lamiaceae 11 Rosa laevigata Rose, family Rosaceae

[0071] Step 1: At a set time point, obtain the instantaneous net photosynthetic rate of the test plants in the target area;

[0072] Specifically, use a 6800 portable photosynthesis instrument to systematically measure the photosynthetic characteristic parameters of the shrub plants in the Tongluo Mountain. When measuring, select 5 plant individuals with the same size and growth vigor as sample plants for each plant species, and select 3 sunny leaves for each plant as leaf replicates to measure their instantaneous net photosynthetic rate and transpiration rate; the measurement period is from 8:00 to 18:00 on the same day, and the leaf net photosynthetic rate and transpiration rate of the plants are measured once every 2 hours. Record 5 instantaneous values for the same leaf each time, and measure the leaf area index of the shrub plants. The measurement results are shown in Figure 1 and Figure 2 ;

[0073] Step 2: Obtain the daily assimilation amount per unit leaf area of the test plants according to the following formula (1). The results are shown in Figure 3 ,

[0074]

[0075] In the formula: P—the total net assimilation amount from 8:00 to 18:00 on the measurement day (mmol·m -2 ),

[0076] P i —the instantaneous net photosynthetic rate at the initial measurement point (μmmol m -2 s -1 ),

[0077] P i+1 —the instantaneous net photosynthetic rate at the next measurement point (μmmol·m -2 s -1 ),

[0078] t i —the instantaneous time at the initial measurement point (h),

[0079] t i +1—the time at the next measurement point (h),

[0080] i—the number of tests;

[0081] Step 3: Obtain the daily carbon fixation amount and daily oxygen release amount per unit leaf area of the test plants according to the following formula (2). The results are shown in Figure 3 ;

[0082]

[0083] In the formula: 44 is the molar mass of carbon dioxide; 32 is the molar mass of oxygen;

[0084] W CO2 — The mass of carbon dioxide fixed by the leaves per unit area (g m -2 d -1 ),

[0085] W O2 — The amount of oxygen released by the leaves per unit area (g m -2 d -1 );

[0086] Step 3, obtain the daily assimilation amount, daily carbon fixation amount, and daily oxygen release amount of a single plant according to the following formula (3), and the results are shown in Figure 4 ;

[0087]

[0088] In the formula: P I is the daily assimilation amount of a single plant (mol d -2 ),

[0089] I CO2 is the daily carbon fixation amount of a single plant (g d -1 ), I O2 is the daily oxygen release amount of a single plant (g d -1 ),

[0090] P — The daily assimilation amount per unit leaf area (mmol·m -2 ),

[0091] ) W co2 — The carbon fixation amount of the leaves per unit area (g m -2 d -1 ),

[0092] W O2 — The daily oxygen release amount per unit area (g m -2 d -1 ),

[0093] S — The total leaf area of a single plant (m -2 );

[0094] Step 4, obtain the daily assimilation amount, daily carbon fixation amount, and daily oxygen release amount of the test plant per unit land area according to the following formula (4), and the results are shown in Figure 5 ;

[0095]

[0096] In the formula: Pc is the daily assimilation amount per unit land area (mmol m -2 d -1 ),

[0097] Cco2 is the daily carbon sequestration amount per unit land area (g m -2 d -1 ),

[0098] C 02 is the daily oxygen release amount per unit land area (g m -2 d -1 ),

[0099] P—the daily assimilation amount per unit leaf area (mmol·m -2 ),

[0100] LAI—the leaf area index,

[0101] W CO2 —the carbon sequestration amount of leaves per unit area (g m -2 d -1 ),

[0102] W O2 —the daily oxygen release amount per unit area (g m -2 d -1 ).

[0103] Step 5: Use the systematic clustering method to classify the test plants according to their carbon sink capacity. The results are shown in Table 2. Among them, the indicators used to construct the carbon sink capacity classification system are the daily assimilation amount per unit leaf area, the daily carbon sequestration amount per unit leaf area, the daily oxygen release amount per unit leaf area, the daily assimilation amount per unit land area, the daily carbon sequestration amount per unit land area, the daily oxygen release amount per unit land area, the daily assimilation amount of a single plant, the daily carbon sequestration amount of a single plant, and the daily oxygen release amount of a single plant, a total of 9 indicators;

[0104] Table 2 Classification Table of Plant Carbon Sink Capacity

[0105]

[0106] As can be seen from Table 2, for shrub species, the comprehensive carbon sink level can be divided into 4 levels. Among them, Bougainvillea spectabilis is at level 1, with the strongest carbon sequestration and oxygen release ability; Coriaria nepalensis, Vitex negundo, and Viburnum chinshanense are at level 2, with good carbon sequestration and oxygen release ability; other plants are at level 3;

[0107] Step 6: Output the classification results. Among them, level 1 is defined as the excellent level of the carbon sink capacity of the test plants, level 2 is defined as the good carbon sink capacity of the test plants, and level 3 is defined as the general carbon sink capacity of the test plants. In subsequent plant configuration studies, the plant species at levels 1 and 2 are recommended plants, and plant configuration patterns are formed through different combinations of plant collocations.

[0108] Based on the conclusion obtained from the aforementioned method for classifying high-carbon sequestration plant species, a plant configuration plan for this karst area is obtained: In the vegetation restoration project of Tongluo Mountain, bougainvillea, Viburnum chinshanense, Coriaria nepalensis, and Vitex negundo can be mixed and configured to achieve the purpose of screening and configuring high-carbon sequestration plants.

[0109] Example 2

[0110] A method for classifying high-carbon sequestration plant species in a karst area, referring to Example 1, the difference from Example 1 is as follows:

[0111] A lifting system is used to load a portable photosynthesis meter to measure the instantaneous net photosynthetic rate of the test plants in the target area; combined with Figure 6 As shown, the lifting system includes a first support frame 1 located at the center of the target area 5, a second support frame 2 located outside the target area 5. The second support frame 2 is installed on a circular track 3. The diameter of the circular track 3 is greater than the maximum span of the target area 5. The first support frame 1 and the second support frame 2 are connected by a cableway 4. A portable photosynthesis meter is placed on the hanging basket 6 of the cableway 4; when the second support frame 2 moves around the circular track 3 for one circle, the cableway 4 rotates around the first support frame 1, and the projection area of the cableway 4 covers the entire target area 5;

[0112] In step 1 of this example, the steps of obtaining the instantaneous net photosynthetic rate of the test plants in the target area 5 include:

[0113] Step 11, select the first test plant in the target area 5 and calibrate the first coordinate position of the first test plant;

[0114] Step 12, control the operation of the cableway 4 to make the hanging basket 6 of the cableway 4 move directly above the first coordinate position;

[0115] Step 13, adjust the height of the hanging basket 6 so that the relative distance between the detection end of the portable photosynthesis meter on the hanging basket 6 and the measured leaf meets the test requirements;

[0116] Step 14, turn on the portable photosynthesis meter to obtain the instantaneous net photosynthetic rate of the leaves of the first test plant; <�

[0117] Step 15, when the second test plant selected in the target area 5 is located on the side of the first test plant (that is, the second test plant and the first test plant are not both directly below the cableway 4 at the same time), first control the second support frame 2 to move along the circular track 3. When the cableway 4 is directly above the second test plant, control the second support frame 2 to stop and fix, then control the operation of the cableway 4 to make the hanging basket 6 of the cableway 4 move directly above the second test plant, and then refer to steps 13 and 14 to obtain the instantaneous net photosynthetic rate of the leaves of the second test plant.

[0118] This embodiment achieves the measurement coverage of all plants in the target area 5 with a clever scheme, and can more conveniently and accurately measure the instantaneous net photosynthetic rate of plant leaves, can more accurately evaluate the carbon sink in karst areas, and can also quickly and flexibly switch to any position in the target area for measurement, especially suitable for karst areas with many stones and crisscrossed gullies.

[0119] Embodiment 3

[0120] A method for regional carbon sink evaluation in karst areas, the steps include:

[0121] Step A, obtaining the classification of high-carbon sink plant species in the target area by referring to the method in Embodiment 1;

[0122] Step B, dividing the target area into several unit areas. The length of the unit area is equal to the entire length or width of the karst area, and the width of the unit area is not less than the maximum plant diameter in the karst area. The specific size of the unit area is divided by those skilled in the art in combination with the specific landform;

[0123] Step C, obtaining the main plant species in each unit area;

[0124] Step D, obtaining the carbon sink degree D of the unit area according to the following formula (5),

[0125] D = the number of Plant 1 X1 * the corresponding classification result value H1 of Plant 1 * R1% + the number of Plant 2 X2 * the corresponding classification result value H2 of Plant 2 * R2% +... + the number of Plant n X n * the corresponding classification result value H of Plant n n * R n %,

[0126] In the formula, X n represents the number of the nth plant, H n represents the classification result corresponding to the nth plant; R n represents the weight ratio occupied by the classification result corresponding to the nth plant. When the classification result is level 1, R n takes 0.5, and the corresponding classification result value when the classification result is level 1 is 3. When the classification result is level 2, R n takes 0.3, and the corresponding classification result value when the classification result is level 2 is 2. When the classification result is level 3, R n takes 0.2, and the corresponding classification result value when the classification result is level 3 is 1;

[0127] Step E, using the systematic clustering method or other common classification methods to classify the carbon sink capabilities of each unit area in the target area, and giving the carbon sink evaluation result of the target area.

[0128] Taking a certain karst area in Tongluo Mountain, Chongqing in Example 1 as an example, referring to the method in Example 1, the classification results of high-carbon sink plant species in the target area are shown in Table 2. Bougainvillea spectabilis is at level 1 (the corresponding weight is taken as 0.5, and the classification result value is taken as 3), and it has the strongest carbon sequestration and oxygen release ability; Coriaria nepalensis, Vitex negundo var. cannabifolia, and Viburnum chinshanense are at level 2 (the corresponding weights are taken as 0.3 respectively, and the classification result values are taken as 2 respectively), and their carbon sequestration and oxygen release abilities are good; other plants are at level 3 (the corresponding weights are taken as 0.2 respectively, and the classification result values are taken as 1 respectively). The target area is divided into three unit areas: in the first unit area, the number of Bougainvillea spectabilis is 56, the number of Viburnum chinshanense is 124, the number of Coriaria nepalensis is 13, the number of Vitex negundo var. cannabifolia is 27, and the number of Rhododendron simsii is 272. Then the carbon sink degree D of the first unit area = 56 * 3 * 0.5 + 124 * 2 * 0.3 + 13 * 2 * 0.3 + 27 * 2 * 0.3 + 272 * 2 * 0.3 = 345.6; in the second unit area, the number of Bougainvillea spectabilis is 11, the number of Viburnum chinshanense is 86, the number of Coriaria nepalensis is 28, the number of Vitex negundo var. cannabifolia is 103, the number of Rhododendron simsii is 68, the number of Rosa laevigata is 76, and the number of Viburnum odoratissimum is 246. Then the carbon sink degree D of the second unit area = 11 * 3 * 0.5 + 86 * 2 * 0.3 + 28 * 2 * 0.3 + 103 * 2 * 0.3 + (68 + 76 + 246) * 2 * 0.3 = 380.7; in the third unit area, the number of Bougainvillea spectabilis is 24, the number of Viburnum chinshanense is 46, the number of Coriaria nepalensis is 71, the number of Vitex negundo var. cannabifolia is 42, the number of Rhododendron simsii is 113, the number of Rosa laevigata is 23, the number of Viburnum odoratissimum is 37, the number of Ligustrum lucidum is 52, the number of Photinia serratifolia is 7, the number of Pyracantha fortuneana is 18, and the number of Pittosporum tobira is 8. Then the carbon sink degree D of the second unit area = 24 * 3 * 0.5 + (46 + 71 + 42) * 2 * 0.3 + (113 + 23 + 37 + 52 + 7 + 18 + 8) * 0.2 * 1 = 183. Then, the carbon sink abilities of the unit areas are classified, and the carbon sink evaluation results of these three unit areas are given as follows: the carbon sink ability of the second unit area is better than that of the first unit area, the carbon sink ability of the first unit area is significantly better than that of the third unit area. The carbon sink ability of the second unit area is defined as level A, the carbon sink ability of the first unit area is defined as level B, and the carbon sink ability of the third unit area is defined as level C.

[0129] In this embodiment, a technical route for evaluating the carbon sink ability of a unit area is proposed for the first time, which is beneficial to accurately guiding and regulating carbon sink projects.

[0130] When quantifying the plant carbon sink capacity, the present invention comprehensively considers the following evaluation indicators: daily assimilation amount per unit leaf area of plants, daily carbon fixation amount per unit leaf area, daily oxygen release amount per unit leaf area, daily assimilation amount per unit land area, daily carbon fixation amount per unit land, daily oxygen release amount per unit land, daily assimilation amount of a single plant, daily carbon fixation amount of a single plant, and daily oxygen release amount of a single plant. This avoids the deviation in the accounting of the overall carbon sink capacity of plants caused by a single scale, maximally reflects the comprehensive carbon fixation capacity of plants, and realizes the carbon sink screening and grading of plant species. The present invention determines the basic methods, processes, and steps suitable for measuring the plant carbon sink capacity in karst areas, and clearly restricts and explains the selection of plant samples, the process steps of photosynthesis measurement, and carbon sink grading, which is convenient for popularization and utilization.

Claims

1. A classification method for high carbon sink plant species in karst areas, characterized in that the steps Including: Step 1, at a set time point, obtain the instantaneous net photosynthetic rate of the test plants in the target area; Step 2, obtain the daily assimilation amount per unit leaf area of the test plants according to the following formula (1), Where: P—the total net assimilation amount from 8:00 to 18:00 on the measurement date (mmol·m -2 ), P i — Instantaneous net photosynthetic rate at the initial measurement point (μmmol m -2 s -1 ), P i+1 — Instantaneous net photosynthetic rate of the next measurement point (μmmol·m -2 s -1 ), t i — Instantaneous time at the initial measurement point (h), t i +1—the time (h) of the next measurement point, i—the number of tests; Step 3, obtain the daily carbon fixation amount and daily oxygen release amount per unit leaf area of the test plants according to the following formula (2), In the formula: 44—the molar mass of carbon dioxide; 32—the molar mass of oxygen; W CO2 — Mass of carbon dioxide fixed by leaves per unit area (g m -2 d -1 ) W O2 — Oxygen release amount of leaves per unit area (g m -2 d -1 ); Step 3, obtain the daily assimilation amount, daily carbon fixation amount and daily oxygen release amount of a single plant according to the following formula (3), Where: P I is the daily assimilation amount of a single plant (mol d -2 ), I CO2 is the daily carbon fixation amount per plant (g d -1 ), I O2 is the daily oxygen release amount per plant (g d -1 ). P - Daily assimilation per unit leaf area (mmol·m -2 ), W co2 —— Carbon sequestration per unit leaf area (g m -2 d -1 ), W O2 ——Daily oxygen release amount per unit area (g m -2 d -1 ), S——Total leaf area of a single plant (m -2 ); Step 4, obtain the daily assimilation amount, daily carbon fixation amount and daily oxygen release amount per unit land area of the test plants according to the following formula (4), Where: P c is the daily assimilation amount per unit land area (mmol m -2 d -1 ), Cco2 is the daily carbon sequestration per unit land area (g m -2 d -1 ), C 02 Daily oxygen release amount per unit land area (g m -2 d -1 ), P - daily assimilation per unit leaf area (mmol·m -2 ), LAI—the leaf area index, W CO2 —— Carbon fixation amount of leaves per unit area (g m -2 d -1 ) W O2 ——Daily oxygen release amount per unit area (g m -2 d -1 ); Step 5, use the systematic clustering method to classify the test plants according to their carbon sink capacity; among them, the indicators used to construct the carbon sink capacity classification system are the daily assimilation amount per unit leaf area, the daily carbon fixation amount per unit leaf area, the daily oxygen release amount per unit leaf area, the daily assimilation amount per unit land area, the daily carbon fixation amount per unit land area, the daily oxygen release amount per unit land area, the daily assimilation amount of a single plant, the daily carbon fixation amount of a single plant, and the daily oxygen release amount of a single plant, these 9 indicators; Step 6, output the classification result, where level 1 is defined as the excellent level of the carbon sink capacity of the test plants, level 2 is defined as the good carbon sink capacity of the test plants, and level 3 is defined as the general carbon sink capacity of the test plants; The target area is a karst area with crisscrossed gullies; Use a lifting system to load a portable photosynthesis meter to measure the instantaneous net photosynthetic rate of the test plants in the target area; the lifting system includes a first support frame (1) located at the center of the target area (5), a second support frame (2) located on the periphery of the target area (5), the second support frame (2) is installed on a circular track (3), the diameter of the circular track (3) is greater than the maximum span of the target area (5), the first support frame (1) is connected to the second support frame (2) by a cableway (4), and a portable photosynthesis meter is placed on the hanging basket (6) of the cableway (4); when the second support frame (2) goes around the circular track (3) for one circle, the cableway (4) rotates around the first support frame (1), and the projection area of the cableway (4) covers the entire target area (5); The steps for obtaining the instantaneous net photosynthetic rate of the test plants in the target area in Step 1 include: Step 11, select the first test plant in the target area and calibrate the first coordinate position of the first test plant; Step 12, control the operation of the cableway (4) to make the hanging basket (6) of the cableway (4) run directly above the first coordinate position; Step 13, adjust the height of the hanging basket (6) so that the relative distance between the detection end of the portable photosynthesis meter on the hanging basket (6) and the measured leaf meets the test requirements; Step 14, turn on the portable photosynthesis meter to obtain the instantaneous net photosynthetic rate of the leaves of the first test plant; Step 15, when the selected second test plant in the target area is located on the side of the first test plant, first control the second support frame (2) to move along the circular track (3). When the cableway (4) is directly above the second test plant, control the second support frame (2) to stop and fix. Then control the cableway (4) to operate so that the hanging basket (6) of the cableway (4) moves to directly above the second test plant, and then refer to Step 13 and Step 14 to obtain the instantaneous net photosynthetic rate of the leaves of the second test plant.

2. The method for classifying high carbon sink plant species in karst areas according to claim 1, wherein: In Step 1, when measuring, five plant individuals of the same size and growth vigor are selected as sample plant replicates for each plant species, and 3 sunny, intact and mature leaves located at the top of the plant are selected as leaf replicates for each plant; the net photosynthetic rate of the plant leaves is measured every 2 hours, and 5 instantaneous values of the same leaf are recorded each time.

3. A method for evaluating regional carbon sinks in karst areas, characterized in that the steps Including: Step A, obtaining the classification of high carbon sink plant species in the target area by using the method described in any one of claims 1-2; Step B, dividing the target area into several unit areas; Step C, obtaining the main plant species in each unit area; Step D, obtaining the carbon sink degree D of the unit area according to the following formula (5), D = Quantity X1 of Plant 1 * Corresponding Grading Result Value H1 of Plant 1 * R1% + Quantity X2 of Plant 2 * Corresponding Grading Result Value H2 of Plant 2 * R2% + …… + Quantity X of Plant n n * Corresponding Grading Result Value H of Plant n n * R n %, where X n represents the quantity of the nth plant, H n represents the classification result corresponding to the nth plant; R n represents the weight ratio of the classification result corresponding to the nth plant. When the classification result is level 1, R n takes 0.

5. When the classification result is level 1, the corresponding classification result value is 3. When the classification result is level 2, R n takes 0.

3. When the classification result is level 2, the corresponding classification result value is 2. When the classification result is level 3, R n takes 0.

2. When the classification result is level 3, the corresponding classification result value is 1; Step E, classifying the carbon sink capacity of the target area and giving the carbon sink evaluation result of the target area.

4. The regional carbon sink assessment method for karst areas according to claim 3, characterized in that: The length of the unit area is equal to the entire length or width of the karst area, and the width of the unit area is not less than the maximum plant diameter in the karst area.

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