A method for gradual structural adjustment, quality improvement and performance evaluation of conifer pure forest

Abstract

This invention discloses a method for gradual structural adjustment, quality improvement, and performance evaluation of pure coniferous forests, comprising the following steps: (1) field survey; (2) division of work areas; (3) canopy boundary determination; (4) thinning of old forests; (5) broadleaf reforestation; and (6) effectiveness evaluation. This method, through a series of procedures, systematically and purposefully implements structural adjustment and species renewal of artificial pure coniferous forests. On the one hand, it significantly enhances coniferous forest species diversity and forest landscape through the gradual supplementation of broadleaf species; on the other hand, it accelerates forest internal quality transformation and community optimization through thinning of old trees and soil improvement, significantly improving forest productivity and forest ecosystem services, promoting superior forest habitats, rational structure, good function, and improved benefits, and providing superior habitat and conservation conditions for various wild animals.

Description

Technical Field

[0001] This invention belongs to the technical field of forest resource cultivation and high-quality development of modern forestry, and mainly relates to a method for progressive structural adjustment, quality improvement cultivation and performance evaluation of coniferous pure forests. Background Technology

[0002] In southern my country, large areas of pure coniferous forests, dominated by species such as Masson pine and Chinese fir, are distributed. These pure coniferous forests are a historical product of forestry development, artificially created from the 1960s to 1980s to meet the high demand for timber during my country's rapid economic development. They have played a vital role in my country's social development and the maintenance of people's daily lives. However, coniferous forests dominated by Masson pine and Chinese fir suffer from a single species composition, low productivity, and poor ecosystem service functions. Their monotonous appearance lacks layering and seasonal variation, resulting in poor visual appeal. Furthermore, their simple structure makes them susceptible to pests and diseases. These negative characteristics increasingly make pure coniferous forests targets for regeneration and transformation. In the current context of my country's vigorous promotion of high-quality forestry development and the collaborative creation of a beautiful China, it is imperative to improve the stability and landscape effect of forest resources and enhance the ecosystem service functions of forest vegetation, thereby implementing forest structure adjustment and quality improvement for the large areas of pure coniferous forests distributed throughout my country.

[0003] Currently, my country's technology for transforming pure coniferous forests is relatively backward, with regeneration still primarily relying on single-stage felling and regeneration. While this method is technically simple, convenient, and efficient, it has several drawbacks: First, the highly uniform regeneration start times result in simple, uniformly aged forests, leading to a sharp decline in forest productivity after several years due to intense competition. Second, this traditional forest cultivation model results in simple plant layers, inevitably exposing forest land in a short period, making it prone to weed growth and requiring significant labor for maintenance. More importantly, this model struggles to simultaneously replenish and expand regeneration areas, causing a rapid loss of forest cover and volume, leading to drastic changes in forest habitat and posing a deadly threat to various wild animals. The risk of geological disasters also increases simultaneously, contradicting my country's current goals and direction of prioritizing forest ecosystem protection and promoting high-quality forestry development. Summary of the Invention

[0004] To overcome the technical deficiencies of traditional forest quality improvement and transformation models in my country, and to break through the technical barriers to structural adjustment and quality improvement of pure coniferous forests, this invention discloses a method for gradual structural adjustment, quality improvement, and performance evaluation of pure coniferous forests. The implementation process includes the following steps:

[0005] (1) Field survey: To gain a comprehensive understanding of the current state of the forest and identify the goals of forest structure adjustment and quality improvement in the transformation area;

[0006] (2) Division of work areas: The transformation area is divided into several work areas based on the dominant tree species method;

[0007] (3) Canopy boundary: The 1m×1m grid method was used to conduct canopy tests on different work areas according to the actual area, and the total number of trees (T) in the work area was investigated. Individual distribution maps of forest stands in each work area were drawn, and the following formula was used:

[0008] Estimate the canopy closure (SD) of each work area;

[0009] (4) Old Forest Thinning: The continuous advancement method is applied to carry out gradual thinning in each work area to determine the annual thinning target (T). i ) and annual modification volume of forest canopy density (SD) i The project will implement non-one-time regeneration of inefficient pure coniferous forests in the transformation area, that is, to complete the sequential transformation over many years and gradually replace the existing coniferous forest stock.

[0010] (5) Broadleaf regeneration: While implementing gradual thinning in the transformation area, ditches are dug to fill the thinned areas, and soil improvement, weeding, irrigation and water replenishment are carried out to gradually increase the distribution ratio of broadleaf tree species in the forest stand, accelerate the cultivation of colorful forests, and improve the quality of the forest.

[0011] (6) Effectiveness evaluation: Construct an effectiveness evaluation index system to achieve a comprehensive evaluation and objective acceptance of the implementation effect of structural adjustment and quality improvement of coniferous pure forests.

[0012] In step (1), the field survey is divided into two parts: stand factors and habitat factors. Stand factors include parameters such as tree species composition, planting year, initial density, distribution area, distribution pattern, total stock volume, understory species and cover, etc., which are investigated using the standard plot survey method. Habitat factors include parameters such as slope, slope position, slope aspect, soil thickness, soil texture, soil bulk density, soil fertility, and soil organic carbon. In actual work, the determination of each indicator is mainly based on relevant national standards and industry regulations, and the soil analysis and field survey method is adopted.

[0013] In step (2), the dominant tree species method refers to taking the dominant tree species that affect the forest structure and ecological function as the key examination element. That is, the dominant tree species is used as the primary indicator for dividing the work area. Different dominant tree species should be divided into different work areas. If there is a significant difference in forest age within the same dominant tree species work area, the forest age is used as the secondary indicator to divide the work area a second time. The same work area has a relatively consistent tree species structure and forest age, and different work areas have relatively clear geographical boundaries.

[0014] In step (4), the annual advancement method uses the actual number of years (a) of operation as the basis for allocating the amount of thinning and improvement cultivation, and determines the annual amount of canopy closure improvement (SD) during the operation period using the following formula. i ):

[0015] i represents the execution year sequence number, i = 3, 4, 5, ..., a;

[0016] Annual renovation volume (SD) i The number of trees covered by ) is used as the annual thinning count (T). i ):

[0017]

[0018] Number of annual thinning plants (T i Once determined, draw up an implementation map of the reduction in canopy closure in each work area and an annual progress table of thinning work as the annual implementation schedule for quality improvement and cultivation; the thinning work and canopy closure improvement in the same year within the same work area are spatially discontinuous to avoid large areas of gaps between forests, so as to reflect the advantages of gradual thinning in forest quality improvement and cultivation.

[0019] In step (5), broadleaf reforestation refers to sowing broadleaf tree seeds collected in the same year in the thinned area, after peeling, shelling, and cleaning, into the soil under the forest canopy. The sowing method is natural mixed broadcasting. After sowing, furrows are dug and covered with 5-10 cm of soil. The sowing amount is 6-10 kg per mu. The broadcasting coverage is in principle equivalent to the reduction in forest canopy closure in the same year to ensure that the seeds have sufficient sunlight after sowing. Among them, the broadleaf tree seeds are Ilex chinensis, Chinese tallow tree (Triadicasebifera), Chinese pistache (Pistacia chinensis), Sapindus mukorossi, Toxicodendron succedaneum, Euscaphis japonica, Lindera glauca, Zelkova schneideriana, Celtis sinensis, and Aphananthera. The mixture of seeds and fruits of sun-loving trees such as aspera was prepared by randomly selecting five species in equal proportions or by mixing them randomly to facilitate the natural succession of broad-leaved tree species in the forest.

[0020] In step (5), soil improvement involves evenly spreading organic fertilizer under the forest canopy in the planting area, with a thickness of 4-5 cm. This can increase the soil temperature, providing a germination-promoting effect for early planting, and also mature the soil, improve soil fertility, and promote the germination and growth of broad-leaved trees. The organic fertilizer formula is a mixture of sawdust, rice husk ash, and manure in a volume ratio of (3-4):2:1, with an appropriate amount of water added for fermentation. After thorough decomposition and even mixing, it is applied. Weeding and cultivation involve carrying out tending operations on the thinned area more than 3 times a year to remove sun-loving weeds and stump sprouts that hinder the growth of young trees. Irrigation and water replenishment involve carrying out water replenishment operations on the thinned area more than 3 times a summer to ensure that the soil moisture content at a depth of 10-20 cm in the forest is not less than 30% in summer.

[0021] In step (6), the effectiveness assessment is completed within one year after the quality improvement and cultivation work is finished. The Forest Ecosystem Quality Index (FEQI) is assessed using a detection and scoring method, and the results are divided into 5 levels. The specific grading standards are shown in Table 1.

[0022] Table 1 Grading Standards for Implementation Effectiveness Evaluation

[0023]

[0024] The Forest Ecosystem Quality Index (FEQI) scoring method is as follows: The total score of the Forest Ecosystem Quality Index (FEQI) is 100 points, which is obtained by weighting the scores of three sub-indices: Soil Environment Index (SE), Forest Structure Index (FS), and Ecosystem Service Potential Index (EF). The weights of each assessment sub-indice are shown in Table 2.

[0025] Table 2. Indicator Weights of Forest Ecosystem Quality Index

[0026] Weight 0.2 0.4 0.4

[0027] The Forest Ecosystem Quality Index (FEQI) score is calculated using the following formula:

[0028] FEQI=0.2×SE+0.4×FS+0.4×EF;

[0029] The scoring method for the soil environmental index (SE) is as follows: The total score for the soil environmental index is 100 points, consisting of an index library composed of three indicators: soil thickness, soil bulk density, and organic matter content. Scores are assigned according to the standards in Table 3, and the score for the soil environmental index is obtained by summing the weights of each assigned score.

[0030] Table 3 Scoring Standards for Soil Environmental Indicators

[0031] Soil thickness (cm) [0，10) [10，20) [20，30) [30，60) ≥60 <![CDATA[Soil bulk density (g·cm -3 )]]> ≥1.5 (1.4，1.5] (1.2，1.4] (1.0，1.2] [0.0，1.0) <![CDATA[Organic matter content (g·kg -1 )]]> <20 [20，30) [30，40) [40，50) ≥50

[0032] The weighting of each indicator is shown in Table 4.

[0033] Table 4 Weighting of Soil Environmental Indicators

[0034] 0.2 0.3 0.5

[0035] The forest structure index has a total score of 100 points and consists of an index library composed of three indicators: canopy structure, stand canopy closure, and number of dominant tree species. Scores are assigned according to the standards in Table 5, and the score for the forest structure index is calculated by summing the weights of each assigned score.

[0036] Table 5 Scoring Standards for Forest Structure Indicators

[0037] Canopy structure Single-layer structure Shrub and grass structure Tree and grass structure Tree and shrub structure Tree-shrub-grass structure Forest stand canopy closure (0，0.2] (02，0.4] (0.4，0.6] (0.6，0.8] (0.8，1] Number of dominant tree species 1 2 3 4 ≥5

[0038] The weighting of each indicator is shown in Table 6.

[0039] Table 6 Weighting of Forest Structure Indicators

[0040] 0.2 0.3 0.5

[0041] The total score for the ecosystem service potential index is 100 points. It consists of an index library composed of three indicators: the Shannon-Wiener index, the leaf area index, and the water conservation index. The indexes are assigned scores according to the standards in Table 7, and the score for the ecosystem service potential index is calculated by summing the weights of each index.

[0042] Table 7 Scoring Standards for Ecosystem Service Potential Indicators

[0043] Shannon-Wiener Index [0，1.0) [.10，1.5) 1.5，2.0) [2.0，2.5) ≥3.0 <![CDATA[Leaf area index (t·hm -2 )]]> <2 [2，3) [3，4) [4，5) ≥5 <![CDATA[Water conservation index (t·hm -2 )]]> <3500 [3500,5000) [5000,6500) [6500,8000) ≥8000

[0044] The weighting of each indicator is shown in Table 8.

[0045] Table 8 Weighting of Ecosystem Service Potential Indicators

[0046] 0.4 0.4 0.3

[0047] Beneficial effects:

[0048] 1) Based on the theory of gradual ecological restoration, this invention implements structural adjustment and quality improvement of artificial coniferous pure forests in a step-by-step and purposeful manner, avoiding the instantaneous disappearance of forest vegetation biomass and stock volume exposed by traditional clear-cutting regeneration, mitigating the reversible changes in forest site habitats, minimizing the impact on the habitats of various wild animals, and conforming to the current principles of priority protection of forest resources and high-quality forest cultivation in my country.

[0049] 2) In practice, the existing forest canopy density is used as the baseline data for the quality improvement and cultivation of coniferous forests, and the actual number of years of operation is used as the basis for allocating the amount of thinning for quality improvement and cultivation. This avoids large fluctuations and the accumulation of tasks, and creates conditions for orderly work and improved work efficiency.

[0050] 3) During the implementation process, while thinning out the upper-layer tree species in different years, superior broad-leaved tree species are selected for synchronous regeneration and soil improvement. No open spaces are left in the forest, making full use of the forest site space, promoting the superior habitat, reasonable structure and good function of artificial coniferous pure forests, and significantly improving forest species diversity and landscape appearance.

[0051] 4) A timely evaluation method for the quality improvement and cultivation project of inefficient coniferous pure forests was proposed, and a complete index system for evaluating the effectiveness of forest structure adjustment and quality improvement and cultivation was constructed, providing support for the comprehensive evaluation and objective acceptance of the implementation effect of coniferous pure forest structure adjustment and quality improvement and cultivation. Attached Figure Description

[0052] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0053] Figure 1 A schematic diagram of individual distribution before the implementation of structural adjustments and quality improvement training within the operation;

[0054] Figure 2 A schematic diagram of the current canopy density before the implementation of structural adjustment and quality improvement in the work area;

[0055] Figure 3 A schematic diagram illustrating the annual changes in canopy density as part of structural adjustments and quality improvement in the work area.

[0056] In the diagram: 1. Boundary of the work area; 2. 1m×1m grid; 3. Individual coniferous trees; 4. Canopy projection; 5. Forest gaps. Detailed Implementation

[0057] The present invention can be better understood from the following embodiments.

[0058] Example 1

[0059] A method for gradual structural adjustment, quality improvement, and performance evaluation of pure coniferous forests, the implementation process of which includes the following steps:

[0060] (1) Field survey: To gain a comprehensive understanding of the current state of the forest and identify the goals of forest structure adjustment and quality improvement in the transformation area. The field survey is divided into two parts: stand factors and habitat factors. Stand factors include parameters such as tree species composition, planting year, initial density, distribution area, distribution pattern, total stock volume, understory species and cover, etc., which are investigated using the standard plot survey method. Habitat factors include parameters such as slope, slope position, slope aspect, soil thickness, soil texture, soil bulk density, soil fertility, and soil organic carbon. In actual work, the measurement of each indicator is mainly based on relevant national standards and industry regulations, using soil analysis and field survey methods.

[0061] (2) Division of work areas: The transformation area is divided into several work areas based on the dominant tree species method. The dominant tree species method refers to taking the dominant tree species that affect the forest structure and ecological function as the key assessment factor. That is, the dominant tree species is used as the primary indicator for dividing work areas. Different dominant tree species should be divided into different work areas. If there is a significant difference in forest age within the same dominant tree species work area, the forest age is used as the secondary indicator to divide the work area a second time. The same work area has a relatively consistent tree species structure and forest age, and different work areas have relatively clear geographical boundaries.

[0062] (3) Canopy boundary: The canopy was measured in different work areas using a 1m×1m grid method based on the actual area. The total number of trees (T) in the work area was investigated, and the individual tree distribution map of each work area was drawn. Figure 1 ), and according to the following formula:

[0063] Estimate the canopy closure (SD) of each work area ( Figure 2 ).

[0064] (4) Old forest thinning: such as Figure 3 As shown, the method of continuous advancement is applied to carry out gradual thinning in each work area to determine the annual thinning target (T). i ) and annual modification volume of forest canopy density (SD) i The transformation of inefficient pure coniferous forests in the transformation area will be carried out in a non-one-time manner, that is, the transformation will be carried out in sequence over many years to gradually replace the existing stock of coniferous forests.

[0065] The annual advancement method uses the actual number of years (a) of operation as the basis for allocating the amount of thinning and improvement cultivation. The annual amount of canopy closure improvement (SD) during the operation period is determined by the following formula. i ):

[0066] i represents the execution year sequence number, i = 3, 4, 5, ..., a;

[0067] Annual renovation volume (SD) i The number of trees covered by ) is used as the annual thinning count (T). i ):

[0068]

[0069] Number of annual thinning plants (T i Once determined, draw up an implementation map of the reduction in canopy closure in each work area and an annual progress table of thinning work as the annual implementation schedule for on-site quality improvement and cultivation; the thinning work and canopy closure improvement in the same year within the same work area are spatially discontinuous to avoid large-area gaps in the forest, so as to reflect the advantages of gradual thinning in forest quality improvement and cultivation.

[0070] (5) Broadleaf regeneration: While implementing gradual thinning in the transformation area, ditches are dug to regenerate broadleaf trees in the thinned areas, and tending and nurturing operations (soil improvement, weeding and irrigation) are carried out to gradually increase the distribution ratio of broadleaf tree species in the forest stand.

[0071] "Ditching and widening" refers to sowing broadleaf tree seeds collected in the same year in the soil under the forest canopy in areas thinned that year. These seeds have been peeled, shelled, and cleaned before being sown. The sowing method is natural mixed broadcasting. After sowing, furrows are dug and covered with 5-10 cm of soil. The sowing rate is 6-10 kg per acre, and the coverage area should ideally be equivalent to the reduction in forest canopy closure that year to ensure sufficient sunlight for the seeds. The broadleaf tree seeds include: Ilex chinensis, Sapium sebifera, Pistacia chinensis, Sapindus mukorossi, Toxicodendron succedaneum, Euscaphis japonica, Linderaglauca, Zelkova spp., Celtis sinensis, and Aphananthera. The mixture of seeds and fruits of sun-loving trees such as aspera was prepared by randomly selecting five species in equal proportions or by mixing them randomly to facilitate the natural succession of broad-leaved tree species in the forest.

[0072] Soil improvement involves evenly spreading organic fertilizer under the forest canopy in the planting area to a thickness of 4-5 cm. This increases soil temperature, providing a strong germination effect for early sowing, and also matures the soil, improving fertility and promoting the germination and growth of broad-leaved trees. The organic fertilizer is formulated by mixing sawdust, rice husk ash, and manure in a volume ratio of (3-4):2:1, adding an appropriate amount of water for fermentation, and then applying it after thorough decomposition and thorough mixing. Weeding and cultivation involve performing tending operations on the thinned areas at least three times a year to remove sun-loving weeds and stump sprouts that hinder the growth of young trees. Irrigation involves replenishing the thinned areas with water at least three times a summer to ensure that the soil moisture content at a depth of 10-20 cm is not less than 30% in summer.

[0073] (6) Effectiveness Assessment: After the project is completed, the implementation effect of structural adjustment and quality improvement of coniferous pure forests will be examined, and the transformation results will be evaluated and accepted. The effectiveness assessment will be completed within one year after the quality improvement work is completed. The Forest Ecosystem Quality Index (FEQI) will be tested and scored using a detection and scoring method, and the results will be divided into 5 levels. The specific grading standards are shown in Table 1:

[0074] Table 1 Grading Standards for Implementation Effectiveness Evaluation

[0075]

[0076] The Forest Ecosystem Quality Index (FEQI) scoring method is as follows: The total score of the Forest Ecosystem Quality Index (FEQI) is 100 points, which is obtained by weighting the scores of three sub-indices: Soil Environment Index (SE), Forest Structure Index (FS), and Ecosystem Service Potential Index (EF). The weights of each assessment sub-indice are shown in Table 2.

[0077] Table 2. Indicator Weights of Forest Ecosystem Quality Index

[0078] Weight 0.2 0.4 0.4

[0079] The Forest Ecosystem Quality Index (FEQI) score is calculated using the following formula:

[0080] FEQI=0.2×SE+0.4×FS+0.4×EF;

[0081] The scoring method for the soil environmental index (SE) is as follows: The total score for the soil environmental index is 100 points, consisting of an index library composed of three indicators: soil thickness, soil bulk density, and organic matter content. Scores are assigned according to the standards in Table 3, and the score for the soil environmental index is obtained by summing the weights of each assigned score.

[0082] Table 3 Scoring Standards for Soil Environmental Indicators

[0083] Soil thickness (cm) [0，10) [10，20) [20，30) [30，60) ≥60 <![CDATA[Soil bulk density (g·cm -3 )]]> ≥1.5 (1.4，1.5] (1.2，1.4] (1.0，1.2] [0.0，1.0) <![CDATA[Organic matter content (g·kg -1 )]]> <20 [20，30) [30，40) [40，50) ≥50

[0084] The weighting of each indicator is shown in Table 4.

[0085] Table 4 Weighting of Soil Environmental Indicators

[0086] 0.2 0.3 0.5

[0087] The forest structure index has a total score of 100 points and consists of an index library composed of three indicators: canopy structure, stand canopy closure, and number of dominant tree species. Scores are assigned according to the standards in Table 5, and the score for the forest structure index is calculated by summing the weights of each assigned score.

[0088] Table 5 Scoring Standards for Forest Structure Indicators

[0089] Canopy structure Single-layer structure Shrub and grass structure Tree and grass structure Tree and shrub structure Tree-shrub-grass structure Forest stand canopy closure (0，0.2] (02，0.4] (0.4，0.6] (0.6，0.8] (0.8，1] Number of dominant tree species 1 2 3 4 ≥5

[0090] The weighting of each indicator is shown in Table 6.

[0091] Table 6 Weighting of Forest Structure Indicators

[0092] 0.2 0.3 0.5

[0093] The total score for the ecosystem service potential index is 100 points. It consists of two indexes: the Shannon-Wiener index and the leaf area index. The indexes are assigned scores according to the standards in Table 7, and the score of the ecosystem service potential index is calculated by summing the weights of each index.

[0094] Table 7 Scoring Standards for Ecosystem Service Potential Indicators

[0095] Shannon-Wiener Index [0，1.0) [.10，1.5) 1.5，2.0) [2.0，2.5) ≥3.0 <![CDATA[Leaf area index (t·hm -2 )]]> <2 [2，3) [3，4) [4，5) ≥5 <![CDATA[Water conservation index (t·hm -2 )]]> <3500 [3500,5000) [5000,6500) [6500,8000) ≥8000

[0096] The weighting of each indicator is shown in Table 8.

[0097] Table 8 Weighting of Ecosystem Service Potential Indicators

[0098] 0.4 0.4 0.3

[0099] This invention provides a method for progressive structural adjustment, quality improvement cultivation, and performance evaluation of pure coniferous forests. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A method for progressive structural adjustment, quality improvement, and performance evaluation of pure coniferous forests, characterized in that, Includes the following steps: (1) Field survey: To gain a comprehensive understanding of the current state of the forest and identify the goals of forest structure adjustment and quality improvement in the transformation area; (2) Division of work areas: The redevelopment area is divided into several work areas based on the dominant tree species method; (3) Canopy boundary: The 1m × 1m grid method was used to conduct canopy tests on different work areas according to the actual area, and the total number of trees (T) in the work area was investigated. Individual distribution maps of forest stands in each work area were drawn, and the following formula was used: (4) Thinning of old forests: The method of continuous advancement is applied to carry out gradual thinning in each work area, and the annual thinning task (T) of the forest stand is determined. i ) and annual modification volume of forest canopy density (SD) i The transformation of inefficient pure coniferous forests in the transformation area will be carried out in a non-one-time renewal process, that is, the transformation will be completed in sequence over many years to gradually replace the existing coniferous forest stock. Among them, the continuous advancement method uses the actual number of years of operation (a) as the basis for allocating the amount of thinning and improvement cultivation, and determines the annual amount of canopy closure improvement (SD) during the operation period using the following formula. i ): Annual renovation volume (SD) i The number of trees covered by ) is taken as the annual thinning count (T) i ): Number of annual thinning plants (T i Once determined, draw up an implementation map of the reduction in canopy density in each work area and an annual progress table of thinning work as the annual implementation schedule for on-site quality improvement and cultivation; the thinning work and canopy density improvement work in the same year within the same work area should not be spatially discontinuous to avoid large areas of gaps in the forest. (5) Broadleaf regeneration: While implementing gradual thinning in the transformation area, ditches are dug to fill the thinned areas, and soil improvement, weeding, and irrigation are carried out to gradually increase the distribution ratio of broadleaf tree species in the forest stand. (6) Effectiveness assessment: Construct an effectiveness assessment index system, use the detection and scoring method to calculate the Forest Ecosystem Quality Index (FEQI), and conduct a comprehensive evaluation and objective acceptance of the implementation effect.

2. The method for progressive structural adjustment, quality improvement, and performance evaluation of pure coniferous forests according to claim 1, characterized in that, In step (1), the field survey is divided into two parts: stand factors and habitat factors. Stand factors include tree species composition, planting year, initial density, distribution area, distribution pattern, total stock volume, understory species and cover, and the standard plot survey method is used. Habitat factors include slope, slope position, slope aspect, soil thickness, soil texture, soil bulk density, soil fertility, and soil organic carbon, and the soil analysis and field measurement survey method is used.

3. The method for progressive structural adjustment, quality improvement, and performance evaluation of pure coniferous forests according to claim 1, characterized in that, In step (2), the dominant tree species method refers to using dominant tree species that affect the forest structure and ecological function as key examination elements. That is, dominant tree species are used as the primary indicator for dividing the work area. If there is a significant difference in forest age within the same dominant tree species work area, forest age is used as the secondary indicator to divide the work area a second time. The same work area has a relatively consistent tree species structure and forest age, and different work areas have relatively clear geographical boundaries, which facilitates subsequent operations.

4. The method for progressive structural adjustment, quality improvement, and performance evaluation of pure coniferous forests according to claim 1, characterized in that, In step (5), broadleaf reforestation refers to sowing broadleaf tree seeds collected in the same year in the thinned area, after peeling, shelling, and cleaning, into the soil under the forest canopy. The sowing method is natural mixed broadcasting. After sowing, furrows are dug and covered with soil for 5-10 cm. The sowing amount is 6-10 kg per mu. The broadcasting coverage is in principle equivalent to the reduction in forest canopy closure in the same year to ensure that the seeds have sufficient sunlight after sowing. Among them, the broadleaf tree seeds are Ilex chinensis, Chinese tallow tree (Triadicasebifera), Chinese pistache (Pistacia chinensis), Sapindus mukorossi, Toxicodendron succedaneum, Euscaphis japonica, Linderaglauca, Zelkova schneideriana, and Celtis sinensis. A mixture of seeds and fruits of *Sinensis* and *Aphanantheaspera* was prepared, with five species randomly selected in equal proportions or mixed randomly to facilitate the natural succession of broad-leaved tree species in the forest.

5. The method for progressive structural adjustment, quality improvement, and performance evaluation of pure coniferous forests according to claim 1, characterized in that, In step (5), soil improvement involves evenly spreading organic fertilizer under the forest canopy in the planting area, with a thickness of 4-5 cm. This can increase the soil temperature, providing a germination-promoting effect for early sowing, and also mature the soil, improve soil fertility, and promote the germination and growth of broad-leaved trees. The organic fertilizer formula is a mixture of sawdust, rice husk ash, and manure in a volume ratio of (3-4):2:1, with an appropriate amount of water added for fermentation. After thorough decomposition and even mixing, it is applied. Weeding and cultivation involve carrying out tending operations on the thinned area more than 3 times a year to remove sun-loving weeds and stump sprouts that hinder the growth of young trees. Irrigation and water replenishment involve carrying out water replenishment operations on the thinned area more than 3 times a summer to ensure that the soil moisture content of 10-20 cm in the forest is not less than 30% in summer.

6. The method for progressive structural adjustment, quality improvement, and performance evaluation of pure coniferous forests according to claim 1, characterized in that, In step (6), the effectiveness assessment shall be completed within one year after the completion of the quality improvement and cultivation operation. The test score of the Forest Ecosystem Quality Index (FEQI) is divided into 5 levels, and the specific grading standards are shown in Table 1:

7. The method for progressive structural adjustment, quality improvement, and performance evaluation of pure coniferous forests according to claim 1, characterized in that, In step (6), the effectiveness evaluation index system consists of three sub-indices: Soil Environment Index (SE), Forest Structure Index (FS), and Ecosystem Service Potential Index (EF). The weights of each evaluation sub-indice are shown in Table 2. The Forest Ecosystem Quality Index (FEQI) has a total score of 100 points, calculated using the following formula: FEQI= 0.2 × SE + 0.4 × FS + 0.4 × EF.

8. The method for progressive structural adjustment, quality improvement, and performance evaluation of pure coniferous forests as described in claim 7, characterized in that... The scoring method for the Soil Environmental Index (SE) is as follows: The soil environmental index has a total score of 100 points, consisting of an index library composed of three indicators: soil thickness, soil bulk density, and organic matter content. Scores are assigned according to the standards in Table 3, and the scores for each indicator are summed based on their respective weights. The weighting of each indicator is shown in Table 4. The forest structure index has a total score of 100 points and consists of an index library composed of three indicators: canopy structure, stand canopy closure, and number of dominant tree species. Scores are assigned according to the standards in Table 5, and the score for the forest structure index is calculated by summing the weights of each assigned score. The weighting of each indicator is shown in Table 6. The total score for the ecosystem service potential index is 100 points. It consists of an index library composed of three indicators: the Shannon-Wiener index, the leaf area index, and the water conservation index. The indexes are assigned scores according to the standards in Table 7, and the score for the ecosystem service potential index is calculated by summing the weights of each index. The weighting of each indicator is shown in Table 8.

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