Progressive structure adjustment, quality-improving cultivation and actual performance evaluation method for needle-leaved pure forest

Abstract

The invention discloses a progressive structure adjustment, quality-improving cultivation and actual performance evaluation method for a needle-leaved pure forest. The method comprises the following steps: (1) on-site treading; (2) dividing an operation area; (3) crown boundary falling; (4) thinning old forests; (5) width reinforcement and forest cultivation; and (6) carrying out actual effect evaluation. According to the method, structure adjustment and tree species updating of the artificial needle-leaved pure forest are implemented step by step and purposefully through a series of working procedures, and on one hand, the species diversity of the needle-leaved forest and the forest appearance landscape are remarkably improved through gradual supplementation of broad-leaved tree species; and on the other hand, forest endoplasm transformation and community optimization are accelerated by thinning old and cultivating young animals and improving soil, the forest productivity and the forest ecological service function are remarkably improved, excellent forest habitat, reasonable structure, good function and benefit improvement are promoted, and excellent inhabiting and nursing conditions are provided for various wild animals.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of forest resource cultivation and high-quality development of modern forestry, and mainly relates to a method for gradual structural adjustment, quality improvement cultivation and performance evaluation of coniferous pure forest. BACKGROUND

[0002] There are large areas of pure forests composed of coniferous tree species such as Pinus massoniana and Cunninghamia lanceolata in southern China, which are simply referred to as coniferous pure forests. These coniferous pure forests are the result of the development of forestry history, and are economic timber forests or fuel forests artificially created in China in the 1960s-1980s to meet the large demand for wood during the rapid economic development, and have played an extremely important role in the development of China's society and the maintenance of people's daily life. However, coniferous forests composed mainly of Pinus massoniana and Cunninghamia lanceolata have single tree species composition, low productivity, and poor ecological service function; the forest appearance is monotonous, lacks levels and seasonal changes, and has poor visual effect; the forest structure is simple and easy to be attacked by diseases and pests, which makes coniferous pure forests increasingly become the object of renovation. Under the background of vigorously promoting high-quality development of forestry and collaborative creation of beautiful China in China, it is imperative to improve the stability and landscape effect of forest resources, and to improve the ecological service function of forest vegetation, and to implement structural adjustment and quality improvement of large-area coniferous pure forests in China.

[0003] At present, the renovation technology of coniferous pure forests in China is relatively backward, and the updating method is still single one-time cutting and one-time updating. This operation method has the advantages of simple technology, convenient operation and high implementation efficiency. However, this traditional renovation mode has the following defects: first, the updating start time is highly consistent, and the structure of the same-aged forest is still simple at the later stage, and the strong competition effect leads to a sharp decline in forest productivity after a few years; second, this traditional forest cultivation mode has simple plant layers, which will inevitably cause forest land exposure in a short period of time, and it is easy to breed weeds, which requires a lot of labor to maintain and manage. More importantly, this forest cultivation mode cannot achieve synchronous reforestation of the updated trace land, the forest green volume and stock volume disappear instantaneously, causing rapid changes in forest habitat, posing a fatal threat to the habitat of wild animals, and increasing the risk of geological disasters, which does not meet the current goal and direction of forest ecosystem protection priority and high-quality development of forestry in China. SUMMARY

[0004] In order to overcome the technical defects of the traditional forest quality improvement and renovation mode in China and solve the technical obstacles of structural adjustment and quality improvement of coniferous pure forests, the present application discloses a method for gradual structural adjustment, quality improvement cultivation and performance evaluation of coniferous pure forests, and the implementation process comprises the following steps:

[0005] (1) On-the-spot investigation: comprehensively understand the current situation of the forest, and lock the target of forest structure adjustment and quality improvement in the transformation area;

[0006] (2) Operation area division: divide the transformation area into several operation areas according to the dominant tree species method;

[0007] (3) Forest canopy boundary: apply 1m x 1m grid method to test the forest canopy in different operation areas according to the actual area, investigate the total number of trees (T) in the operation area, draw the individual distribution map of the forest in each operation area, and estimate the canopy density (SD) of each operation area according to the following formula:

[0008]

[0009] (4) Old forest thinning: apply the continuous advance method to implement progressive thinning in each operation area, determine the annual task quantity (T i ) and the annual transformation quantity (SD i ) of the forest canopy, and implement non-one-time renovation in the transformation area of low-efficiency needle-leaf pure forest, that is, implement sequential transformation for many years to gradually replace the existing needle-leaf forest;

[0010] (5) Supplementary broad-leaved forest cultivation: while implementing progressive thinning in the transformation area, simultaneously implement ditching and broadening in the thinning site, and carry out soil improvement, grass removal, irrigation and water supplementing, etc. to gradually increase the distribution proportion of broad-leaved species in the forest stand, accelerate the cultivation of colorful forest, and improve the quality of the forest;

[0011] (6) Effect evaluation: construct an effect evaluation index system to comprehensively evaluate and objectively accept the implementation effect of needle-leaf pure forest structure adjustment and quality improvement.

[0012] In step (1), on-the-spot investigation is divided into two parts of forest factors and habitat factors. The forest factors include tree species composition, planting age, initial density, distribution area, distribution pattern, total volume, lower wood species and coverage, etc., which are investigated by standard plot method. The habitat factors include slope, slope position, slope direction, soil thickness, soil texture, soil bulk density, soil fertility, soil organic carbon, etc., which are measured by soil analysis and actual investigation method according to the relevant national standards and industry regulations.

[0013] In step (2), the dominant tree species method refers to taking the dominant tree species affecting the forest structure and ecological function as the key examination element, that is, taking the dominant tree species as the first-level index for dividing the operation area, different dominant tree species should be divided into different operation areas, if the age difference is obvious in the same dominant tree species operation area, the age should be taken as the second-level index for secondary division of the operation area, and the same operation area has relatively consistent tree species structure and age, and different operation areas have relatively obvious geographical area boundaries.

[0014] ​In step (4), the continuous promotion method is to take the actual operation period (a) as the basis for allocating the quality improvement thinning amount, and the annual canopy density transformation amount (SD i ) in the operation period is determined by the following formula:

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

[0016] The number of trees covered by the annual transformation amount (SD i ) is used as the annual thinning tree number (T i ):

[0017]

[0018] After the annual thinning tree number (T i ) is determined, the canopy density reduction execution diagram and the annual thinning work amount promotion table for each operation area are drawn as the annual implementation progress of quality improvement cultivation; the thinning work amount and the canopy density transformation amount in the same operation area in the same year are not continuous in space, so as to avoid large gaps in the forest and to reflect the superiority of gradual thinning in forest quality improvement cultivation.

[0019] In step (5), the broad-leaved forest is to apply the broad-leaved tree seeds collected in the current year to the thinning site in the current year, and to sow them in the soil under the forest after peeling, shelling and cleaning the seeds. The sowing method is natural mixed sowing, and the sowing amount is 6-10 kg per mu after ditching and covering 5-10 cm of soil. The sowing coverage is equal to the canopy density reduction amount in the current year in principle to ensure sufficient sunlight after the seeds are sown. The broad-leaved tree seeds are a mixture of positive tree seeds such as wintergreen (Ilex chinensis), Chinese date (Triadicasebifera), Chinese pistache (Pistacia chinensis), soapberry (Sapindus mukorossi), wild lacquer tree (Toxicodendron succedaneum), wild jay plum (Euscaphis japonica), Japanese spicebush (Lindera glauca), Zelkova schneideriana, Celtis sinensis, and Aphananthe aspera. The mixing method is to randomly mix 5 kinds of seeds in equal proportions to facilitate the natural succession of broad-leaved tree species in the forest land.

[0020] In step (5), the soil improvement is to apply the organic improvement fertilizer uniformly to the understory of the forest canopy seeding operation area, with a thickness of 4-5 cm. On the one hand, it can improve the ground temperature to provide the germination effect for the early seeding, and on the other hand, it can mature the soil, improve the soil fertility, and promote the germination and growth of broad-leaved tree species. The formula of the organic improvement fertilizer is that sawdust, rice husk ash and manure are mixed in a volume ratio of 3-4:2:1, fermented by adding an appropriate amount of water, and then applied after being fully decomposed and uniformly stirred. The reclamation and weeding is to carry out more than 3 times of tending operation on the felling trace land every year to remove the positive weeds and felling pile sprouts that hinder the growth of young trees. The irrigation and water supplement is to carry out more than 3 times of water supplement operation on the felling trace land every summer to ensure that the soil water content of the forest land is not less than 30% in the summer.

[0021] In step (6), the effectiveness evaluation is completed within 1 year after the quality improvement and cultivation operation is completed. The detection and scoring method is used to detect and score the forest ecosystem quality index (FEQI). The results are divided into 5 grades, and the specific grading standards are shown in Table 1:

[0022] Table 1 Grading standard table 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 the weighted score of the soil environment index (SE), the forest structure index (FS) and the ecological service potential index (EF). The weight of each evaluation index is shown in Table 2,

[0025] Table 2 Index weight of forest ecosystem quality index

[0026] Sub-index SE FS EF Weight 0.2 0.4 0.4

[0027] The forest ecosystem quality index (FEQI) score is calculated according to the following formula:

[0028] FEQI=0.2×SE+0.4×FS+0.4×EF;

[0029] The scoring method of the soil environment index (SE) is as follows: The total score of the soil environment index is 100 points, which is composed of the soil thickness, the soil bulk density and the organic matter content. According to the standard in Table 3, the score is assigned, and then the score of the soil environment index is obtained by summing the weight of each score:

[0030] Table 3 Soil environment index scoring standard

[0031] Evaluation index 20 40 60 80 100 Soil thickness (cm) [0，10) [10，20) [20，30) [30，60) ≥60 Soil bulk density (g·cm -3 ) ≥1.5 (1.4，1.5] (1.2，1.4] (1.0，1.2] [0.0，1.0) Organic matter content (g·kg -1 ) <20 [20，30) [30，40) [40，50) ≥50

[0032] The weight distribution of each index is shown in Table 4,

[0033] Table 4 Weight distribution of soil environment indicators

[0034] Soil thickness Soil bulk density Organic matter content 0.2 0.3 0.5

[0035] The total score of the forest structure indicators is 100 points, which is composed of three indicators of canopy layer structure, stand canopy density and dominant tree species number, and the scores are assigned according to the standard in Table 5, and then the scores of each indicator are summed to obtain the score of the forest structure indicators,

[0036] Table 5 Scoring standard of forest structure indicators

[0037] Evaluation index 20 40 60 80 100 Forest canopy structure Single layer structure Shrub-grass structure Tree-grass structure Tree-shrub structure Tree-shrub-grass structure Stand canopy density (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 weight distribution of each indicator is shown in Table 6,

[0039] Table 6 Weight distribution of forest structure indicators

[0040] Forest layer structure Stand canopy density Number of dominant tree species 0.2 0.3 0.5

[0041] The total score of the ecological service potential indicators is 100 points, which is composed of three indicators of Shannon-Wiener index, leaf area index and water conservation index, and the scores are assigned according to the standard in Table 7, and then the scores of each indicator are summed to obtain the score of the ecological service potential indicators,

[0042] Table 7 Scoring standard of ecological service potential indicators

[0043] Evaluation index 20 40 60 80 100 Shannon-Wiener index [0，1.0) [.10，1.5) 1.5，2.0) [2.0，2.5) ≥3.0 Leaf area index (t·hm -2 ) <2 [2，3) [3，4) [4，5) ≥5 Water retention index (t·hm -2 )]]> <3500 [3500,5000) [5000,6500) [6500,8000) ≥8000

[0044] The weight distribution of each indicator is shown in Table 8,

[0045] Table 8 Weight distribution of ecological service potential indicators

[0046] Shannon-Wiener index Leaf area index Water conservation index 0.4 0.4 0.3

[0047] Beneficial effects:

[0048] 1) The present application is based on the theory of progressive ecological restoration, and the structure adjustment and quality improvement of artificial coniferous pure forest are implemented step by step and purposefully, which avoids the instantaneous disappearance of forest vegetation biomass and stock volume exposed by traditional clear-cutting and regeneration, moderates the reverse change of forest site habitat, reduces the impact on various wildlife habitats to the minimum, and meets the principle requirements of current forest resource protection and high-quality forest cultivation in China.

[0049] 2) In actual operation, the existing forest canopy density is used as the background data for quality improvement of coniferous forest, and the actual operation period is used as the basis for distribution of thinning amount for quality improvement, which avoids large fluctuations and task aggregation, and creates conditions for actual orderly work and improves work efficiency.

[0050] 3) In the implementation process, thinning the upper tree species year by year, while implementing synchronous updating and soil improvement of the preferred superior broad-leaved tree species, no empty space is left in the forest, the forest site space is fully utilized, the artificial needle leaf pure forest habitat is superior, the structure is reasonable, the function is good, and the forest species diversity and landscape appearance are significantly improved.

[0051] 4) The effectiveness evaluation method of the low-efficiency needle leaf pure forest quality improvement project is put forward in time, and a complete index system for the effectiveness evaluation of forest structure adjustment and quality improvement is constructed, which provides support conditions for the comprehensive evaluation and objective acceptance of the implementation effect of needle leaf pure forest structure adjustment and quality improvement. BRIEF DESCRIPTION OF DRAWINGS

[0052] The above and / or other aspects of the present application will become more apparent by describing in detail the preferred embodiments thereof with reference to the attached drawings.

[0053] Figure 1 It is a schematic diagram of individual distribution before the implementation of the structure adjustment and quality improvement in the work area;

[0054] Figure 2 It is a schematic diagram of the current situation of canopy density before the implementation of the structure adjustment and quality improvement in the work area;

[0055] Figure 3 It is a schematic diagram of the annual change process of canopy density in the structure adjustment and quality improvement in the work area.

[0056] In the figure: 1, the boundary of the work area; 2, 1m x 1m grid; 3, needle leaf forest individual; 4, forest canopy projection; 5, forest gap. DETAILED DESCRIPTION

[0057] The present application can be better understood according to the following examples.

[0058] Example 1

[0059] A needle leaf pure forest gradual structure adjustment, quality improvement and performance evaluation method, the implementation process has the following steps:

[0060] (1) Field investigation: comprehensively understand the current situation of the forest, and lock the target of forest structure adjustment and quality improvement in the transformation area. Field investigation is divided into two parts of stand factors and habitat factors. The stand factors include tree species composition, planting age, initial density, distribution area, distribution pattern, total volume, lower wood species and coverage, etc. The standard plot investigation method is adopted. The habitat factors include slope, slope position, slope direction, soil thickness, soil texture, soil bulk density, soil fertility, soil organic carbon, etc. In actual work, the determination of each index mainly depends on the relevant national standards and industry regulations, and the soil analysis and actual measurement investigation method is adopted.

[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) Thinning of old forests: 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)Supplementing and broadening forest: while implementing progressive thinning in the transformation area, ditching and supplementing and broadening are simultaneously implemented in the thinning trace area, and nurturing and cultivating operations (soil improvement, reclamation and weeding, irrigation and water supplementing) are carried out, so as to gradually increase the distribution proportion of broad-leaved species in the stand;

[0071] Ditching and supplementing and broadening refers to sowing the broad-leaved species seeds collected in the current year in the soil under the forest after peeling, shelling, and cleaning the seeds, adopting natural mixed sowing, ditching and covering the soil 5-10 cm after sowing, and sowing 6-10 kg per mu, and the sowing coverage is equal to the canopy density reduction in principle to ensure that the seeds have sufficient sunlight after sowing; wherein the broad-leaved species seeds are a mixture of seeds of positive trees such as Ilex chinensis, Triadica sebifera, Pistacia chinensis, Sapindus mukorossi, Toxicodendron succedaneum, Euscaphis japonica, Linderaglauca, Zelkova schneideriana, Celtis sinensis, and Aphananthe aspera, and the mixing method is to randomly mix 5 kinds of seeds at the same proportion or randomly, so as to facilitate the natural succession of broad-leaved species in the forest land.

[0072] Soil improvement is to uniformly spread the organic improvement fertilizer in the understory of the canopy sowing operation area, with a spreading thickness of 4-5 cm, which can on the one hand increase the ground temperature to provide germination effect for the early sowing, and on the other hand mature the soil, improve the land, and promote the germination and growth of broad-leaved species; wherein the formula of the organic improvement fertilizer is to mix sawdust, rice chaff ash, and manure at a volume ratio of (3-4):2:1, add an appropriate amount of water to ferment, and fully mature and mix uniformly before application; reclamation and weeding is to carry out more than 3 times of nurturing operation in the thinning trace area every year to remove positive weeds and stumps and sprouts that hinder the growth of young trees; irrigation and water supplementing is to carry out more than 3 times of water supplementing operation in the thinning trace area every summer to ensure that the soil water content in the forest land is not less than 30% in summer.

[0073] (6) Effect evaluation: after the completion of the project, the implementation effect of the coniferous pure forest structure adjustment and quality improvement and cultivation is examined, and the transformation results are evaluated and accepted. The effect evaluation is completed within 1 year after the completion of the quality improvement and cultivation operation, and the detection and scoring method is used to detect and score the forest ecosystem quality index (FEQI), and the results are divided into 5 levels, and the specific grading standards are shown in Table 1:

[0074] Table 1 Grading standard table for implementation effect evaluation

[0075]

[0076] The forest ecosystem quality index (FEQI) scoring method is as follows: the forest ecosystem quality index (FEQI) total score is 100 points, which is obtained by the weighted score of the soil environment index (SE), the forest structure index (FS), and the ecological service potential index (EF), and the weight of each evaluation index is shown in Table 2.

[0077] Table 2 Index weight of forest ecosystem quality index

[0078] Sub-index SE FS EF Weight 0.2 0.4 0.4

[0079] The forest ecosystem quality index (FEQI) score is calculated according to the following formula:

[0080] FEQI = 0.2 x SE + 0.4 x FS + 0.4 x EF;

[0081] The scoring method of the soil environment index (SE) is as follows: the soil environment index total score is 100 points, which is composed of the soil thickness, soil bulk density, and organic matter content, and the index library is scored according to the standard in Table 3, and the score of the soil environment index is obtained by summing the weight of each score:

[0082] Table 3 Soil environment index scoring standard

[0083] Evaluation index 20 40 60 80 100 Soil thickness (cm) [0，10) [10，20) [20，30) [30，60) ≥60 Soil bulk density (g·cm -3 )]]> ≥1.5 (1.4，1.5] (1.2，1.4] (1.0，1.2] [0.0，1.0) Organic matter content (g·kg -1 )]]> <20 [20，30) [30，40) [40，50) ≥50

[0084] The weight distribution of each index is shown in Table 4.

[0085] Table 4 Weight distribution of soil environment index

[0086] Soil thickness Soil bulk density Organic matter content 0.2 0.3 0.5

[0087] The forest structure index total score is 100 points, which is composed of the canopy layer structure, stand canopy density, and dominant tree species number, and the index library is scored according to the standard in Table 5, and the score of the forest structure index is calculated by summing the weight of each score,

[0088] Table 5 Forest structure index scoring standard

[0089] Evaluation index 20 40 60 80 100 Forest canopy structure Single layer structure Shrub-grass structure Tree-grass structure Tree-shrub structure Tree-shrub-grass structure Stand canopy density (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 weight distribution of each index is shown in Table 6.

[0091] Table 6 Weight distribution of forest structure index

[0092] Forest layer structure Stand canopy density Number of dominant tree species 0.2 0.3 0.5

[0093] The total score of the ecological service potential index is 100 points, which is composed of the Shannon-Wiener index and the leaf area index, is scored according to the standard in Table 7, and is calculated by summing the weights of the respective scores to obtain the score of the ecological service potential index.

[0094] Table 7: Scoring standard of the ecological service potential index

[0095] Evaluation index 20 40 60 80 100 Shannon-Wiener index [0，1.0) [.10，1.5) 1.5，2.0) [2.0，2.5) ≥3.0 Leaf area index (t·hm -2 )]]> <2 [2，3) [3，4) [4，5) ≥5 Water retention index (t·hm -2 )]]> <3500 [3500,5000) [5000,6500) [6500,8000) ≥8000

[0096] The weight distribution of each index is shown in Table 8.

[0097] Table 8: Weight distribution of the ecological service potential index

[0098] Shannon-Wiener index Leaf area index Water conservation index 0.4 0.4 0.3

[0099] The present application provides a method for gradual structural adjustment, quality improvement and performance evaluation of coniferous pure forest. There are many methods and approaches to realize the technical scheme, and the above description is only the preferred embodiment of the present application. It should be pointed out that for ordinary skilled persons in the technical field, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application. The components not explicitly described in the embodiments can be realized by existing technology.

Claims

1. A method for gradual structural adjustment, quality improvement cultivation and performance evaluation of a coniferous pure forest, characterized by, Comprising the following steps: (1) On-site investigation: comprehensively understand the current situation of the forest, and lock the target of forest structure adjustment and quality improvement in the transformation area; (2) Operation area division: divide the transformation area into several operation areas according to the dominant tree species method; (3) Forest canopy boundary: apply 1m x 1m grid method to test the forest canopy in different operation areas according to the actual area, investigate the total number of trees (T) in the operation area, draw the individual distribution map of the forest in each operation area, and according to the following formula: Estimating the canopy density (SD) of each work area; (4) Old forest thinning: Apply the method of continuous promotion to implement progressive thinning in each operation area, determine the annual task quantity (T i ) and the annual transformation quantity of canopy density (SD i ) of the forest stand, and implement non-one-time renewal in the low-efficiency needle pure forest in the transformation area, that is, take multi-year sequential transformation to gradually replace the existing needle forest; (5) Broad-leaved forest cultivation: while implementing gradual thinning in the transformation area, simultaneously implement ditching and broadening in the thinning site, and carry out soil improvement, reclamation, weeding, irrigation and other nurturing and cultivation operations, and gradually increase the distribution proportion of broad-leaved species in the forest stand; (6) Effect evaluation: build an effectiveness evaluation index system, calculate the forest ecosystem quality index (FEQI) by detection scoring method, and comprehensively evaluate and objectively accept the implementation effect.

2. The method according to claim 1, wherein the method is characterized by: In step (1), on-site investigation is divided into two parts of forest factors and habitat factors. The forest factors include tree species composition, planting age, initial density, distribution area, distribution pattern, total volume, lower wood species and coverage, etc. The standard plot investigation method is adopted. The habitat factors include slope, slope position, slope direction, soil thickness, soil texture, soil bulk density, soil fertility, soil organic carbon, etc. The soil analysis and actual measurement investigation method is adopted.

3. The method according to claim 1, wherein the method is characterized by: In step (2), the dominant tree species method refers to taking the dominant tree species affecting the forest structure and ecological function as the key examination element, i.e. taking the dominant tree species as the first-level index for dividing the operation area. If the forest age difference is obvious in the same dominant tree species operation area, the forest age is taken as the second-level index for secondary division of the operation area. The same operation area has relatively consistent tree species structure and forest age, and different operation areas have relatively obvious geographical area boundaries, which is convenient for subsequent operation.

4. The method according to claim 1, wherein the method is characterized by: In Step (4), the continuous promotion method is to use the actual working age (a) as the basis for allocating the quality improvement and cultivation thinning amount, and the annual change in canopy density (SD) during the working period is determined by the following formula: i ) i denotes the execution year number, i = 3, 4, 5,..., a; The number of trees covered by the annual transformation amount (SD i ) is used as the annual thinning number (T i ): Number of annual thinning trees (T i ) After the determination, draw the crown canopy reduction execution chart and annual thinning workload progress table for each operation area as the annual implementation progress of on-site quality cultivation. The thinning workload and canopy reconstruction volume in the same operation area and the same year are not continuous in space to avoid large gaps in the forest.

5. The method according to claim 1, wherein the method is characterized by: In step (5), broad-leaved forest cultivation refers to sowing the broad-leaved tree species seeds collected in the same year in the forest soil after peeling, shelling and cleaning. The sowing method adopts natural mixed sowing, and the sowing amount is 6-10 kg per mu. The sowing coverage is equal to the canopy density reduction in the same year to ensure sufficient sunlight after sowing. The broad-leaved tree species seeds are a mixture of positive trees such as wintergreen (Ilex chinensis), Chinese date (Triadicasebifera), Chinese pistache (Pistacia chinensis), soapberry (Sapindus mukorossi), Toxicodendron succedaneum, Euscaphisjaponica, Lindera glauca, Zelkova schneideriana, Celtis sinensis and Aphananthe aspera. The mixing method adopts optional 5:1 ratio or random mixing to facilitate the natural succession of broad-leaved trees in the forest.

6. The method according to claim 1, wherein the method is characterized by: In step (5), the soil improvement is to apply the organic improvement fertilizer uniformly to the understory of the forest canopy seeding operation area, with a thickness of 4-5 cm. On the one hand, it can improve the ground temperature and provide the pre-seeding with the effect of accelerating germination. On the other hand, it can mature the soil, improve the soil fertility, and promote the germination and growth of broad-leaved tree species. The formula of the organic improvement fertilizer is that sawdust, rice chaff ash, and manure are mixed in a volume ratio of 3-4:2:1, fermented with an appropriate amount of water, and applied after being fully decomposed and uniformly stirred. The reclamation and weeding is to carry out more than 3 times of tending operation on the thinning site every year to remove the positive weeds and stumps sprouts that hinder the growth of young trees. The irrigation and water supplement is to carry out more than 3 times of water supplement operation on the thinning site in summer every year to ensure that the soil water content of 10-20 cm in the forest land in summer is not less than 30%.

7. The method according to claim 1, wherein the method is characterized by: In step (6), the effectiveness evaluation is completed within 1 year after the quality improvement cultivation operation is completed. The detection and evaluation results of the forest ecosystem quality index (FEQI) are divided into 5 grades, and the specific grading standards are shown in Table 1: Table 1 Grading standard table for implementation effectiveness evaluation 8. The method according to claim 1, wherein the method is characterized by: In step (6), the effectiveness evaluation index system is composed of 3 sub-indices of soil environment index (SE), forest structure index (FS), and ecological service potential index (EF). The weights of the evaluation sub-indices are shown in Table 2. Table 2 Index weight of forest ecosystem quality index The total score of the forest ecosystem quality index (FEQI) is 100 points, and the result is calculated according to the following formula: FEQI = 0.2 × SE + 0.4 × FS + 0.4 × EF.

9. The method according to claim 8, wherein the method is characterized by, The scoring method of the soil environment index (SE) is as follows: The total score of the soil environment index is 100 points, which is composed of 3 indexes of soil thickness, soil bulk density, and organic matter content to form an index library. The scores are assigned according to the standards in Table 3, and then the scores of the soil environment index are obtained by summing the weights of the respective scores. Table 3 Soil environment index assignment standard The weight distribution of each index is shown in Table 4. Table 4 Weight distribution of soil environment index The total score of the forest structure index is 100 points, which is composed of 3 indexes of canopy layer structure, stand canopy density, and number of dominant tree species to form an index library. The scores are assigned according to the standards in Table 5, and then the scores of the forest structure index are obtained by summing the weights of the respective scores. Table 5 Forest structure index assignment standard The weight distribution of each index is shown in Table 6. Table 6 Weight distribution of forest structure index The total score of the ecological service potential index is 100 points, which is composed of 3 indexes of Shannon-Wiener index, leaf area index, and water conservation index to form an index library. The scores are assigned according to the standards in Table 7, and then the scores of the ecological service potential index are obtained by summing the weights of the respective scores. Table 7 Ecological service potential index assignment standard The weight distribution of each index is shown in Table 8. Table 8 Weight distribution of ecological service potential index 。

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