Structure regulation and function improvement method for water source conservation forest of drinking water source land

Abstract

The invention discloses a drinking water source land water source conservation forest structure regulation and function improvement method. The method comprises the following steps: (1) investigating a water source land; (2) classifying sites; (3) operation division; (4) forest cultivation regulation and control; (5) reclaiming and raising juveniles; and (6) litter distribution. According to the technical method provided by the invention, on one hand, forest ecological service benefits of the water conservation forest can be improved in a short time, and a vigorous high-quality forest with a reasonable structure can be recovered; and on the other hand, through scientific partitioning, land-based implementation and flexible operation, tree species updating and conservation function improvement of the water source conservation forest can be achieved, and the water source conservation forest is beneficial to being stable in structure, excellent in forest phase and graceful in landscape.

Description

Technical Field

[0001] The present invention relates to the technical field of ecological environment protection and forest resource quality improvement and transformation engineering, and in particular to a method for regulating the structure and improving the functions of water conservation forests in drinking water sources. Background Art

[0002] Drinking water sources are closely related to human life and social and economic activities. They are natural ecosystems that are related to the drinking water health of residents and need to be protected.

[0003] Forest planting design places too much emphasis on the annual volume growth and volume growth per unit area of ​​forests, but not enough attention on the soil and water conservation and retention and storage functions that make important contributions to the protection of water sources. The forest structure is monotonous, the species configuration is improper, the richness is not high, and the overall water conservation efficiency of the forest is low. Literature review found that some ecologists have studied the function improvement technology of water conservation forests and put forward their own constructive opinions accordingly. For example, the published patent documents CN201610999987.1, CN200810240189.6, CN202011287101.3, and CN201610399794.2 all discuss the transformation of water conservation forests. Although the water source conservation forest improvement projects proposed by these scholars have incorporated the transformation concepts of nature, ecology, and humanity to a certain extent, they are still not very mature in terms of restoration engineering technologies such as plant selection, community construction, implementation steps, and community succession. They still remain at the simple low-level design of plant replacement, terrain transformation, and nurturing and renewal. There is a lack of research on key technologies for improving the benefits of water source conservation forests, and there are drawbacks such as improper plant selection, insufficient system structure, neglect of biodiversity conservation, and unsatisfactory water source protection. It is difficult to achieve the improvement of the ecological function of water source conservation forests in protecting water sources. Summary of the invention

[0004] Purpose of the invention: The technical problem to be solved by the present invention is to propose a method for regulating the structure and improving the functions of water conservation forests in drinking water sources in view of the serious deficiencies in existing water conservation forest construction and function improvement technologies. The method is developed based on ecology, hydrology, soil science, and ecosystem structure theory, using the water conservation forest community survey data conducted in recent years as a basis, and integrating the research results of soil and water conservation, hydrological ecology, litter retention, water conservation forest forest phase transformation technology practice, etc. Through basic surveys, scientific zoning, local policies and flexible operations, the technical effect of achieving twice the result with half the effort and improving both functions and forest phases in water conservation forest transformation under existing technical conditions can be achieved.

[0005] In order to solve the above technical problems, the present invention discloses a method for regulating the structure and improving the function of a water conservation forest in a drinking water source area, comprising the following steps:

[0006] (1) Water source investigation;

[0007] (2) Site classification;

[0008] (3) Operational zoning;

[0009] (4) silviculture and regulation;

[0010] (5) Reclamation and raising children;

[0011] (6) Litter distribution.

[0012] Wherein, in step (1), the purpose of the water source survey is to fully understand the forest community status and habitat characteristics of the water conservation forest. The forest community status includes parameters such as forest structure, tree species composition, forest age, canopy density, forest layer, young forest cover, litter thickness, leaf area index, etc., and also includes indicators such as stand density, planting age, afforestation method, seedling source, and pest and disease status; the habitat characteristics include parameters such as soil texture, soil thickness, soil fertility, soil pH, litter thickness, etc., and also include indicators such as slope aspect, slope, and slope position.

[0013] Among them, in step (2), the site classification is to divide the site types of water conservation forest land according to the site conditions, and the site type division is carried out according to the method listed in Table 1, that is, the slope (including S, E, W, N) is used as the first-level indicator, the soil thickness (ST) is used as the second-level indicator, and the soil organic carbon mass fraction (SOC) is used as the third-level indicator to divide into 36 site types, and number them in sequence. After the site classification is completed, a 20-24 cm wide and 25-30 cm deep isolation ditch is required to be set between adjacent types on site, the site type is outlined on the map, and the site is clearly marked with a sign.

[0014] Table 1 Classification of site types

[0015]

[0016]

[0017] Among them, in step (3), the operation zoning is to divide the water conservation forest control area into several large operation areas, and the zoning is based on the community habitat characteristics completed in the early stage, combined with community characteristic parameters such as tree species composition, forest age, canopy density, forest layer, young forest coverage, litter thickness, leaf area index, etc.; each large operation area is required to have relatively consistent site conditions, but if the community parameters such as tree species composition, forest age, canopy density, forest layer, young forest coverage, leaf area index, etc. are significantly different within the same site type, it is refined into several secondary operation areas, each of which has relatively consistent community characteristics, and the large operation area and the secondary operation area can be concentrated and connected, or they can be distributed across.

[0018] Among them, in step (4), the afforestation regulation refers to the implementation of corresponding regulation measures in different operation areas according to the site conditions, so as to achieve the goal of adapting to local conditions and taking targeted measures. The regulation measures include density adjustment, pure to mixed, steep to step, removal of diseased and rotten wood, etc.; density adjustment means determining the number of thinning or replanting adjustments based on the number of trees per unit area of ​​the forest stand, and the specific adjustment standard is based on the number of retained trees, that is, 60 to 75 trees / mu for broad-leaved forests, 70 to 80 trees / mu for coniferous forests, 70 to 75 trees / mu for mixed coniferous and broad-leaved forests, and 180 to 220 trees / mu for bamboo forests; pure to mixed means thinning and replanting when the tree species composition is a pure forest, and on the premise of meeting the density adjustment and retention tree quantity standard In the next step, coniferous trees shall be cut down to replace broad-leaved trees, or broad-leaved trees shall be cut down to replace coniferous trees, or broad-leaved trees shall be cut down to replace broad-leaved trees, or bamboos shall be cut down to replace heterophyllous trees, so that the number of tree species in a single operation area is greater than 1, and the replanting shall follow the following principles: existing positive tree species shall be replaced with negative tree species, and existing negative tree species shall be replaced with positive tree species; existing coniferous tree species shall be replaced with broad-leaved tree species, and existing broad-leaved tree species shall be replaced with coniferous tree species; existing fast-growing tree species shall be replaced with slow-growing tree species, and existing slow-growing tree species shall be replaced with fast-growing tree species; existing evergreen tree species shall be replaced with deciduous tree species, and existing deciduous tree species shall be replaced with evergreen tree species; existing deep-rooted tree species shall be replaced with shallow-rooted tree species, and existing shallow-rooted tree species shall be replaced with deep-rooted tree species, so as to achieve ecological overlap and complementary advantages and disadvantages; if there is a bamboo forest in the operation area, heterophyllous bamboo of the same genus shall be planted.

[0019] Among them, in step (4), the steepening step is to implement steepening step transformation on the forest land when the slope of the site in the operation area is greater than 40 degrees. The transformation method is to dig steep steps in parallel to the contour lines in concentric circles, and the excavation in the soil transfer area is moved into the filling area. The excavation angle at the base of the excavation is controlled at 90-100°, and the slope length between the upper and lower steepening steps is controlled at 3-4m. Attention is paid to the backfilling of topsoil and humus. The topsoil and humus in the soil transfer area cover the upper layer of the filling area, and the base of the soil transfer area receives the topsoil and humus in the upper filling area, so as to ensure that the humus in the surface soil of the forest land is not reduced, thereby enhancing the permeability, interception capacity and conservation capacity of the forest land soil.

[0020] Among them, in step (4), the diseased and rotten wood removal is to move the trees, branches and roots that are damaged by pests and diseases in the forest to outside the forest for treatment to eliminate the infection source.

[0021] Among them, in step (5), the reclamation and promotion of young trees refers to the implementation of humus regulation, irrigation and water replenishment, and young forest tending measures after afforestation regulation in different operation areas to maintain the results of afforestation regulation. The humus regulation is to adjust the soil humus according to the habitat characteristics of the previous investigation. If the surface coniferous litter is the majority, then add decomposed acidic organic fertilizers, such as Biom acidic organic fertilizers, to promote litter decomposition, and the amount per mu shall not exceed 15kg; if the surface broad-leaved litter is the majority, then add decomposed neutral or slightly acidic organic fertilizers, such as decomposed farmyard manure, compost, etc., and the amount per mu shall not exceed 10kg; the irrigation and water replenishment refers to determining the water management measures for the young forest land according to the soil moisture conditions of the forest land, and implementing irrigation and water replenishment operations when the volumetric water content of the forest land soil is lower than 25%; the young forest tending is to implement weeding and loosening the soil within a radius of 1m for newly planted young trees 3 times during the growing season each year, with an interval of 2 months each time.

[0022] Among them, in step (6), the litter distribution refers to the implementation of quantitative spreading of litter according to the surface litter conditions during the young forest tending period, so that the forest litter is evenly covered, surface runoff and water loss are reduced, and water conservation and regulation are enhanced. When the litter is spread quantitatively, the litter quantitative regulation and distribution is carried out according to the amount of litter accumulated in the forest each year to reduce the surface gap and enhance the litter interception capacity. The regulation principle is to use the annual average thickness (M) of the forest litter survey in the operation area as the base number, and the allocation quantity satisfies the following formula:

[0023] M=X±Y,

[0024] Where Y is the litter thickness that needs to be quantitatively spread (cm), X is the litter thickness investigated on site (cm), and M is the annual average thickness (cm).

[0025] Beneficial effects: Aiming at the serious deficiencies in the current construction and function improvement technologies of water conservation forests in my country, the present invention proposes a method for regulating the structure and improving the functions of water conservation forests in drinking water sources. The method is developed based on the theories of ecology, hydrology, soil science, and ecosystem structure, and utilizes the water conservation forest community survey data completed in recent years, and integrates the technical research results of soil and water conservation, hydrological ecology, litter retention, and water conservation forest phase transformation carried out in the early stage. From the implementation effect point of view, the present invention overcomes the defects of forestry technology in existing literature such as arbitrary plant renewal, simple transformation methods, neglect of terrain transformation, and improper litter treatment. It grasps the key to restricting the function of water conservation forests in drinking water sources, and implements the internal transformation and fine management of water conservation forest ecosystems by targeting core elements such as operation zoning, structural regulation, maintenance and management, and litter retention. On the one hand, it can improve the forest regulation function of water conservation forests in a short period of time, and restore high-quality forests with a reasonable structure and full of vitality; on the other hand, through scientific zoning, local measures and flexible operations, it can achieve tree species renewal, structural stability, better forest appearance and more beautiful landscape in water conservation forests, which is in line with the goals and directions of my country's "Guidelines for Ecological Protection and Restoration of Mountains, Rivers, Forests, Farmlands, Lakes and Grasses (Trial)" (Ministry of Natural Resources, Ministry of Finance, Ministry of Ecology and Environment 2020). BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0027] Figure 1 Technical flow chart for implementation;

[0028] Figure 2 A side view of the implementation of steepening steps in afforestation regulation;

[0029] Figure 3 A bird's-eye view of the implementation of steepening steps in afforestation regulation.

[0030] In the figure, A is the higher altitude of the working area (top of the mountain), a is the horizontal line of the steep change step, 1 is the soil moving area, 1′ is the topsoil and humus in the soil moving area, 2 is the filling area, 2′ is the topsoil and humus in the filling area, n is the excavation angle of the soil moving area, and L is the slope length between the upper and lower steep change steps. DETAILED DESCRIPTION

[0031] The present invention can be better understood according to the following examples. The contents described in the examples are only used to illustrate the present invention, and should not and will not limit the present invention described in detail in the claims.

[0032] Example 1

[0033] From September 2022 to October 2023, an experiment on the structural regulation and function improvement of water source conservation forests in drinking water sources was carried out in the upper reaches of Tianmu Lake Wetland Park in Liyang City, Jiangsu Province (Tianmu Lake Town, Liyang City, Jiangsu Province). The implementation process is as follows:

[0034] (1) Water source survey: From September to October 2022, a systematic survey was conducted in the implementation area to fully understand the status of the forest community and habitat characteristics of the water conservation forest. The forest community status mainly investigated parameters such as forest structure, tree species composition, forest age, canopy density, forest layer, young forest cover, litter thickness, leaf area index, as well as indicators such as stand density, planting age, afforestation method, seedling source, and pest and disease status; the habitat characteristics investigated parameters such as soil texture, soil thickness, soil fertility, soil pH, litter thickness, as well as indicators such as slope aspect, slope, and slope position. All survey results are uniformly registered and recorded.

[0035] (2) Site classification: The water conservation forest was divided into 36 site types according to the site conditions. The classification method was as listed in Table 1 below, that is, the slope (including S, E, W, N) was used as the first-level indicator, the soil thickness (ST) was used as the second-level indicator, and the soil organic carbon mass fraction (SOC) was used as the third-level indicator to divide the site into 36 types and number them in sequence. After the classification was completed, a 20-24 cm wide and 25-30 cm deep isolation ditch was set up on site between adjacent site types, and a sign was inserted to mark them. All site types were completed and drawn on the above map.

[0036] Table 1 Classification of site types

[0037]

[0038]

[0039] (3) Operational zoning: After the site type classification was completed, the operational zoning was carried out, and 36 large operational areas were divided. The zoning was based on the community habitat characteristics, combined with community characteristic parameters such as tree species composition, forest age, canopy density, forest layer, young forest cover, litter thickness, leaf area index, etc.; each large operational area had relatively consistent site conditions, but if the community parameters such as tree species composition, forest age, canopy density, forest layer, young forest cover, leaf area index, etc. within the same site type were significantly different, they were further refined into several sub-operation areas, and each sub-operation area had relatively consistent community characteristics;

[0040] (4) Silviculture and Regulation: Different operation areas have implemented corresponding regulation measures according to the site conditions, including density adjustment, conversion from pure to mixed, steep to terraced, and removal of diseased and rotten trees. Density adjustment is based on the principle of retaining the number of trees, 60 trees / mu for broad-leaved forests, 70 trees / mu for coniferous forests, 75 trees / mu for mixed coniferous and broad-leaved forests, and 180 trees / mu for bamboo forests. Pure to mixed conversion means that when the tree species composition becomes a pure forest, thinning and replanting are carried out. Thinning and replanting are carried out under the premise of meeting the density adjustment standard of the number of retained trees, so that the number of tree species in a single operation area is greater than 1. The implementation principles of replanting are: replant with elm wood in pine forests, replant with baldcypress in pure elm wood forests, replant with beech in fir forests, replant with alnus in elm wood forests, replant with Chinese tallow tree in locust forests, and replant with maple in holly forests. At the same time, the high integration of negative tree species and positive tree species, fast-growing tree species and slow-growing tree species, evergreen tree species and deciduous tree species, deep-rooted tree species and shallow-rooted tree species is taken into account, so as to facilitate ecological overlap and complementary advantages and disadvantages.

[0041] At the same time, when the slope of the site in each operation area was greater than 40 degrees, the forest land was steepened and stepped. The transformation method was to dig steep steps in concentric circles parallel to the contour lines ( Figure 2 , Figure 3 ). During the transformation, the excavation in the soil moving area 1 is moved into the filling area 2, the excavation angle n at the base of the excavation is controlled at 90-100°, the slope length L between the upper and lower steep steps is controlled at 3-4m, and attention is paid to the backfilling of topsoil and humus 1′. The topsoil and humus 1′ in the soil moving area cover the upper layer 2′ of the filling area, and the base of the soil moving area receives the topsoil and humus 2" of the filling area above, ensuring that the humus in the surface soil of the forest land is not reduced, and enhancing the permeability, interception capacity and nutrient conservation capacity of the forest land soil.

[0042] At the same time, in each operation area, the trees, branches and roots that are damaged by pests and diseases in the forest are moved outside the forest, crushed and landfilled to eliminate the source of infection and effectively reduce the spread of pests and diseases.

[0043] (5) Reclamation and promotion of young forests: After afforestation and regulation in different operation areas, humus regulation, irrigation and water replenishment, and young forest tending measures were implemented. Among them, the humus regulation is to adjust the soil humus according to the habitat characteristics of the previous investigation. Since the on-site investigation shows that the surface coniferous litter accounts for more than 85%, Biom acidic organic fertilizer is added to the forest land to promote the decomposition of litter, with an application rate of 15kg per mu. The water management measures for young forests are determined according to the soil moisture conditions of the forest land. When the volumetric water content of the forest soil is lower than 25%, irrigation and water replenishment operations are implemented, and water is replenished 4 times a year. During the implementation period, weeding and loosening the soil within a radius of 1m for newly planted saplings are carried out 3 times a year during the growing season, with an interval of 2 months each time.

[0044] (6) Litter distribution: Carry out quantitative regulation and distribution of litter based on the annual accumulated litter survey statistics of the forest land, so that the forest land is evenly covered with litter, reducing surface runoff and water loss, and enhancing water conservation and regulation. The regulation principle is to use the annual average thickness (M) of the litter survey in the forest land in the operation area as the base number, and the allocation quantity satisfies the following formula:

[0045] M=X±Y,

[0046] Where Y is the litter thickness that needs to be quantitatively spread (cm), X is the litter thickness investigated on site (cm), and M is the annual average thickness (cm).

[0047] (7) Implementation effect: A survey of the implementation area has been conducted since October 2024. The replanted trees are growing robustly and recovering well, species diversity has increased significantly, Simpson's Diversity Index has increased by 30%, and the forest phase has become perfect; the litter in the forest is evenly distributed, with an average thickness of 4.4 cm, and the effective water retention capacity exceeds 26 t·hm -2 It effectively reduces soil erosion, ensures clear reservoir water, stable storage capacity and water quality, and has significant potential economic benefits.

[0048] The present invention provides ideas and methods for regulating the structure of water conservation forests in drinking water sources and improving their functions. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention. All components not specified in this embodiment can be implemented using existing technologies.

Claims

1. A method for regulating the structure and improving the function of water conservation forests in drinking water sources, characterized in that: The steps include: (1) Water source survey: comprehensively understand the status of forest communities and habitat characteristics of water source conservation forests; (2) Site classification: The water conservation forest site types are divided according to site conditions. A 20-24 cm wide and 25-30 cm deep isolation ditch is set between adjacent types. The site types are drawn on the map and marked on site; (3) Operational zoning: After the site type classification is completed, the operational zoning is carried out to divide several large operational areas. The zoning is based on the community habitat characteristics and combines community characteristic parameters such as tree species composition, forest age, canopy density, forest layer, young forest cover, litter thickness, leaf area index, etc. Each large operational area has relatively consistent site conditions. However, if the community parameters such as tree species composition, forest age, canopy density, forest layer, young forest cover, leaf area index, etc. within the same site type are significantly different, they are divided into several sub-operation areas. Each sub-operation area has relatively consistent community characteristics. The large operational area and the sub-operation area can be concentrated and connected, or they can be distributed across. (4) Silviculture and Regulation: Different operation areas implement corresponding regulation measures according to the site conditions, so as to adapt to local conditions and take targeted measures. The regulation measures include density adjustment, conversion from pure to mixed, conversion from steep to steep, and removal of diseased and rotten wood; (5) Reclamation and afforestation: After afforestation and regulation in different operation areas, humus regulation, irrigation and water replenishment, and young forest cultivation measures are implemented; (6) Litter distribution: During the young forest cultivation period, litter is quantitatively spread according to the surface litter conditions to ensure that the forest litter is evenly covered, reduce surface runoff and water loss, and enhance water conservation and regulation capabilities.

2. The method for regulating the structure and improving the function of water conservation forests in drinking water sources according to claim 1 is characterized in that: In step (1), the forest community conditions include parameters such as forest structure, tree species composition, forest age, canopy density, forest layer, young forest cover, litter thickness, leaf area index, etc., and also include indicators such as stand density, planting age, afforestation method, seedling source, and pest and disease status; the habitat characteristics include parameters such as soil texture, soil thickness, soil fertility, soil pH, litter thickness, etc., and also include indicators such as slope aspect, slope gradient, and slope position.

3. The method for regulating the structure and improving the function of water conservation forests in drinking water sources according to claim 1 is characterized in that: In step (2), the site type classification is carried out according to the method listed in Table 1, that is, the slope aspect (including S, E, W, N) is used as the primary indicator, the soil thickness (ST) is used as the secondary indicator, and the soil organic carbon mass fraction (SOC) is used as the tertiary indicator to divide the site into 36 types and number them in sequence. Table 1 Classification of site types 4. The method for regulating the structure and improving the function of water conservation forests in drinking water sources according to claim 1, characterized in that: In step (4), the density adjustment is to determine the number of thinning or replanting adjustments based on the number of trees per unit area of ​​the forest stand. The specific adjustment standard is based on the number of retained trees, i.e., 60 to 75 trees per mu for broad-leaved forests, 70 to 80 trees per mu for coniferous forests, 70 to 75 trees per mu for mixed coniferous and broad-leaved forests, and 180 to 220 trees per mu for bamboo forests.

5. The method for regulating the structure and improving the function of water conservation forests in drinking water sources according to claim 1 is characterized in that: In step (4), when the pure-to-mixed forest is formed, thinning and replanting are carried out. On the premise of meeting the density adjustment and retention tree quantity standard, coniferous trees are cut and replaced with broadleaf trees, or broadleaf trees are cut and replaced with coniferous trees, or broadleaf trees are cut and replaced with broadleaf trees, or bamboo trees are cut and replaced with heterophyllous trees, so that the number of tree species in a single operation area is greater than 1. The replanting follows the following principles: existing positive tree species are replaced with negative tree species, and existing negative tree species are replaced with positive tree species; existing coniferous tree species are replaced with broadleaf tree species, and existing broadleaf tree species are replaced with coniferous tree species; existing fast-growing tree species are replaced with slow-growing tree species, and existing slow-growing tree species are replaced with fast-growing tree species; existing evergreen tree species are replaced with deciduous tree species, and existing deciduous tree species are replaced with evergreen tree species; existing deep-rooted tree species are replaced with shallow-rooted tree species, and existing shallow-rooted tree species are replaced with deep-rooted tree species, so as to achieve ecological overlap and complementary advantages and disadvantages; if the operation area is a bamboo forest, heterophyllous bamboo of the same genus is planted.

6. The method for regulating the structure and improving the function of water conservation forests in drinking water sources according to claim 1, characterized in that: In step (4), the steepening step is to implement steepening step transformation on the forest land when the slope of the site in the operation area is greater than 40 degrees. The transformation method is to dig steepening steps in parallel to the contour lines in concentric circles, and the excavation of the soil transfer area (1) is moved into the filling area (2). The excavation angle (n) of the excavation base is controlled at 90-100 degrees, and the slope length (L) between the upper and lower steepening steps is controlled at 3-4 meters. Attention is paid to the backfilling of topsoil and humus (1'). The topsoil and humus (1') of the soil transfer area cover the upper layer (2') of the filling area, and the base of the soil transfer area receives the topsoil and humus (2") of the upper filling area, so as to ensure that the humus in the surface soil of the forest land is not reduced, and enhance the permeability, interception capacity and conservation capacity of the forest land soil.

7. The method for regulating the structure and improving the function of water conservation forests in drinking water sources according to claim 1, characterized in that: In step (4), the diseased and rotten wood removal is to move the trees, branches and roots that are damaged by pests and diseases in the forest to outside the forest for treatment to eliminate the infection source.

8. The method for regulating the structure and improving the function of water conservation forests in drinking water sources according to claim 1 is characterized in that: In step (5), the humus adjustment is to adjust the soil humus according to the habitat characteristics of the preliminary investigation. If the surface coniferous litter is the majority, then add decomposed acidic organic fertilizer, such as Biom acidic organic fertilizer, to promote the decomposition of litter, and the amount per mu shall not exceed 15 kg; if the surface broad-leaved litter is the majority, then add decomposed neutral or slightly acidic organic fertilizer, such as decomposed farmyard manure, compost, etc., and the amount per mu shall not exceed 10 kg; the irrigation and water replenishment refers to determining the water management measures for the young forest according to the soil moisture conditions of the forest, and implementing irrigation and water replenishment operations when the volumetric water content of the forest soil is lower than 25%; the young forest cultivation refers to weeding and loosening the soil within a radius of 1 m for the newly planted young trees 3 times during the growing season each year, with an interval of 2 months each time.

9. The method for regulating the structure and improving the function of water conservation forests in drinking water sources according to claim 1, characterized in that: In step (6), the quantitative spreading of litter is to carry out litter regulation and allocation according to the amount of litter accumulated in the forest each year, so as to reduce the surface blank and enhance the litter interception capacity. The regulation principle is to use the annual average thickness (M) of the litter survey in the forest in the operation area as the base number, and the allocation quantity satisfies the following formula: M=X±Y, Where Y is the litter thickness that needs to be quantitatively spread (cm), X is the litter thickness investigated on site (cm), and M is the annual average thickness (cm).

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