Method for establishing multi-layer mixed forest by thinning poplar shelter forest

Abstract

The application relates to the technical field of mixed forest, and particularly discloses a method for cutting and renewing a multi-layer mixed forest in a poplar protective forest, which comprises the following steps: S1, selecting a protective forest; S2, establishing a forest window; S3, selecting seedlings; S4, treating the seedlings; S5, transplanting the seedlings; S6, tending the seedlings; and S7, managing the forest stand. The preparation method has the advantages of improving the stability of the poplar protective forest and enhancing the protection efficiency of the poplar protective forest.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of mixed forest, in particular to a method for establishing multi-layer mixed forest by inter-felling and renewing poplar protective forest. BACKGROUND

[0002] The protective forest is a natural forest and artificial forest for maintaining soil and water, preventing sand and wind, storing water, adjusting climate, reducing pollution, and is a forest community for the main purposes of preventing natural disasters, maintaining infrastructure, protecting production, improving environment and maintaining ecological balance. Because the protective forest is planted in a relatively harsh environment, the first consideration is the vitality, and the poplar has strong vitality and can grow very high and fast, so the poplar is mostly selected for the protective forest, and therefore, in the northern region of China, especially in the high-altitude region, many poplar protective forests are established.

[0003] However, except for a few intensive poplar fast-growing and high-yield forests with continuous fertilization and watering, most poplar pure forests have poor site conditions and low soil fertility, and the growth of the trees is small, resulting in the death of a large area of poplar and causing many ecological problems. The main reason is that the forest community structure is too simple, the species diversity is low, and the stability of the forest stand is poor, so that the protective efficiency of the poplar protective forest is insufficient. SUMMARY

[0004] In order to improve the stability of the poplar protective forest and enhance the protective efficiency of the poplar protective forest, the application provides a method for establishing multi-layer mixed forest by inter-felling and renewing poplar protective forest, which adopts the following technical scheme:

[0005] A method for establishing multi-layer mixed forest by inter-felling and renewing poplar protective forest, comprising the following steps:

[0006] S1, selecting a protective forest: selecting a highland poplar protective forest with more than 8 years of age and degraded biological environment of the forest land;

[0007] S2, establishing a forest window: before the soil is thawed from late February to late March, cutting down dead wood, decayed wood, and trees with a tree leaf and tree trunk death rate of more than 60%, and according to the cut-down trees, selecting and cutting down poplar trees with good growth to form a plurality of forest windows, and the adjacent two rows of poplar trees in the plurality of forest windows are connected from one side to the other side in a wave shape, and the cut-off tree trunks and branch residues are removed from the protective forest;

[0008] S3, seedling selection: selecting one-year-old willow seedlings with strong growth and no diseases and insect pests, the seedlings having a height of 1.5-2.5 m and a diameter of 1.8-2.8 cm;

[0009] S4, seedling treatment: 20-30 days before transplanting, trimming, retaining 2-3 branches, 5-10 days before transplanting, seedling, pruning roots, main root is cut to 10-15 cm, the root system is wrapped with cloth into a soil ball, the root is fully immersed in water for 3-5 days before transplanting, shading, windproof and avoiding damage during transportation;

[0010] S5, seedling transplanting: after the soil of the forest window is thawed in late April to early May, the seedlings are planted, the seedlings treated in step S4 are planted in the hole and backfilled with soil, the soil is compacted, and timely irrigation is formed. Wave type Salix mongolica seedling belt;

[0011] S6, seedling cultivation: remove shrub and grass vegetation in the forest window, irrigate once 15 days and 30 days after transplanting Salix mongolica seedlings, apply fertilizer once in mid-to-late April and supplement phosphorus fertilizer, and clean the shrub and grass vegetation within 0.5 m around the seedlings again;

[0012] S7, stand management: continuous cultivation management is implemented on the transplanted seedlings in the forest window to prevent the occurrence of diseases, pests and forest fires, and grazing and logging interference is prohibited.

[0013] By adopting the above technical scheme, the poplar is a deciduous tree of the Salicaceae poplar genus, grows rapidly, is tall and straight, the Salix mongolica is a low shrub willow species, the height is usually about 1 m, the Salix mongolica grows fast, reproduces simply, and has strong adaptability to external adverse environment; the poplar has obvious apical dominance, the trunk is straight, the Salix mongolica has slightly poor apical dominance, and the tree shape is relatively chaotic, but can form good stem shape in mixed forest, and the biological characteristics of the two tree species are beneficial to form good interspecific relationship.

[0014] The characteristics of the poplar and the Salix mongolica make the two trees have different heights and canopy layers in the stand, the first layer is the poplar, which is above the second layer canopy, has sufficient light and smooth air, and is suitable for maximum growth, the second layer canopy is the Salix mongolica forest, and the poplar has sparse leaves, and still can obtain relatively sufficient light and ventilation conditions, the two tree species form a complex layer forest, and due to different ecological niches, each has certain space and light conditions. Moreover, the poplar and the Salix mongolica are both light-loving tree species, and the Salix mongolica is slightly shade-tolerant; due to the strong solar radiation on the plateau, the newly planted Salix mongolica seedlings have poor resistance, and the seedlings are prone to sunburn, and the survival rate is reduced, and the mature poplar forest can provide shade for the Salix mongolica seedlings, and provide a suitable environment for the growth of the Salix mongolica seedlings.

[0015] In addition, the poplar is a deep-rooting tree species, the main root is developed and grows vertically, the Salix mongolica is a shallow-rooting tree species, the main root is not obvious, the lateral root is developed and grows horizontally, and after the two are mixed, the root systems are staggered up and down, and the soil nutrients are maximally utilized.

[0016] The poplar and Salix wallichiana mixed forest is mixed according to the different height and canopy layer of plants, the growth cycle of plants, and the depth and direction of the roots of the trees, so as to fully utilize the light energy in the space above ground and the water and nutrients in the soil below ground, and maximize the economic benefits.

[0017] The construction of the poplar and Salix wallichiana mixed forest can improve the forest microclimate, promote the effective use of light, heat, water and air by the forest stand, enhance the microbial activity, reduce the occurrence of diseases and pests, change the biological environment of the forest land, accelerate the decomposition of litter and roots, increase the nutrient content of the soil, and improve the biodiversity and stability of the forest stand; the root system of the mixed forest is more developed, and the effects of water retention and wind prevention and sand fixation are more significant.

[0018] Preferably, the method for constructing the wave-shaped forest gap is as follows:

[0019] S201, determining the position and quantity of poplar trees, and dividing the poplar trees into regions according to the original planting rules;

[0020] S202, taking every two adjacent rows of poplar trees as a group, taking the first poplar tree in the first row as the starting point, and connecting the poplar trees in the first row and the second row in turn at the diagonal positions, the poplar trees in the diagonal positions are replanted with poplar seedlings, and a wave-shaped poplar belt is formed;

[0021] S203, taking the region where the first row of poplar trees and the second row of poplar trees are not connected into a wave-shaped poplar belt as a forest gap, taking the first forest gap in the second row as the starting point, connecting adjacent forest gaps in turn at the diagonal positions, forming a wave-shaped forest gap, and the wave-shaped poplar belt and the wave-shaped forest gap intersect with each other;

[0022] S204, dividing the wave-shaped poplar belt and the wave-shaped forest gap in the other regions in turn according to the above steps.

[0023] By adopting the above technical scheme, a wave-shaped poplar belt and a wave-shaped forest gap are formed from one side to the other between every two adjacent rows of poplar trees, Salix wallichiana seedlings are planted in the wave-shaped forest gap, a wave-shaped Salix wallichiana seedling belt is formed, the wave-shaped poplar belt and the wave-shaped Salix wallichiana seedling belt intersect with each other, so as to realize the reasonable allocation of the space above ground and below ground, the poplar belt and the Salix wallichiana seedling belt above ground have sufficient light and smooth air flow, the roots below ground are uniformly distributed, and the soil nutrients are appropriately allocated, so that the multi-layer mixed forest stand is stable and the protection effect is significant.

[0024] Preferably, after the Salix wallichiana seedlings are planted, a soil ridge is piled up along the roots of the Salix wallichiana seedlings, and the height of the soil ridge is 30-50 cm.

[0025] By adopting the technical scheme, since shrub species generally like soil environment with good air permeability and no water accumulation. When the Salix mongolica seedling is planted in a low-lying place, water accumulation or over-wet soil is easy to occur, which will affect the root respiration of the shrub and often cause root rot or root decay. Therefore, the soil ridge with a certain height is piled up along the root of the Salix mongolica seedling, which can effectively reduce the above problems of the root of the Salix mongolica seedling.

[0026] Preferably, the soil ridge is internally embedded with a gas-permeable pipe, and the gas-permeable pipe extends from the surface of the soil ridge to the root of the Salix mongolica seedling.

[0027] By adopting the technical scheme, when the seedling is irrigated for many times or the soil is relatively heavy, the soil is easy to be compacted, which causes poor air permeability of the root and affects the normal growth of the seedling. The gas-permeable pipe is embedded in the soil ridge, which can timely loosen the soil and improve the air permeability after the surface is slightly dry after irrigation, so as to reduce the soil compaction.

[0028] Preferably, the trees with a tree leaf and tree trunk death rate of more than 60% and the better-growing poplar are dug out together with the root system when felled.

[0029] By adopting the technical scheme, since the root of the felled tree occupies the underground space and competes with the healthy growing trees for water and nutrients in the soil, the root of the felled tree is dug out and cleaned, which can reduce the waste of soil nutrients, prevent the root of the felled tree from rotting, reduce the occurrence of diseases and pests, and balance the pH value of the soil.

[0030] Preferably, the diameter of the pit is 40-50 cm, the depth of the pit is 40-50 cm, and the distance between the two adjacent pits is 1.5-2.5 m.

[0031] By adopting the technical scheme, since the Salix mongolica is a shallow-rooted tree species with no obvious main root and developed lateral roots growing horizontally, the diameter and depth of the pit are set in the range, which not only can accommodate the soil ball wrapped after pruning, but also can make the growth of the Salix mongolica not be limited. In addition, since the distance between the two adjacent rows or two adjacent columns of poplar trees is 1-2 m, and the two adjacent pits for planting the Salix mongolica are diagonally adjacent, the distance between the two adjacent pits is in the above range.

[0032] Preferably, 1.5-2 kg of light carbon nuclear fertilizer is added to the soil dug out from the pit, and the soil is fully mixed and then backfilled into the pit.

[0033] By adopting the technical scheme, the light carbon nuclear fertilizer is used as a medium and solar energy as a power to capture carbon dioxide in the air for the seedling to absorb and utilize, so as to promote the gestation and growth of the seedling. The addition of the light carbon nuclear fertilizer in the soil can effectively improve the soil quality and provide nutrients for the seedling.

[0034] Preferably, the light carbon nucleus fertilizer comprises sodium carbonate, sodium bicarbonate, coke, organic matter, soil conditioner, bacillus subtilis, jelly-like paenibacillus and fulvic acid.

[0035] By adopting the technical scheme, sodium carbonate and sodium bicarbonate can produce carbon dioxide in contact with air in the soil, and provide carbon for the root system of the sapling, which in turn transports the carbon to the stem and leaf parts of the sapling, and the stem and leaves provide nutrients for the sapling through photosynthesis, so that the sapling grows vigorously. The coke can act as an adsorbent to absorb the carbon dioxide gas released by sodium carbonate and sodium bicarbonate. The soil conditioner can effectively improve the soil texture and balance the soil pH.

[0036] In summary, the present application has the following beneficial effects:

[0037] 1. According to the present application, different heights and canopy layers of plants, growth cycles of plants, and depths and directions of tree roots are mixed, so as to fully utilize the light energy in the above-ground space and the water and nutrients in the underground soil, maximize economic benefits, reduce the occurrence of diseases and pests, change the biological environment of the forest land, speed up the decomposition of litter and roots, increase the nutrient content of the soil, improve the biodiversity and stability of the forest stand, and the root system of the mixed forest is more developed, so that the effects of water retention and wind and sand fixation are more remarkable.

[0038] 2. In the present application, a wave-shaped poplar belt and a wave-shaped forest window are formed from one side to the other side between every two adjacent rows of poplar forests, Tibetan willow seedlings are planted in the wave-shaped forest window, a wave-shaped Tibetan willow seedling belt is formed, and the wave-shaped poplar belt and the wave-shaped Tibetan willow seedling belt intersect each other, so as to reasonably allocate the above-ground and underground space, the poplar belt and the Tibetan willow seedling belt have sufficient light and smooth air flow, the underground root system is evenly distributed, and the soil nutrients are properly distributed, so that the multi-layer mixed forest stand is stable and the protection effect is remarkable.

[0039] 3. The present application embeds a ventilation pipe in the soil ridge, which can timely loosen the soil and ventilate after watering and when the ground is slightly dry, so as to reduce soil compaction. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 is a structural schematic diagram of the method provided by the present application.

[0041] BRIEF DESCRIPTION OF DRAWINGS: 1, poplar; 2, Tibetan willow seedling. DETAILED DESCRIPTION

[0042] The present application will be further described in detail below in combination with the accompanying drawings and examples. Figure 1

[0043] EMBODIMENT

[0044] EMBODIMENT 1 ​

[0045] A method for establishing multi-layer mixed forest in poplar shelter forest by thinning and renewing, comprising the following steps:

[0046] S1, selecting a shelter forest: selecting a highland poplar shelter forest with more than 8 years of age and degraded biological environment.

[0047] S2, establishing forest gap: before the soil is thawed in late February, cut down dead wood, decayed wood, and trees with more than 60% of tree leaf and trunk mortality, and select and cut down trees with good growth according to the cut down trees, form several forest gaps, and the connecting lines of the several forest gaps in the two adjacent rows of poplar forest from one side to the other side are in a wave shape, and the cut down tree trunks and branch residues are removed from the shelter forest.

[0048] The dead wood, decayed wood, trees with more than 60% of tree leaf and trunk mortality, and trees with good growth are also dug out together with the roots when cutting down.

[0049] S3, seedling selection: select one-year-old Tibetan willow seedlings with strong growth and no pests and diseases, with a seedling height of 1.5 m and a diameter of 1.8 cm.

[0050] S4, seedling treatment: trim 2 branches 20 days before transplanting, take seedlings 5 days before transplanting, prune the root system, shorten the main root to 10 cm, wrap the root system with a soil ball, and transplant after the root system is fully soaked for 3 days. Protect the seedlings from light, wind, and damage during transportation.

[0051] S5, seedling transplanting: plant seedlings in late April after the soil in the forest gap is thawed, dig holes in the corresponding forest gap positions, the hole diameter is 40 cm, the hole depth is 40 cm, and the distance between adjacent two holes is 1.5 m. Plant the Tibetan willow seedlings treated in step S4 into the holes and backfill the soil, compact the soil, irrigate in time, and form a wave-shaped Tibetan willow seedling belt.

[0052] Add 1.5 kg of light carbon core fertilizer to the soil in the hole, mix thoroughly, and then backfill the hole. The light carbon core fertilizer includes sodium carbonate, sodium bicarbonate, coke, organic matter, soil conditioner, Bacillus subtilis, jelly-like Paenibacillus, and fulvic acid.

[0053] A soil ridge is built along the root of the Tibetan willow seedling after the Tibetan willow seedling is planted, and the soil ridge is 30 cm high. A ventilation pipe is buried in the soil ridge, which extends from the surface of the soil ridge to the root of the Tibetan willow seedling. The ventilation pipe is a hollow pipe, and ventilation nets are arranged at both ends of the pipe.

[0054] S6, seedling cultivation: remove the shrub and grass vegetation in the forest gap, irrigate once 15 days and 30 days after transplanting the Tibetan willow seedling, apply fertilizer once and supplement phosphorus fertilizer in the middle and late April, and clean the shrub and grass vegetation within a range of 0.5 m around the seedling again.

[0055] S7, stand management: the transplanted seedlings in the forest gap are continuously managed to prevent the occurrence of diseases, pests and forest fires, and grazing and logging interference is prohibited.

[0056] The method for building the wave-shaped forest gap is as follows:

[0057] S201, the positions and quantities of poplars are determined, and the poplars are divided into areas according to original planting rules.

[0058] S202, every two adjacent rows of poplars form a group, the first poplar in the first row is taken as a starting point, the poplars in the first row and the second row are connected in turn at opposite angles, the poplar in the position at the opposite angle is replanted with a poplar seedling, and a wave-shaped poplar belt is formed.

[0059] S203, the area where the poplars in the first row and the second row are not connected into the wave-shaped poplar belt is taken as a forest gap, the first forest gap in the second row is taken as a starting point, adjacent forest gaps are connected in turn at opposite angles, a wave-shaped forest gap is formed, and the wave-shaped poplar belt and the wave-shaped forest gap intersect with each other.

[0060] S204, other areas are divided into wave-shaped poplar belts and wave-shaped forest gaps in turn according to the above steps.

[0061] Embodiment 2

[0062] A method for building a multi-layer mixed forest by intermediate cutting and updating of a poplar shelter forest, comprising the following steps:

[0063] S1, selecting a shelter forest: selecting a highland poplar shelter forest with an age of more than 8 years and a degraded biological environment of the forest land.

[0064] S2, building a forest gap: before the soil is thawed in early March, cutting down dead wood, decayed wood, and trees with a tree leaf and tree trunk death rate of more than 60%, according to the cut-down trees, selectively cutting down poplars with good growth, forming a plurality of forest gaps, and connecting lines of the plurality of forest gaps in adjacent two rows of poplar forests from one side to the other side in a wave shape, and removing all the cut-off tree trunks and branch residues out of the shelter forest.

[0065] The dead wood, decayed wood, trees with a tree leaf and tree trunk death rate of more than 60%, and poplars with good growth are also dug out together with the roots when cutting down.

[0066] S3, seedling selection: selecting one-year-old willow seedlings with good growth and no diseases and pests, with a seedling height of 2.5 m and a diameter at breast height of 2.8 cm.

[0067] S4, seedling treatment: trimming 30 days before transplanting, retaining 3 branches, taking seedlings 10 days before transplanting, pruning roots, shortening main roots to 15 cm, wrapping roots with cloth into soil balls, transplanting after the roots are fully soaked for 5 days, and shading, windproofing and avoiding damage during transportation.

[0068] S5, transplanting seedlings: after the soil of the forest gap is thawed in late April, the seedlings are planted, pits are dug at the positions of the corresponding forest gaps, the diameter of the pits is 50 cm, the depth of the pits is 50 cm, and the distance between two adjacent pits is 2.5 m. The Salix mongolica seedlings treated in step S4 are planted in the pits, and the soil is backfilled, compacted, irrigated in time, and a wavy Salix mongolica seedling belt is formed.

[0069] The soil dug out from the pits is added with 2 kg of light carbon core fertilizer, and after being fully mixed, the soil is backfilled into the pits. The light carbon core fertilizer comprises sodium carbonate, sodium bicarbonate, coke, organic matter, soil conditioner, Bacillus subtilis, jelly-like Paenibacillus, and fulvic acid.

[0070] After the Salix mongolica seedlings are planted, an earth ridge is built along the roots of the Salix mongolica seedlings, and the height of the earth ridge is 50 cm. A gas-permeable pipe is buried in the earth ridge, the gas-permeable pipe extends from the surface of the earth ridge to the roots of the Salix mongolica seedlings, the gas-permeable pipe is a hollow pipe, and gas-permeable nets are arranged at both ends of the pipe.

[0071] S6, seedling cultivation: the shrub and grass vegetation in the forest gap is removed, the Salix mongolica seedlings are irrigated once at 15 days and 30 days after being transplanted, phosphorus fertilizer is applied once and supplemented in mid-to-late April, and the shrub and grass vegetation within a range of 0.5 m around the seedlings is cleaned again.

[0072] S7, stand management: the transplanted seedlings in the forest gap are continuously cultivated and managed to prevent the occurrence of diseases, pests and forest fires, and grazing and logging interference is prohibited.

[0073] The method for constructing the wavy forest gap is as follows:

[0074] S201, the positions and quantity of the poplars are determined, and the poplars are divided into regions according to the original planting rules.

[0075] S202, each two adjacent rows of poplars form a group, the first poplar in the first row is taken as a starting point, the poplars in the first row and the second row are connected in a diagonal manner, the poplar at the diagonal position is replanted with a poplar seedling if the poplar has been cut down, and a wavy poplar belt is formed.

[0076] S203, the region in which the poplars in the first row and the second row are not connected into a wavy poplar belt is taken as a forest gap, the first forest gap in the second row is taken as a starting point, and adjacent forest gaps are connected in a diagonal manner, a wavy forest gap is formed, and the wavy poplar belt and the wavy forest gap intersect with each other.

[0077] S204, the other regions are divided into wavy poplar belts and wavy forest gaps according to the above steps in sequence.

[0078] Example 3

[0079] A method for constructing a multi-layer mixed forest by intermediate cutting and updating of a poplar shelter forest, comprising the following steps:

[0080] S1, selecting shelter forest: selecting 8 years or more, the biological environment of forest land appears degradation of high plateau poplar shelter forest.

[0081] S2, building forest window: in late March before soil thawing, cutting down dead wood, disease wood and trees with more than 60% of tree leaf and trunk death rate, according to the felled trees, corresponding to the selection of good growth poplar, forming a number of forest windows, the adjacent two rows of poplar forest in a number of forest windows from one side to the other side in turn connected line presents wave type, the felled tree trunk and branch residue are all removed from the shelter forest;

[0082] The dead wood, disease wood, tree leaf and tree trunk with more than 60% of tree death rate and the poplar with good growth are dug out together with the root system when cutting down.

[0083] S3, seedling selection: selecting one-year-old Tibetan willow seedlings with strong growth and no disease and insect pests, seedling height 2.0 m, diameter 2.3 cm.

[0084] S4, seedling treatment: trimming 25 days before transplanting, retaining 3 branches, taking seedlings 8 days before transplanting, pruning root system, shortening main root to 12.5 cm, wrapping root system with cloth into soil ball, transplanting after fully soaking root with water for 4 days, shading, avoiding wind and avoiding damage during transportation.

[0085] S5, seedling transplanting: planting seedlings after soil thawing in early May in forest window, digging hole in corresponding forest window position, the hole diameter is 45 cm, the depth is 45 cm, the distance between adjacent two holes is 2.0 m. Planting Tibetan willow seedlings treated in step S4 into the hole and backfilling soil, compacting soil, timely irrigation, forming wave type Tibetan willow seedling belt.

[0086] Adding 1.8 kg of light carbon nuclear fertilizer in the soil dug out from the hole, fully mixing and backfilling the hole. The light carbon nuclear fertilizer includes sodium carbonate, sodium bicarbonate, coke, organic matter, soil conditioner, bacillus subtilis, gelatinous bacillus and fulvic acid.

[0087] The soil ridge is 40 cm high along the root of the Tibetan willow seedling. The soil ridge is buried with a breathable pipe, which extends from the surface of the soil ridge to the root of the Tibetan willow seedling. The breathable pipe is a hollow pipe, and the pipe has a breathable net at both ends.

[0088] S6, seedling cultivation: removing shrub and grass vegetation in forest window, irrigating once respectively 15 days and 30 days after transplanting Tibetan willow seedlings, applying fertilizer once and supplementing phosphorus fertilizer in middle and late April, and removing shrub and grass vegetation within 0.5 m around the seedlings again.

[0089] S7, stand management: implementing continuous cultivation management on the seedlings transplanted in the forest window, preventing the occurrence of diseases, insect pests and forest fire, and prohibiting grazing and logging interference.

[0090] The method for building the wave-shaped forest gap is as follows:

[0091] S201, determine the position and quantity of poplar trees, and divide the poplar trees according to the original planting rules.

[0092] S202, each adjacent two rows of poplar trees form a group, and the first poplar tree in the first row is taken as the starting point. The poplar trees in the first row and the poplar trees in the second row are connected in turn at the diagonal position, and the poplar seedlings are replanted in the poplar trees that have been cut down at the diagonal position, forming a wave-shaped poplar belt.

[0093] S203, the area where the first row of poplar trees and the second row of poplar trees are not connected into a wave-shaped poplar belt is taken as a forest gap. The second row of the first forest gap is taken as the starting point, and adjacent forest gaps are connected in turn at the diagonal position, forming a wave-shaped forest gap. The wave-shaped poplar belt and the wave-shaped forest gap intersect with each other.

[0094] S204, the other areas are divided into wave-shaped poplar belts and wave-shaped forest gaps according to the above steps in turn.

[0095] Comparative example

[0096] Comparative example 1

[0097] A method for building a multi-layer mixed forest by intermediate cutting and updating of a poplar shelter forest, comprising the following steps:

[0098] S1, selecting a shelter forest: selecting a highland poplar shelter forest with more than 8 years of age and degraded biological environment of the forest land.

[0099] S2, building forest gaps: before the soil is thawed in early March, cutting down dead wood, decayed wood, and trees with a tree leaf and tree trunk death rate of more than 60%, and selecting and cutting down poplar trees with good growth according to the cut-down trees, to form a plurality of forest gaps. The forest gaps and the poplar trees are mixed, and the cut-down tree trunks and branch residues are removed from the shelter forest. The dead wood, decayed wood, trees with a tree leaf and tree trunk death rate of more than 60%, and poplar trees with good growth are also dug out with their root systems during cutting.

[0100] S3, seedling selection: selecting one-year-old willow seedlings with good growth and no pests and diseases, with a seedling height of 2.5 m and a diameter at breast height of 2.8 cm.

[0101] S4, seedling treatment: trimming 30 days before transplanting, retaining 3 branches, taking seedlings 10 days before transplanting, pruning the root system, shortening the main root to 15 cm, wrapping the root system with a cloth to form a soil ball, and transplanting after the root system is fully soaked for 5 days. During transportation, the seedlings are shaded, wind-protected, and protected from damage.

[0102] S5, transplanting seedlings: after the soil in the forest gap is thawed in late April, the seedlings are planted, a hole is dug in the corresponding forest gap, the hole has a diameter of 50 cm and a depth of 50 cm, and the distance between two adjacent holes is 2.5 m. The Salix mongolica seedlings treated in step S4 are planted in the hole and the soil is backfilled, the soil is compacted, irrigation is performed in time, and a wavy Salix mongolica seedling belt is formed.

[0103] 2 kg of light carbon core fertilizer is added to the soil dug out of the hole, and the light carbon core fertilizer is fully mixed and then backfilled into the hole. The light carbon core fertilizer comprises sodium carbonate, sodium bicarbonate, coke, organic matter, soil conditioner, Bacillus subtilis, jelly-like Paenibacillus, and fulvic acid.

[0104] After the Salix mongolica seedlings are planted, an earth ridge is built along the roots of the Salix mongolica seedlings, and the earth ridge has a height of 50 cm. A gas-permeable pipe is embedded in the earth ridge, the gas-permeable pipe extends from the surface of the earth ridge to the roots of the Salix mongolica seedlings, the gas-permeable pipe is a hollow pipe, and gas-permeable nets are arranged at both ends of the pipe.

[0105] S6, seedling cultivation: the shrub and grass vegetation in the forest gap is removed, the Salix mongolica seedlings are irrigated once 15 days and 30 days after being transplanted, phosphorus fertilizer is applied once in mid-to-late April to supplement the phosphorus fertilizer, and the shrub and grass vegetation within a range of 0.5 m around the seedlings is cleaned up again.

[0106] S7, stand management: the transplanted seedlings in the forest gap are subjected to continuous cultivation and management to prevent the occurrence of diseases, pests, and forest fires, and grazing and logging interference is prohibited.

[0107] Comparative Example 2

[0108] A pure poplar forest in the same period and the same region is selected as a reference, and in late February before the soil is thawed, dead and decayed wood, as well as trees with a tree leaf and tree trunk death rate of more than 60% are cut down, and the roots are also dug out, and the same measures as the poplar and Salix mongolica mixed forest are taken for the later cultivation and management.

[0109] Performance test

[0110] Test method

[0111] The newly built poplar and Salix mongolica mixed forest is compared with the pure poplar forest in the same region, the tree height and diameter at breast height of the poplar in the mixed forest are measured and recorded at the initial stage of the mixed forest, and the tree height and diameter at breast height of the pure poplar forest in the same period and the same region are also measured and recorded, after 3 years, the tree height and diameter at breast height of the poplar in the mixed forest are measured and recorded again, and the tree height and diameter at breast height of the pure poplar forest in the same period and the same region are also measured and recorded, and the average value of the tree height and diameter at breast height in each record item in this test is taken.

[0112] Table 1: Poplar growth condition record table

[0113]

[0114] It can be seen from the combination of Example 2 and Comparative Example 2 and Table 1 that the height growth rate of the poplar-salix mix forest is 57.2-67.4%, which is increased by 25.6-35.8% compared with the pure forest; the diameter growth rate is 34.8-53.2%, which is increased by 9.6-28% compared with the pure forest, which shows that the poplar-salix mixed forest can effectively utilize the light energy in the space of the aboveground part, the water and nutrients in the soil of the underground part, promote the growth and development of the poplar, and further stabilize the shelter forest stand and significantly improve the protection effect.

[0115] It can be seen from the combination of Comparative Example 1 and Table 1 that the height growth rate of the poplar-salix mix forest is 57.2%, and the diameter growth rate is 34.8, which is obviously lower than the height and diameter of the poplar in the mix forest in which the wave-shaped poplar belt and the wave-shaped salix seedling belt intersect with each other, which shows that the mix forest in which the wave-shaped poplar belt and the wave-shaped salix seedling belt intersect with each other has more advantages.

[0116] The specific embodiment is only an explanation of the present application, and is not a limitation of the present application. Those skilled in the art can make modifications to the present embodiment without creative contribution after reading the present specification, but as long as the present application is within the scope of the claims, it is protected by the patent law.

Claims

1. A method for growing a multi-layer mixed forest in a poplar shelter forest by thinning and regeneration, characterized in that, The method comprises the following steps: S1, selecting a shelter forest: selecting a shelter forest of Populus euphratica with an age of more than 8 years and a degraded biological environment of the forest land; S2, building a forest window: in late February to late March before the soil is thawed, cutting down dead wood, decayed wood, and trees with a tree leaf and tree trunk death rate of more than 60%, according to the cut-down trees, selecting and cutting down well-growing Populus euphratica to form a plurality of forest windows, and connecting the forest windows from one side to the other side of the adjacent two rows of Populus euphratica forest to form a wave-shaped Populus euphratica forest, and removing all the cut-off tree trunks and branch residues from the shelter forest; S3, seedling selection: selecting one-year-old Populus euphratica seedlings with strong growth and no diseases and insect pests, the seedlings having a height of 1.5-2.5 m and a diameter of 1.8-2.8 cm; S4, seedling treatment: 20-30 days before transplanting, the seedlings are trimmed to retain 2-3 branches, 5-10 days before transplanting, the seedlings are dug up, the root system is trimmed to a length of 10-15 cm, the root system is wrapped with a piece of cloth to form a soil ball, the root system is fully soaked for 3-5 days, and then the seedlings are transplanted, the seedlings are shaded, wind-protected, and prevented from being damaged during transportation; S5, seedling transplanting: in late April to early May after the soil in the forest window is thawed, the seedlings are planted, a hole is dug in the corresponding forest window, the Populus euphratica seedlings treated in step S4 are planted in the hole, and the soil is backfilled and compacted, the seedlings are irrigated in time, and a wave-shaped Populus euphratica seedling belt is formed; S6, seedling cultivation: the shrub and grass vegetation in the forest window is removed, the Populus euphratica seedlings are irrigated once 15 days and 30 days after being transplanted, the seedlings are fertilized once in mid-to-late April and supplemented with phosphorus fertilizer, the shrub and grass vegetation within a range of 0.5 m around the seedlings is removed again; S7, stand management: the Populus euphratica seedlings in the forest window are continuously cultivated and managed to prevent diseases and insect pests and forest fires, and grazing and logging are prohibited; The wave-shaped forest window is built in the following manner: S201, determining the positions and quantity of Populus euphratica, and dividing the Populus euphratica into regions according to the original planting rules; S202, each two adjacent rows of Populus euphratica form a group, the first Populus euphratica in the first row is taken as a starting point, the Populus euphratica in the first row is connected to the Populus euphratica in the second row in a diagonal manner, a Populus euphratica seedling is replanted in a Populus euphratica in a diagonal position that has been cut down to form a wave-shaped Populus euphratica belt; S203, the region in which the Populus euphratica in the first row and the Populus euphratica in the second row are not connected to form the wave-shaped Populus euphratica belt is taken as a forest window, the second forest window in the second row is taken as a starting point, and adjacent forest windows are connected in a diagonal manner to form a wave-shaped forest window, and the wave-shaped Populus euphratica belt and the wave-shaped forest window intersect with each other; S204, the other regions are divided into the wave-shaped Populus euphratica belt and the wave-shaped forest window according to the above steps.

2. The method for growing complex mixed forest between poplar shelter forest and thinning according to claim 1, characterized in that, After the Populus euphratica seedlings are planted, a soil ridge is formed along the root system of the Populus euphratica seedlings, and the soil ridge has a height of 30-50 cm.

3. The method for growing complex mixed forest between poplar shelter forest and thinning according to claim 2, characterized in that, A ventilation pipe is embedded in the soil ridge, and the ventilation pipe extends from the surface of the soil ridge to the root system of the Populus euphratica seedlings.

4. The method for growing complex mixed forest between poplar shelter forest and thinning according to claim 1, characterized in that, The dead wood, decayed wood, trees with a tree leaf and tree trunk death rate of more than 60%, and well-growing Populus euphratica are cut down together with the root system.

5. The method for growing complex mixed forest between poplar shelter forest and thinning according to claim 1, characterized in that, The hole has a diameter of 40-50 cm and a depth of 40-50 cm, and the distance between two adjacent holes is 1.5-2.5 m.

6. The method for growing complex mixed forest between poplar shelter forest and thinning according to claim 1, characterized in that, 1.5-2 kg of light carbon nuclear fertilizer is added to the soil in the hole, and the soil is mixed thoroughly before being backfilled into the hole.

7. The method for growing complex mixed forest between poplar shelter forest and thinning according to claim 6, characterized in that, The light carbon nuclear fertilizer comprises sodium carbonate, sodium bicarbonate, coke, organic matter, soil conditioner, bacillus subtilis, jelly-like paenibacillus and fulvic acid.

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