Method for rapidly constructing choerospondias axillaris mixed forest with near-natural community structure

Abstract

The invention discloses a method for quickly constructing a choerospondias axillaris mixed forest with a near-natural community structure, which comprises the following steps: by taking an existing natural secondary forest as an operating object, simulating a local top-level forest mode, selecting forest land, selecting tree species, constructing a construction mode and cultivating and managing. The method comprises the following steps: properly thinning and tending, complementarily planting choerospondias axillaris in a forest window, effectively maintaining the soil fertility and quickly recovering a community structure by utilizing the characteristics that the choerospondias axillaris grows quickly and has a large amount of fallen leaves, and performing organic matter coverage and community density regulation and control on target broad-leaved trees. The problems that traditional secondary forest transformation is large in risk, poor in structural stability, low in economic benefit and the like are solved. A local top-level forest mode is simulated, a community composed of an arbor layer I mainly comprising a deciduous plant choerospondias axillaris and an arbor layer II mainly comprising a lauraceae plant evergreen broadleaf plant is rapidly built, the optimal community recovery mode of a natural forest is achieved, the purposes of short recovery period, large annual growth and stable community growth are achieved, the production cost is reduced, and the economic benefit is increased. Wide production and application prospects are realized.

Description

Technical Field

[0001] The invention belongs to the technical field of forest management, and in particular relates to a method for rapidly constructing a Choerospondias axillaris mixed forest with a near-natural community structure. Background Art

[0002] Forest management is the core issue of forestry development and also the shortcoming that has long restricted forestry construction. In recent years, the forestry and grassland departments have always regarded strengthening forest management and improving forest quality as the main direction and core task of forestry. For a long time, local governments have adopted long-term closure management measures for secondary broad-leaved forests in the southern coastal mountainous areas. However, due to unclear understanding of the laws of community succession and poor implementation of tending measures, problems such as dense shrubs and vines, insufficient light, and poor ventilation have occurred in the forest, resulting in slow growth of trees, simple community structure, many depreciating positive species, and difficulty in regenerating high-quality trees.

[0003] In order to improve forest quality, forestry workers have proposed since the 1980s that building mixed forests is the best solution to low forest yields and unstable forest stands. However, the traditional mixed forest model ignores the difference in growth rate between dominant species and other tree species in the community, as well as the many problems in the construction of community spatial density and forest stand management, resulting in poor results in secondary forest transformation and restoration, and failing to achieve the expected goals.

[0004] After searching, CN105165529B and CN111788981B both adopt the afforestation design and thinning of artificial mixed forests that imitate natural forests to build mixed forests, but the objects of the invention methods are all artificial forests. At the same time, the mixed forests built by imitating nature are not typical "top forests". The trees are only divided into three age classes to determine the density and intermixing degree of construction. It is difficult to accurately extract mature, stable and efficient community characteristics. It only solves the early density of different age classes and increases the intermixing degree of tree species. It fails to effectively solve the problem of small number of potential target species for building communities in natural secondary forests and simple vertical structure of communities, making it difficult to apply in production. Summary of the invention

[0005] In response to the poor transformation effect of traditional natural secondary broad-leaved forests, the inventors investigated and studied typical mature broad-leaved forest communities in subtropical valleys and found that in natural top forests, Choerospondias axillaris (Roxb.) BL Burtt & AW Hill were distributed in clusters, not only occupying the main forest layer (tree height 18-24m, coverage 50-60%, Table 1), but also growing well, with large importance values ​​and strong regeneration ability. Therefore, the inventors used the tree height, branch height and tree height / DBH change process of the tree in the tree layer of the typical mature broad-leaved forest of Choerospondias axillaris as the theoretical basis ( Figure 1), constructed a silviculture method that can artificially simulate the natural community structure and distribution pattern of Choerospondias axillaris in valley areas, and built a near-natural Choerospondias axillaris mixed forest to solve the current problems of simple secondary forest community structure, many positive depreciating species, low tree yield, and long silviculture cycle. It is an effective way to accurately improve forest quality and has good application prospects.

[0006] Table 1 Community of mature Choerospondias axillaris forest

[0007] The purpose of the present invention is to address the phenomenon of low productivity of large-scale natural secondary forests and propose a method for rapidly constructing a mixed forest of Choerospondias axillaris with a near-natural community structure, so as to achieve the goals of rapidly restoring the vertical structure of the community, increasing the number and abundance of target community-building species, reducing competition among trees, shortening community development time, and increasing tree growth, thereby reducing production costs and increasing economic benefits.

[0008] The specific technical solution for achieving the purpose of the present invention is: A method for rapidly constructing a mixed forest of Choerospondias axillaris with a near-natural community structure, which is characterized by comprising the following steps: (1) Forest land selection: Select secondary broad-leaved communities with an altitude of ≤400 m, valley mountains, red soil, soil thickness ≥0.6 m, tree height 7-8 m, and canopy density ≥0.6; (2) Tree species selection: Select one-year-old strong seedlings of Choerospondias axillaris from local provenance, with a seedling height of ≥1.6 m and a ground diameter of ≥1.8 cm, to construct the tree layer of the target community; use zonal broad-leaved tree species to construct the sub-tree layer and shrub layer of the target community; (3) Construction method: clear 6-8 forest gaps per mu in the forest stand, with each forest gap area ≥35m2; plant trees in the forest gaps with a row spacing of 3-3.5m*3-3.5m; when the tree height of the tree layer is ≥10m, select zonal broad-leaved target trees with a density of 20-22 trees per mu and a tree height / DBH value of >90; when the tree height of the tree layer is ≥15m, the target tree density is 16-18 trees per mu and the tree height / DBH value is 80±2; when the tree height of the tree layer is ≥20m, the target tree density is 13-15 trees per mu and the tree height / DBH value is <70; (4) Cultivation and management: Carry out light felling and tending, remove wind-fallen, dead, weak, diseased and insect-infested trees and positive depreciated species with no future, and remove rattan, bamboo and weeds; then prepare the land and dig holes in December, with the hole size of 0.5m*0.5m*0.35m; plant Choerospondias australis in forest windows or open spaces in late February; weed and tend the forest land within 1m of the young trees in May and September respectively, and continue to do so for 3 years; apply compound fertilizer to the seedlings in early February of the following year, with a fertilizer amount of 0.3-0.4kg / plant; in the 10th year after planting, carry out thinning and tending, select target trees, and cover the target trees with organic matter, and cover them with 2-3cm of fine soil and compact them; among which: The target tree species for the zonal broad-leaved tree species retained in step (2) are composed of Choerospondias axillaris, Phoebe chinensis, Phoebe rubrum, Phoebe rubrum, Osmanthus fragrans, Sassafras chinensis, Phoebe chekiangensis, Litsea cubeba, Liquidambar formosana, Acer oleifera, Hovenia dulcis and Fennel lanceolate, and the sub-tree layer is composed of at least three of the above species; The target trees in step (3) are required to be excellent individuals that are seedling-grown, strong, have round and straight trunks, tall and long branches, thin forked branches, and are free of damage from diseases and insect pests; The compound fertilizer in step (4) is a compound fertilizer with N:P:K=16:16:16; The organic matter covering in step (4) has the following preparation requirements: 100-120 kg of fresh grass, 80-100 kg of fallen branches or leaves, and 2-2.5 kg of compound fertilizer. Beneficial Effects

[0009] (1) The present invention uses Choerospondias axillaris to construct the main forest layer of the community. Choerospondias axillaris has strong adaptability and fast growth. A 15-year-old tree can reach a height of 12 meters, and a 20-year-old tree can reach a height of 15 meters. It can quickly form a tall community appearance, increasing the composition ratio of the target community species. It promotes the growth of trees, makes the branches grow taller, shortens the community development time by more than 15 years, has a clear restoration goal, and is easy to operate.

[0010] (2) The present invention imitates the natural top-level forest to build the community, and uses the retained camphor, liquidambar formosana and other plants to build the sub-tree layer, which is close to the characteristics of the constituent tree species of the sub-tree layer of the top-level forest. The community structure is relatively complete, and the diversity and stability of the community structure are improved. The forest grows vigorously, has high productivity and strong stability.

[0011] (3) The present invention adopts the method of planting Choerospondias axillaris in forest gaps or open spaces to construct the tree layer, and selecting broad-leaved tree species for community building in the secondary forest, which can effectively utilize the value-added resources of community building tree species, maximize the utilization of forest land, and realize sustainable forest management. It is cost-saving and economical.

[0012] (4) The present invention can produce heat insulation effect on the soil by covering the southern jujube with organic matter, and has a buffering effect of cooling down at high temperature and keeping warm at low temperature. It can reduce the evaporation of surface soil water and the loss of water and fertilizer, and increase drought resistance. It can effectively increase the tree height and breast diameter growth of forest trees, cultivate precious large-diameter timber, and improve the quality and economic benefits of forest trees. It uses local materials, is easy to operate, and is economical and applicable. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the changes in the tree height, branch height and tree height / DBH of Choerospondias axillaris; Figure 2 This is a curve of the total height growth of the Choerospondias axillaris trees. DETAILED DESCRIPTION

[0014] The following examples serve to illustrate the invention. Example

[0015] The implementation site is located in Tiantong Forest Area, Yinzhou District, Ningbo City, Zhejiang Province, with an altitude of 250-300m, sloping to the southeast with a slope of about 25°.

[0016] (1) Forest land selection: Select secondary broad-leaved communities with an altitude of ≤400 m, valley mountains, red soil, soil thickness of about 0.7 m, tree height of 7-8 m, and canopy density ≥0.6; (2) Tree species selection: Select one-year-old strong seedlings of Choerospondias axillaris from local provenance, with a seedling height of ≥1.6m and a ground diameter of ≥1.8cm, to construct the tree layer of the target community; use zonal broad-leaved tree species to construct the sub-tree layer or shrub layer of the target community; (3) Construction method: clear 6-8 forest gaps per mu in the forest stand, with each forest gap area ≥35m2; plant trees in the forest gaps with a row spacing of 3-3.5m*3-3.5m; when the tree height of the tree layer is about 10m, select broad-leaved trees such as Choerospondias australis with a target tree density of 20-22 trees per mu, with a tree height / DBH value of >90; when the tree height of the tree layer is about 15m, the target tree density is 16-18 trees per mu, with a tree height / DBH value of about 80; when the tree height of the tree layer is about 20m, the target tree density is 13-15 trees per mu, with a tree height / DBH value of <70; (4) Cultivation and management: Carry out light felling and tending, remove wind-fallen, dead, weak, diseased and insect-infested trees and positive depreciated species with no future, and remove rattan, bamboo and weeds; then prepare the land and dig holes in December, with the hole size of 0.5m*0.5m*0.35m; plant Choerospondias australis in forest windows or open spaces in late February; weed and tend the forest land within 1m of the young trees in May and September respectively, and continue to do so for 3 years; apply compound fertilizer to the seedlings in early February of the following year, with a fertilizer amount of 0.3-0.4kg / plant; in the 10th year after planting, carry out thinning and tending, select target trees, and cover the target trees with organic matter such as fresh grass, and cover them with 2-3cm of fine soil and compact them; The broad-leaved tree species retained in step (2) are composed of Choerospondias axillaris, Phoebe chinensis, Phoebe rubrum, Phoebe macranthoides, Osmanthus fragrans, Sassafras chinensis, Liquidambar formosana, Acer oleifera, Hovenia dulcis and Fennel lanceolate, and the sub-tree layer is composed of at least three species; The compound fertilizer in step (4) is a compound fertilizer with N:P:K=16:16:16; The mass ratio of the organic matter mulch prepared in step (4) is 100-120 kg of fresh grass, 80-100 kg of fallen branches or leaf residues and 2-2.5 kg of compound fertilizer.

[0017] It is worth noting that Choerospondias axillaris was selected as the target tree species for community construction in step (2) and was selected as the main tree species for the tree layer of the community because it is the same tree species as the tree species of the "top forest" tree layer. At the same time, Choerospondias axillaris young trees grow rapidly in the early stage, and the tree heights at 10 and 15 years of planting are 7m and 12.5m respectively ( Figure 2 ), gradually forming a canopy layer. After 20 years of planting, the trees are up to 15m high and have occupied the top layer of the community, becoming the canopy layer with the largest light receiving area.

[0018] Positive Effects In the area with similar site conditions, tree species composition and age, two 20m*20m survey plots were set up for the transformation and management area (after forest window planting of Choerospondias australis and 25 years of cultivation) and the control area (only closed mountain measures), and the density, tree height, breast diameter, height under branches (DBH ≥ 18cm) and crown size of the trees in the community tree layer were investigated. The results showed that the various indicators in the transformation area were significantly better than those in the control area. In the tree layer I, the density per mu, average tree height and breast diameter of broad-leaved trees in the transformation area and the control area were 16 and 2, 15m and 14m, 18cm and 15cm respectively; in the tree layer II of the community, the density per mu, average tree height and breast diameter of the transformation area and the control area were 25 and 30, 12m and 11.8m, 16cm and 15cm respectively. This shows that the community structure has been improved after the technical transformation of the present invention, and a multi-layered structure of different ages dominated by top community-building tree species has been formed, showing the considerable community construction effect of Choerospondias australis. At the same time, the forest stock per mu in the transformed area and the control area was 7.5m³ and 3.7m³ respectively, which also shows that the forest stock increased significantly after the transformation, thereby improving the overall ecological function and service value of the community.

Claims

1. A method for rapidly constructing a mixed forest of Choerospondias axillaris with a near-natural community structure, characterized in that: The following steps are involved: (1) Forest land selection: Select secondary broad-leaved communities with an altitude of ≤400 m, valley mountains, red soil, soil thickness ≥0.6 m, tree height 7-8 m, and canopy density ≥0.6; (2) Tree species selection: Select one-year-old strong seedlings of Choerospondias axillaris from local provenance, with a seedling height of ≥1.6 m and a ground diameter of ≥1.8 cm, to construct the tree layer of the target community; use zonal broad-leaved tree species to construct the sub-tree layer and shrub layer of the target community; (3) Construction method: clear 6-8 forest gaps per mu in the forest stand, with each forest gap area ≥35m2; plant trees in the forest gaps with a row spacing of 3-3.5m*3-3.5m; when the tree height of the tree layer is ≥10m, select zonal broad-leaved target trees with a density of 20-22 trees per mu and a tree height / DBH value of >90; when the tree height of the tree layer is ≥15m, the target tree density is 16-18 trees per mu and the tree height / DBH value is 80±2; when the tree height of the tree layer is ≥20m, the target tree density is 13-15 trees per mu and the tree height / DBH value is <70; (4) Cultivation and management: Carry out light felling and tending, remove wind-fallen, dead, weak, diseased and insect-infested trees and positive depreciated species with no future, and remove rattan, bamboo and weeds; then prepare the land and dig holes in December, with the hole size of 0.5m*0.5m*0.35m; plant Choerospondias australis in forest windows or open spaces in late February; weed and tend the forest land within 1m of the young trees in May and September respectively, and continue to do so for 3 years; apply compound fertilizer to the seedlings in early February of the following year, with a fertilizer amount of 0.3-0.4kg / plant; in the 10th year after planting, carry out thinning and tending, select target trees, and cover the target trees with organic matter, and cover them with 2-3cm of fine soil and compact them; among which: The target tree species for the zonal broad-leaved tree species retained in step (2) are composed of Choerospondias axillaris, Phoebe chinensis, Phoebe rubrum, Phoebe rubrum, Osmanthus fragrans, Sassafras chinensis, Phoebe chekiangensis, Litsea cubeba, Liquidambar formosana, Acer oleifera, Hovenia dulcis and Fennel lanceolate, and the sub-tree layer is composed of at least three of the above species; The target trees in step (3) are required to be excellent individuals that are seedling-grown, strong, have round and straight trunks, have tall and long branches, have thin forked branches, and are free of damage from diseases and insect pests; The compound fertilizer in step (4) is a compound fertilizer with N:P:K=16:16:16; The organic matter covering in step (4) has the following preparation requirements: 100-120 kg of fresh grass, 80-100 kg of fallen branches or leaves, and 2-2.5 kg of compound fertilizer.

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