A method for cultivating large-diameter knotless larch-poplar mixed high-quality wood

Abstract

The present application relates to the technical field of forest cultivation, and provides a large-diameter-grade knot-free fine timber cultivation method for pine-broadleaf mixed forest, which comprises the following steps: selecting a forestation site and then carrying out site preparation, planting pine seedlings and broadleaf tree species, pruning according to a pine branch stake embedding area formula, applying an external growth agent to the pruning mouth, thinning and adjusting the pine forest density, and harvesting the pine when it is matured. The pine and broadleaf tree species are planted and mixed at the same time, which can promote the growth of the pine, improve the soil environment, enhance the resistance to the outside world, and significantly improve the comprehensive benefits per unit area. In addition, after pruning and applying the external growth agent, the cultivation period of the knot-free pine fine timber is shorter.

Description

Technical Field

[0001] This invention relates to the field of forest tree cultivation technology, and in particular to a method for cultivating large-diameter, knot-free high-quality timber from mixed pine and broadleaf trees. Background Technology

[0002] Early management of pine plantations primarily focused on timber production, employing monoculture practices. A significant portion of these plantations suffered from poor stand structure, decreased ecosystem components, sparse understory vegetation, and severe soil erosion. Consequently, the stands exhibited reduced ecological benefits, such as decreased water conservation and soil stabilization. Compared to evergreen forests, the forest landscape was monotonous, with low biodiversity, poor stability, and weak resistance to forest fires and pests. Mixed forests, on the other hand, involve planting two or more tree species together in specific proportions. Mixed forests effectively improve stand productivity, enhance soil fertility, regulate microclimates, and reduce pest and disease occurrence, resulting in significant ecological, economic, and social benefits. Therefore, mixed forests represent an inevitable trend in forestry development. At present, the construction of mixed forests has three significant advantages. First, pine is a pioneer afforestation species that is tolerant of poor soil and drought, with low initial afforestation and tending costs and rapid forest formation. Second, in the middle and later stages of resin tapping forest management, only resin is tapped without cutting down trees, increasing income while protecting the balance of forest ecological functions. Third, in the middle and later stages, the space under the resin tapping forest is fully utilized to mix other tree species, always keeping pine trees on top and other trees below, regulating and improving the balance of the upper (canopy) and lower (root) environments of the forest stand, giving full play to the nutrient release and decomposition functions of rhizobia, soil-fertilizing bacteria and litter among mixed tree species, reducing the application of chemical fertilizers, regulating the microclimate of the forest stand, and significantly reducing the probability of forest diseases and pests.

[0003] Masson pine (Pinus massoniana) is an important native pioneer afforestation tree species in subtropical regions of my country, characterized by its long cultivation history, diverse uses, and strong adaptability, playing a vital role in forestry development. Genetic improvement and efficient cultivation of Masson pine in my country have focused on five major uses: pulpwood, construction timber, general-purpose timber, dual-purpose timber and resin timber, and large-diameter timber. Genetic improvement and targeted cultivation have been carried out for each of these five types of timber, resulting in over 200 corresponding improved varieties and the establishment of cultivation technology systems for different species. Large-diameter Masson pine specifically refers to species with a diameter at breast height (DBH) of 26 cm or greater. The cultivation of knot-free large-diameter timber is an efficient and integrated cultivation model proposed to meet the current demand for high-quality and high-priced Masson pine. It solves common problems in the cultivation of high-quality Masson pine species through innovative integration of improved varieties, site control, density regulation, artificial pruning, and forest age effects.

[0004] In natural conditions, after the canopy of an artificial commercial forest closes, branches at the base of the crown gradually wither and fall off due to insufficient sunlight, easily forming dead knots and affecting timber quality. Since Mayer Wegelin proposed the concept of forest pruning in 1936, forest pruning and tending techniques have been widely used in forestry and horticulture production practices. In forestry production, the main purpose of pruning is to properly remove useless branches, vigorous shoots, and competing branches, improve the straightness and taper of the trunk, and enhance the sanitary environment within the forest. This has a significant effect on promoting tree growth, improving tree shape, and producing high-quality knot-free timber. Research on forest pruning techniques in my country mainly focuses on the pruning effects on species such as poplar and eucalyptus, and is mostly in the research stage, not yet applicable to large-scale production. At present, the structure of Masson pine species in my country is simple, the cultivation technology is relatively backward, the management objectives are not clear, and the management methods are extensive. The key technical measures to achieve knot-free and high-quality timber are still the traditional method of cutting branches while clearing grass and tending trees. There is a lack of professional pruning technology, and the timber produced by extensive management has many knots, poor trunk shape and low timber quality.

[0005] Therefore, conducting research on pruning and tending, planting density, intergenerational tending (number and intensity), and related technologies of Masson pine plantations will help to formulate reasonable tending and management plans and provide technical support for the cultivation of high-quality Masson pine and the production of high-quality timber. Summary of the Invention

[0006] The purpose of this invention is to provide a method for cultivating large-diameter knotless high-quality pine trees in mixed pine and broadleaf trees. This method can not only promote the growth of Masson pine, improve the soil environment, enhance its resistance to external factors, and significantly improve the comprehensive benefits per unit area, but also shorten the cultivation cycle of knotless Masson pine trees.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] This invention provides a method for cultivating large-diameter, knot-free high-quality timber from mixed loose and broadleaf trees, comprising the following steps:

[0009] (1) After selecting the afforestation site, prepare the land and plant Masson pine seedlings and broad-leaved tree species to obtain a mixed coniferous and broad-leaved forest.

[0010] If the slope of the afforestation site is ≤22 degrees and ≤33 degrees, plant Masson pine seedlings in each hole with a row spacing of 2.5-3 meters and a plant spacing of 1.5-2 meters; if the slope of the afforestation site is <22 degrees, plant Masson pine seedlings with a row spacing of 2-3 meters and a plant spacing of 2-2.5 meters.

[0011] The planting density of the broad-leaved tree species is 60-110 trees / acre;

[0012] (2) Prune the branches according to the formula for the area of ​​the buried pine branch stump, and apply an external growth agent to the pruning wound; the formula for the area of ​​the buried pine branch stump is S=1 / 2×(C+C')×L+π×r 2 =π×R×L+π×n×△d×L+π×(n×△d) 2 ;

[0013] In the formula: S represents the area of ​​the pine branch stump buried; C represents the circumference of the upper base of the pine branch stump; C' represents the circumference of the lower base of the pine branch stump; L is the length of the branch stump retained; R is the radius of the lower base circle of the pine branch stump; π is pi, taken as 3.14; r is the radius of the upper base circle of the pine branch stump; n represents the burying time; △d represents the average annual radial growth of the pine.

[0014] The range of L is 0 ≤ L ≤ 1 cm, and the range of r is 0 < r ≤ 1.5 cm;

[0015] (3) Thinning should be carried out according to the principles of cutting small trees and keeping large ones, cutting curved trees and keeping straight ones, cutting diseased and insect-infested trees, and cutting dense trees and keeping sparse ones. The density of Masson pine forest should be adjusted to 70-100 trees / mu and cultivated until the Masson pine matures and is harvested.

[0016] Preferably, the broad-leaved tree species mentioned in step (1) includes any one of the following: large-leaved oak, jasmine, and Michelia champaca.

[0017] Preferably, the topical growth agent in step (2) is prepared from the following components in parts by weight: 10-16 parts lysine, 4-7 parts potassium chloride, 3-6 parts potassium phosphate, 1-2 parts magnesium sulfate, 0.7-0.9 parts zinc nitrate, 0.6-0.8 parts ferric chloride, 0.5-0.7 parts copper chloride, 0.5-0.7 parts sodium borate, 1-1.4 parts calcium nitrate, 0.3-0.5 parts fatty alcohol polyoxyethylene ether ammonium sulfate, 1-1.6 parts naphthaleneacetic acid, 1.2-1.8 parts cytokinin, 0.8-1.5 parts gibberellin, 0.4-0.7 parts cosolvent, and 260-500 parts water.

[0018] Preferably, the co-solvent is acetamide.

[0019] Preferably, in step (2), the amount of topical growth agent applied to each pruning cut is 7.4-9.5g.

[0020] Preferably, the pruning treatment in step (2) is performed in January to March.

[0021] Preferably, the land preparation in step (1) includes pit tillage and / or full land preparation; if the slope of the afforestation land is between 22 and 33 degrees, pit tillage is carried out; if the slope of the afforestation land is less than 22 degrees, full land preparation is carried out.

[0022] Preferably, the cultivation and planting time of Masson pine in step (3) is no less than 20 years.

[0023] By adopting the above technical solution, the present invention has the following beneficial effects:

[0024] 1. In the technical solution of this invention, the suitable mixed tree species for planting Masson pine can be selected from fire-resistant species such as large-leaved oak, *Gnaphalium affine*, and *Symplocos edulis*. The method of this invention not only promotes the growth of Masson pine, improves the soil environment, and reduces forest fires, but also significantly improves the overall benefits per unit area.

[0025] 2. The external growth agent of the present invention comprises macro-elements, micro-elements, surfactants, and auxins. By adding a certain amount of co-solvent, they are made compatible and produce a synergistic effect. By selecting appropriate raw material composition and dosage, and adjusting the optimal dosage of external growth agent, the absorption of nutrients by pine trees can be effectively promoted, the pruning wounds of Masson pine can be rapidly healed, and the branches can be prevented from dying and falling off before being buried, forming dead knots or cavities. This shortens the cycle of cultivating knot-free high-quality timber. Moreover, the economic benefits obtained by the method of the present invention are far greater than those obtained by traditional pruning methods. Attached Figure Description

[0026] Figure 1 A mixed forest of pine and broadleaf trees of similar age;

[0027] Figure 2 A schematic diagram of a Masson pine branch stump;

[0028] Figure 3 The image shows the results of the pile healing test.

[0029] Figure 4 This is a diagram showing the results of a seasonal pruning experiment on horsetail. Detailed Implementation

[0030] This invention provides a method for cultivating large-diameter, knot-free high-quality timber from mixed loose and broadleaf trees, comprising the following steps:

[0031] (1) After selecting the afforestation site, prepare the land and plant Masson pine seedlings and broad-leaved tree species to obtain a mixed coniferous and broad-leaved forest.

[0032] (2) Prune the branches according to the formula for the area of ​​the buried pine branch stump, and apply an external growth agent to the pruning wound; the formula for the area of ​​the buried pine branch stump is S=1 / 2×(C+C')×L+π×r 2 =π×R×L+π×n×△d×L+π×(n×△d) 2 ;

[0033] In the formula: S represents the area of ​​the pine branch stump buried; C represents the circumference of the upper base of the pine branch stump; C' represents the circumference of the lower base of the pine branch stump; L is the length of the branch stump retained; R is the radius of the lower base circle of the pine branch stump; π is pi, taken as 3.14; r is the radius of the upper base circle of the pine branch stump; n represents the burying time; △d represents the average annual radial growth of the pine.

[0034] (3) Thinning should be carried out according to the principles of cutting small trees and keeping large ones, cutting curved trees and keeping straight ones, cutting diseased and insect-infested trees, and cutting dense trees and keeping sparse ones. The density of Masson pine forest should be adjusted to 70-100 trees / mu and cultivated until the Masson pine matures and is harvested.

[0035] In this invention, the afforestation site is selected, cleared, and prepared. If the slope of the afforestation site is 22 degrees or less and 33 degrees or less, pit clearing and land preparation are carried out; if the slope of the afforestation site is less than 22 degrees, full land preparation is carried out.

[0036] In this invention, after land preparation, Masson pine seedlings and broad-leaved tree species are planted to obtain a mixed coniferous and broad-leaved forest. In this invention, if the slope of the afforestation site is 22 degrees ≤ 33 degrees, Masson pine seedlings are planted in each hole. The preferred row spacing is 2.5-3 meters, further preferably 2.6-2.9 meters, and even more preferably 2.8 meters; the preferred plant spacing is 1.5-2 meters, further preferably 1.6-1.9 meters, and even more preferably 1.8 meters. If the slope of the afforestation site is < 22 degrees, Masson pine seedlings are planted directly. The preferred row spacing is 2-3 meters, further preferably 2.1-2.9 meters, and even more preferably 2.5 meters; the preferred plant spacing is 2-2.5 meters, further preferably 2.2-2.4 meters, and even more preferably 2.3 meters. In this invention, after the Masson pine seedlings are planted, suitable broad-leaved tree species are selected and evenly planted in the Masson pine seedling forest to form a mixed pine and broad-leaved forest (e.g., Figure 1 The preferred planting density of the broadleaf tree species is 60-110 trees / mu, more preferably 70-100 trees / mu, and even more preferably 85 trees / mu; the preferred broadleaf tree species include any one of *Quercus macrocarpa*, *Gnaphalium affine*, and *Michelia champaca*. The mixed planting method of pine and broadleaf trees described in this invention can effectively improve forest stand productivity, improve forest soil fertility, and reduce the occurrence of forest fires.

[0037] In this invention, after the Masson pine seedlings have grown, pruning is performed according to the formula for the area of ​​Masson pine branch stump embedment to facilitate the formation of knot-free, high-quality timber. Preferably, pruning begins when the Masson pine is 4-5.5 years old (approximately 5m tall), with a second pruning at 6-7 years, reducing the height to 8-9m. The preferred pruning season is January to March, more preferably February; the degree of pruning is preferably removing branches below 40-60% of the tree height, more preferably below 45-55%, and even more preferably below 50%.

[0038] In this invention, the formula for the embedded area of ​​the Masson pine branch stump is S=1 / 2×(C+C')×L+π×r 2 =π×R×L+π×r×L+π×r 2 =π×R×L+π×n×△d×L+π×(n×△d) 2 In the formula for the embedding area of ​​the Masson pine branch stump described in this invention, S represents the embedding area of ​​the Masson pine branch stump. When completely embedded, it can form knot-free, high-quality timber; C and C' are the upper and lower circumferences of the Masson pine branch stump, respectively; L is the length of the branch stump to be retained, where L satisfies: 0 ≤ L ≤ 1 cm. When L > 1 cm, embedding cannot be formed, and the branch stump dies and falls off before embedding, forming dead knots or cavities. Pruning should not exceed 1 cm; 1 / 2 × (C + C') × L represents the lateral surface area of ​​the Masson pine branch stump; R is the radius of the lower base circle of the Masson pine branch stump; π is pi, taken as 3.14; r is the radius of the upper base circle of the Masson pine branch stump, π × r 2 Let r represent the area of ​​the upper circular surface of the pine branch stump, where r satisfies: 0 < r ≤ 1.5 cm. When r > 1.5 cm, it cannot be encased, and the branch stump will die and fall off before encasing, forming dead knots or cavities. The radius of the upper circular surface of the pine branch stump should not exceed 1.5 cm during pruning. n represents the encasing time, calculated in years. △d represents the average annual radial growth of the pine. Let rn × △d > 0, indicating that it is not completely encased in the nth year. Let r - (n-1) × △d > 0 and r - (n+1) × △d < 0, indicating that it is completely encased in the nth year. Let r = n × △d.

[0039] In this invention, the wound healing method for pruning Masson pine is to bury the branch from both sides towards the center. The area of ​​complete burial and healing is influenced by the radius of the upper base circle of the pine branch stump, the length of the branch stump, the average annual radial growth of the Masson pine, and the season of pruning. The larger the radius of the upper base circle of the pruned branch stump, the longer the burial time required and the slower the healing. When the radius of the upper base circle of the pine branch stump exceeds 1.5cm, the pruned branch stump cannot be completely buried and healed; the branch stump dies and falls off before burial, forming dead knots or cavities, and cannot form knot-free timber. The longer the length of the retained branch stump, the longer the burial and healing time required, and the greater the probability of forming dead knots or cavities. When the length of the retained branch stump is greater than 1cm, the pruned branch stump cannot be completely buried and healed. If the stump dies and falls off before being buried, it forms dead knots or cavities, preventing the formation of knot-free timber. The smaller the average annual radial growth of Masson pine, the longer and slower the healing time required for the pruned stump to be completely buried. Conversely, the larger the average annual radial growth of Masson pine, the shorter and faster the healing time required for the pruned stump to be completely buried. This is more conducive to the formation of knot-free timber, thereby improving economic benefits. The season of pruning affects the healing speed and the average annual radial growth, thus affecting the burying time.

[0040] In this invention, after the pruning process is completed according to the formula for the area of ​​the buried pine branch stump, an external growth agent is applied to the pruning site. The topical growth agent is prepared from the following components in parts by weight: 10-16 parts lysine, 4-7 parts potassium chloride, 3-6 parts potassium phosphate, 1-2 parts magnesium sulfate, 0.7-0.9 parts zinc nitrate, 0.6-0.8 parts ferric chloride, 0.5-0.7 parts copper chloride, 0.5-0.7 parts sodium borate, 1-1.4 parts calcium nitrate, 0.3-0.5 parts fatty alcohol polyoxyethylene ether ammonium sulfate, 1-1.6 parts naphthaleneacetic acid, 1.2-1.8 parts cytokinin, 0.8-1.5 parts gibberellin, 0.4-0.7 parts co-solvent, and 260-500 parts water; more preferably, 11-14 parts lysine, 5-6.5 parts potassium chloride, 3.5-5 parts potassium phosphate, 1.4-1.8 parts magnesium sulfate, 0.75-0.85 parts zinc nitrate, and 0. The composition comprises: 0.76 parts of 65-76 parts of sodium borate, 0.54-0.63 parts of copper chloride, 0.56-0.65 parts of sodium borate, 1.2-1.35 parts of calcium nitrate, 0.35-0.42 parts of fatty alcohol polyoxyethylene ether ammonium sulfate, 1.1-1.4 parts of naphthaleneacetic acid, 1.3-1.6 parts of cytokinin, 0.9-1.3 parts of gibberellin, 0.5-0.65 parts of co-solvent, and 300-450 parts of water; more preferably, 12 parts of lysine, 6 parts of potassium chloride, 4 parts of potassium phosphate, 1.6 parts of magnesium sulfate, 0.8 parts of zinc nitrate, 0.7 parts of ferric chloride, 0.6 parts of copper chloride, 0.6 parts of sodium borate, 1.3 parts of calcium nitrate, 0.4 parts of fatty alcohol polyoxyethylene ether ammonium sulfate, 1.2 parts of naphthaleneacetic acid, 1.4 parts of cytokinin, 1 part of gibberellin, 0.6 parts of co-solvent, and 400 parts of water. The co-solvent used in this invention is preferably acetamide.

[0041] In this invention, the preparation method of the topical growth agent includes the following steps: mixing lysine, potassium chloride, potassium phosphate, magnesium sulfate, zinc nitrate, ferric chloride, copper chloride, sodium borate, calcium nitrate, a solubilizer, and water to obtain mixture A; adding fatty alcohol polyoxyethylene ether ammonium sulfate, naphthaleneacetic acid, cytokinin, and gibberellin to mixture A, and mixing to obtain the topical growth agent. The mixing process of lysine, potassium chloride, potassium phosphate, magnesium sulfate, zinc nitrate, ferric chloride, copper chloride, sodium borate, calcium nitrate, solubilizer, and water in this invention is accompanied by stirring. The stirring speed is preferably 1000-2000 rpm, more preferably 1200-1800 rpm, and even more preferably 1400 rpm; the mixing time is preferably 25-32 min, more preferably 26-31 min, and even more preferably 30 min. During the mixing of mixture A with fatty alcohol polyoxyethylene ether ammonium sulfate, naphthaleneacetic acid, cytokinin and gibberellin, stirring is also carried out. The stirring speed is preferably 700-800 rpm, more preferably 730-780 rpm, and even more preferably 750 rpm. The mixing time is preferably 40-50 min, more preferably 42-48 min, and even more preferably 44 min.

[0042] In this invention, the amount of external growth agent applied to each pruning cut is preferably 7.4-9.5g, more preferably 7.6-9.2g, and even more preferably 8g.

[0043] In this invention, the thinning of Masson pine is carried out according to the principles of cutting small trees and leaving large ones, cutting curved trees and leaving straight ones, removing diseased and insect-infested trees, and thinning dense trees and leaving sparse ones. The density of the pine forest is adjusted according to the thinning ratio selected based on the survival rate. The preferred density is 70-100 trees / mu, further preferably 80-90 trees / mu, and even more preferably 86 trees / mu. After thinning, the Masson pine is cultivated until it reaches maturity and is harvested, and the cultivation period is no less than 20 years.

[0044] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0045] Example 1

[0046] A method for cultivating large-diameter, knot-free high-quality timber from mixed loose and broadleaf trees, comprising the following steps:

[0047] (1) Select and clear the afforestation site. The slope of the afforestation site is 30.2 degrees. Carry out pit reclamation and land preparation.

[0048] (2) After the land preparation is completed, plant Masson pine seedlings and broad-leaved tree species. The ground slope is 30.2 degrees. Plant Masson pine seedlings in each hole with a row spacing of 2.5 meters and a plant spacing of 2 meters. Select the Hematite tree species and plant Hematite tree species evenly in the Masson pine seedling forest with a planting density of 70 trees / mu to form a mixed forest of pine and broad-leaved trees of different ages.

[0049] (3) When the Masson pine is 4 years old, prune it in February according to the pruning intensity of removing branches below 40% of the tree height. Then, wrap the branches with the wrapping area calculated according to the formula for the wrapping area of ​​Masson pine branches to form knot-free high-quality timber. The formula for the wrapping area of ​​Masson pine branches is S=1 / 2×(C+C')×L+π×r 2 =π×R×L+π×r×L+π×r 2 =π×R×L+π×n×△d×L+π×(n×△d) 2 L = 0.5cm, r = 0.5cm, n = 3, π is taken as 3.14;

[0050] (4) After pruning, apply 9.5g of external growth agent to each pruning cut. The external growth agent is composed of: 10 parts lysine, 4 parts potassium chloride, 3 parts potassium phosphate, 1 part magnesium sulfate, 0.7 parts zinc nitrate, 0.6 parts ferric chloride, 0.5 parts copper chloride, 0.7 parts sodium borate, 1 part calcium nitrate, 0.3 parts fatty alcohol polyoxyethylene ether ammonium sulfate, 1 part naphthaleneacetic acid, 1.2 parts cytokinin, 0.8 parts gibberellin, 0.4 parts acetamide, and 260 parts water.

[0051] The preparation method of the topical growth agent includes the following steps: lysine, potassium chloride, potassium phosphate, magnesium sulfate, zinc nitrate, ferric chloride, copper chloride, sodium borate, calcium nitrate, acetamide, and water are mixed and stirred at 1000 rpm for 32 min to obtain mixture A; fatty alcohol polyoxyethylene ether ammonium sulfate, naphthaleneacetic acid, cytokinin, and gibberellin are added to the obtained mixture A and stirred at 700 rpm for 50 min to obtain the topical growth agent;

[0052] (5) The planting density of Masson pine is 133 trees / mu. In the 5th year after planting, a sanitary felling is carried out once, and the number of trees retained after felling is 119 trees / mu. Diseased, pest-infested or compressed trees with a diameter at breast height of less than 4cm are felled. In the 7th and 15th years, pine trees are thinned according to the principles of felling small trees and keeping large trees, felling curved trees and keeping straight trees, felling diseased and pest-infested trees, and felling dense trees and keeping sparse trees. The intensity of the first thinning is 19.3%, and the density is 96 trees / mu. The intensity of the second thinning is 16.7%, and the final density of Masson pine forest is adjusted to 80 trees / mu.

[0053] (6) After thinning, the Masson pine is cultivated until it matures and is harvested. The Masson pine is cultivated for 22 years. The Masson pine trunk is knot-free and of good quality, and can be harvested and sold.

[0054] Example 2

[0055] A method for cultivating large-diameter, knot-free high-quality timber from mixed loose and broadleaf trees, comprising the following steps:

[0056] (1) Select and clear the afforestation site. The slope of the afforestation site is 25.6 degrees. Carry out pit reclamation and land preparation.

[0057] (2) After the land preparation is completed, plant Masson pine seedlings and broad-leaved tree species. The ground slope is 25.6 degrees. Plant Masson pine seedlings in each hole with a row spacing of 3 meters and a plant spacing of 2 meters. Select the Kalanchoe blossfeldiana tree species and plant it evenly in the Masson pine seedling forest with a planting density of 100 trees / mu to form a mixed forest of pine and broad-leaved trees of different ages.

[0058] (3) When the Masson pine is 5 years old, prune it in February according to the pruning intensity of removing branches below 50% of the tree height. Then, wrap the branches with the pine branches according to the formula for the pine branch stub embedment area to form knot-free high-quality timber. The formula for the pine branch stub embedment area is S=1 / 2×(C+C')×L+π×r 2 =π×R×L+π×r×L+π×r 2 =π×R×L+π×n×△d×L+π×(n×△d) 2 L = 0.5cm, r = 0.5cm, n = 3, π is taken as 3.14;

[0059] (4) After pruning, apply 8g of external growth agent to each pruning cut. The external growth agent is composed of: 12 parts lysine, 6 parts potassium chloride, 4 parts potassium phosphate, 1.6 parts magnesium sulfate, 0.8 parts zinc nitrate, 0.7 parts ferric chloride, 0.6 parts copper chloride, 0.6 parts sodium borate, 1.3 parts calcium nitrate, 0.4 parts fatty alcohol polyoxyethylene ether ammonium sulfate, 1.2 parts naphthaleneacetic acid, 1.4 parts cytokinin, 1 part gibberellin, 0.6 parts acetamide, and 400 parts water.

[0060] The preparation method of the topical growth agent includes the following steps: lysine, potassium chloride, potassium phosphate, magnesium sulfate, zinc nitrate, ferric chloride, copper chloride, sodium borate, calcium nitrate, acetamide, and water are mixed and stirred at 1400 rpm for 30 min to obtain mixture A; fatty alcohol polyoxyethylene ether ammonium sulfate, naphthaleneacetic acid, cytokinin, and gibberellin are added to the obtained mixture A and stirred at 750 rpm for 44 min to obtain the topical growth agent;

[0061] (5) The afforestation density is 133 trees / mu. In the 5th year after afforestation, a sanitary felling is carried out once, and the number of trees retained after felling is 117 trees / mu. Diseased, pest-infested or compressed trees with a diameter at breast height of less than 4cm are felled. In the 8th and 16th years, pine trees are thinned according to the principles of felling small trees and keeping large trees, felling curved trees and keeping straight trees, felling diseased and pest-infested trees, and felling dense trees and keeping sparse trees. The intensity of the first thinning is 11.9%, and the density is 103 trees / mu. The intensity of the second thinning is 12.6%, and the pine forest density is finally adjusted to 90 trees / mu.

[0062] (6) After thinning, the Masson pine is cultivated until it matures and is harvested. The Masson pine is cultivated for 21 years. The Masson pine trunk is knot-free and of good quality, and can be harvested and sold.

[0063] Example 3

[0064] A method for cultivating large-diameter, knot-free high-quality timber from mixed loose and broadleaf trees, comprising the following steps:

[0065] (1) Select and clear the afforestation site. The slope of the afforestation site is 19.8 degrees. Carry out pit reclamation and land preparation.

[0066] (2) After the land preparation is completed, plant Masson pine seedlings and broad-leaved tree species. The ground slope is 19.8 degrees. Plant Masson pine seedlings directly with a row spacing of 3 meters and a plant spacing of 2.5 meters. Select the Kalanchoe blossfeldiana tree species and plant it evenly in the Masson pine seedling forest with a planting density of 80 trees / mu to form a mixed forest of pine and broad-leaved trees of different ages.

[0067] (3) When the Masson pine reaches 5.5 years of age, prune it in February according to the pruning intensity of removing branches below 45% of the tree height. Then, use the embedded area calculated according to the formula for the embedded area of ​​Masson pine branches to embed the branches, so as to form knot-free high-quality timber. The formula for the embedded area of ​​Masson pine branches is S=1 / 2×(C+C')×L+π×r 2 =π×R×L+π×r×L+π×r 2 =π×R×L+π×n×△d×L+π×(n×△d) 2 L = 0.5cm, r = 0.5cm, n = 3, π is taken as 3.14;

[0068] (4) After pruning, apply 7.4g of external growth agent to each pruning wound. The external growth agent is composed of: 16 parts lysine, 7 parts potassium chloride, 6 parts potassium phosphate, 2 parts magnesium sulfate, 0.9 parts zinc nitrate, 0.8 parts ferric chloride, 0.7 parts copper chloride, 0.5 parts sodium borate, 1.4 parts calcium nitrate, 0.5 parts fatty alcohol polyoxyethylene ether ammonium sulfate, 1.6 parts naphthaleneacetic acid, 1.8 parts cytokinin, 1.5 parts gibberellin, 0.7 parts acetamide, and 500 parts water.

[0069] The preparation method of the topical growth agent includes the following steps: lysine, potassium chloride, potassium phosphate, magnesium sulfate, zinc nitrate, ferric chloride, copper chloride, sodium borate, calcium nitrate, acetamide, and water are mixed and stirred at 2000 rpm for 25 min to obtain mixture A; fatty alcohol polyoxyethylene ether ammonium sulfate, naphthaleneacetic acid, cytokinin, and gibberellin are added to the obtained mixture A and stirred at 800 rpm for 40 min to obtain the topical growth agent;

[0070] (5) The afforestation density is 133 trees / mu. In the 5th year after afforestation, a sanitary felling is carried out once, and the number of trees retained after felling is 116 trees / mu. Diseased, pest-infested or compressed trees with a diameter at breast height of less than 4cm are felled. In the 7th and 16th years, pine trees are thinned according to the principles of felling small trees and keeping large trees, felling curved trees and keeping straight trees, felling diseased and pest-infested trees, and felling dense trees and keeping sparse trees. The intensity of the first thinning is 13.8%, and the density is 100 trees / mu. The intensity of the second thinning is 14.0%, and the final pine forest density is adjusted to 86 trees / mu.

[0071] (6) After thinning, the Masson pine is cultivated until it matures and is harvested. The Masson pine is cultivated for 21 years. The Masson pine trunk is knot-free and of good quality, and can be harvested and sold.

[0072] Comparative Example 1

[0073] The method for cultivating knot-free high-quality timber is the same as in Example 2, except that no external growth agent is applied to the pruning cuts after pruning.

[0074] Comparative Example 2

[0075] The method for cultivating knot-free timber is the same as in Example 2, except that the pruning is done using the traditional pruning method, which is to cut the branches randomly with a knife, leaving uneven cuts and branches of varying lengths.

[0076] Experimental Example 1

[0077] The economic benefits per mu of Masson pine in Examples 1-3 and Comparative Examples 1-2 are shown in Table 1.

[0078] Table 1. Economic benefits per mu of Masson pine in different groups

[0079] Experimental Project Timber revenue (ten thousand yuan) Wood morphology Example 1 5.45 Unrefined timber Example 2 5.57 Unrefined timber Example 3 5.51 Unrefined timber Comparative Example 1 4.59 Unrefined timber Comparative Example 2 2.53 There are cavities and knots

[0080] As shown in the table above, the economic benefits obtained by the methods of Examples 1-3 are far greater than those obtained by the methods of Comparative Examples 1-2. Examples 1-3 are 18.73%, 21.35%, and 20.04% higher than Comparative Example 1, respectively, and 115.42%, 120.16%, and 117.79% higher than Comparative Example 2, respectively. The average usable value of the knot-free high-quality timber cultivated by the pruning method in Examples 1-3 and Comparative Example 1 is 108.70% greater than that of the unpruned (Comparative Example 2). The use of external growth agents can shorten the healing time of the branch stumps and significantly reduce the risk of cavities forming before embedding, with an average increase of 20.03% compared to the untreated (Comparative Example 2).

[0081] Experimental Example 2

[0082] Masson pine branch stump (similar to a truncated cone, specifically as follows) Figure 2 When completely enclosed (as shown), knot-free high-quality timber can be formed; otherwise, dead knots will form, which is not conducive to improving economic efficiency.

[0083] The formula for the area of ​​the pine branch stump embedded in the ground is:

[0084] S = 1 / 2 × (C + C') × L + π × r 2

[0085] =π×R×L+π×r×L+π×r 2

[0086] =π×R×L+π×n×△d×L+π×(n×△d) 2

[0087] In the formula: S represents the area of ​​the pine branch stump buried; when completely buried, it can form knot-free high-quality timber; C and C' are the upper and lower circumferences of the pine branch stump, respectively; L is the length of the branch stump to be retained, where L satisfies: 0 ≤ L ≤ 1 cm. When L > 1 cm, burying cannot be achieved, and the branch stump will die and fall off before burying, forming dead knots or cavities. Pruning should not exceed 1 cm; 1 / 2 × (C + C') × L represents the lateral surface area of ​​the pine branch stump; R is the radius of the lower base circle of the pine branch stump; π is pi, taken as 3.14; r is the radius of the upper base circle of the pine branch stump, π × r 2Let r represent the area of ​​the upper circular surface of the pine branch stump, satisfying: 0 < r ≤ 1.5 cm. When r > 1.5 cm, it cannot be encased, and the branch stump will die and fall off before encasing, forming dead knots or cavities. The radius of the upper circular surface of the pine branch stump cannot exceed 1.5 cm during pruning. n represents the encasing time, calculated in years. △d represents the average annual radial growth of the pine. Let rn × △d > 0, indicating that it was not completely encased in the nth year. Let r - (n-1) × △d > 0 and r - (n+1) × △d < 0, indicating that it was completely encased in the nth year. Let r = n × △d. When the average annual radial growth of the pine is larger than △d, the encasing time in years n is shorter, which is more conducive to complete encasing, preventing dead knots or cavities, and forming knot-free good timber. In addition, it is also affected by the season of pruning. The season affects the average annual radial growth of the pine △d, allowing the stump wound to heal quickly and avoiding the formation of dead knots or cavities.

[0088] Experimental Example 3: Study on the Influence of Different Retained Lengths of Masson Pine Branch Stumps on the Burial Effect

[0089] 1. Overview of the test site

[0090] The experimental site is located in Huashan Forest Farm, Huanjiang Maonan Autonomous County, Guangxi (108°18′22.88″E, 25°07′44.21″N), on the southern slope of the Jiwan Mountains, at an altitude of 340m and a slope of 15°, in a low mountain and hilly terrain. It has a mid-subtropical monsoon climate with abundant sunshine and heat throughout the year, distinct wet and dry seasons, an average annual temperature of 20.2℃, an annual rainfall of 1388.7mm, a frost-free period of 290 days, and an average annual sunshine duration of 1251.3 hours. The parent rock of the forest soil is sandstone, with red soil, a topsoil layer of about 10cm thick, a soil layer of about 80cm thick, and a gravel content of less than 20%.

[0091] 2. Experimental Materials and Design

[0092] The experimental forest was established in May 2008 with an initial planting density of 2,500 trees / hm². 2 The 4-year-old stands are completely closed, and natural pruning begins at the 5-year-old stage. Pruning is carried out when the stands reach the 6-year-old stage. Before pruning, the stand density is 2125 trees / hm². 2 Four treatments were set up for pruning, with retained branch stump lengths of 0.0cm, 1.0cm, 1.5cm, and 2.0cm, with 11 plants in each treatment. The healing of the cuts was observed. Various indicators were measured every December after pruning, and the monitoring was carried out continuously for two years.

[0093] 3. Healing status of pruning wounds

[0094] Observations revealed that pruning wounds in Masson pine heal by burying the trunk from both sides, while wounds with retained branch stumps cannot heal through the cambium layer surrounding the cut. The healing rate of pruning wounds in Masson pine decreases with increasing branch stump length. The healing mechanism of pruning wounds in Masson pine involves burying the trunk from both sides towards the center, and the healing speed is influenced by wound size, branch stump length, and the radial growth rate of the tree. Larger pruning wounds require longer burying times and heal more slowly; longer branch stumps also require longer burying times and heal more slowly; slower radial growth rates also require longer burying times and heal more slowly. Wounds with retained branch stumps of 1.0 cm can heal, while wounds larger than 1.0 cm cannot heal; the branch stump dies and falls off before burying, forming dead knots or cavities (e.g., Figure 3 ).

[0095] Experimental Example 4: Seasonal Experimental Study on Pruning of Masson Pine

[0096] 1. Overview and Experimental Design

[0097] (1) Annual growth pattern of young Masson pine trees

[0098] Masson pine begins its height growth in early March, followed by 7-10 days of slow growth. Growth then accelerates, reaching its peak from late March to mid-April, with an average daily growth of 1-2 cm. This peak occurs in early or mid-April, followed by a significant decline in late April, and then stagnation in early May. Normally, 90% of a plant's growth is completed between early March and early May. In August, the terminal bud begins to elongate, and height growth slightly resumes.

[0099] The diameter growth of Masson pine begins in early March and ends in early December, starting almost simultaneously with height growth, but ending later. The first peak of direct growth arrives before the peak of new shoot height growth (mid to late March). When height growth is at its peak, diameter growth declines until mid to late May, when height growth enters a dormant period, and diameter growth enters a rapid growth period, reaching a second peak in mid-June. A smaller peak appears in mid-July, and it declines slightly in late July, remaining at a certain level after August until late October, when it slows down and eventually stops in early December.

[0100] (2) Experimental design of seasonal pruning of young Masson pine trees

[0101] a) Experimental Design: A 4-year-old stand was selected, and a completely randomized block design was adopted. Four pruning time treatments were set up: control (no pruning), pruning in the early sprouting stage (early February), rapid height growth stage (early April), and rapid diameter growth stage (early June). Each treatment had a fixed plot area of ​​20m × 20m (no less than 60 trees), with two protective rows set around the plot. The experiment was repeated 3 times (e.g., ...). Figure 4 ).

[0102] b) Pruning method: Use the reverse pruning method, retaining all branch stumps at 0cm length. The first pruning height is 35-50% of the tree height, followed by pruning once every other year, for a total of 3 or more pruning sessions (requiring the branch height to be above 8m). The reference branch height after pruning is 1.9m for 4 years, 3.7m for 6 years, 5.8m for 8 years, 7.5m for 10 years, and 9.2m for 12 years.

[0103] 2. Results and Analysis

[0104] (1) Analysis of growth differences in the year of pruning (Year 1, the year in which pruning was carried out)

[0105] The annual growth of each growth index in the first year after pruning varied significantly depending on the pruning season. As shown in Table 2, the growth of each growth index decreased as the pruning time progressed, indicating that pruning during the growing season has a negative impact on the growth of Masson pine. From February to June, the impact of pruning on the growth of trees increased over time.

[0106] Table 2. Statistical results of various growth indicators in the year of pruning for different pruning times.

[0107]

[0108] Note: Different letters in the table represent DUNCAN multiple comparison differences.

[0109] (2) Analysis of growth differences in the second year after pruning (the second year is the year in which no pruning is performed).

[0110] Table 3. Statistical results of various growth indicators in the second year after pruning for different pruning time treatments.

[0111]

[0112] As shown in Table 3, there were no significant differences in the annual growth of each growth index in the second year after pruning for different pruning seasons, indicating that different pruning seasons had no significant impact on the growth of trees in the second year after pruning.

[0113] (3) Analysis of growth differences in the year of pruning (the third year, in which pruning was carried out)

[0114] Table 4. Statistical results of various growth indicators in the year of pruning for different pruning times.

[0115]

[0116] Note: Different letters in the table represent DUNCAN multiple comparison differences.

[0117] The annual growth of various growth indicators in the third year after pruning under different pruning seasons showed significant differences in diameter at breast height (DBH) and volume, except for tree height (which did not differ significantly) (as shown in Table 4). This indicates that different pruning seasons have a negative impact on the DBH and volume growth of trees after pruning.

[0118] (4) Analysis of growth differences in the second year after pruning (the fourth year, in which no pruning was performed).

[0119] Table 5. Statistical results of various growth indicators in the second year after pruning for different pruning times.

[0120]

[0121] As shown in Table 5, there were no significant differences in the annual growth of each growth index in the fourth year after pruning for different pruning seasons, indicating that different pruning seasons had no significant impact on the growth of trees in the second year after pruning.

[0122] (5) Analysis of differences in total growth among treatments after 4 years of pruning

[0123] Table 6. Statistical results of total growth of various growth indicators after 4 years of pruning at different pruning times.

[0124]

[0125] Note: Different letters in the table represent DUNCAN multiple comparison differences.

[0126] As shown in Table 6, during the 4-year pruning period, apart from the significant difference in diameter at breast height (DBH) growth, there were no significant differences among the other growth indicators. This indicates that pruning during the growing season has a negative impact on DBH growth of Masson pine, with the greatest negative impact occurring from April to June. The long-term effects on tree height and volume growth are not significant.

[0127] 3. Conclusion

[0128] In conclusion, pruning during the growing season of Masson pine negatively impacts its diameter at breast height (DBH), tree height, and timber volume growth for the current year. While there was no significant difference in growth between February and the control (CK), pruning produces knot-free timber, with the greatest negative impact occurring between April and June. Furthermore, the earlier the pruning, the faster the stump heals. The base of the trunk has a larger volume, resulting in higher unit prices for knot-free timber; the closer to the base, the higher the income. However, pruning too early directly reduces photosynthesis, affecting tree growth. Therefore, the optimal time for pruning is February.

[0129] As can be seen from the above embodiments and experimental examples, the method of the present invention can not only promote the cultivation of knot-free high-quality pine trees and shorten the cultivation cycle, but also the economic benefits obtained by the method of the present invention are far greater than those obtained by traditional pruning methods, and can also significantly improve the comprehensive benefits per unit area.

[0130] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for cultivating large-diameter, knot-free high-quality timber from a mixed loose and broadleaf tree species, comprising the following steps: (1) After selecting the afforestation site, prepare the land and plant Masson pine seedlings and broad-leaved tree species to obtain a mixed coniferous and broad-leaved forest. If the slope of the afforestation site is ≤22 degrees and ≤33 degrees, plant Masson pine seedlings in each hole with a row spacing of 2.5-3 meters and a plant spacing of 1.5-2 meters; if the slope of the afforestation site is <22 degrees, plant Masson pine seedlings with a row spacing of 2-3 meters and a plant spacing of 2-2.5 meters. The planting density of the broad-leaved tree species is 60-110 trees / acre; (2) The pruning treatment is carried out on branches aged 4-5.5 years after the pruning is carried out according to the formula for the burial area of ​​Masson pine branches; and an external growth agent is applied to the pruning wound. The formula for the burial area of ​​Masson pine branches is S=1 / 2×(C+C')×L+π×r 2 =π×R×L+π×n×△d×L+π×(n×△d) 2 ; In the formula: S represents the area of ​​the pine branch stump buried; C represents the circumference of the upper base of the pine branch stump; C' represents the circumference of the lower base of the pine branch stump; L is the length of the branch stump retained; R is the radius of the lower base circle of the pine branch stump; π is pi, taken as 3.14; r is the radius of the upper base circle of the pine branch stump; n represents the wrapping time. △d represents the average annual radial growth of Masson pine. The range of L is 0 ≤ L ≤ 1 cm, and the range of r is 0 < r ≤ 1.5 cm; (3) Thinning should be carried out according to the principles of cutting small trees and keeping large ones, cutting curved trees and keeping straight ones, cutting diseased and insect-infested trees, and cutting dense trees and keeping sparse ones. The density of Masson pine forest should be adjusted to 70-100 trees / mu and cultivated until the Masson pine matures and is harvested. The broad-leaved tree species mentioned in step (1) include any one of the following: large-leaved oak, sago palm, and Michelia champaca; The topical growth agent described in step (2) is prepared from the following components in parts by weight: 10-16 parts lysine, 4-7 parts potassium chloride, 3-6 parts potassium phosphate, 1-2 parts magnesium sulfate, 0.7-0.9 parts zinc nitrate, 0.6-0.8 parts ferric chloride, 0.5-0.7 parts copper chloride, 0.5-0.7 parts sodium borate, 1-1.4 parts calcium nitrate, 0.3-0.5 parts fatty alcohol polyoxyethylene ether ammonium sulfate, 1-1.6 parts naphthaleneacetic acid, 1.2-1.8 parts cytokinin, 0.8-1.5 parts gibberellin, 0.4-0.7 parts cosolvent, and 260-500 parts water; The co-solvent is acetamide; In step (2), the amount of external growth agent applied to each pruning cut is 7.4-9.5g.

2. The method according to claim 1, characterized in that, The pruning treatment described in step (2) is carried out from January to March, and the pruning intensity is to remove branches that are 40-60% or less taller than the tree.

3. The method according to claim 1, characterized in that, The land preparation in step (1) includes pit tillage and / or full land preparation; If the slope of the afforestation site is between 22 and 33 degrees, pit clearing and land preparation should be carried out; if the slope of the afforestation site is less than 22 degrees, full land preparation should be carried out.

4. The method according to claim 1, characterized in that, The cultivation and planting time of Masson pine in step (3) shall not be less than 20 years.

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