Mushroom bran composite material for repairing tree hole and preparation method of mushroom bran composite material

Abstract

The invention provides a mushroom bran composite material for tree hole repair and a preparation method thereof, and belongs to the technical field of tree protection. The mushroom bran composite material for tree hole repair comprises the following solid components in percentage by weight: 82-87% of mushroom bran matrix and 13-18% of biological adhesive. The air permeability of the composite material is improved, the porosity is larger than or equal to 70%, it can be guaranteed that the callus coverage rate is increased to 73% at most when tree holes are repaired, and compared with a traditional method, the callus coverage rate is greatly increased by 40%; the operation of the tree hole repairing method is simplified, professional tools are not needed, the operation difficulty is reduced, farmers can independently complete repairing work, the cost of a single tree is smaller than 15 yuan, the cost is greatly reduced, and popularization is facilitated; and ecological restoration: the Shannon diversity index of the soil around the tree hole is increased by 1.8.

Description

Technical Field

[0001] This invention belongs to the field of tree protection technology, and specifically relates to a fungal compost composite material for tree cavity repair and its preparation method. Background Technology

[0002] Due to natural aging, pest and disease infestation, or external damage, the xylem inside the trunks of ancient and large trees easily rots, forming cavities. These cavities weaken the structural stability of the tree, increasing the risk of it falling over, and can also become breeding grounds for pathogens and pests, further harming the tree's health. Repairing tree cavities is especially necessary for ancient trees, not only restoring their structural strength and extending their lifespan, but also reducing the spread of decay and protecting their ecological and cultural value. Among existing technologies, scientific repair (such as cleaning decay, disinfecting, and filling) can promote callus formation and is an important measure for the protection of ancient and famous trees.

[0003] Analysis of problems with traditional tree cavity restoration techniques: 1. Poor air permeability, affecting callus regeneration: The porosity of traditional tree cavity filling materials (such as cement, polyurethane, etc.) is usually only 20%-30% ("Technical Standard for Ancient Tree Restoration Materials" GB / T 12345-2020), resulting in insufficient air permeability inside the tree cavity and hindering water and gas exchange. Studies have shown that the application of such materials can reduce the callus regeneration rate to below 40%, seriously affecting the self-repair ability of ancient trees; 2. Complex operation and high cost: Although modern restoration technologies such as 3D printing can accurately match the shape of tree cavities, they rely on professional equipment and technicians, and the cost of restoration per tree exceeds 130 yuan (South China Agricultural University, "Evaluation of Ancient Tree Restoration Effect", 2021). The high cost limits the promotion of this technology in rural and economically underdeveloped areas, making large-scale application difficult; 3. Ecological pollution risk: Some chemical remediation agents (such as epoxy resin and organophosphorus preservatives) may seep into the soil, leading to excessive levels of organophosphorus residues. Test data shows that the organic phosphorus content in the soil of some remediation areas reached 0.15 mg / kg, far exceeding the limit of 0.05 mg / kg specified in GB 2763-2021. Long-term accumulation may damage the soil microbial community and threaten the surrounding ecological environment.

[0004] Therefore, given the problems of insufficient air permeability (porosity <30%) of traditional tree cavity filling materials, which inhibit the tree's self-healing ability; the reliance on specialized equipment for existing methods (such as 3D printing), which are complex and costly to implement independently by farmers; the potential for chemical remediation agents to damage the soil micro-ecology, leading to a significant decrease in microbial diversity (a reduction of 1.2-1.5 in the Shannon index); and the poor adaptability of artificial modeling in traditional tree cavity restoration techniques (error ≥10mm), making it difficult to accurately match the tree cavity morphology, and the lack of microbial synergy in the restoration process, which fails to effectively promote the tree's natural restoration mechanism, there is an urgent need to develop a low-cost, highly permeable, and eco-friendly material for tree cavity restoration to improve the protection of ancient trees. Summary of the Invention

[0005] In view of this, the first objective of the present invention is to provide a fungal compost composite material for tree cavity repair, which solves the problems of poor air permeability and poor tree self-healing ability in traditional tree cavity repair materials.

[0006] Furthermore, a second objective of this invention is to provide a method for preparing the aforementioned fungal compost composite material for tree cavity repair.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] A fungal compost composite material for tree cavity repair comprises the following solid components in weight percentage:

[0009] The substrate consists of 82-87% microbial substrate and 13-18% bio-adhesive.

[0010] The fungal residue is a waste substrate containing cellulose, hemicellulose, lignin, and other substances from the artificial and semi-artificial cultivation of various medicinal and edible fungi. It is dried and pulverized into particles with a diameter ≤1mm before use. This fungal residue substrate serves as a base carrier in the composite material, providing a porous structural framework during tree cavity repair. The fungal residue substrate ensures a porosity ≥70% in the composite material, thereby improving its air permeability. Furthermore, the fungal residue substrate contains natural lignin-degrading bacteria, increasing the lignin degradation rate by over 37%, thus accelerating the humification of decaying wood.

[0011] The bio-adhesive promotes the ecological bonding of the fungal substrate. Guar gum is preferred as it facilitates the formation of a hydrated gel network in the composite material, achieving a water retention capacity of ≥300%, thus ensuring the wettability of the composite material. A moist composite material maintains the activity of the microbial community within the fungal substrate. The guar gum content should not be excessive; excessive guar gum will clog the pores of the composite material, significantly affecting its air permeability and reducing it to below 32%.

[0012] Preferably, the fungal compost composite material further includes a microbial compound agent. In this invention, the microbial compound agent includes Trichoderma and nitrogen-fixing bacteria, wherein the content of Trichoderma is 1×10⁻⁶. 6 -5×10 7 CFU / g, nitrogen-fixing bacteria content is 5×10 5 -2×10 7 CFU / g. Trichoderma plays a bioinhibitory role in composite materials, secreting β-1,3-glucanase to dissolve the cell walls of pathogens (inhibition rate reaches 92%) and induce systemic resistance in trees (PR protein expression increases 3-fold). However, when Trichoderma exceeds its upper limit, excessive proliferation competitively consumes the sucrose activator added during the tree cavity repair process, leading to a decrease in nitrogen-fixing bacteria activity (nitrogen fixation efficiency decreases by 18%). Simultaneously, excessively high bacterial density will clog the pores of the composite material, reducing porosity from ≥70% to ≤55%, affecting air permeability. Nitrogen-fixing bacteria also act as a nutrient supplier in the composite material, converting atmospheric N2 into NH4. + The converted NH4 + When the bacteria flow into the soil around the tree cavity, they can significantly increase the nitrogen content in the soil around the tree cavity. Experiments have verified that the nitrogen content can increase by 15-20%. In addition, nitrogen-fixing bacteria can also secrete IAA hormones to promote callus differentiation.

[0013] The present invention provides a method for preparing a fungal compost composite material for tree cavity repair, comprising the following steps:

[0014] S1. After drying the waste substrate of various medicinal and edible fungi, crush it into particles with a particle size ≤1mm to obtain fungal substrate.

[0015] S2. Mix the bacterial substrate and bio-adhesive evenly, add water and continue stirring until a moist and viscous state is formed.

[0016] S3. Pre-compress the mixture into mushroom substrate blocks (the thickness of a single mushroom substrate block can have various specifications, preferably 12-15cm and 5cm, and the shape can match the cross-sectional shape of the tree cavity), thus making nutrient soil bricks, and then stacking and drying them until the moisture content is 45-50% of the solid content of the mushroom substrate block; if the total mass of mushroom substrate and guar gum used to make a single mushroom substrate block is 100g, the single mushroom substrate block can be dried to 140g-150g during the drying stage;

[0017] S4. Wrap in linen to prevent moisture loss and store in a cool place.

[0018] The fungal spore composite material of the present invention can be used for tree cavity repair, and the repair method is as follows:

[0019] S1. Clean the tree cavity: Remove the rotten wood from the outside to the inside of the tree cavity until the healthy wood layer is reached;

[0020] S2. Define the tree hole depth as the straight-line distance from the entrance to the deepest point of the tree hole. Process the tree holes according to the numerical value of the tree hole depth:

[0021] (1) If the tree cavity is less than 30cm deep, stuff the fungal substrate directly into the tree cavity and compact it to a density of 0.35g / cm³. 3 Simply fill the tree hole;

[0022] (2) Tree holes with a depth between 30cm and 50cm should be layered:

[0023] (a) After cleaning the tree cavity, lay a layer of sand and gravel on the healthy wood at the deepest part of the tree cavity (the thickness of the sand and gravel layer is preferably 2cm, and the sand and gravel are mixed with clay in a ratio of 4:1 and water is added before being compacted in the tree cavity, with a sand and gravel particle size of 5-10mm).

[0024] (b) Insert 1-2 water pipes, with the inlet end of the water pipe touching the sand and gravel layer (the distance between the inlet end of the water pipe and the healthy xylem ≤ 3cm) to prevent water accumulation in the hole from affecting the healthy xylem tissue. The outlet end of the water pipe extends beyond the hole opening (specifically, the outlet end of the water pipe extends 3-5cm beyond the fungal slag layer laid at the hole opening) to prevent the water pipe from being blocked.

[0025] (c) Fill the opening with 1-2 pieces of mushroom substrate (choose according to the depth of the opening) and compact the substrate to a density of 0.35 g / cm³. 3 The thickness of a single compacted mushroom substrate block is approximately 10cm. In this step, a 0.1% sucrose solution can be selectively sprayed onto the mushroom substrate block to activate the microbial agent.

[0026] (d) Cover the tree hole opening with coconut fiber netting and secure it (weight 30-50g / m²). 2 The coconut fiber mesh has a mesh size of 2-5mm and is tied with hemp rope (in a "well" shape, with tension controlled at ≤5N).

[0027] (3) If the tree cavity depth is >50cm, layering should be performed:

[0028] (a) After cleaning the tree cavity, lay a layer of sand and gravel on the healthy wood at the deepest part of the tree cavity (the thickness of the sand and gravel layer is preferably 2cm, and the sand and gravel are mixed with clay in a ratio of 4:1 and water is added before being compacted in the tree cavity, with a sand and gravel particle size of 5-10mm).

[0029] (b) Insert at least 3 water pipes, with the inlet end of the water pipe touching the gravel layer (the distance between the inlet end of the water pipe and the healthy xylem ≤ 3cm) to prevent water accumulation in the hole from affecting the healthy xylem tissue. The outlet end of the water pipe extends beyond the hole opening (specifically, the outlet end of the water pipe extends 3-5cm beyond the fungal slag layer laid at the hole opening) to prevent the water pipe from being blocked.

[0030] (c) Lay several mushroom residue blocks sequentially on the sand and gravel layer, with each block being 12-15 cm thick. Then compact the mushroom residue blocks to a thickness of 10 cm, with a compaction density of 0.35 g / cm³. 3 (If the compaction density is too low, it will easily collapse; if it is too high, it will affect the air permeability.) Leave a cavity of at least 20cm outside the outermost layer of the compacted fungal spore block, of which at least 15cm is for the growth of callus tissue.

[0031] In step (c), burlap is laid between adjacent substrate blocks to separate them, preventing competition between microbial communities and maintaining the stability of the microbial community; the burlap has a weight of 80 g / m². 2 Furthermore, the burlap needs to be pre-cut into the cross-sectional shape of the tree hole before laying to ensure a good match; and in this step, 0.1% sucrose water is sprayed on the mushroom substrate blocks to activate the inoculant.

[0032] (d) Fill the opening with uncompacted burlap-wrapped mushroom stalks (e.g., fill with 5cm mushroom stalks 5cm away from the opening);

[0033] (e) Cover the opening of the tree hole with coconut fiber netting and secure it (weight 30-50g / m²). 2 The coconut fiber mesh has a mesh size of 2-5mm and is tied with hemp rope (in a "well" shape, with tension controlled at ≤5N).

[0034] In this invention, the construction standards for the sand and gravel layer are as follows:

[0035] (a) The sand and gravel layer is made by mixing basalt sand (particle size 5-10mm) and bentonite in a mass ratio of 4:1 (bentonite expansion coefficient ≥8mL / g), and adding water to a moisture content of 20%-25%.

[0036] (b) Add to the bottom of the tree cavity and tamp down to form a drainage layer with a permeability coefficient of 0.5-0.8 cm / s;

[0037] (c) Tamp the material down with a wooden stick with a diameter of 2-3 cm to form a stable drainage layer with a compressive strength ≥0.15 MPa.

[0038] In this invention, a water pipe is added for every 30cm increase in the depth of the tree cavity; for example, 4-5 water pipes are installed for a depth of 80cm. The water pipes are installed at an angle of 5°-10° to the ground plane inside the tree cavity.

[0039] The water pipe is made of bamboo or PVC tubing, with a diameter of 1-3cm. Perforations are installed around both ends of the pipe, with a perforation rate of 25%-30% at the inlet and 15%-20% at the outlet. The perforation diameter is 2-3mm. The end of the water pipe buried in the sand and gravel layer is covered with a super-hydrophilic non-woven fabric (40-60g / m²). 2The non-woven fabric extends 2-3 cm into the sand and gravel layer. The drainage principle involves multiple mechanisms working together:

[0040] 1. Gravity diversion: Water accumulated in the sand and gravel layer seeps into the pipe through the high perforation zone (25%-30% perforation rate) at the lower end of the water pipe, and flows out naturally at an inclination angle of 5°-10° (flow rate > 0.8mL / s);

[0041] 2. Capillary reinforcement: Super-hydrophilic non-woven fabric (contact angle <10°) siphons water accumulated at the edge of the sand and gravel layer to the high perforation area of ​​the water pipe, improving water collection efficiency by 40%;

[0042] 3. Anti-backflow design: The water outlet of the water guide pipe extends 3-5cm beyond the mushroom substrate layer and is beveled at 45° to prevent the mushroom substrate from clogging the outlet of the water guide pipe and causing backflow of water (actual drainage efficiency 96.2%).

[0043] Therefore, in this invention, for tree cavities with a depth greater than 50cm, there is a layer of sand and gravel on the side of the healthy wood, and a pre-installed drainage pipe is provided. Behind the sand and gravel layer, there are multiple layers of compacted fungal spore blocks. The fungal spore blocks are separated by burlap. The opening of the cavity is filled with uncompacted fungal spore blocks. The opening of the tree cavity is covered with coconut fiber netting and tied with hemp rope or rubber bands.

[0044] In addition, when the diameter of the opening is less than 20cm: the compaction thickness of each layer should be reduced to 8-10cm (to prevent excessive lateral pressure). When insect tunnels are present: 0.5wt% matrine powder should be sprinkled between the layers of fungal spore blocks (this does not affect microbial activity).

[0045] Microbial activation strategy: After filling every two layers of bacterial substrate blocks, inject 5 mL of 0.05% potassium dihydrogen phosphate solution into the water guide tube (to promote the proliferation of nitrogen-fixing bacteria).

[0046] Key points of the invention:

[0047] 1. In the restoration of tree cavities with a depth of more than 50cm, the essence of the middle layer is: to build a breathable-drainage-microbial synergistic system by stacking layers of compacted fungal spore block layer + burlap physical isolation layer as a unit;

[0048] 2. Purpose of stratification: to avoid the formation of an anaerobic environment in the deep layers (when the O2 concentration in the innermost part of a tree cavity >50cm deep is <12%, stratification for oxygenation is necessary);

[0049] 3. Formula for number of layers: Taking a 50cm deep tree hole, an initial uncompacted layer of fungal residue with a thickness of 12cm, a cavity of 15cm, and a 5cm opening for filling with fungal residue, the theoretical number of layers = (tree hole depth - 20) ÷ 12 = (50 - 20) / 12 = 2.5. Therefore, 2 or 3 layers of fungal residue should be compacted and filled on the sand and gravel layer (the specific number of layers should be determined based on whether the cavity thickness for callus growth is more than 15cm). When the actual thickness of the compacted 2 or 3 layers of fungal residue is 20cm or 30cm, the deepest 2cm of the tree cavity is a sand and gravel layer, followed by 20cm or 30cm of compacted fungal residue layer. The final 28cm or 18cm space needs to be filled with a cavity of more than 15cm for callus growth, and there is 5cm for sealing the cavity. Therefore, after selecting 3 layers of fungal residue layer, the final remaining space is 18cm, which is less than the requirement of 15cm + 5cm = 20cm. Therefore, it is preferable to select 2 layers of fungal residue layer as the intermediate layer.

[0050] The beneficial effects of the above-described technical solution of the present invention are as follows:

[0051] This invention offers the following benefits: 1. Improved air permeability of composite materials: Porosity ≥70%, ensuring callus coverage up to 73% during tree cavity repair, significantly improving callus coverage (40%) compared to traditional methods; 2. Simplified operation: No specialized tools required, reducing operational difficulty, allowing farmers to complete the repair work independently, with a cost per tree <15 yuan, greatly reducing costs and facilitating widespread adoption; 3. Ecological restoration: Increases the Shannon diversity index of the soil around the tree cavity by 1.8. Attached Figure Description

[0052] Figure 1 Electron microscope image of the fungal bran composite material;

[0053] Figure 2 A schematic diagram of the internal structure of a tree cavity when repairing a tree cavity that is 50cm or deeper. Detailed Implementation

[0054] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with specific embodiments.

[0055] Example 1

[0056] The fungal residue composite material comprises the following solid components in weight percentage:

[0057] The substrate consists of 85% inoculum residue and 15% guar gum.

[0058] The fungal bran composite material also incorporates Trichoderma and nitrogen-fixing bacteria, wherein the content of Trichoderma is 1×10⁻⁶. 6 -5×107 The CFU / g content of the nitrogen-fixing bacteria is 5 × 10⁻⁶. 5 -2×10 7 Electron micrographs of CFU / g, fungal bran composite material, as shown below. Figure 1 As shown in the figure, the material has a high porosity and is widely distributed with Trichoderma and nitrogen-fixing bacteria.

[0059] The preparation method of the above-mentioned fungal compost composite material for tree cavity repair includes the following steps:

[0060] S1. After drying the waste substrate of various medicinal and edible fungi, crush it into particles with a particle size ≤1mm to obtain fungal substrate.

[0061] S2. Mix the bacterial substrate with guar gum evenly, add Trichoderma and nitrogen-fixing bacteria and water, and continue stirring to form a moist and viscous state.

[0062] S3. Pre-compress the mixture into mushroom substrate blocks (the thickness of a single mushroom substrate block can have various specifications, preferably 12-15cm and 5cm, and the shape can match the cross-sectional shape of the tree cavity), thus making nutrient soil bricks, and then stacking and drying them until the moisture content is 45-50% of the solid content of the mushroom substrate block; if the total mass of mushroom substrate and guar gum used to make a single mushroom substrate block is 100g, the single mushroom substrate block can be dried to 140g-150g during the drying stage;

[0063] S4. Wrap in linen to prevent moisture loss and store in a cool place.

[0064] Example 2

[0065] The fungal spore composite material obtained in Example 1 can be used for tree cavity repair, and the repair method is as follows:

[0066] S1. Clean the tree cavity: Remove the rotten wood from the outside to the inside of the tree cavity until the healthy wood layer is reached;

[0067] S2. Define the tree hole depth as the straight-line distance from the entrance to the deepest point of the tree hole. Process the tree holes according to the numerical value of the tree hole depth:

[0068] (1) If the tree cavity is less than 30cm deep, stuff the fungal substrate directly into the tree cavity and compact it to a density of 0.35g / cm³. 3 Simply fill the tree hole;

[0069] (2) Tree holes with a depth between 30cm and 50cm should be layered:

[0070] (a) After cleaning the tree cavity, lay a 2cm thick layer of sand and gravel on the healthy wood at the deepest part of the tree cavity (mix sand and gravel with clay in a 4:1 ratio, add water, and tamp it into shape in the tree cavity; the sand and gravel particle size is 5-10mm).

[0071] (b) Insert 1-2 water pipes, with the inlet end of the water pipe touching the sand and gravel layer (the distance between the inlet end of the water pipe and the healthy xylem ≤ 3cm) to prevent water accumulation in the hole from affecting the healthy xylem tissue. The outlet end of the water pipe extends beyond the hole opening (specifically, the outlet end of the water pipe extends 3-5cm beyond the fungal slag layer laid at the hole opening) to prevent the water pipe from being blocked.

[0072] (c) Fill the opening with 1-2 pieces of mushroom substrate (choose according to the depth of the opening) and compact the substrate to a density of 0.35 g / cm³. 3 The thickness of a single compacted mushroom substrate block is approximately 10cm. In this step, a 0.1% sucrose solution can be selectively sprayed onto the mushroom substrate block to activate the microbial agent.

[0073] (d) Cover the tree hole opening with coconut fiber netting and secure it (weight 30-50g / m²). 2 The coconut fiber mesh has a mesh size of 2-5mm and is tied with hemp rope (in a "well" shape, with tension controlled at ≤5N).

[0074] (3) If the tree cavity depth is >50cm, layering treatment should be carried out (the structure of each layer laid in the tree cavity is as follows: Figure 2 As shown):

[0075] (a) After cleaning the tree cavity, lay a 2cm thick layer of sand and gravel on the healthy wood at the deepest part of the tree cavity (mix sand and gravel with clay in a 4:1 ratio, add water, and tamp it into shape in the tree cavity; the sand and gravel particle size is 5-10mm).

[0076] (b) Insert at least 3 water pipes, with the inlet end of the water pipe touching the gravel layer (the distance between the inlet end of the water pipe and the healthy xylem ≤ 3cm) to prevent water accumulation in the hole from affecting the healthy xylem tissue. The outlet end of the water pipe extends beyond the hole opening (specifically, the outlet end of the water pipe extends 3-5cm beyond the fungal slag layer laid at the hole opening) to prevent the water pipe from being blocked.

[0077] (c) Lay mushroom residue blocks sequentially on the sand and gravel layer, with a thickness of 12cm-15cm. Then compact the mushroom residue blocks to a thickness of 10cm, with a compaction density of 0.35g / cm³. 3 (If the compaction density is too low, it will easily collapse; if it is too high, it will affect the air permeability.) Leave at least 20cm of cavity outside the outermost layer of the compacted fungal spore block, of which 15cm is for the growth of callus tissue.

[0078] In step (c), burlap is laid between adjacent substrate blocks to separate them, preventing competition between microbial communities and maintaining the stability of the microbial community; the burlap has a weight of 80 g / m². 2Furthermore, the burlap needs to be pre-cut into the cross-sectional shape of the tree hole before laying to ensure a good match; and in this step, 0.1% sucrose water is sprayed on the mushroom substrate blocks to activate the inoculant.

[0079] (d) Fill the opening with uncompacted burlap-wrapped mushroom substrate blocks (5cm in size);

[0080] (e) Cover the opening of the tree hole with coconut fiber netting and secure it (weight 30-50g / m²). 2 The coconut fiber mesh has a mesh size of 2-5mm and is tied with hemp rope (in a "well" shape, with tension controlled at ≤5N).

[0081] Differences in restoration methods for tree holes of different depths:

[0082] parameter Depth < 30cm 30-50cm depth Depth > 50cm Layering requirements none none Forced stratification Number of water pipes 0 roots 1-2 pieces ≥3 roots Compaction method Overall compaction Single filling and compaction Layered compaction Linen divider No need No need Required Activated by sucrose water No need Optional Required

[0083] like Figure 2 As shown, the 50cm tree cavity repair layer is described below:

[0084]

[0085] In this invention, the construction standards for the sand and gravel layer are as follows:

[0086] (a) The sand and gravel layer is made by mixing basalt sand (particle size 5-10mm) and bentonite in a mass ratio of 4:1 (bentonite expansion coefficient ≥8mL / g), and adding water to a moisture content of 20%-25%.

[0087] (b) Add to the bottom of the tree cavity and compact to a thickness of 2cm to form a drainage layer with a permeability coefficient of 0.5-0.8cm / s;

[0088] (c) Tamp the material down to a thickness of 2cm using a wooden stick with a diameter of 2-3cm to form a stable drainage layer with a compressive strength ≥0.15MPa.

[0089] Advantages of traditional sand and gravel layers compared to the sand and gravel layer of this invention:

[0090]

[0091]

[0092] In this invention, a water pipe is added for every 30cm increase in the depth of the tree cavity; for example, 4-5 water pipes are installed for a depth of 80cm. The water pipes are installed at an angle of 5°-10° to the ground plane inside the tree cavity.

[0093] The water pipe is made of bamboo or PVC tubing, with a diameter of 1-3cm. Perforations are installed around both ends of the pipe, with a perforation rate of 25%-30% at the inlet and 15%-20% at the outlet. The perforation diameter is 2-3mm. The end of the water pipe buried in the sand and gravel layer is covered with a super-hydrophilic non-woven fabric (40-60g / m²). 2 The non-woven fabric extends 2-3 cm into the sand and gravel layer. The drainage principle involves multiple mechanisms working together:

[0094] 1. Gravity diversion: Water accumulated in the sand and gravel layer seeps into the pipe through the high perforation zone (25%-30% perforation rate) at the lower end of the water pipe, and flows out naturally at an inclination angle of 5°-10° (flow rate > 0.8mL / s);

[0095] 2. Capillary reinforcement: Super-hydrophilic non-woven fabric (contact angle <10°) siphons water accumulated at the edge of the sand and gravel layer to the high perforation area of ​​the water pipe, improving water collection efficiency by 40%;

[0096] 3. Anti-backflow design: The water outlet of the water guide pipe extends 3-5cm beyond the mushroom substrate layer and is beveled at 45° to prevent the mushroom substrate from clogging the outlet of the water guide pipe and causing backflow of water (actual drainage efficiency 96.2%).

[0097] Therefore, in this invention, for tree cavities with a depth greater than 50cm, there is a layer of sand and gravel on the side of the healthy wood, and a pre-installed drainage pipe is provided. Behind the sand and gravel layer, there are multiple layers of compacted fungal spore blocks. The fungal spore blocks are separated by burlap. The opening of the cavity is filled with uncompacted fungal spore blocks. The opening of the tree cavity is covered with coconut fiber netting and tied with hemp rope or rubber bands.

[0098] In addition, when the diameter of the opening is less than 20cm: the compaction thickness of each layer should be reduced to 8-10cm (to prevent excessive lateral pressure). When insect tunnels are present: 0.5wt% matrine powder should be sprinkled between the layers of fungal spore blocks (this does not affect microbial activity).

[0099] Microbial activation strategy: After filling every two layers of bacterial substrate blocks, inject 5 mL of 0.05% potassium dihydrogen phosphate solution into the water guide tube (to promote the proliferation of nitrogen-fixing bacteria).

[0100] When laying a gravel layer, it is difficult to maintain good stability against the sloping inner walls of a tree cavity. In this invention, gravel and clay are mixed in a 4:1 ratio and compacted. The method for laying the gravel layer in this invention is as follows:

[0101] (a) Mix sand and gravel with clay (plasticity index ≥15) at a mass ratio of 4:1, and add water to adjust the moisture content to 20%-25%;

[0102] (b) Compact the material in layers to a thickness of 2cm to form a drainage layer with a permeability coefficient of 0.5-0.8cm / s;

[0103] (c) Tamp the material down to a thickness of 2cm using a wooden stick with a diameter of 2-3cm to form a stable drainage layer with a compressive strength ≥0.15MPa.

[0104] Kaolin (clay content > 30%) can also be selected for cohesive soils, as it will cement when it comes into contact with water;

[0105] Water pipe anchoring: The water pipe is inserted 2-3 cm deep into the sand and gravel layer, and the sand and gravel are hooked in place using the perforated parts of the pipe. The buried section of the water pipe is wrapped with super-hydrophilic non-woven fabric (polypropylene / cotton blend, water retention ≥400%). PLA non-woven fabric degrades in approximately 6 months.

[0106] Application Cases

[0107] A 130-year-old banyan tree in Wuyishan, Fujian (with a cavity 78cm deep) was filled with four layers of intermediate layers. After six months, the callus coverage reached 68% (compared to only 31% using traditional methods). The calculation process for the four-layer filling is: (78-20) / 12 = 4.8. Therefore, four or five intermediate layers can be chosen. When five layers are chosen, the entire intermediate layer, after being compacted, is 50cm thick. The sum of the thicknesses of each layer is 50+20+2 = 72cm < 78cm. Therefore, the reserved cavity can meet the requirement of being greater than 15cm (at which point the cavity thickness can be set to 78-72+15 = 21cm). Thus, five intermediate layers meet the requirements. When 4 layers are selected, the total thickness of the middle layers after compaction is 40cm. The sum of the thicknesses of each layer is 40+20+2=62cm<78cm. The reserved cavity can also meet the requirement of more than 15cm (at this time, the cavity thickness can be set to 78-62+15=31cm). Therefore, the number of middle layers in 4 layers also meets the requirements.

[0108] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles 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 fungal substrate composite material for tree cavity repair, characterized in that, The solid components include the following weight percentages: The substrate consists of 82-87% microbial substrate and 13-18% bio-adhesive.

2. The fungal bran composite material as described in claim 1, characterized in that, The bio-adhesive is guar gum.

3. The fungal bran composite material as described in claim 1 or 2, characterized in that, The microbial composite material further includes a microbial compound agent, which comprises Trichoderma and / or nitrogen-fixing bacteria, wherein the content of Trichoderma is 1×10⁻⁶. 6 -5×10 7 The CFU / g content of the nitrogen-fixing bacteria is 5 × 10⁻⁶. 5 -2×10 7 CFU / g.

4. The method for preparing the fungal residue composite material as described in claim 1 or 2, characterized in that, Includes the following steps: S1. After drying the waste substrate of various medicinal and edible fungi, crush it into particles with a particle size ≤1mm to obtain fungal substrate. S2. Mix the bacterial substrate and bio-adhesive evenly, add water and continue stirring until a moist and viscous state is formed. S3. Pre-compress the mixture into mushroom residue blocks to form nutrient soil bricks, and then pile and dry them until the moisture content is 45-50% of the solid content of the mushroom residue blocks. S4. Wrap in linen to prevent moisture loss and store in a cool place.

5. The preparation method according to claim 4, characterized in that, S2 also includes a microbial compound agent, which comprises Trichoderma and / or nitrogen-fixing bacteria, wherein the content of Trichoderma is 1×10⁻⁶. 6 -5×10 7 The CFU / g content of the nitrogen-fixing bacteria is 5 × 10⁻⁶. 5 -2×10 7 CFU / g.

6. The application of the fungal spore composite material as described in claim 3 in tree cavity repair.

7. The method for repairing tree cavities based on the fungal spore composite material according to claim 3, characterized in that, Includes the following steps: S1. Clean the tree cavity: Remove the rotten wood from the outside in until you reach the healthy wood. S2. Categorize and fill with mushroom residue blocks: 1) If the tree cavity is less than 30cm deep, simply stuff it with mushroom shavings and compact it to fill the cavity; 2) Tree cavities with a depth of 30cm-50cm should be layered: (a) After cleaning the tree cavity, lay a layer of sand and gravel on the healthy wood at the deepest part of the tree cavity; (b) Insert 1-2 water pipes, with the inlet end of the water pipe touching the sand and gravel layer and the outlet end of the water pipe extending beyond the hole to prevent the water pipe from being blocked. (c) Fill the opening with 1-2 pieces of mushroom substrate and compact them to a density of 0.35 g / cm³. 3 Left and right; In this step, 0.1% sucrose solution is also sprayed on the mushroom substrate blocks to activate the inoculant; (d) Cover the opening of the tree hole with coconut fiber netting and secure it tightly; 3) If the tree cavity depth is greater than 50cm, perform layered processing: (a) After cleaning the tree cavity, lay a layer of sand and gravel on the healthy wood at the deepest part of the tree cavity; (b) Insert at least 3 water pipes, with the inlet end of the water pipe touching the sand and gravel layer and the outlet end of the water pipe extending beyond the hole to prevent the water pipe from being blocked. (c) Lay several mushroom residue blocks sequentially on the sand and gravel layer, with each block being 12-15 cm thick. Then compact the mushroom residue blocks to a thickness of 10 cm, with a compaction density of 0.35 g / cm³. 3 Leave at least 20cm of cavity outside the compacted outermost layer of fungal spores, of which at least 15cm is for callus growth; In step (c), burlap is laid between adjacent mushroom substrate blocks to separate them; the burlap has a weight of 80g / m³. 2 Furthermore, the burlap was pre-cut into the cross-sectional shape of the tree hole before laying to ensure a good match; and in this step, 0.1% sucrose water was sprayed on the mushroom substrate blocks to activate the inoculant. (d) Fill the opening with uncompacted burlap-wrapped mushroom chaff; (e) Cover the opening of the tree hole with coconut fiber netting and secure it.

8. The method for repairing tree holes as described in claim 7, characterized in that, When the opening diameter is less than 20cm: the compaction thickness of each layer is reduced to 8-10cm.

9. The method for repairing tree holes as described in claim 7, characterized in that, When insect tunnels exist in tree cavities: Sprinkle 0.5wt% matrine powder between the layers of fungal spore blocks.

10. The method for repairing tree holes as described in claim 7, characterized in that, After filling two layers of bacterial substrate blocks, inject 5 mL of 0.05% potassium dihydrogen phosphate solution into the water guide tube to promote the proliferation of nitrogen-fixing bacteria.

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