Physical method for promoting liquidambar formosana hance to become red and application of physical method in forest management

Abstract

The invention discloses a physical method for promoting liquidambar formosana hance to become red and application of the physical method in forest management. The physical method comprises any one of side branch thin filament cutting, side branch xylem girdling and trunk base xylem girdling. Lateral branch fine filament cutting is to select lateral branches of three-year-old sweetgum plants and tightly wind nylon fine filaments in the middles of the lateral branches for three circles; the step of girdling the xylem on the side branch is that the side branch of a triennial sweetgum plant is selected, girdling is carried out for one circle at the position 3 cm away from the base part of the side branch, the girdling width is 3 cm, and then the girdled wound is wrapped with a preservative film; the step of girdling the xylem at the base part of the trunk comprises the following steps: selecting a triennial sweetgum plant, girdling a circle at the position 10 cm away from the base part of the trunk, and wrapping the girdled wound with a preservative film. According to the method, a physical method is adopted, chemical promoting agents are not used, it can also be guaranteed that the whole forest stand grows continuously, the whole plant color changing effect is good, directional color changing of a single plant can be achieved, and the advanced, timed and positioned color changing effect is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of liquidambar cultivation, and particularly relates to a physical method for promoting liquidambar to turn red and an application thereof in forestry. Background Art

[0002] Liquidambar formosana Liquidambar formosana Hance.) is a species of Liquidambar formosana of the Hamamelidaceae family. Liquidambar ) is a deciduous tree, mainly distributed in the south of the Qinling Mountains and the Huaihe River in my country. Liquidambar is a strong sun-loving tree species, suitable for warm and humid climates, requires deep and moist soil for growth, is resistant to waterlogging, and is also resistant to drought. At the same time, Liquidambar roots usually go deep into the soil, with thick taproots, so it has strong wind resistance and is suitable for growing in acidic or neutral soils. It grows very fast, has strong germination, and has fast natural renewal. It is a dominant tree species in secondary forests. After the fall, the leaves of Liquidambar gradually change from green to red and other colors. It is an autumn-colored leaf tree species that mainly changes to red. Because of its bright colors and great ornamental value, it is widely used in landscape afforestation. However, the Liquidambar forests built in the south, such as Guangxi, generally have the problem of poor color change effect, which seriously restricts the performance of its landscape function. At present, the method of promoting the redding of Liquidambar is still focused on the use of chemical promoters, while there are few reports on the research of promoting the color change of Liquidambar by physical methods and obtaining good color change effects. Summary of the invention

[0003] In view of the above-mentioned shortcomings, the present invention discloses a physical method for promoting the redding of Liquidambar formosana and its application in afforestation. The physical method is adopted instead of chemical promoting agents, and the continuous growth of the entire forest stand and the good color change effect of the whole plant can be ensured. Moreover, the directional color change of a single plant can be achieved, and the same tree can have both color change and no color change effects, thereby enriching the colors and achieving early, timed and positioned color change effects.

[0004] The present invention is achieved by adopting the following technical solutions: A physical method for promoting reddening of Liquidambar formosana, comprising any one of the following methods: ligating filaments of side branches, girdling the xylem of side branches, and girdling the xylem of the base of the trunk; The side branch filament strangulation is to select the side branch of the 3-year-old Liquidambar formosana plant, and then tightly wrap the nylon filament 3 times around the middle of the side branch and ensure that it does not fall off; The side branch girdling xylem is to select the side branch of a 3-year-old Liquidambar formosana plant, then girdling once at a position 3 cm away from the base of the side branch, and the girdling width is 3 cm, and then wrap the girdling wound with plastic wrap; The method of ring-barking the xylem at the base of the trunk is to select a 3-year-old Liquidambar plant, then ring-bark the Liquidambar plant once at a distance of 10 cm from the base of the trunk, with a ring-barking width of 3 cm, and then wrap the ring-barking wound with plastic wrap.

[0005] Furthermore, the three-year-old Liquidambar formosana plant has a ground diameter of 7.5 ± 1.00 cm, a breast diameter of 3.8 ± 0.50 cm, a tree height of 3.3 ± 1.0 m, and a crown width of 3.2 × 3.5 cm to 3.8 × 4.2 cm.

[0006] Furthermore, the treatment time of any one of the treatment methods including filament cutting of side branches, girdling of xylem of side branches and girdling of xylem of main trunk base is November every year.

[0007] Furthermore, the thickness of the side branches is between 1.0 and 2.0 cm.

[0008] Furthermore, the thickness of the nylon filament is between 0.2 and 0.8 mm.

[0009] The application of the physical method for promoting the redding of Liquidambar formosana in constructing a colorful Liquidambar formosana forest comprises the following steps: (1) When planting a pure Liquidambar formosana forest, the initial planting density is controlled at 100 to 120 plants per mu. After 3 to 5 years of planting, the plants to be thinned are determined. Then, the plants to be thinned are subjected to the aforementioned girdling of the xylem at the base of the trunk, and the thinned plants are cut down after they die. High-density afforestation can promote the early closure of Liquidambar formosana, thereby promoting the growth of tree height and straight trunk shape. On the other hand, the suppression of lateral branch growth is also conducive to artificial pruning. In the early stage of afforestation, no treatment is performed to ensure the good growth of Liquidambar formosana, which lays the foundation for the color change measures to be taken in the later stage. The treatment of ring-barking the xylem at the base of the trunk can make the color change effect very obvious in the current year, and the thinned plants will be cut down after they die. At the same time, the same measures can be adopted for secondary thinning when the trees grow up in the later stage, so that the trees that need to be thinned can achieve good color change effect in the current year. (2) Among the plants that have not been thinned, select the side branches that need to change color in the current year or are scheduled to be pruned, and perform the side branch xylem girdling treatment as described above. After the side branches change color in the current year, prune them away or allow them to break off on their own; (3) Among the plants that have not been thinned, select the side branches that are not scheduled to be pruned and treat them according to the side branch filament cutting method described above; For Liquidambar formosana plants that have not been thinned, treatment is carried out based on the number of lateral branches and whether pruning is needed. For lateral branches that need to change color in the same year or need to be pruned, the lateral branch xylem ringing method described above can be used for treatment, and a color-changing effect can be obtained in the same year; for lateral branches that need to change color in the following year and need to be retained, the lateral branch filament cutting method described above can be used for treatment, and a good color-changing effect can be obtained in the following year.

[0010] Compared with the prior art, this technical solution has the following beneficial effects: According to the growth characteristics of Liquidambar formosana, the present invention formulates physical measures suitable for promoting the color change of Liquidambar formosana in autumn and extending the color change period, namely, including three treatment methods of lateral branch filament cutting, lateral branch ring exfoliation of xylem and trunk base ring exfoliation of xylem, and according to the characteristics of the above three treatment methods, Liquidambar formosana forest management measures are formulated to provide an effective way to improve the ornamental value of Liquidambar formosana in autumn. At the same time, the present invention can ensure the continuous growth of the entire forest stand and the good color change effect of the whole plant, and can achieve directional color change of a single plant, and can also make the same tree have both color change and non-color change effects, enrich the color, so as to achieve early, regular, and localized color change effects. Moreover, the three treatment methods described in the present invention are easy to operate, and different treatment methods can be combined and used according to actual conditions. The three treatment methods do not use chemical agents to treat Liquidambar formosana, avoiding the adverse effects of residual chemical agents on the forest environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 Schematic diagram of the leaf color parameter determination described in the experimental example.

[0012] Figure 2 It is a cluster analysis diagram of the data obtained in the experimental example. DETAILED DESCRIPTION

[0013] The present invention is further described by the following examples, but is not intended to be limiting of the present invention. Specific experimental conditions and methods not specified in the following examples are conventional methods commonly known to those skilled in the art.

[0014] Example 1: A physical method to promote the redding of Liquidambar formosana is to cut the side branches with filaments; the side branch cutting is to select the side branches of three-year-old Liquidambar formosana plants, then tightly wrap nylon filaments around the middle of the side branches for 3 turns and ensure that they do not fall off. As the side branches grow, the nylon filaments will naturally embed into the side branches. When observed the following year, the nylon filaments are embedded in the side branches to a depth of 2 / 3; the side branch cutting treatment time is November; the side branches are 1.5 cm thick; the nylon filaments are 0.5 mm thick.

[0015] Example 2: A physical method to promote the redding of Liquidambar formosana is to girdle the xylem of side branches; the girdling of the xylem of side branches is to select the side branches of a 3-year-old Liquidambar formosana plant, then girdle the side branches once at a distance of 3 cm from the base of the side branches, and the girdling width is 3 cm, and then wrap the girdling wound with plastic wrap; the treatment time of the girdling of the xylem of side branches is in November; the thickness of the side branches is 1.5 cm.

[0016] Example 3: A physical method to promote the reddening of Liquidambar formosana is to ring-bark the xylem at the base of the trunk; the ring-barking of the xylem at the base of the trunk is performed by selecting a 3-year-old Liquidambar formosana plant, then ring-barking the Liquidambar formosana plant once at a distance of 10 cm from the base of the trunk, with a ring-barking width of 3 cm, and then wrapping the ring-barking wound with plastic wrap; the treatment time for ring-barking the xylem at the base of the trunk is in November; the thickness of the side branches is 1.5 cm.

[0017] Example 4: The method described in Examples 1 to 3 is used to construct a colorful liquidambar forest, which comprises the following steps: (1) When planting a pure Liquidambar formosana forest, the initial planting density is controlled at 111 plants / mu. After 3 years of planting, the plants to be thinned are determined. Then, the plants to be thinned are subjected to the xylem ringing treatment at the base of the trunk as described in Example 3. The thinned plants are cut down after they die. (2) Among the plants that have not been thinned, select the side branches that need to change color in the current year or are scheduled to be pruned, and perform the side branch xylem girdling treatment as described in Example 2, and then prune them after they change color in the current year; (3) Among the plants that have not been thinned, side branches that are not scheduled to be pruned are selected and treated with the side branch filament cutting described in Example 1; the thickness of the nylon filament is 0.5 mm; the thickness of the side branch is 1.0 cm; the treatment time for any of the side branch filament cutting, side branch girdling and trunk base girdling is November.

[0018] Example 5: The method described in Examples 1 to 3 is used to construct a colorful liquidambar forest, which comprises the following steps: (1) When planting a pure Liquidambar formosana forest, the initial planting density is controlled at 100 plants / mu. After 4 years of planting, the plants to be thinned are determined. Then, the plants to be thinned are subjected to the xylem ringing treatment at the base of the trunk as described in Example 3. The thinned plants are cut down after they die. (2) Among the plants that have not been thinned, select the side branches that need to change color in the current year or are scheduled to be pruned, and perform the side branch xylem girdling treatment as described in Example 2, and wait for the side branches to break off automatically after changing color in the current year; (3) Among the plants that have not been thinned, select the side branches that are not scheduled to be pruned, and treat them with the side branch filament cutting method described in Example 1; the thickness of the nylon filament is 0.2 mm; The thickness of the side branches is 1.5 cm; the treatment time of any one of the treatment methods including filament cutting of the side branches, girdling of the xylem of the side branches and girdling of the xylem of the base of the main trunk is November.

[0019] Example 6: The method described in Examples 1 to 3 is used to construct a colorful liquidambar forest, which comprises the following steps: (1) When planting a pure Liquidambar formosana forest, the initial planting density is controlled at 120 plants / mu. After 5 years of planting, the plants to be thinned are determined. Then, the plants to be thinned are subjected to the xylem ringing treatment at the base of the trunk as described in Example 3. The thinned plants are cut down after they die. (2) Among the plants that have not been thinned, select the side branches that need to change color in the current year or are scheduled to be pruned, and perform the girdling of the xylem of the side branches as described in Actual Example 2. Prune and remove the side branches after they change color in the current year; (3) Among the plants that have not been thinned, select the side branches that are not scheduled to be pruned, and treat them with the side branch filament cutting method described in Example 1; the thickness of the nylon filament is 0.8 mm; The thickness of the side branches is 2.0 cm; the treatment time of any one of the treatment methods including filament cutting of the side branches, girdling of the xylem of the side branches and girdling of the xylem of the base of the main trunk is November.

[0020] Experimental example: The Liquidambar experimental forest constructed by the Dongsheng Branch of Gaofeng Forest Farm in January 2019 was used as the research base. The plant spacing during afforestation was 2×3 m, and it was planted on the sunny slope; when the experiment was carried out in 2021, three-year-old Liquidambar was used as the test object, and the average growth conditions of the Liquidambar used in the experiment were as follows: ground diameter was 7.5 ± 1.00 cm, breast diameter was 3.8 ± 0.50 cm, tree height was 3.3 ± 1. 0 m, and crown width was 3.2 × 3.5 cm to 3.8 × 4.2 cm; Examples 1 to 3 and all the following treatment methods were observed for two consecutive years, and while observing the discoloration, it was recorded whether the growth condition was affected.

[0021] Treatment 1 (main vein cutting): 9 plants with uniform growth and low branching points were selected as test trees. Three undiscolored leaves were selected at 2 / 3 of the height of the top and on each of the 4 side branches in different directions, that is, 12 leaves were selected from each tree. The main vein was cut at a distance of 0.5 cm from the base of the leaf. The leaf color was observed at intervals of 10 days after cutting until the leaf died. When the leaf color was measured, the average value was taken as the mean of the tree. At the same time, the leaves treated with the side branches were used as controls, and the leaf color changes were observed and recorded in the same way.

[0022] Treatment 2 (lateral branch banding and Example 1): 9 plants with uniform growth, low branching points and uniform lateral branches (thickness of 1.5 cm) were selected as test trees, and a white glass rope was tied in the middle of 3 of the lateral branches for banding treatment (banding width of 2 cm); the other 3 adjacent lateral branches were treated according to the method described in Example 1; at the same time, the leaves of the treated lateral branches were used as controls, and the leaf color changes were observed and recorded in the same way; after the start of the experiment, the color change degree and leaf color parameters of Liquidambar formosana were observed and recorded every 10 days.

[0023] Treatment three (lateral branch girdling phloem): 24 Liquidambar plants with good growth and similar size under the same habitat were selected for research, and the 24 Liquidambar plants were randomly divided into 4 groups, with 6 plants in each group; the first group was the control group (CK), that is, no girdling treatment; the second group was 1 / 3 girdled on the phloem; the third group was 2 / 3 girdled on the phloem; the fourth group was full girdled on the phloem; the girdled lateral branch thickness was 1.5 cm, the girdled positions were all 3 cm away from the base of the lateral branch of the plant, and the girdling width was 3 cm; at the same time, the wound was tightly wrapped with plastic wrap to prevent excessive water loss and insect bites; the color change degree and leaf color parameters of the Liquidambar were observed and recorded every 10 days after the start of the experiment.

[0024] Treatment 4 (girdling of xylem on lateral branches): 24 Liquidambar plants with good growth and similar size under the same habitat were selected for research, and the 24 Liquidambar plants were randomly divided into 4 groups, with 6 plants in each group; the first group was the control group (CK), that is, no girdling treatment; the second group was girdled with 1 / 3 circle of xylem; the third group was girdled with 2 / 3 circle of xylem; the fourth group was the method described in Example 2; the girdling of lateral branches was 1.5 cm in thickness, the girdling positions were all 3 cm from the base of the lateral branches of the plants, and the girdling width was 3 cm; at the same time, the wounds were tightly wrapped with plastic wrap to prevent excessive water loss and wounds from being bitten by insects, etc.; the discoloration degree and leaf color parameters of the Liquidambar were observed and recorded every 10 days after the start of the experiment.

[0025] Treatment 5 (phloem ring cutting at the base of the trunk): 24 Liquidambar plants with good growth and similar size under the same habitat were selected for research; the 24 Liquidambar plants were randomly divided into 4 groups, with 6 plants in each group; the first group was the control group (CK), that is, no ring cutting treatment; the second group was 1 / 3 ring cutting of the phloem; the third group was 2 / 3 ring cutting of the phloem; the fourth group was full ring cutting of the phloem; the ring cutting site was 10 cm from the base of the plant trunk, and the ring cutting width was 3 cm; at the same time, the wound was tightly wrapped with plastic wrap to prevent excessive water loss and wound bites by insects; the color change degree and leaf color parameters of the Liquidambar were observed and recorded every 10 days after the start of the experiment.

[0026] Treatment 6 (ringing of xylem at the base of the trunk): 24 Liquidambar plants with good growth and similar size under the same habitat were selected for research; the 24 Liquidambar plants were randomly divided into 4 groups, with 6 plants in each group; the first group was the control group (CK), that is, no ringing treatment; the second group was ringed 1 / 3 of the phloem; the third group was ringed 2 / 3 of the phloem; the fourth group was the method described in Example 3; the ringing site was 10 cm from the base of the plant trunk, and the ringing width was 3 cm; at the same time, the wound was tightly wrapped with plastic wrap to prevent excessive water loss and wound bites by insects; various physiological parameters of Liquidambar were observed every 10 days after the start of the experiment.

[0027] Determination indicators: (1) Determination of color change ratio and time: The treatment was carried out according to the experimental design, and the characterization characteristics such as the time of each observation, color change ratio, color change degree, and the duration after the final color change exceeded 70% were recorded under different treatments.

[0028] (2) Determination of leaf parameters: The determination of leaf color attribute parameters refers to Sarker's method. The measuring instrument is Spectrophotometer CS-650, test mode SCI, D65 light source, angle 10°. The measuring position is 10 points on the upper, middle and lower sides of the main vein on the front of the leaf and the upper and lower sides of the lateral veins on both sides. Avoid the leaf veins during measurement and record L * , a * , b * ,like Figure 1 shown.

[0029] Experimental results and analysis: (A) The percentage of discoloration (%) and the duration of discoloration exceeding 70% (days) in different experimental groups are shown in Table 1.

[0030] The proportion of leaf color change and the duration of color change can intuitively show the color change effect of Liquidambar formosana leaves. Since the control group generally changed less, the average value of the control group of each experimental group was taken for the convenience of analysis.

[0031] The results of this experiment show that: (1) Experimental Group 2 (main vein cutting), Experimental Group 4 (Example 1), Experimental Group 10 (Example 2), and Experimental Group 16 (Example 3) can make the leaves of Liquidambar formosana turn bright red, and the color change rate is more than 90%; among them, Experimental Group 10 and Experimental Group 16 can ensure a long color change time of up to 40 days.

[0032] (2) Experimental groups 7 (3 / 3 of the phloem of lateral branches), 9 (2 / 3 of the xylem of lateral branches), 12 (3 / 3 of the phloem of the main trunk base), and 15 (2 / 3 of the xylem of the main trunk base) caused the leaves of Liquidambar formosana to turn dark red in the year of the experiment, and the color change exceeded 90% for up to 30 days.

[0033] Table 1 The percentage of discoloration in different test groups (%) and the duration of discoloration exceeding 70% (days)

[0034] 2. Changes in leaf color parameters in different experimental groups Among the leaf color parameters, L * Represents the brightness of the color.L * The larger the value, the brighter the leaf color; a * , b * is the hue parameter, a * Represents the red-green attribute of leaf color, positive values ​​indicate reddishness, negative values ​​indicate greenishness; b * It indicates the yellow-blue attribute of leaf color. Positive values ​​indicate yellowish color and negative values ​​indicate bluish color. The specific results are shown in Table 2.

[0035] The results of this experiment show that: (1) Experimental Group 2 (main vein cutting), Experimental Group 4 (Example 1), Experimental Group 10 (Example 2), Experimental Group 16 (Example 3), the above 4 groups can make the leaves of Liquidambar formosana turn into bright red leaves, representing the red-green attribute of the leaf color. a * The value is relatively large, with a value of about 33 ± 5; (2) Experimental group 7 (3 / 3 of the lateral branch girdling phloem), experimental group 9 (2 / 3 of the lateral branch girdling xylem), experimental group 12 (3 / 3 of the base girdling phloem), and experimental group 15 (2 / 3 of the trunk base girdling xylem) can make the leaves of Liquidambar formosana turn dark red in the year of the experiment, representing the red-green attribute of the leaf color. a * The value is second, which is about 12±3; (3) Other experimental groups with less or no discoloration a * The values ​​are all less than 3 and most of them are negative.

[0036] Table 2 Changes of leaf color parameters in different experimental groups

[0037] 3. Cluster analysis The two sets of data for each experimental group were uniformly numbered according to the color change ratio and duration, leaf color parameters L *、 a *、 b * and other 5 indicators for cluster analysis.

[0038] The results are as follows Figure 2As shown: Based on the distance 5, it is mainly divided into 3 categories, corresponding to bright red, dark red, and unchanged color. Among the bright red, test group 2 (main vein cutting) is distinguished from test group 4 (Example 1), test group 10 (Example 2), and test group 16 (Example 3) due to the short time, and it is a separate category 1; dark red test group 7 (lateral branch ringing phloem 3 / 3), test group 9 (lateral branch ringing xylem 2 / 3), test group 12 (base ringing phloem 3 / 3), test group 15 (main trunk base ringing xylem 2 / 3) are in category 1; others that do not change color are in category 1.

[0039] In summary, combined with the various indicators of color change ratio, color change duration and leaf color parameter changes, the results show that: (1) Experimental group 2 (main vein cutting), experimental group 4 (Example 1), experimental group 10 (Example 2), and experimental group 16 (Example 3), the above 4 groups can make the leaves of Liquidambar formosana turn bright red, but experimental group 2 (main vein cutting) is not suitable for application in actual forest management due to its too short time; (2) Experimental group 7 (3 / 3 of the lateral branch girdling phloem), experimental group 9 (2 / 3 of the lateral branch girdling xylem), experimental group 12 (3 / 3 of the base girdling phloem), and experimental group 15 (2 / 3 of the trunk base girdling xylem) caused the leaves of Liquidambar formosana to turn dark red in the first year of the experiment, but the color change effect was not very good. (3) The other experimental groups basically did not change color; It can be seen that the method of the present invention can achieve the best color change effect of Liquidambar formosana for the longest time, and can be applied in the afforestation of colorful Liquidambar formosana. At the same time, the three treatment methods of filament cutting of side branches, ring exfoliation of the xylem of side branches, and ring exfoliation of the xylem of the base of the trunk described in the present invention each have their own characteristics. Filament cutting of side branches is a measure taken on the side branches, and the color can only be changed in the next year, and the growth of the whole tree is not affected; ring exfoliation of the xylem of side branches is also a measure taken on the side branches, but the side branches can be changed in the same year, and the side branches will be broken in the next year, but the growth of the whole tree is not affected; ring exfoliation of the xylem of the base of the trunk is a measure taken on the main trunk, and the color of the whole plant can be changed in the same year, but the growth of the whole tree is affected, causing the Liquidambar formosana to be close to death, and can be used for thinning plants. Therefore, combined with the growth characteristics of Liquidambar formosana such as liking the sun, the above three treatment methods can be used alone when constructing a colorful Liquidambar formosana forest, or the three treatment methods can be used in combination according to actual needs.

[0040] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A physical method for promoting the reddening of Liquidambar formosana, characterized in that: The method comprises any one of the following methods: cutting the filaments of the side branches, girdling the xylem of the side branches, and girdling the xylem of the base of the trunk; The side branch filament strangulation is to select the side branch of the 3-year-old Liquidambar formosana plant, and then tightly wrap the nylon filament 3 times around the middle of the side branch and ensure that it does not fall off; The side branch girdling xylem is to select the side branch of a 3-year-old Liquidambar formosana plant, then girdling once at a position 3 cm away from the base of the side branch, and the girdling width is 3 cm, and then wrap the girdling wound with plastic wrap; The method of ring-barking the xylem at the base of the trunk is to select a 3-year-old Liquidambar plant, then ring-bark the Liquidambar plant once at a distance of 10 cm from the base of the trunk, with a ring-barking width of 3 cm, and then wrap the ring-barking wound with plastic wrap.

2. The physical method for promoting reddening of Liquidambar formosana according to claim 1, characterized in that: The three-year-old Liquidambar formosana plant has a ground diameter of 7.5 ± 1.00 cm, a breast diameter of 3.8 ± 0.50 cm, a tree height of 3.3 ± 1.0 m, and a crown width of 3.2 × 3.5 cm to 3.8 × 4.2 cm.

3. The physical method for promoting reddening of Liquidambar formosana according to claim 1, characterized in that: The treatment time of any one of the treatment methods of filament cutting of side branches, girdling of xylem of side branches and girdling of xylem of main trunk base is November every year.

4. The physical method for promoting reddening of Liquidambar formosana according to claim 1, characterized in that: The thickness of the side branches is between 1.0 and 2.0 cm.

5. The physical method for promoting reddening of Liquidambar formosana according to claim 1, characterized in that: The thickness of the nylon filament is between 0.2 and 0.8 mm.

6. The use of the physical method for promoting reddening of Liquidambar formosana according to any one of claims 1 to 5 in afforestation, characterized in that: The application is the application of the physical method for promoting the redding of Liquidambar formosana in the construction of a colorful Liquidambar formosana forest, which comprises the following steps: (1) When planting a pure Liquidambar formosana forest, the initial planting density is controlled at 100 to 120 plants per mu. After 3 to 5 years of planting, the plants to be thinned are determined. Then, the plants to be thinned are treated by girdling the xylem at the base of the trunk as described above, which can make the plants turn obviously red during the color change period of the year. The thinned plants are cut down after they die. (2) Among the plants that have not been thinned, select the side branches that need to change color in the current year or are scheduled to be pruned, and perform the side branch xylem girdling treatment as described above. After the side branches change color in the current year, prune them away or allow them to break off on their own; (3) Among the plants that have not been thinned, select the side branches that are not scheduled to be pruned and process them according to the above-mentioned side branch filament cutting.

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