A method for studying the impact of herbs on the natural regeneration of trees using high-coverage plots

Abstract

The present invention discloses a method for studying the impact of herbs on the natural regeneration of trees using high-coverage product, which relates to the field of forestry ecological technology. First, values are taken within the corresponding herb height range and coverage range, and the high-coverage product is obtained by multiplying the height mean value by the coverage mean value. A method for determining its appropriate range by associating and fitting the high-coverage product with the main target. The method of the present invention does not require complex sample analysis, only needs to control the height and coverage of herbs, does not need to consider the water content and types of herbs, nor does it need to carry out cumbersome work such as a large amount of vegetation cutting and weighing of herbs. It has a small workload, low investment cost, strong scientificity, environmental friendliness, and does not affect the growth of seedlings, and is of great significance for ecological restoration and vegetation management.

Description

Technical Field

[0001] The present invention belongs to the technical field of forestry ecology, and particularly relates to a method for studying the impact of herbs on the natural regeneration of trees using high coverage and height product Background Art

[0002] With the sublimation of people's understanding of the importance of ecological civilization construction and the continuous deepening of the understanding of the laws of forestry ecological construction, the forestry function has realized a historical transformation from emphasizing timber production to near-natural multi-functional forestry. Near-natural multi-functional forestry requires that the forest stand is a healthy and stable forest ecosystem with multiple tree species, multiple layers, multiple forest ages, and capable of natural regeneration. However, the natural regeneration of some tree species is relatively difficult, restricted by various factors, especially the height and coverage of herbs.

[0003] Currently, in forestry ecological research, single-factor studies on height and coverage are mostly used, and for the comprehensive study of the two factors, the biomass method is basically used. However, the biomass method has some limitations that are difficult to overcome and is not suitable for continuously studying the impact of herbs on the natural regeneration of trees in the growth state. For example, the limitations of the traditional biomass method are as follows:

[0004] 1. Even for the same kind of herb with the same height and coverage, due to different water contents at different harvesting times, its biomass is different, and the research accuracy can only be limited to a specific time;

[0005] 2. For different kinds of herbs with the same height and coverage, due to different specific gravities, their biomasses are also different, and the research accuracy can only be limited to a specific herb species;

[0006] 3. The biomass method requires cutting the grass, which affects the subsequent experiments and makes them unable to be carried out.

[0007] Therefore, based on the above problems, how to comprehensively study, analyze and control the impact of herb height and coverage on the natural regeneration of trees is an urgent problem to be solved in the development of near-natural multi-functional forestry. Summary of the Invention

[0008] Aiming at the defect that the traditional biomass method is not suitable for continuously studying the impact of herbs on the natural regeneration of trees in the growth state, and there are many limitations in the current methods to solve this problem, the present invention provides a method for studying the impact of herbs on the natural regeneration of trees using high coverage and height product. By proposing the concept of high coverage and height product and carrying out a comprehensive study of the two factors, the research on the comprehensive impact of herb height and coverage on the natural regeneration of trees is realized.

[0009] The solution adopted by the present invention to solve its technical problems is: A method for studying the impact of herbs on the natural regeneration of trees using high coverage and height product, including the following steps:

[0010] S1. Set the herb height interval and calculate the average value of the herb height interval;

[0011] S2. Set the herb coverage interval and calculate the average herb coverage within the interval;

[0012] S3. Calculate the high coverage product; based on the average herb height interval and the average herb coverage within the interval calculated in the above steps, multiply the two to calculate the high coverage product;

[0013] S4. Conduct a fitting analysis with the corresponding high coverage product and data points of the main target to obtain the range of the optimal double combination of herb height and coverage suitable for the natural regeneration of the studied tree species, thereby determining the optimal high coverage product combination beneficial to the natural regeneration of the tree species.

[0014] Furthermore, in step S1, the herb height interval can be set to ≤20 cm, 20 - 40 cm, 40 - 60 cm, and ≥60 cm.

[0015] Furthermore, in step S2, the herb coverage interval can be set to 20% - 40%, 40% - 60%, 60% - 80%, and ≥80%.

[0016] Furthermore, in step S4, the main target includes tree species survival rate, growth rate, or other data on the natural regeneration of tree species.

[0017] Furthermore, in step S4, the methods of fitting analysis include regression analysis, cluster analysis, or correlation analysis.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] The method for studying the impact of herbs on the natural regeneration of trees provided by the present invention calculates the high coverage product by measuring and calculating the average height and coverage of herbs, and then multiplying them. It does not require complex sample analysis. Only the height and coverage of herbs need to be controlled, without considering the water content and species of herbs, nor the cumbersome work such as a large amount of vegetation cutting and weighing of herbs, greatly reducing the workload and time cost; and it also effectively avoids the damage to the seedling environment, ensuring the integrity and sustainability of the forestry ecosystem.

[0020] By fitting and analyzing the high coverage and the main body target, the present invention can scientifically and accurately determine the optimal combination range of herb height and coverage, providing a scientific basis for ecological restoration and vegetation management. Moreover, the method of the present invention can conduct natural regeneration research for specific tree species, optimize the growth environment of tree species by adjusting the height and coverage of herbs, and improve the survival rate and growth rate of tree species. It can also be directly applied to ecological restoration and vegetation management practices to guide grassland management and tree species introduction, etc., with high practical value. The method of the present invention is simple and easy to implement, with small workload, low investment cost, strong scientificity, environmental friendliness, and does not affect the growth of seedlings, ensuring the continuous progress of experiments, which is of great significance for ecological restoration and vegetation management. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic flow chart of the method of the present invention;

[0022] Figure 2 is a schematic diagram of the experimental design of herb height and coverage;

[0023] Figure 3 is a comparison chart of the influence of herb height and coverage on the growth of seedlings;

[0024] Figure 4 is a comparison chart of the influence of herb height and coverage on the dynamic growth of seedlings;

[0025] Figure 5 is a curve chart of the suitable high coverage interval for Larix principis-rupprechtii seedlings;

[0026] Figure 6 is an actual application diagram of the experimental layout of herb height and coverage;

[0027] Figure 7 is an operation diagram of artificially controlling herb height and coverage. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The present invention will be further described below with reference to the drawings and embodiments.

[0029] Please refer to Figure 1-7, the present invention provides a technical solution for a method of studying the impact of herbs on the natural regeneration of trees using high coverage product. When studying the factors affecting the natural regeneration of Larix principis-rupprechtii in the previous work, a single-factor method was adopted. That is, first, the herb height intervals were determined, and the coverage ranges suitable for the natural regeneration of Larix principis-rupprechtii corresponding to different herb height intervals were clarified. Similarly, the method of fixing the herb coverage range was also used to clarify the height ranges suitable for the natural regeneration of Larix principis-rupprechtii corresponding to different herb coverage intervals. It was found that the ranges of these two suitable intervals change with the change of the herb height or herb coverage intervals, showing a trend that the suitable range gradually decreases as the herb height increases and the herb coverage gradually decreases, and the herb height gradually decreases as the herb coverage increases. Therefore, the present invention proposes the concept of high coverage product and adopts a two-factor comprehensive research method to comprehensively analyze and control the combined impact of herb height and coverage on the natural regeneration of trees, providing a scientific basis for ecological restoration or vegetation management. Example

[0030] This example provides a method of studying the impact of herbs on the natural regeneration of trees using high coverage product. First, values are taken within the corresponding herb height range and coverage range, and the high coverage product is obtained by multiplying the height mean (in centimeters) by the coverage mean. The method of determining its appropriate range by associating and fitting the high coverage product with the main target specifically includes the following steps:

[0031] 1. Set the herb height intervals and calculate the average herb height within the intervals (unit: cm); for example, in practical applications, the herb height intervals can be set as ≤20 cm, 20 - 40 cm, 40 - 60 cm, and ≥60 cm; the corresponding average herb heights within the intervals are specified as 10 cm, 30 cm, 50 cm, 70 cm.

[0032] 2. Set the herb coverage intervals and calculate the average herb coverage within the intervals (%); for example, in practical applications, the herb coverage intervals can be set as 20% - 40%, 40% - 60%, 60% - 80%, and ≥80%; the corresponding average herb coverages within the intervals are specified as 30 cm, 50 cm, 70 cm, 90 cm.

[0033] 3. Calculate the high coverage product; based on the corresponding average herb height within the intervals and the average herb coverage within the intervals calculated in the above steps, multiply the two to calculate the high coverage product, that is:

[0034] High coverage product = average herb height within the intervals × average herb coverage within the intervals

[0035] 4. Based on the high canopy cover product calculated in the above step 3, perform fitting analysis (such as using regression analysis, clustering analysis, correlation analysis, etc.) on the data points corresponding to the high canopy cover product and the main body targets (such as tree species survival rate, growth rate, etc.), and obtain the dual-combination optimal range suitable for the natural regeneration of the studied tree species for herb height and coverage, that is, determine which high canopy cover combinations are most conducive to the natural regeneration of the tree species.

[0036] For example, in actual application, fit the measured high canopy cover product at each point with the number of surviving seedlings of Larix principis-rupprechtii, and obtain the dual-combination optimal range suitable for the growth of Larix principis-rupprechtii for herb height and coverage. Through the analysis results, the optimal high canopy cover range for the natural regeneration of the tree species can be determined, thereby providing a scientific basis for ecological restoration or vegetation management.

[0037] Based on the above method, in this embodiment, taking the natural regeneration research of Larix principis-rupprechtii as an example, refer to Figure 6 the experimental layout of herb height and coverage, adopt the above method to determine the range of the growth interval suitable for Larix principis-rupprechtii seedlings, and through Figure 7 the method shown in the figure to manually control the herb height and coverage, specifically:

[0038] S1. Set the herb height and coverage

[0039] (1) From 2022 to 2023, control experiments on high canopy cover were carried out in Shuigou Forest Farm, Daxueshan Forest Farm, and Jinhua Forest Farm in Yuanzhou District, Liupan Mountain. The specific methods include the following steps:

[0040] Considering the influence of the dual factors of herb height and coverage on seedling regeneration, in November 2022, 48 1m×1m experimental quadrats were set up in Shuigou Forest Farm (Zhangzigou) in Yuanzhou District. About 3g (about 500 grains) of snow-preserved seeds from Liupan Mountain were sown in each quadrat. When the herb height was controlled at ≤20cm, 20-40cm, 40-60cm, and ≥60cm in turn, the coverage was controlled at 20%-40%, 40%-60%, 60%-80%, and >80% respectively, with a total of 4 treatment intervals ( Figure 2 ) with 3 replicates, for a total of 48 quadrats. Cut the herbs for treatment, directly sow the seeds, and then use a rake to rake the seeds into the soil.

[0041] From Figure 3 the curve of the change process of herb height and coverage on the number of seedlings at the forest edge, it can be seen that from the change process of the number of surviving seedlings decaying with time, the density of the number of seedlings with different coverages shows a "single peak" change with time. Before late June, since the herb height and coverage did not grow to the corresponding artificially controlled intervals, the survival of seedlings was not affected by artificial interference control.

[0042] When the herb height ≤ 20 cm, the maximum number of surviving seedlings (plants / m²) in the herb coverage intervals are, in descending order, 60% - 80% (14), ≥ 80% (10), 40% - 60% (4), 20% - 40% (3); however, with the subsequent control of the artificial herb height and coverage, significant changes occurred after July 1st. The statistical survey in October showed that the number of surviving plants (plants / m²) in the corresponding coverage intervals were, in descending order, 60% - 80% (32), ≥ 80% (20), 40% - 60% (20), 20% - 40% (9). The number of surviving seedlings with a coverage of 60% - 80% was 71%, 56%, and 37% higher than those with coverages of ≥ 80%, 40% - 60%, and 20% - 40% respectively. Therefore, it can be concluded that when the herb height in Shuigou Forest Farm is controlled at ≤ 20 cm, a coverage of 60% - 80% is the best for the survival of seedlings. This may be because when the herb height is too low, an appropriate coverage helps shade the seedlings, preventing sunburn on the ground surface or seedling death caused by water shortage ( Figure 3 a).

[0043] When the herb height is 20 - 40 cm, the maximum number of surviving seedlings (plants / m²) in the herb coverage intervals are, in descending order, 40% - 60% (36), 20% - 40% (29), 60% - 80% (23), ≥ 80% (17); however, with the subsequent control of the artificial herb height and coverage, significant changes occurred after July 8th. With the artificial control of trimming the herb height and coverage (dense or sparse), the attenuation changes were obvious. The statistical survey in October showed that the number of surviving plants (plants / m²) in the corresponding coverage intervals were, in descending order, 40% - 60% (35), 20% - 40% (27), 60% - 80% (23), ≥ 80% (14). The number of surviving seedlings with a coverage of 40% - 60% was 60%, 34%, and 20% higher than those with coverages of ≥ 80%, 60% - 80%, and 20% - 40% respectively. Therefore, it can be concluded that when the herb height in Shuigou Forest Farm is controlled at 20 - 40 cm, a coverage of 40% - 60% is the best for the survival of seedlings ( Figure 3 b).

[0044] When the herb height is 40 - 60 cm, the maximum number of surviving seedlings (plants / m²) in the herb coverage intervals are in the order of 20% - 40% (54), 60% - 80% (54), 40% - 60% (53), ≥80% (45); however, with the subsequent artificial control of the herb height and coverage, obvious changes occurred after June 22. With the artificial control of pruning the herb height and coverage (dense or sparse), the attenuation changes were obvious. The statistical survey in October showed that the number of surviving plants (plants / m²) in the corresponding herb coverage intervals were in the order of 40% - 60% (45), 20% - 40% (39), 60% - 80% (31), ≥80% (11). The final number of surviving seedlings with a coverage of 40% - 60% was 13%, 31%, and 76% higher than those with coverages of 20% - 40%, 60% - 80%, and ≥80% respectively. Therefore, it can be seen that when the herb height in Shuigou Forest Farm is controlled at 40 - 60 cm and the coverage is controlled at 40% - 60%, the survival of seedlings is the best ( Figure 3 c).

[0045] When the herb height ≥60 cm, the maximum number of surviving seedlings (plants / m²) in the herb coverage intervals are in the order of 20% - 40% (58), 40% - 60% (42), 60% - 80% (35), ≥80% (28); however, with the subsequent artificial control of the herb height and coverage, obvious changes occurred after June 22. With the artificial control of pruning the herb height and coverage (dense or sparse), the attenuation changes were obvious. The statistical survey in October showed that the number of surviving plants (plants / m²) in the corresponding herb coverage intervals were in the order of 20% - 40% (48), 40% - 60% (38), 60% - 80% (21), ≥80% (9). The number of surviving seedlings with a coverage of 20% - 40% was 21%, 56%, and 79% higher than those with coverages of 40% - 60%, 60% - 80%, and ≥80% respectively ( Figure 3 d). Therefore, it can be seen that when the herb height in Shuigou Forest Farm is controlled at ≥60 cm and the coverage is controlled at 20% - 40%, the survival of seedlings is the best ( Figure 3 d).

[0046] (2) Conducted again in Daxueshan Forest Farm in Jingyuan County, Jinhua Forest Farm in Longde County, and Shuigou Forest Farm in Yuanzhou District. Seeds were sown in the spring of 2022. The plot area was 1m × 1m. When the herb height was 40 - 60 cm, 4 intervals of herb coverage (20% - 40%, 40% - 60%, 60% - 80%, and ≥80%) were set, and there were 3 replicates for the herb coverage; when the herb coverage was set at 60% - 80%, 4 intervals of herb height (≤20 cm, 20 - 40 cm, 40 - 60 cm, and ≥60 cm) were set; at the same time, the growth monitoring of seedlings was carried out in June 2022. The premise was to monitor once a week during the seedling growth stage and about once every half month in the middle stage.

[0047] As shown Figure 4 in the figure, the curves of the change process of the herb height and coverage on the number of seedlings in different forest areas of the forest farm are shown (left figure: herb height and coverage of Daxueshan Forest Farm ( Figure 4 a and b); right figure: herb height and coverage of Jinhuafeng Forest Farm in Longde County ( Figure 4 c and d). Judging from the attenuation change process of the number of surviving seedlings over time, before late June, since the herb height and coverage did not grow to the corresponding artificially controlled range, the survival quantity of seedlings was not affected by artificial interference control. The number of surviving seedlings (plants / m2) of herb height and coverage in Daxueshan Forest Farm reached the peak on June 14th.

[0048] From Figure 4 a, it can be seen that when the herb height is in the range of 40 cm - 60 cm, the order of the maximum number of surviving seedlings in Daxueshan Forest Farm in the range of herb coverage is ≥80% (72), 40% - 60% (63), 60% - 80% (51), 20% - 40% (42); however, with the subsequent artificial control of herb height and coverage, obvious changes occurred after July. With the artificial control of pruning the herb height and coverage (dense and sparse), the attenuation change was obvious. Later, with the increase in rainfall, the demand of seedlings for light (temperature) would increase somewhat. The number of surviving plants of herb coverage (plants / m2) is in the order of 40% - 60% (24), 20% - 40% (20), 60% - 80% (14), ≥80% (3). Therefore, it can be known that when the herb coverage in Daxueshan Forest Farm is ≥80%, it is very difficult for the annual seedlings to survive. At the same time, when the herb coverage is 40% - 60%, it is the best for the survival of seedlings, and the worst when it is ≥80%. With the continuous observation of seedlings, the final number of surviving plants of 2-year-old seedlings is 20% - 40% and 40% - 60% (8), 60% - 80% (6), ≥80% (0). Therefore, it can be known that the greater the herb coverage, the more difficult it is to preserve the seedlings.

[0049] From Figure 4 b, it can be seen that when the herb coverage is in the range of 60 - 80%, the order of the maximum number of surviving seedlings in Daxueshan Forest Farm in the range of herb height is ≤20 cm (65), 40 - 60 cm (50), ≥60 cm (45), 20 - 40 cm (42); by October, the number of surviving plants of herb height of seedlings (plants / m2) is in the order of ≤20 cm (8), 20 - 40 cm (5), 40 - 60 cm (4), ≥60 cm (0); at the same time, with the continuous observation of seedlings, the final number of surviving plants of 2-year-old seedlings is ≤20 cm (1), and the rest are 0. Therefore, it can be known that the greater the herb height, the more difficult it is to preserve the seedlings.

[0050] From Figure 4It can be seen from c that when the herb height is in the range of 40 cm - 60 cm, the maximum number of surviving seedlings in Jinhua Forest Farm in the herb coverage range is in the order of 40% - 60% (116), ≥80% (83), 20% - 40% (61), 60% - 80% (23); by October, the number of surviving plants (plants / m2) in the herb coverage is in the order of 40% - 60% (51), 20% - 40% (31), 60% - 80% (10), ≥80% (4); therefore, it can be seen that in Jinhua Forest Farm, when the herb coverage ≥80%, it is very difficult for the annual seedlings to survive and be preserved. At the same time, when the herb coverage is 40% - 60%, it is the best for the survival and preservation of seedlings, and the worst when ≥80%. With the continuous observation of the seedlings, the final number of surviving plants of the two-year-old seedlings is 40% - 60% (8), 20% - 40% (3), 60% - 80% (2), ≥80% (0). Therefore, it can be seen that the greater the herb coverage, the more difficult it is to preserve the seedlings.

[0051] It can be seen from Figure 4 d that when the herb coverage is in the range of 60 - 80%, the maximum number of surviving seedlings in Jinhua Forest Farm in the herb height range is in the order of ≤20 cm (8), ≥60 cm (7), 20 - 40 cm (6), 40 - 60 cm (5); by October, the number of surviving plants of the seedling herb height (plants / m2) is in the order of ≤20 cm (2), 20 - 40 cm (2), 40 - 60 cm (1), ≥60 cm (0); therefore, it can be seen that when the herb height ≥60 cm, it is very difficult for the seedlings to survive and be preserved. With the continuous observation of the seedlings, the final number of surviving plants of the two-year-old seedlings is 0. Therefore, it can be seen that the greater the herb height, the more difficult it is to preserve the seedlings.

[0052] Therefore, through the above experiments, it can be seen that when the herb height is in the range of 40 cm - 60 cm, the survival and preservation of annual seedlings are in the order of 40% - 60%, 20% - 40%, 60% - 80%, ≥80%; when the herb coverage is 40% - 60%, the survival and preservation of annual seedlings are in the order of ≤20 cm, 20 - 40 cm, 40 - 60 cm, ≥60 cm. Due to the influence of the surrounding complex environment in the later stage, the influence of the herb is not enough to be the main influencing factor for the two-year-old seedlings.

[0053] S2. Calculate and fit the double combination of herb height and coverage for the optimal suitable range for the growth of Larix principis-rupprechtii regeneration seedlings in North China

[0054] As Figure 5As shown, based on 176 survey data points from 48 quadrats of the herb height of 40 - 60 cm (0.2 - 0.4, 0.4 - 0.6, 0.6 - 0.8, >0.8) and coverage of 0.6 - 0.8 (≤20 cm, 20 - 40 cm, 40 - 60 cm, >60 cm) in Daxueshan and Jinhua Forest Farms; 75 survey data points from 15 quadrats of the herb height of 40 - 60 cm (0 - 0.2, 0.2 - 0.4, 0.4 - 0.6, 0.6 - 0.8, >0.8) in Yangling; 256 data points from 16 quadrats of the herb height of ≤20 cm (0.2 - 0.4, 0.4 - 0.6, 0.6 - 0.8, ≥0.8), 20 - 40 cm (0.2 - 0.4, 0.4 - 0.6, 0.6 - 0.8, ≥0.8), 40 - 60 cm (0.2 - 0.4, 0.4 - 0.6, 0.6 - 0.8, ≥0.8), ≥60 cm (0.2 - 0.4, 0.4 - 0.6, 0.6 - 0.8, ≥0.8) in Shuigou Forest Farm, totaling 507 data from 79 quadrats.

[0055] The means of the above data were taken within the corresponding height range and coverage range, and the high coverage - product range was obtained by continuous multiplication. Then, through fitting the corresponding data points, the optimal double - combination range of herb height and coverage ( R 2 =0.93) suitable for the growth of Larix principis - rupprechtii was obtained. That is, the higher the herb height, the stronger the shading effect on the seedlings, and the worse the light conditions, which will affect the photosynthesis and growth and development of the seedlings. At the same time, the larger the herb coverage, the higher the coverage of the soil surface, and the growth space of the seedlings will be restricted, making it difficult to obtain sufficient nutrients and water. Through fitting the data points, it can be seen that when the high coverage - product is between 14 and 25, it is a more suitable growth interval for Larix principis - rupprechtii seedlings; therefore, in the wild, artificial intervention measures can be taken to improve the growth environment of the seedlings and promote the germination of seeds and the growth of seedlings.

[0056] The method provided by the present invention for studying the impact of herbs on the natural regeneration of trees using high coverage - product only controls the herb height and coverage, does not consider the water content and species of the herbs, and does not need to cut the herbs. It is simple and easy to implement, with small workload, low investment cost, and does not affect the growth of seedlings, ensuring the continuous progress of the experiment.

[0057] The above is only the preferred embodiment of the present invention and does not limit the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for studying the effects of herbs on natural regeneration of trees using high cover, characterized by: The following steps are involved: S1. Set the grass height interval and calculate the average grass height interval; S2. Setting the herb cover interval and calculating the average herb cover value within the interval; S3, calculating the high cover area; based on the corresponding herb height interval average calculated in the above step and the interval herb cover average, multiplying the two to calculate the high cover area; S4. Perform fitting analysis on the data points corresponding to the high cover area and the main target to obtain the range of the dual combination of herb height and cover that is most suitable for the natural regeneration of the studied tree species, thereby determining the optimal high cover area combination that is conducive to the natural regeneration of the tree species.

2. The method of claim 1 for studying the influence of herbaceous plants on natural regeneration of trees using high cover, characterized in that: In step S1, the grass height intervals can be set to ≤20 cm, 20-40 cm, 40-60 cm and ≥60 cm.

3. The method of claim 1 for studying the effect of herbs on natural regeneration of trees using high cover, characterized in that: The coverage intervals of the herbs in step S2 can be set to 20%-40%, 40%-60%, 60%-80% and ≥80%.

4. The method of claim 1, wherein: The main objectives in step S4 include tree species survival rate, growth rate or other tree species natural renewal data.

5. The method of studying the influence of herbaceous plants on natural regeneration of trees using high cover area according to claim 1, characterized in that: The fitting analysis method in step S4 includes regression analysis, cluster analysis or correlation analysis.

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