CN111523781B - Method for comprehensively evaluating growth vigor of Minjiang fir seedlings in forest environment - Google Patents

Abstract

The invention discloses a method for comprehensively evaluating the growth of Minjiang fir seedlings in the forest line environment. First, the ground diameter, height, crown width, lateral branch dimension, longest live branch age, longest branch upper age, longest branch lower age, upper live live branch, top branch number, Branch length and live leaf percentage of the current year. Second, these indicators were combined into seven indicators: height/ground diameter, crown width/age, old live branch/longest branch old, side branch dimension, current year branch length, live leaf ratio and top branch number. Thirdly, the combined seven indexes were weighted and summed to obtain the comprehensive index of Minjiang fir seedlings quantified. Finally, according to the obtained value range, the growth status of Abies Minjiang fir seedlings was graded into excellent, good, medium and poor. The invention comprehensively analyzes the specific form and growing state of the Minjiang fir seedlings in the treeline environment, and then quantitatively evaluates and classifies the growing state of the Minjiang fir seedlings in the treeline environment.

Description

A method for comprehensive evaluation of the growth of Abies Minjiang in treeline environment

technical field

The invention belongs to the technical field of evaluating the growth of conifer seedlings in the forest line environment, and in particular relates to a method for quantitatively evaluating and grading the growth of Minjiang fir seedlings in the forest line environment.

Background technique

Minjiang fir (Abies faxoniana) belongs to the genus Abies (Pinaceae) of Pinaceae (Pinales), and is a unique tree species in my country. It is distributed in the Taohe River Basin and Bailong River Basin in southern Gansu, the upper reaches of the Minjiang River Basin in Sichuan, and the Da and Xiao Jinchuan Basins. As well as the eastern slope of Kangding Zheduo Mountains and other high mountain areas with an altitude of 2700-3900 meters. It has strong tolerance to shade and likes cold and humid climate. It forms a large area of pure forest on well-drained acid brown podzolite and mountain meadow forest soil. The upper reaches of the Zagu River, a tributary of the Minjiang River, are the most distributed in the valleys at an altitude of 3200-3700 meters, forming dense pure forests. The vast Minjiang fir forest formed by this tree species is one of the dominant forest types in the alpine forests in Southwest my country, and has important ecological functions such as water conservation, soil and water conservation, and biodiversity maintenance.

The alpine timberline refers to the high latitude area or high mountain, due to low temperature (the highest monthly average temperature is below 7°C) and wind and soil conditions, the boundary of the forest cannot be formed. Timberline is an important ecological transition zone that divides alpine landscape types, and the trees growing in it are very sensitive to changes in environmental critical conditions. Abies Minjiang is one of the main tree species that form timberlines on the southeastern margin of the Qinghai-Tibet Plateau. Compared with low-altitude areas, the living environment of Abies Minjiang in timberline environments is worse, and its seedlings are more severely stressed by the environment and difficult to survive.

The existing methods for evaluating the growth of Abies Minjiang fir seedlings are mainly based on the cumulative size of biomass and the size of a single index (such as base diameter, tree height, etc.). However, in the treeline environment, the life and death of the top buds of Abies chinensis seedlings and the percentage of live branches and live leaves in the current year are very important, and the combination of single external morphological indicators (such as height/ground diameter, crown width/age, old live branches/ The combination of the longest branch age and other indicators) will be more comprehensive and objective. Therefore, it is the first time that the method proposed by the present invention adopts the external comprehensive morphological index to comprehensively and quantitatively evaluate the growth of Abies Minjiang River seedlings under the treeline environment.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the prior art and provide an objective method for quantitatively evaluating the growth of Abies Minjiang in treeline environment.

The object of the present invention is achieved through the following technical solutions: a method for comprehensively evaluating the growth of Abies japonica seedlings under the treeline environment, it may further comprise the steps:

S1. Measure the ground diameter, height, crown width, lateral branch dimension, longest live branch age, longest branch upper age, longest longest branch lower age, upper live live branch, number of top branches, and current year branch length of Minjiang fir seedlings. Percentage of living leaves, and calculate height/ground diameter, crown width/age and live branch/oldest branch age;

S2. Select the following seven indicators: height/ground diameter, crown width/age, old live branch/longest branch old, side branch dimension, current year old branch length, live leaf ratio and top branch number;

S3. Giving weights to the seven indicators described in step S2;

S4. Do weighting and convert the seven indexes after weighting into a percentage system to obtain the total growth index Z' of the Minjiang fir seedlings, evaluate the growth of the Minjiang fir seedlings, wherein, the growth of the Minjiang fir seedlings is divided into dead state, poor , medium, good and excellent five grades.

The specific calculation process of steps S3 and S4 is as follows:

According to the seven indicators of N Minjiang fir individual samples and above, a data matrix with N rows and 7 columns is established:

Index weighting adopts the coefficient of variation method, and the coefficient of variation

为单个指标的均值，

S_j为单个指标的标准差，

in,

is the mean value of a single indicator,

S _j is the standard deviation of a single indicator,

The coefficient of variation of each index is normalized to obtain the weight W _j of each index,

The total growth index of the Minjiang fir seedlings is represented by _Zi :

Among them, H _ij is the static individual index,

Finally, to convert the total index to a percentile scale,

Among them, Z _max is the maximum value of the total index among all individuals.

Further, the index weighting of the Minjiang fir seedlings adopts the variation index method.

Further, the total growth index of the Minjiang fir seedlings is constructed using a static index.

Further, when Z'=0, the Minjiang fir seedlings are dead;

When 0<Z’≤20, the individual growth level is poor;

When 20<Z'≤40, the growth level of the individual is medium;

When 40<Z'≤60, the individual growth grade is good;

When 60<Z'≤100, the individual growth level is excellent.

Among the present invention, ground diameter is the diameter at the soil mark place of nursery stock base; Height is the seedling trunk length from ground diameter to terminal bud base; Canopy width is the average value of the maximum width of north-south and east-west direction; Side branch dimension is the lateral branch development direction Quantity (for the seedlings of Minjiang fir on the timberline, it is generally up to 4 dimensions); the longest living branch age is the age of the longest side branch of the seedling individual; the longest branch age is the trunk part above the intersection position of the trunk and the longest side branch the growth age of the longest branch; the age of the longest branch is the growth age of the trunk part below the intersection position of the trunk and the longest side branch; The number is the number of branches with terminal buds; the length of the branch in the current year is the length of the top branch of the year (there can be multiple top branches and their lengths); the percentage of live leaves is the number of surviving needles and the total number of leaves on the top branch of the year Percentage of (live leaves + remaining dead leaves + leaf scars after falling off).

Advantages of the present invention: the present invention provides a method for evaluating the growth of Abies Minjiang seedlings under a treeline environment, the present invention links the morphological indicators of Abies Minjiang seedlings with the growth, and can accurately and conveniently evaluate the growth of Abies Minjiang fir seedlings Quantitative evaluation and classification of the growth of Abies Minjiang seedlings provides an effective method for quantitative evaluation of the growth of Abies Minjiang fir seedlings in treeline environment.

Detailed ways

The present invention will be further described below in conjunction with embodiment, protection scope of the present invention is not limited to the following:

In August 2019, at the pass of Zhegu Mountain in Miyaluo Town, Li County, Sichuan Province, at an altitude of 4,300 meters, two forest community quadrats of 40 meters by 100 meters were set up, and the interval between the two quadrats was 10 meters. The seedling quadrats of 5 m x 5 m were surveyed at an altitude, and 257 fir seedlings of Minjiang River (tree height < 1.3 m) were surveyed. The specific method is as follows:

S1. Measure the ground diameter, height, crown width, lateral branch dimension, longest live branch age, longest branch upper age, longest longest branch lower age, upper live live branch, number of top branches, and current year branch length of Minjiang fir seedlings. Live leaf percentage, and calculate height/ground diameter, crown width/age and live branch/age of the longest branch.

Among them: the ground diameter is the diameter of the soil mark at the base of the seedling; the height is the length of the seedling trunk from the ground diameter to the base of the terminal bud; the crown width is the average value of the maximum width in the north-south and east-west directions; the lateral branch dimension is the number of lateral branch expansion directions ( For the seedlings of Minjiang fir at the timberline, generally the maximum is 4 dimensions); the longest living branch age is the age of the longest side branch of the seedling; the longest branch age is the growth of the main trunk above the intersection position of the trunk and the longest side branch Age; the age of the longest branch is the growth age of the main trunk below the intersecting position of the trunk and the longest side branch; the number of living branches of the upper age is the number of side branches growing on the main trunk above the intersecting position of the trunk and the longest side branch; the number of top branches is The number of branches with terminal buds; the length of the branch in the current year is the length of the top branch of the year (there can be multiple top branches and their lengths); leaves + remaining dead leaves + leaf scars after falling off).

S2. Select the following seven indicators: height/ground diameter, crown width/age, old live branch/longest branch old, side branch dimension, current year old branch length, live leaf ratio and top branch number;

S3. Giving weights to the seven indicators described in step S2;

S4. Weighting the seven indicators after weighting and converting them into percentages to obtain the total growth index Z' of Abies Minjiang River seedlings, and evaluating the growth of Abies Minjiang River seedlings.

The specific process of steps S3 and S4 is as follows:

According to 257 samples and 7 indicators, a data matrix with 257 rows and 7 columns is established:

Index weighting adopts the coefficient of variation method, and the coefficient of variation

为单个指标的均值，

S_j为单个指标的标准差，

in,

is the mean value of a single indicator,

S _j is the standard deviation of a single indicator,

The coefficient of variation of each index is normalized to obtain the weight W _j of each index,

The total growth index of the Minjiang fir seedlings is represented by _Zi :

Among them, H _ij is the static individual index,

Finally, to convert the total index to a percentile scale,

Among them, Z _max is the maximum value of the total index among all individuals.

The analysis results show that there are 30 seedlings rated as excellent in growth, accounting for 11.67% of the total sampling; 89 seedlings rated as good in growth, accounting for 34.63% of the total sampling; 86 seedlings rated as medium in growth, accounting for The total sampling ratio was 33.46%; there were 52 seedlings with poor growth rating, accounting for 20.23% of the total sampling ratio. This data is consistent with the results of the seedling quality determined by the observation of the field investigation site, indicating that by adopting this technical method, the growth of Minjiang fir seedlings in the treeline environment can be accurately quantified and graded, and the growth of each individual plant can also be scored and evaluated. assignment.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any person familiar with the technical field within the technical scope disclosed in the present invention, according to the technical solution of the present invention Equivalent replacements or changes to the inventive concepts thereof are all covered within the protection scope of the present invention.

Claims (3)

1. a kind of method that Minjiang fir seedling growth is comprehensively evaluated under treeline environment, is characterized in that, it comprises the following steps: S1. Measure the ground diameter, height, crown width, lateral branch dimension, longest live branch age, longest branch upper age, longest longest branch lower age, upper live branch number, top branch number, current year branch length of Minjiang fir seedlings and the percentage of live leaves, and calculate height/ground diameter, crown width/age and last-age live branch/longest branch age; among them, the ground diameter is the diameter at the soil mark at the base of the seedling; the height is from the ground diameter to the base of the terminal bud The length of the seedling trunk; the crown width is the average value of the maximum width of the north-south and east-west directions; the side branch dimension is the number of side branches in the direction of expansion; the longest live branch age is the age of the longest side branch of the seedling individual; the longest branch age is the age of the trunk and The growth age of the trunk part above the intersection position of the longest side branch; the growth age of the trunk part below the intersection position of the longest branch and the longest branch; the number of living branches at the old age is the trunk above the intersection position of the trunk and the longest side branch The number of lateral branches growing on top; the number of top branches is the number of branches with terminal buds; the length of the current year's branches is the length of the top branches of the current year; the percentage of live leaves is the percentage of the number of surviving needles on the top branches of the current year to the total number of leaves , the total number of leaves is living leaves+residual dead leaves+leaf scars after shedding; S2. Select the following seven indicators: height/ground diameter, crown width/age, number of old live branches/longest branch old, side branch dimension, current year branch length, percentage of live leaves and number of top branches; S3. Giving weights to the seven indicators described in step S2; S4. weighting the seven indexes after weighting and converting into a percentage system to obtain the total growth index Z' of Abies Minjiang seedlings, evaluate the Abies Minjiang seedlings growth, wherein, the growth of Abies Minjiang seedlings is divided into dead state, poor , medium, good and excellent five grades; The specific calculation process of steps S3 and S4 is as follows: According to the seven indicators of N Minjiang fir individual samples and above, a data matrix with N rows and 7 columns is established:

Index weighting adopts the coefficient of variation method, and the coefficient of variation

in,

is the mean value of a single indicator,

S _j is the standard deviation of a single indicator,

The coefficient of variation of each index is normalized to obtain the weight W _j of each index,

The total growth index of the Minjiang fir seedlings is represented by _Zi :

Among them, H _ij is the static individual index,

Finally, to convert the total index to a percentile scale,

Among them, Z _max is the maximum value of the total index among all individuals. 2. A method for comprehensively evaluating the growth of Abies Minjiang River seedlings under the treeline environment according to claim 1, characterized in that the index weighting of Abies Minjiang River seedlings adopts the coefficient of variation method. 3. a kind of method that the Minjiang fir seedling growth condition is comprehensively evaluated under the timberline environment according to claim 1, is characterized in that, when Z'=0, the Minjiang fir seedling is dead state; When 0<Z'≤20, the growth level of Abies Minjiang is poor; When 20<Z'≤40, the growth level of Abies Minjiang is medium; When 40<Z’≤60, the growth grade of Minjiang fir seedlings is good; When 60<Z'≤100, the growth level of Abies Minjiang is excellent.