阅读说明：本技术 基于近邻关系的树种空间隔离程度评价方法 (Tree species space isolation degree evaluation method based on neighbor relation ) 是由 琚存勇 盛后财 孙晓新 段亮亮 蔡体久 于 2020-04-20 设计创作，主要内容包括：一种基于近邻关系的树种空间隔离程度评价方法,属于树种空间分布多样性、复杂性评价领域。本发明为解决现有基于近邻关系评价树木间混交程度的指数在实际应用中不能全面评价树木间空间隔离关系的问题。包括确定目标树与近邻树；计算目标树与多株近邻树的简单混交度；确定多株近邻树树种,获得多株近邻树树种中不同于目标树树种的累计数,计算所述累计数相对于多株近邻树总株数的树种比例；进而计算得到树种多样性混交度；再确定多株近邻树中,两两相邻的近邻树为不同树种的累计次数；计算累计次数相对于多株近邻树总株数的占有比例；最后得到树种空间混交度；所述树种空间混交度用于评价树种空间的隔离程度。本发明可实现树种多样性的空间测度。(A tree species space isolation degree evaluation method based on a neighbor relation belongs to the field of tree species space distribution diversity and complexity evaluation. The invention aims to solve the problem that the existing index for evaluating the mixing degree between trees based on the neighbor relation cannot comprehensively evaluate the spatial isolation relation between trees in practical application. Determining a target tree and a neighbor tree; calculating simple mixed crossing degrees of the target tree and the neighbor trees; determining a plurality of neighbor tree species, obtaining the cumulative number of the neighbor tree species different from the target tree species, and calculating the proportion of the cumulative number to the total number of the neighbor tree species; further calculating to obtain tree species diversity mixing degree; determining the cumulative frequency of every two adjacent neighbor trees in the multiple neighbor trees as different tree species; calculating the occupation proportion of the accumulated times relative to the total number of the neighbor trees; finally, obtaining the spatial mixing degree of the tree seeds; the tree species space mixing degree is used for evaluating the isolation degree of the tree species space. The invention can realize the spatial measurement of the tree species diversity.)

1. A tree species space isolation degree evaluation method based on a neighbor relation is characterized by comprising the following steps:

selecting a target tree, and determining a plurality of neighbor trees corresponding to the target tree in a target structure unit;

calculating simple mixed degree of the target tree and a plurality of neighbor trees;

determining a plurality of neighbor tree species, obtaining the cumulative number of the neighbor tree species different from the target tree species, and calculating the ratio of the cumulative number to the total number of the neighbor tree species; multiplying the tree seed proportion by the simple cross mixing degree to obtain tree seed diversity cross mixing degree;

determining the cumulative frequency of every two adjacent neighbor trees in the multiple neighbor trees as different tree species; calculating the occupation proportion of the accumulated times relative to the total number of the neighbor trees; multiplying the occupation proportion by the tree species diversity mixing degree to obtain a tree species space mixing degree; the tree species space mixing degree is used for evaluating the isolation degree of the tree species space.

2. The method of claim 1, wherein the degree of spatial isolation of tree species based on the nearest neighbor relation is determined by the degree of spatial isolation of tree species,

the simple degree of mixing M_iThe calculating method comprises the following steps:

in the formula N_iRepresents the total number of neighbor trees, v_ijA tree species coefficient representing the number of each neighbor tree and the target number; when the neighbor tree is different from the target tree, v_ij1 is ═ 1; when the neighbor tree is the same as the target tree, v_ij＝0。

3. The method of claim 2, wherein the degree of spatial isolation of tree species based on the nearest neighbor relation is determined by the degree of spatial isolation of tree species,

the tree species diversity mixing degree MS_iThe calculating method comprises the following steps:

in the formula S_iRepresenting the cumulative number of the neighbor tree species different from the target tree species.

4. The method of claim 3, wherein the degree of spatial isolation of tree species based on the nearest neighbor relation is determined by the degree of spatial isolation of tree species,

the spatial mixed crossing MSP of the tree seeds_iThe calculating method comprises the following steps:

in the formula P_iThe cumulative number of times that two adjacent neighbor trees are different tree species is represented.

5. The method for evaluating the degree of spatial isolation of tree species based on neighbor relation according to any one of claims 1 to 4, wherein the method for selecting the target structural unit comprises:

around the target tree, target structural units are determined with a preset radius.

6. The method for evaluating the degree of spatial isolation of tree species based on neighbor relation according to any one of claims 1 to 4, wherein the method for selecting the target structural unit further comprises:

and determining target structural units according to Thiessen polygons around the target tree.

Technical Field

The invention relates to a tree species space isolation degree evaluation method based on a neighbor relation, and belongs to the field of tree species space distribution diversity and complexity evaluation.

Background

The structure of the forest determines the forest ecological service function. The more complex the internal structure of the forest, the more stable the ecological system is represented.

The forest structure can be divided into a vertical structure and a horizontal structure, the abundance of tree species in the structure is irrelevant to the position, and the mixed relation of the tree species is relevant to the position. At present, the horizontal spatial structure of a forest is mainly evaluated in three aspects: horizontal distribution pattern, size ratio among trees and blending degree among trees.

An index for evaluating the mixed degree of trees based on a neighbor relation is proposed in 2002, and at present, the index mainly comprises four forms: the simple cross degree of Gadow, the tree species diversity cross degree of tangram, the full cross degree and the tree species space diversity index of virtuous vigor, which only concern the tree species difference between the target tree and the adjacent tree but do not consider the species difference between the adjacent trees, or concern the species difference between the target tree and the adjacent tree and between the adjacent tree and the adjacent tree but do not consider the position relation of the adjacent trees. The full degree of mixing is considered relatively comprehensive, but the numerical physical meaning is not clear enough. The value of the total degree of mixing varies with the size of the structure, and the maximum value varies.

Therefore, the indexes used for evaluating the mixing degree among trees at present have more or less defects, and the spatial isolation relationship among trees is difficult to be evaluated accurately and comprehensively in practical application.

Disclosure of Invention

The invention aims to solve the problem that the existing index for evaluating the mixing degree among trees based on the neighbor relation cannot comprehensively evaluate the spatial isolation relation among trees in practical application, and provides a method for evaluating the spatial isolation degree of tree species based on the neighbor relation.

The invention discloses a tree species space isolation degree evaluation method based on a neighbor relation, which comprises the following steps:

selecting a target tree, and determining a plurality of neighbor trees corresponding to the target tree in a target structure unit;

calculating simple mixed degree of the target tree and a plurality of neighbor trees;

determining a plurality of neighbor tree species, obtaining the cumulative number of the neighbor tree species different from the target tree species, and calculating the ratio of the cumulative number to the total number of the neighbor tree species; multiplying the tree seed proportion by the simple cross mixing degree to obtain tree seed diversity cross mixing degree;

determining the cumulative frequency of every two adjacent neighbor trees in the multiple neighbor trees as different tree species; calculating the occupation proportion of the accumulated times relative to the total number of the neighbor trees; multiplying the occupation proportion by the tree species diversity mixing degree to obtain a tree species space mixing degree; the tree species space mixing degree is used for evaluating the isolation degree of the tree species space.

According to the method for evaluating the tree species space isolation degree based on the neighbor relation,

the simple degree of mixing M_iThe calculating method comprises the following steps:

in the formula N_iRepresents the total number of neighbor trees, v_ijA tree species coefficient representing the number of each neighbor tree and the target number; when the neighbor tree is different from the target tree, v_ij1 is ═ 1; when the neighbor tree is the same as the target tree, v_ij＝0。

According to the method for evaluating the tree species space isolation degree based on the neighbor relation,

the tree species diversity mixing degree MS_iThe calculating method comprises the following steps:

in the formula S_iRepresenting the cumulative number of the neighbor tree species different from the target tree species.

According to the method for evaluating the tree species space isolation degree based on the neighbor relation,

the spatial mixed crossing MSP of the tree seeds_iThe calculating method comprises the following steps:

in the formula P_iThe cumulative number of times that two adjacent neighbor trees are different tree species is represented.

According to the method for evaluating the tree species space isolation degree based on the neighbor relation, the method for selecting the target structural unit comprises the following steps: around the target tree, target structural units are determined with a preset radius.

According to the method for evaluating the tree species spatial isolation degree based on the neighbor relation, the method for selecting the target structural unit further comprises the following steps: and determining target structural units according to Thiessen polygons around the target tree.

The invention has the advantages that: the method can be used for evaluating the complexity of the spatial distribution of the tree species. The isolation degree of the tree species space can be evaluated by calculating the obtained numerical value of the tree species space mixing degree, and the larger the numerical value is, the higher the isolation degree of the same tree species space is, and the more complex the forest internal structure is.

The method can realize the spatial measurement of the variety of the tree species, and the finally obtained spatial mixing degree of the tree species can reflect the variety of the tree species in the forest ecological system and also reflect the variety of the spatial position relationship of the trees; the method can correctly evaluate the degree of the spatial isolation of the tree species, comprehensively embody the spatial isolation relationship among the trees, and provide reference for judging the diversity and stability in the forest ecological system.

Drawings

FIG. 1 is a flow chart illustrating a method for evaluating a spatial isolation degree of a tree species based on a neighbor relation according to the present invention;

FIG. 2 is a diagram of a first arrangement of a target tree and a plurality of neighbor trees in a target building block;

FIG. 3 is a diagram of a second arrangement of a target tree and a plurality of neighbor trees in a target building block;

FIG. 4 is a diagram of a third arrangement of a target tree and a plurality of neighbor trees in a target building block;

FIG. 5 is a diagram of a fourth arrangement of a target tree and a plurality of neighbor trees in a target building block.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.