CN105243050A

CN105243050A - Method for calculating maximum forest stand volume

Info

Publication number: CN105243050A
Application number: CN201510602533.1A
Authority: CN
Inventors: 冯仲科; 闫飞凡; 邱梓轩
Original assignee: Beijing Forestry University
Current assignee: Beijing Forestry University
Priority date: 2015-09-18
Filing date: 2015-09-18
Publication date: 2016-01-13

Abstract

The present invention discloses a method for calculating a maximum forest stand volume. According to the method, when the growth of forest stand tends to be mature, a 3D angle gauge instrument is used for observing forest stand parameters at a fixed point at an interval of about 5-10 years. Observed data in the year comprises tree height Hij, an individual diameter-at-breast-height dij, and forest stand density Nij. According to a forest stand growth model, increments delta dij and delta Hij and other data are calculated; then, a known mathematical model is used for calculating a forest stand volume; and at last, a determination condition is used for calculating the maximum forest stand volume.

Description

A kind of method calculating the maximum accumulation of standing forest

One, technical field

The present invention relates to a kind of method measuring the maximum accumulation of standing forest, particularly calculate the maximum accumulation of standing forest based on 3D angle gauge measuring technique.

Two, technical background

Accumulation is the important indicator of qualification forest quantity, is also the height index indicating PRODUCTIVITY OF FOREST SOIL, and measuring forest land Stand Volume is one of important evidence of Stand investigation, and it provides important quantity basis for orest management and felling utilize.The maximum accumulation of present stage estimation standing forest has many inconveniences:

1. Stand Volume is annual all in change, although can calculate Stand Volume by observed parameter, its maximum value is difficult to hold, and is difficult to reach utilize maximize.

2. adopt classic method field process amount comparatively large, more time-consuming, observation interval is difficult to hold.

Three, summary of the invention

In order to calculate and estimate the maximum accumulation of standing forest, adopt and every n (it is 5-10 that n generally adopts) observation mode once, standing forest parameter is calculated.

Object implementation of the present invention:

1. a slice forest generates and acquires a certain degree, during close to mature forest, under the prerequisite that the supposition density of crop is substantially constant, namely there is not the measures such as artificial transplanting, selective cutting, felling, adopt 3D angle gauge to observe standing forest parameter year by year, specifically known parameter has: seeds i (i=1 ... m), wooden j (j=1 is counted ... n), height of tree H _ij, single wooden diameter of a cross-section of a tree trunk 1.3 meters above the ground is d _ij, density of crop N _ij.

2. according to prediction of stand growth model predicted growth amount Δ d _ijtwith Δ H _ijt.

3. according to known mathematical model: ask and calculate Stand Volume.

4.n value is generally 5-10, can adopt Beijing n=5, the scheme of other regional n=10.

5. because the category-A accuracy requirement of China's Forest Resources forestry resource survey reaches 85%, permissible error is 15%, and medial error is then 7.5%, so its negligible error is 2.5% (E/3).

6. so judge whether stand reaches maximum, can adopt (M _t+n-M _t)/M _tthe decision condition of <=2.5%, think when namely accumulation increment is less than or equal to 2.5% that stand growth reaches minimum substantially, the maximum accumulation of standing forest reaches peak value, now M _tbe the maximum accumulation of standing forest.

This invention has the following advantages:

1. the method calculation of measured data is simple, and instrumentation is simple, decreases the enforcement difficulty of outdoor workers, very low for manpower and materials requirement condition.

2 tradition measure Stand Volume and are difficult to judge whether standing forest reaches maximum accumulation, the method achieve the simple mode measuring the maximum accumulation of standing forest, provide valuable reference for work on forestry.

Four, embodiment:

1. under the supposed premise that there are not the measures such as artificial transplanting, selective cutting, felling, at fixed point erection 3D angle gauge, the height of tree H of observation counting wood respectively _ij, single wooden diameter of a cross-section of a tree trunk 1.3 meters above the ground is d _ij, density of crop N _ij.

2. increment Δ d _ijwith Δ H _ijdata are obtained by known Stand Growth Model.

3. by known mathematical model ask and calculate Stand Volume.

4. measure a secondary data every n, under usual conditions, n is about 5 to 10 years, adopts area, Beijing n=5, the scheme of other regional n=10.

1) judge whether stand reaches maximum, can adopt (M _t+n-M _t)/M _tthe decision condition of <=2.5%, when namely accumulation increment is less than or equal to 2.5%, then thinks that Stand Volume reaches maximal value, now M _tbe the maximum accumulation of standing forest.

Claims

1. calculate a method for the maximum accumulation of standing forest, it is characterized in that: 1. when Stand Growth levels off to maturation, adopt 3D angle gauge technology fixed point to measure standing forest parameter, every n observation once; Concrete observed parameter has then: seeds i (i=1 ... m), wooden j (j=1 is counted ... n), height of tree H _ij, single wooden diameter of a cross-section of a tree trunk 1.3 meters above the ground is d _ij, density of crop N _ij; 2. increment Δ d is gone out according to Stand Growth Model precomputation _ijtwith Δ H _ijt; 3. n value is generally 5-10, can adopt Beijing n=5, and other areas can adopt the scheme of n=10; 4. according to known mathematical model: ask and calculate Stand Volume; 5. because the category-A accuracy requirement permissible error of China's Forest Resources forestry resource survey is 15%, medial error is then 7.5%, and its negligible error is 2.5%, therefore judges whether standing forest reaches maximum condition and be: (M _t+n-M _t)/M _t<=2.5%, when meeting this condition, M _tbe the maximum accumulation of standing forest.