Research Of Technology And Methord Of Forest Resource Inventory

Forest is an important part of the ecosystem of the Earth and the basis of healthy and sustainable development of human society. In order to grasp the comprehensive situation and dynamic of forest resource, after fifty years of efforts, China has built up a whole perfect set of National Forest Inventory (NFI) technology system (referred to as a class of inventory), and it takes five years as a survey cycle to form the final summary report on the results of forest resource inventory for the country. The key technology is the precise determination of preliminary investigation and review data of the same fixed sample, and directly compare and analyze the value in pairs obtained, so as to get the status of forest resources and their growth and decline.This paper takes "Technology and Methord of Forest Resource Inventory," the important issue of forestry science and technology as the center to launch a more innovative and systematic research which mainly includes the analysis of various errors and interrelationships which contains in the forestry a class of inventory by using the law of error propagation and statistical methods. In order to eliminate these errors as many as possible, the high-precision forest survey instruments has been development and their effectiveness and accuracy has been verified. Meanwhile, the study of polygon method can be used to estimate the forest volume, and analyze other new equipments using for forest survey and their effects.Firstly, in accordance with China’s continuous technical requirements of forest inventory, errors generated from the research can be divided into sampling error and non-sampling error by using simple system sampling setting fixed sample plots. The accuracy of forest inventory is represented by sampling error, and measuring error is not included. So there may be a high sampling accuracy but a low actual accuracy. According to the different links resulting from errors, non-sampling errors can be divided into the sample plot area error, the sample plot observation error and the sample plot model error. The article uses the law of error propagation and statistical methods, combined with a number of practical examples for introducing the calculation method of each error and the overall error and their relationships. Finally, to solve the imperfections of the current national forest resource inventory system, such as the simple design and low efficiency of sampling methods of sample plot, the article proposes the inventory method of lamination clustering placement of sample plots and part repetition and joint estimation.Secondly, in order to eliminate errors as many as possible to improve the accuracy of the survey, the author made an innovative research on the key technical methods of a class of forest resources inventory, which took self-developed FTS-2total station as inventory equipment, took large trees in30permanent plots, about24,500sample trees as object to imitate a class of fixed sample plot to conduct the research. The results showed that the use of high-accuracy total station for the investigation of a class of fixed sample plots can obtain the three-dimensional coordinates of each tree in the fixed sample.Among which, error in coordinate measurement is less than4mm, and error in height measurement is less than7mm. The height measurement accuracy of each tree is about97%, and the average time is less than5seconds. The relative error of diameter at breast height value measurement of each tree is only2%, and the average time is about3seconds. The relative error of crown amplitude measurements of each tree is less than10%. The tree volume measurement accuracy is up to95%. The three-dimensional modeling of sample wood distribution map, precision reset of sample wood in sample plot, and digitization of sample plot. In addition, the article took three-dimensional coordinates of total station of each tree as the discrete points of information, and used Voronoi polygon algorithm to extract and analyze the parameter information of the stand spatial structure so as to provide advanced equipment, precision instruments and survey methods to China’s key technologies of a class of forest inventory. What’s more, the terrestrial laser scanning system and the self-developed Electronic measuring tree gun were used to investigate the forest sample plots.Finally, the article took FTS-2total station as survey instrument, and polygon method as survey methods of the forest volume and investigated a total of70angle gauge sampling points randomly in the experimental tree farms in Beijing and its surrounding counties. Through the comparison with traditional investigation methods of angle gauge of stock volume, conclusion can be get that octagonal sample plot namely, taking eight trees as boundary wood in sample plot, can lead to a higher accuracy of stand volume estimation. According to the estimation result, the stock volume estimation accuracy can be up to90%by excluding gross errors and under the95%reliability. It meets the accuracy requirement of a class of inventory of China’s forest. Meanwhile, this research can provide new method and technology to estimate China’s forest volume.