| In traditional forest inventory measurement, lots of manual measurement is necessary. Therefore, it is of great significance to discover accurate and efficient method for forest inventory in information explosion and efficiency priority society. With the development of science and technology, electronic computer technology and “3S” technology have been greatly applied in forest inventory, and many parameters could be extracted through new technology. Terrestrial laser scanning with digital processing technology is gradually becoming a tool to estimate stand state characters in forest inventory. Terrestrial Laser Scanning(short for TLS) with digital processing technology, represented by Leica Scanstation C10, providing a better platform for forest inventory. The main research contents and conclusions are as follow:The main contents are as follow:1、The study established a simulated scenario of forest inventory in plots according to scanning characteristics. Several surveyor’s pole with cylinder-shaped were used to simulate trunks of the trees and placed in the sample plots. After scanning process, the top diameters of different tree height were achieved by adequate algorithm. The research aims at setting a reference calibration of forest inventory using TLS, in considered of achieving higher accuracy and lower time consuming. Simultaneously, the calibration result will taking full advantage of TLS in forest inventory, laying a foundation of extraction of stem curve and establishment of merchantable volume table.2、After registrated by Cyclone, the point cloud data was classified according to two eigenvalues: flatness and normal vector. The 3D models of trees can be created by classified point cloud data, and the heights, DBH and top diameters at certain height of each tree can be acquired by data processing. Taper equations proposed by Ormerod, Meng Xianyu, Kozak, Yan Ruohai, Schumacher, et al. were selected as alternative models for the study. Parameters were acquired by regression analysis of data extracted from TLS. Eventually stem analysis data is used to inspect and optimize taper equation fitted by point cloud data.3、The research further analyze the relationship between DBH with bark and DBH without bark, and analyze the merchantable trunk length. With the taper equation acquired by TLS, the merchantable volume table of each age and each sample plot is established. The method and the process for establishing merchantable volume table can be applied into practical production and can save human and physical resources.The main results of the research are as follow:1、During inventory with TLS, the resolutions setting from TLS instrument doesn’t affect the accuracy of estimate result, they only have effect on scanning time and data storage. The estimate accuracy of diameter at breast high is the best because TLS has the same height of DBH. Both of the plots of 10 m radius and 15 m radius have better performance in estimate accuracy. However, it depends on the stand density in practical use.2、Taper equation established by point cloud data and by traditional method respectively. The result shows that Schumacherstemtaperequationwith4 parameters is the most suitable function to describe the growth regularity of poplar in Jiangsu Province. The model has better fitting characteristics and higher accuracy. By testing with stem analysis, the results shows that TLS taper equation has accurate estimation of merchantable trunk length and top diameter. TLS taper equation can be the foundation of yield estimations and biomass calculation.3、The research use TLS taper equation and relationship between DBH with bark and DBH without bark to establish taper equation-merchantable length-volume system, which is based on simplified specification of timbers. The system is used for theoretical bucking. The results show that merchantable volume table established by TLS taper equation can approximately replace the table established by taper equation fitted by stem analysis. Both of accuracy and residual of the table are acceptable and it can be applied into practical production.Using TLS to extract forest inventory data can save human, physical and time resources. The destruction of stand can be minimized when using TLS, which is ecological sustainability and meets the needs of forest management. The research establish a system of forest inventory by TLS, and set a basic process of using TLS to broad-leaved stand investigation, which can be the foundation of applying TLS into forest inventory. |
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