Study And Application Of TLS Technology In Investigation Of Bamboo Forest

Bamboo is an important forest in southern China,it not only has high economic benefit,but also plays an important ecological benefit in preserving water resources,maintaining soil and water loss,carbon sequestration and oxygen release and biodiversity conservation.Bamboo and boradleaved mixed forest is a new type of economy of bamboo planting pattern,is conducive to maintaining the balance of the bamboo ecosystem,improve the stand structure of Phyllostachys pubescens,adjust the bamboo forest ecological quality,directly related to the economic and ecological benefits of bamboo forest.Because of Terrestrial Laser Scanning has high resolution and anti-jamming and other unique advantages,so that the object can be obtained in single tree stand structure and parameter information of high precision forest plots,provides high resolution three-dimensional forest canopy measuring means a non destructive for us.Compared with the traditional means of forestry investigation,Terrestrial Laser Scanning to obtain forest parameters(tree height,DBH,crown width,leaf area index,aboveground biomass,etc.)can not only save manpower,not affected by external conditions and interference,can obtain the traditional method is not easy to obtain the tree canopy(surface area,the volume and contour)parameter information,to supplement the existing forest monitoring means.Therefore,in this paper,bamboo and broad-leaved mixed forest as the research object,the bamboo and broad-leaved mixed forest plots for data acquisition using ground-based laser radar technology,the extraction of single tree attribute parameters to obtain the point cloud data,a brief analysis of competition between bamboo and broad-leaved mixed forest,obtained the following conclusions:(1)Identification rate of single tree in Bamboo and Broad-leaved mixed forest based on TLSThe data of Phyllostachys pubescens and broad-leaved trees in bamboo and broad-leaved mixed forest were measured and compared with single-station scanning data and multi-station splicing data.The results showed that the total identification of multi-station splicing was 96.6% and the overall recognition rate of single station scanning at the central site was 81.4%.In the six bamboo and broad-leaved mixed forest plots,the regression accuracy of the DBH of the broad-leaved tree and bamboo and the DBH by actual measuring were more than 99%,the overall regression fitting accuracy was 99.5%,and the residual standard error was 0.25.(2)Effects of Broad-leavel trees on Phyllostachys pubescens in bamboo and broad-leaved mixed forest plotsThe number and average DBH of Phyllostachys pubescens in the different ring bands of broadleaf trees increased rapidly with the increase of distance from the broad-leaved trees.The number of Phyllostachys pubescens per unit area in the 1m to 6m ring zone of broad-leaved trees was 0.29 plants/m~2,0.33 plants/m~2,0.37 plants/m~2,0.32 plants/m~2,0.35 plants/m~2 and 0.30 plants/m~2,with an average DBH of 6.6 cm,9.1 cm,9.8 cm,9.7 cm,9.7 cm,9.7 cm.The maximum increase in the number of Phyllostachys pubescens and the average DBH in the range of 1m to 3m of broadleaf trees were 13.8% and 48% respectively.After 3m,the number of Phyllostachys pubescens per unit area and the average DBH decreased,and even stabilized.(3)Study on Interspecies competition between species of bamboo and broad-leaved mixed forestIn this paper,based on the simple competition index model,the volume overlap degree of broadleaf trees and bamboo crowns was used as the competition factor for the first time.The canopy competition index model based on the canopy factor was established by defining the volume of the overlapping part of the broadleaf tree and bamboo crown and the tree height and DBH ratio of broadleaf and bamboo.The results of canopy competition index showed that the canopy competition index(CCI)of Quercus acutissima 1,Quercus acutissima 2 and Quercus acutissima 3 and its surrounding Phyllostachys pubescens were 35,33.5 and 35.2 respectively.The results show that the Point Cloud data acquisition technology can extract the crown canopy information of traditional research is not easy to obtain,the canopy information can provide competitive factor for the study of canopy competition bamboo and broad-leaved mixed forest,TLS can provide technical support for better research of mixed forest competition.