Abstract: In order to improve the efficiency of the investigation of forest resources,a design for monitoring forest resources disturbance based on 7-tree is developed,which proceeds from the Voronoi diagram and Delaunay triangulation by constructing spatial structure units that is achieved by some characteristic parameters on sample tress acquired by high-precision prism total station with the aid of south CASS software.In this study,on analysis of forest resource inventory data sampled from five representative plots in Baihua Mountain of Beijing,the proposed technique is compared with other traditional methods.The optimal plot covers between 0.005 and 0.015 ha,which can resolve the problem that the tree height growth could not be measured due to the low precision in conventional altimeters.The results show that there has less steadiness in precision of the data collected in mingled forests and wildwoods than those from plantation and single-layered forest.Fortunately,the precision can be improved with the more plots.From these data,it can be indicated that in the mean stand height,the error is ±0.005mm and in the tree height growth,the relative error is 1%,and the Sampling accuracy can remain 83%~98% in the stand density and over 92% in the stand stock.This method is advantageous in many aspects over those available,such as efficiency,precision and digitization,which is essentially easy to operate in monitoring forest resources disturbance.

Key words: 7-tree method, forest resources disturbance, monitoring, precision