基于林分垂直空间结构特征的杉木人工林抚育间伐可视化模拟研究

Visual Simulation of Thinning of Chinese Fir Based on Stand Spatial Vertical Structure Characteristics

[目的]针对抚育间伐目前存在较少利用垂直空间结构参数的问题,以林分三维可视化模拟系统为基础,加入森林结构功能模块,研究一种以林分垂直空间结构参数A_Pvi为依据,对森林经营方案原定的抚育强度进行改进的方法。[方法]利用林分三维场景可视化模拟系统中的森林结构功能模块,通过读取杉木样地调查表中的每木数据,在虚拟场景中模拟样地的真实情况,分析样地的各空间结构参数。[结果]经过考虑林分垂直结构的间伐强度间伐后的4块样地与原定间伐强度相比,平均A_Pvi更加趋近于0,样地内林木竞争状况更加均匀,1号样地的平均A_Pvi由0.46降到了-0.24,2号样地由0.46降为0,3号样地由-0.19提升到了-0.04,4号样地由0.40降到了0.04;平均角尺度无大幅度变化,4块样地都呈随机分布状态;4块样地中,除了3号样地外,平均大小比数均出现了较大幅度的减少。[结论]考虑林分垂直结构的间伐强度与原林场森林经营方案既定的间伐强度相比,改善了林分的竞争状况,使林分内的竞争状况趋近均势。林分三维场景可视化模拟系统可以精确模拟采用不同间伐强度进行间伐后的林分拟真场景及其空间结构变化情况。

[Objective] To add stand vertical spatial structure as a parameter into forest structure module of three-dimensional visualization simulation system to make better use of vertical structure as a parameter in thinning. [Method] Using the forest structure function module in the forest three-dimensional scene visualization simulation system,by reading the data of individual trees in Chinese fir sample plot survey table, a kind of vertical space structure parameter structure parameters of the plot. [Result] The average A_Pv_i considering the thinning intensity of the vertical structure of the stand. The competition in the plot was more uniform.The average A_Pv_i average A_Pv_i of plot 3 increased from-0.19 to-0.04, and the average A_Pv_i No significant change was observed for the average angular scale, and all the four plots were randomly distributed.Among the four plots, the average size ratio decreased significantly except for the plot 3. [Conclusion] The thinning intensity taking stand vertical structure into consideration can better improve the competition status of the stand compared with the established thinning intensity specified by the forest management plan, and make the competition within the stand approaching to balance. The forest three-dimensional scene visualization simulation system can accurately simulate the forest-like immersive scenes and their spatial structure changes after thinning with different thinning intensities.