森林动态演替现象的可视化模拟

由于自然环境、资源竞争、生长繁衍等因素的影响，森林中树木的空间分布格局不断发生着变化。本文基于森林生态学的相关理论，对森林的这种动态演替现象进行了研究和模拟。我们采用一种二维分布图的形式来着重展现森林演替过程中的自然稀疏、多树种演替和聚集生长三种重要的变化规律，并以此为基础，通过迭代推演的方式实现了森林景观动态演替过程的可视化模拟。模拟计算过程中，为了加速迭代推演过程中最耗时的树木相交测试，本文还提出一种“扩展边界的四叉树”方法，提高了计算效率。本文在生成森林初始分布信息时参考了有关森林空间数据的概念，能够生成符合林业上树木胸径分布的森林数据。本文技术方法不仅可应用于影视动画、虚拟现实等领域，而且在林业科学研究与应用上也具有潜在的应用价值。

Simulation of the dynamic evolution of spatial distribution of trees in the forest

As the impact of natural environment, resource competition, propagation of trees and other factors, the spatial distribution of trees in forest is changing continuously. In this paper, we put forward the method to simulate this dynamic evolution of forest based on the theory of forest ecology. In the method, the spatial distribution information of trees is recorded and visualized in a form of two-dimensional distribution diagram, and three important evolution rules of forest: self-thinning, species succession and clustering growth, are simulated with iterated deduction manner. Based on the simulation results above, this paper realize the visual performance of the procedure of forest dynamic simulation. In the simulation, for the seek of speeding up the process of making intersection test among trees which is the most time-consuming process in iterated deduction, we proposes the improved quadtree algorithm quadtree with extended boundaries to reduce the number of intersection test. This paper generates the initial distribution information of trees by reference to the conception of the foresty spatial data, which can make the initial data of forest to better fit the diameter distribution of trees. The method can be used to provide the dynamic distribution data of forest for further realizing the realistic simulation of dynamic forest scenes. Furthermore, it also has potential value in forestry research and applications. Method in this paper can be applied to the area like film and animation, virtual reality, but also has great potential applications of research and application of forestry science.