论林分系统的存在与演变

天然森林中包含着多种类型的林分类型,各个林分系统具有自然历史确定的地理分布范围,外界的“能量流”和“物质流”都呈非均匀分布状态,因此造成林分系统“结构状态”和“演变动态”的多样性。林分系统中的各个林分与外界进行能量、物质转换的规律相似,林分内部的“优胜劣汰”规律也相似。因此可用“内部时间T(D)”：3、4、5……32所刻画的“立木度／蓄积度”序列和“株数递减率／蓄积量递增率”序列的数学模型,来描述林分从幼林到过熟林的演变过程,这就是林分系统的“周期行为”。进入过熟林分以后,林分平均直径“D”的变化无规律性,但过熟林分仍然通过“新生林木更替衰老林木”而向前演变发展,这种“非周期行为”表达了林分系统“从存在到演化”的永恒性。

A Research on Existence and Evolvement of Forest System

There were many types of forests in natural forest, each type has its distribution area formed by the natural law. It is diversiform of the structure and evolvement trends of the forests, because the environmental "energy flow" and "matter flow" distribution is asymmetric. The law of each type of forest changes energy and matter with the environment is similar, and the law of competition in the forests is also similar, so a mathematical model formed by the list of "stand time T(D) " 3,4,5......32, equaling to "stand number/volume"and "reducing rate of tree number/increasing rate of cumulation", which can be used to describe the process of the forests from young to over mature, this is the periodicity of the forests. When a forest become over mature, the average diameter of the forest changes irregularly, but the over mature stand will go on evolving with young trees taking place of old trees. And this "nonperiodic phenomenon" shows that the evolvement process of the forest system is immutability.