森林系统的存在与演化

第四纪的热带、亚热带、温带、寒带森林,可划分为"单层同龄林分"类型和"复层异龄林分"类型,它们都遵循着由"初始林分"走入"过熟林分"的"优胜劣汰"规则。森林产生的"死亡量"必定小于"净生长量",这种非线性的"物质运动"与热力学过程的"熵"联系起来,则能更深刻地诠释由孢子植物进化为裸子植物,进而进化为被子植物的多样性树种所组成森林的"森林耗散结构"特性。现代的森林包涵着两类林分:一类是由单一树种组成的"单层同龄林分",是不通过"树种演替"就能形成"初始林分"的林分,因而其具有简单的"内部结构"和"内部时间";另一类是由多"种群"组成的"复层异龄林分",其必需通过"树种演替"才能形成"初始林分",因而它具有复杂的"内部结构"和"内部时间"。对云南的森林,已量测到亚热带阔叶林的"过熟林分"。却缺少"先锋种群"演变为"初始林分"的先前事件,因此不可能描述出其"复层异龄林分"的先前概率。由对云南森林的分析得出,两类"林分"虽都遵循"优胜劣汰"规则,但却只能导算出"单层同龄林分"的"株数递减率和蓄积量递增率"的过程。

Existence and Evolution of Forest System

The forest types in the 4th Era including tropical,subtropical,temperate and cold zone could be classified into identical age and single-storied forest and different age and multiple-storied forest,all the forest types follow the rules of survival of the fittest from primary forest to over-mature forest.The death components in forests are definitely smaller than net growth,connected with entropy concept in thermodynamics,this kind of non-linear material movement can deeply explain the dissipative structure characteristics of forest,namely the evolution from spore plant to gymnosperm and angiosperm.Modern forest include two categories of stand,identical age and single-storied forest and different age and multiple-storied forest.Identical age and single-storied forest can form primary stand without species succession,with simple "inner time" and "inner structure";different age and multiple-storied forest can form primary stand only after species succession,therefore with complex "inner structure" and "inner time".Over-mature stands of subtropical broadleaved forests have been found in forest of Yunnan,however the events of succession from pioneer species to primary stand,therefore it is not possible to describe the probability of different age and multiple-storied forest.Both identical age and single-storied forest and different age and multiple-storied forest in Yunnan follow the rules of survival of the fittest,only the process of individual degression and volume additive increase rate can be deduced.