森林生态系统内灌草植被生物量估测方法的研究

摘要

The understory shrub and herbs in three forest types,including Pinus tabulaeformis forest,Quercus variabilis forest and mixed coniferous forest in Beijing Forestry University Experimental Forest farm of Mi-aofengshan,were selected as the research obj ects.The shrub layer biomass were studied by the method of model and the herb layer biomass were studied by the method of sample.Biomass models were constructed for different organs and the whole plant of species widely distributed in the shrub layer using product of base diam-eter and plant height (DH),product of the square of base diameter and plant height (D2 H),tree crown area (A),volume (V)as the independent variables,then the biomasses of species of shrubs of different forest types were evaluated by selecting the optimal models with largest coefficient of determination and the smallest esti-mated standard deviation;Herb layer biomasses were calculated by the method of harvesting all quadrat.The results showed that the optimal biomass models for different organs and the whole plant of a single species is that cubic equations is the largest in all models,that is cubic equations>power function>quadratic>linear. The independent variables suitable for the optimal models is that V is the largest in all variables,that is V>D2 H>DH>A.The biomasses of shrub and herbs layer varied significantly among different forest types.The shrub layer biomass of three forest:P.tabulaeformis forest>Q.variabilis forest>mixed coniferous forest;The herb layer biomass of three forest:mixed coniferous forest>Q.variabilis forest>P.tabulaeformis for-est;The total biomass of shrub and herb layers:mixed coniferous forest>Q.variabilis forest>P.tabulaefor-mis forest;The proportional distribution of organ of shrub is that trunk and root is larger than branch and leaf, aboveground biomass is greater than the below-ground biomass of herb layer,and shrub biomass>herb layer biomass.%以相同立地条件下北京林业大学妙峰山实验林场的油松林、栓皮栎林和针阔混交林林下灌草为对象，分别采用模型法和样方全收获法对灌木层和草本层生物量进行研究，其中灌木层调查灌木种高度、基径、冠幅范围和干湿比，通过回归分析构建物种以地径平方与株高乘积（D2 H、DH）、植冠面积（A）和植冠体积（V）为自变量的各器官及全株生物量模型，选出R2较大、SEE较小的模型作为最优模型，并用最优模型对不同类型林下灌木层各物种生物量进行了研究；草本层通过样方全收获法将选取的样方草本全部收获烘干称重计算干湿比，从而推算林分草本生物量。结果表明，灌木层单一物种各器官生物量采用的最优模型由多到少依次为三次方程、幂函数方程、二次方程和一次方程；各器官最优模型采用自变量多为V、D 2 H、DH和A。不同森林的灌草生物量组成存在较大差异，其中灌木层生物量为：油松林＞栓皮栎林＞针阔混交林；草本层生物量为：针阔混交林＞栓皮栎林＞油松林；林下灌草层总生物量为：针阔混交林＞栓皮栎林＞油松林；灌木层单一物种器官茎和根的生物量大于枝和叶的生物量，不同林型草本层的地上生物量大于地下生物量，灌木层生物量大于草本层。