毛竹林生态系统动态经济阈值

DYNAMIC ECONOMIC THRESHOLD OF PHYLLOSTACHYS PUBESCENS ECOSYSTEM

运用经济阈值 (ET)的研究方法建立了毛竹林生态系统经济阈值模型 ,探讨了毛竹林生态系统一元和二元复合动态经济阈值 .研究结果表明 :对于不同的毛竹林分 ,林分立竹度 (N)越大 ,其经济阈值 (ET)也随之增大 ;对于同一毛竹林分来说 ,经济阈值随着笋的平均价格 (PS)、贴现率 (δ)、笋的平均单重 (WS)、每年挖去笋增量的比例 (k)和经营时间 (t)等因子的增大而增大 ,而随着竹材的平均价格 (PB)、成竹率 (R)的增大而减少 .此外 ,还进一步分析了毛竹林经济阈值与PS、PB 两个主要影响因子之间的复合动态变化关系 ,结果表明PB 对毛竹林经济阈值的影响较PS 大 ,并编制了毛竹林生态系统二元复合动态经济阈值一览表 ,从而为实现毛竹林的丰产经营提供方便与指导 .图 1表 3参

The method of economic threshold was introduced to establish the economic threshold model of P. pubescens ecosystem,and based on the model, the dynamic relationships between economic threshold and each of its effect factors, including N,P S, P B, R,W S , δ,k and t , were studied,where N was density of stand, P S meant price of bamboo shoot, P B price of bamboo, R survival rate of bamboo shoots, W S individual weight of bamboo shoot, δ discount rate, k digged proportion of increment of bamboo shoots every year and t management time.The results indicated that as for different stands of P. pubescens ,the larger the N was,the larger the economic threshold was; as for the same stand of P. pubescens ,the economic threshold increased as P S, δ , W S, k and t increased, and it decreased while P B and R increased.Moreover,the compound dynamic relations of the economic threshold with two main effect factors ( P S, P B) were further studied in this paper. The results showed that the influence of P B on the economic threshold was greater than that of P S. Thus,this paper provides convenience and guidance for high yield management of P. pubescens .Fig 1,Tab 3,Ref 14