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首页> 外文期刊>Biotropia: the Southeast Asian journal of tropical biology >MODELLING NATURAL MORTALITY FOR TROPICAL PLANTATION SPECIES OF Acacia mangium Willd.
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MODELLING NATURAL MORTALITY FOR TROPICAL PLANTATION SPECIES OF Acacia mangium Willd.

机译：马占相思热带植物的自然死亡率建模。

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摘要

Natural mortality of trees is extremely variable due to the uncertainty and complexity of the functioning of forest ecosystems. To overcome this uncertainty, a two-step mortality model was applied for unthined stands of Acacia mangium species. The model was developed using data from measurements of l97 permanent sample plots in South Sumatra, Indonesia. The model consists of two complementary equations. The first equation is a logistic function predicting the probability of mortality incidence depending on stand density, site index and stand age. The second equation estimates the reduction in the number of surviving stems that is observed in a stand where natural mortality occurs. Nine equations were fitted using data from permanent sample plots where trees died over the time period and the best model was selected. Estimates from this second model are then adjusted by a factor equal to the probability of mortality applying three different approaches: a probabilistic two-step approach, a deterministic threshold approach and a stochastic approach. All methods revealed no significant difference between the observed and the predicted number of surviving stems per ha. The probabilistic two-step approach, however, produced more consistent and the most accurate estimates. This method should provide reliable prediction when it is to be used in forest productivity prediction and management system for the species.
机译：由于森林生态系统功能的不确定性和复杂性，树木的自然死亡率变化很大。为了克服这种不确定性，将两步死亡率模型应用于马占相思树种的稀疏林分。该模型是使用来自印度尼西亚南苏门答腊省的19个永久性样地的测量数据开发的。该模型由两个互补方程组成。第一个方程是一个逻辑函数，根据林分密度，林地指数和林分年龄预测死亡率的概率。第二个方程式估计在自然死亡率发生的林分中观察到的存活茎数的减少。使用来自永久样本地的数据拟合了九个方程，在该永久性样本地中树木在一段时间内死亡，并选择了最佳模型。然后使用三种不同的方法，通过等于死亡率概率的因子来调整来自第二个模型的估计值：概率两步法，确定性阈值法和随机法。所有方法均显示每公顷存活茎数与预测茎数之间无显着差异。但是，概率两步法得出的结果更加一致且最准确。当该方法用于该物种的森林生产力预测和管理系统时，应提供可靠的预测。

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