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首页> 外文期刊>Indonesian Journal of Forestry Research >GENERALIZED HEIGHT-DIAMETER MODELS FOR Acacia mangium Willd. PLANTATIONS IN SOUTH SUMATRA
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GENERALIZED HEIGHT-DIAMETER MODELS FOR Acacia mangium Willd. PLANTATIONS IN SOUTH SUMATRA

机译：马占相思（Acacia mangium Willd）的广义身高模型。南苏门答腊的人工林

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The aim of this study was to develop a generalized height-diameter model for predicting tree height of A caci a mangium plantations in South Sumatra that could account for the variability of site and stand conditions. Six commonly used non-linear growth functions (i.e. Gompertz, Chapman-Richards, Lundqvist-Korf, Weibull, modified logistic, and exponential) were selected as candidate base models and were fitted to individual tree’s height-diameter data of A . ma n g i u m plantations. A total of 13,302 trees collected from permanent sample plots with various spacing , stand age, and site quality were available for this study. The data were split into two sets: one set being the majority (75%) was used to estimate model parameters and the remaining data set (25%) was used to validate the models. The results showed that the six base models produced almost identical fits with a relatively high root mean squared error (± 3.4 m) and a relatively low proportion of the total variation in obser ved tree height (52.5 - 53.4%). The Lundqvist-Korf (LK) model performed slightly better than the other models based on the goodness of fit as well as bias and standard errors of the predictions. This LK model can be fitted easily and provided more satisfactory fit when additional variables were included into the model, hence was selected as the base model. Introducing stand variables into the selected base model resulted in a significant improvement of the accuracy for predicting heights. The root mean squared error decreased by the value between 0.5564 and 1.4252 m and the proportion of variation explained by the model increased by the value between 13.88 and 33.21%. The best improvement based on fit and model validation was achieved by the generalized height-diameter model with inclusion of stand age and site index.
机译：这项研究的目的是建立一个通用的高度-直径模型，以预测南苏门答腊岛A aci a mangium人工林的树高，该模型可以解释场地和林分条件的变化。选择了六个常用的非线性增长函数（即Gompertz，Chapman-Richards，Lundqvist-Korf，Weibull，修改的对数和指数）作为候选基本模型，并将其拟合到单个树的A的直径直径数据。种植园从永久性样地收集的总共13,302棵树木具有不同的间距，林分年龄和站点质量，可用于本研究。数据分为两组：一组（占大多数（75％））用于估计模型参数，其余组（25％）用于验证模型。结果表明，六个基本模型产生几乎相同的拟合，具有相对较高的均方根误差（±3.4 m）和相对较小的观测树木高度总变化的比例（52.5-53.4％）。基于拟合优度以及预测的偏倚和标准误，Lundqvist-Korf（LK）模型的性能比其他模型稍好。当模型中包含其他变量时，此LK模型可以轻松拟合并提供更令人满意的拟合，因此被选作基本模型。将林分变量引入所选的基本模型中，可显着提高预测高度的准确性。均方根误差减少了0.5564至1.4252 m之间的值，模型解释的变化比例增加了13.88至33.21％之间的值。基于拟合和模型验证的最佳改进是通过包含林分年龄和站点指数的广义高度直径模型实现的。

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