ABSTRACT

Generalized height (h)–diameter (d) models were developed for Crimean pine stands in the Kastamonu Regional Directorate of Forestry, northwestern Turkey. Nine generalized h-d models were fitted and evaluated based on data set consisting of 2697 h-d measurements obtained from 274 sample plots located in three ecoregions of the studied region. The best results were obtained by modified Richards h-d model accounting for the 93% of the total variance in height–diameter relationship. It is a known fact that h-d relationship can vary in ecological conditions, especially for regions with large areas and various ecological conditions such as Kastamonu. To investigate the differences of height–diameter relationship among the ecoregions located in Kastamonu region, nonlinear extra sum of squares method was performed. The test results showed that there were significant differences, especially between coastal and the inland ecoregions. When compared to reduced model with the same set of parameters for the whole region, full model with a different set of parameters for each ecoregion achieved better accuracy in estimating tree height. Besides, applying h-d model fitted for the coastal ecoregion to the others, or vice versa, could lead under- or over-estimates of tree heights by about 1.8%.

摘要

为土耳其西北部 Kastamonu 地区林业局的克里米亚松林开发了广义高度 (h)-直径 (d) 模型。基于从位于研究区域的三个生态区域的 274 个样本地块获得的 2697 个 hd 测量值组成的数据集，对九个广义 hd 模型进行了拟合和评估。改进的 Richards hd 模型获得了最好的结果，占高度-直径关系总方差的 93%。众所周知，hd 关系在生态条件下会有所不同，特别是对于像 Kastamonu 这样面积大、生态条件多样的地区。为了研究位于 Kastamonu 地区的生态区之间的高度-直径关系的差异，进行了非线性额外平方和方法。测试结果表明存在显着差异，特别是在沿海和内陆生态区之间。与整个区域具有相同参数集的简化模型相比，每个生态区域具有不同参数集的完整模型在估计树高方面取得了更好的准确性。此外，将适用于沿海生态区的 hd 模型应用于其他生态区，反之亦然，可能导致对树高的低估或高估约 1.8%。