Habashi H, Hosseiniand S M, Rahmani R, Mohammadi J
Faculty of Natural Resources, Tarbiat Modarres University, Noor, Mazandaran, P.O. Box 46414-356, Iran.
Pak J Biol Sci. 2007 Apr 15;10(8):1205-12. doi: 10.3923/pjbs.2007.1205.1212.
The mixed beach forests (Fagus orientalis) commonly dominate by shade tolerance species with irregular uneven age stand structure. The aim of this study was to analyze the stand structure and spatial pattern in order to identify specific structural patterns. Data was collected from a 16 ha permanent plot. We mapped all stems > 7.5 cm in diameter at breast height on permanent plot. The six main species were divided into two groups based on density and stand structure. Group A had higher density than group B, as well as L-shaped DBH distribution of live stems. Species in group B had bell-shaped DBH distributions. Species in group A have clump spatial distribution pattern in all layers but clump intensity is more than in understory layer and size of patch clump is small in this group. This phenomenon for group A may explaining by having numerous coppice, sucker and patch regeneration in the understory layer. Middlestory and understory stems of the six major tree species were patchily distributed throughout the plot but for Alder and Maple species common pattern in canopy layer was complete spatial randomness. The distribution of Beech and Hornbeam trees were negatively associated with other species. These results suggest species differences in favorable canopy condition.
混交海滩森林（东方山毛榉）通常以耐荫物种为主，具有不规则的不均匀年龄林分结构。本研究的目的是分析林分结构和空间格局，以确定特定的结构模式。数据收集自一个16公顷的永久样地。我们在永久样地上绘制了所有胸径大于7.5厘米的树干。根据密度和林分结构将六个主要物种分为两组。A组的密度高于B组，活立木的胸径呈L形分布。B组物种的胸径呈钟形分布。A组物种在所有层次上均具有团块状空间分布格局，但团块强度在林下层更大，且该组中斑块团块的大小较小。A组的这种现象可能是由于林下层有大量的萌生苗、根蘖和斑块更新。六种主要树种的中层和下层树干在整个样地中呈斑块状分布，但对于桤木和枫香树种，冠层的常见格局是完全空间随机分布。山毛榉和鹅耳枥树的分布与其他物种呈负相关。这些结果表明了在适宜冠层条件下的物种差异。
