Context Western Olympic valley bottoms, disturbed by alluvial processes, are dominated by Picea sitchensis and isolated cohorts of Pseudotsuga menziesii , while upland contexts, disturbed by wind and fire, are dominated by P. menziesii . These forests have distinct structure and produce large trees with habitat for endangered birds. Objectives Describe how disturbance and forest development create landscape forest patterns and distribution of large trees in valley bottom and upland forests. Methods LiDAR data of ~ 9700 ha within Olympic National Park, USA was classified based on vegetation height and percent cover to contrast valley bottom and upland forests. Within-crown structure from 36 P. sitchensis and 12 P. menziesii was then used to predict locations of the largest and most complex trees. Results Valley bottoms comprise small patches of dense tall (11%), medium-height trees (19%), and gaps (7%) embedded in open-canopy forest with scattered tall trees (63%). Upland forests comprise larger patches of tall (16%), medium (58%), and open-canopy forest (25%) with few gaps (1%). The largest trees are more abundant in valley bottoms (0.05 tree ha −1 ) than upland (0.02 tree ha −1 ) due to small patches of tall trees within open-canopy forest. Conclusions Alluvial disturbance, fungi-wind interaction, and dominance of late-successional fast-growing P. sitchensis create open-canopy forest with more large trees, while severe fire and wind interacting with P. menziesii create patchy closed-canopy forest with fewer large trees. Management for large habitat trees should use aggregated retention with P. menziesii, multi-aged selection techniques with P. sitchensis, and indefinitely retain a low density of large trees .

中文翻译：

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干扰和物种组成驱动美国奥林匹克雨林中大树的冠层结构和分布

背景 受到冲积过程干扰的西部奥林匹克谷底以云杉和 Pseudotsuga menziesii 的孤立群落为主，而受风和火干扰的高地背景以 P. menziesii 为主。这些森林具有独特的结构，并生产大树，为濒临灭绝的鸟类提供栖息地。目标 描述干扰和森林发展如何创造景观森林格局以及谷底和高地森林中大树的分布。方法 根据植被高度和覆盖百分比对美国奥林匹克国家公园内约 9700 公顷的 LiDAR 数据进行分类，以对比谷底和高地森林。然后使用 36 P. sitchensis 和 12 P. menziesii 的冠内结构来预测最大和最复杂树木的位置。结果 谷底包括小块密集的高大 (11%)、中等高度的树木 (19%) 和嵌入开放树冠林中的间隙 (7%)，高大树木分散 (63%)。高地森林包括大片的高 (16%)、中 (58%) 和开放的树冠林 (25%)，几乎没有间隙 (1%)。由于开阔的树冠林中的小块高大树木，最大的树木在谷底（0.05 树公顷 -1 ）比高地（0.02 树公顷 -1 ）更丰富。结论 冲积扰动、真菌-风相互作用以及后期连续快速生长的西洋参的优势创造了具有更多大乔木的开放林冠，而与孟氏西洋杉相互作用的严重火灾和风则创造了具有较少大乔木的斑块状封闭林。树木。大型栖息地树木的管理应使用与 P. menziesii 的聚合保留，