Standardized vegetation cover data from mature forests on federal lands of Washington, Oregon, and California

This data publication contains tabular data of overstory and understory vegetation composition collected from the mid-1950s to early 2000s in relatively undisturbed, mostly mature stands across forested federal lands of Oregon, Washington, and California. Most plots are on National Forest System lands, with some on Bureau of Land Management or Tribal land. Plots were distributed to represent the diversity of vegetation types across each National Forest or other management unit. These Ecology plots are not, and were never intended to be, permanent plots. Data include vegetation cover data such as lifeform, scientific name, and species cover for 38,560 plots. The longitude, latitude, and Regional ID number are also provided for each plot, with a supplemental file relating Regional IDs to land management units.These data were used to create typologies of potential vegetation ("Plant Associations") or ecological types (plant communities) that would allow forest managers to infer site conditions (topographic, climatic, edaphic, etc.) from the existing overstory and understory composition. Plant Association or Ecological Type (Plant Community) Guides were developed for groups of National Forests and adjacent lands across Forest Service Regions 5 and 6. Supplemental information includes a list of citations of these Plant Association and Ecological Type Guides, most of which were developed based on these plot data.本数据集发布内容包含1950年代中期至21世纪初，在俄勒冈州、华盛顿州与加利福尼亚州境内受干扰程度较低、以成熟林分为主的联邦林地中采集的上层植被与下层植被组成的表格型数据。多数样地位于国家森林系统（National Forest System）用地范围内，少量样地隶属于美国土地管理局（Bureau of Land Management）或部落土地。样地布设覆盖各国家森林或其他管理单元内的各类植被类型，以充分体现区域植被多样性。本生态样地并非永久样地，且从设计初衷上便未被设定为永久样地。本次数据集涵盖38560个样地的植被盖度相关数据，包括生活型、物种学名及物种盖度等信息。每个样地还附带经纬度信息与区域编号（Regional ID），另有补充文件用于关联区域编号与土地管理单元。本数据集被用于构建潜在植被分类体系——即“植物群丛（Plant Associations）”——或生态类型（植物群落），以便森林管理者能够通过现有上层与下层植被组成，推断样地的立地条件（包括地形、气候、土壤条件等）。美国林务局（Forest Service）第5、6大区范围内的国家森林群及其毗邻林地，均开发了对应的植物群丛或生态类型（植物群落）指南。补充信息包含上述植物群丛与生态类型指南的引用文献列表，其中多数指南均基于本次采集的样地数据编制而成。