Data from: The downed and dead wood inventory of forests in the United States

The quantity and condition of downed dead wood (DDW) is emerging as a major factor governing forest ecosystem processes such as carbon cycling, fire behavior, and tree regeneration. Despite this, systematic inventories of DDW are sparse if not absent across major forest biomes. The Forest Inventory and Analysis program of the United States (US) Forest Service has conducted an annual DDW inventory on all coterminous US forest land since 2002 (~1 plot per 38,850 ha), with a sample intensification occurring since 2012 (~1 plot per 19,425 ha). The data are organized according to DDW components and by sampling information which can all be linked to a multitude of auxiliary information in the national database. As the sampling of DDW is conducted using field efficient line-intersect approaches, several assumptions are adopted during population estimation that serve to identify critical knowledge gaps. The plot- and population-level DDW datasets and estimates provide the first insights into an understudied but critical ecosystem component of temperate forests of North America with global application. Resources in this dataset:Resource Title: Data files. File Name: Web Page, url: https://www.nature.com/articles/sdata2018303#Sec9 Data Citations: USDA Forest Inventory and Analysis DataMart https://apps.fs.usda.gov/fia/datamart/datamart.html (2018); Woodall, C. W. et al. Dryad Digital Repository https://doi.org/10.5061/dryad.9sv4765 (2018)
(data links appear at the bottom of the References section)

枯死木（DDW）的数量与状况正逐渐成为影响森林生态系统过程的关键因素，这些过程包括碳循环、火行为和树木更新。尽管如此，在主要的森林生物群落中，对DDW的系统调查却极为稀少，甚至不存在。自2002年以来，美国森林服务局森林资源清查与分析项目每年对所有大陆性美国森林土地进行DDW年度清查（平均每38,850公顷约有一个样地），自2012年起样地密度有所增加（平均每19,425公顷约有一个样地）。数据按照DDW组成部分及采样信息进行组织，这些信息均可与国家数据库中的多种辅助信息相连接。由于DDW的采样采用现场高效的线交方法，因此在人口估计过程中采纳了若干假设，这些假设有助于识别关键的知识空白。样地和人口层面的DDW数据集及估计结果首次为北美温带森林这一研究不足但至关重要的生态系统组成部分提供了洞见，并具有全球应用价值。本数据集包含资源：资源标题：数据文件。文件名：网页，网址：https://www.nature.com/articles/sdata2018303#Sec9 数据引用：美国农业部森林资源清查与分析数据市场 https://apps.fs.usda.gov/fia/datamart/datamart.html（2018年）；Woodall, C. W. 等人。Dryad数字存储库 https://doi.org/10.5061/dryad.9sv4765（2018年）（数据链接见参考文献部分的底部）