CameraStationVegetationData

This file contains all the vegetation measurements taken at each camera station pair. Cameras were set up in the Summer and Fall seasons of 2013 and 2014 on the grounds of the Smithsonian Conservation Biology Institute in Front Royal, VA USA. Cameras were only established in forest habitat. Camera stations were made up of pairs of cameras, one at a log feature or game trail, the other at a random nearby location. Vegetation measurements were taken at the midpoint between the two cameras. In addition to the PairID, Grid location, and vegetation sampling date, 4 vegetation variables are included. "CovAll" is the overall level vegetative cover percentage recorded as the average percent of a 2-m high cover pole obscured from 10 m away in each cardinal direction. Cover pole was divided in 20 1-dm sections. Data were recorded as the percentage of 1-dm sections obscured ( >50%) by vegetative or structural cover. "CovLow" is the average percent of low portion (<0.5 m) of cover pole obscured by vegetative or structural cover. "UnderStem_D" is the number of woody stems >1.5 m in height and <7.5 cm dbh counted within 3 arm's-length transects, divided by 33 square meters. Transect were parallel, 20-m transects extending perpendicular to the aspect of the plot. Transects were placed both through the actual sampling location as well as 10 m up and down slope of location."OverStem_D" is the number of woody stems >7.5 cm dbh counted within 3 arm's-length transects, divided by 33 square meters. Transects used were same as for "UnderStem_D".

本文件包含所有在各相机站点对处采集的植被测量数据。2013年与2014年的夏季和秋季，研究人员于美国弗吉尼亚州方特罗亚尔市的史密森尼保护生物学研究所（Smithsonian Conservation Biology Institute）园区内布设相机，且仅在森林生境中设置相机站点。

每个相机站点由成对相机组成：一台设于枯原木位点或兽径处，另一台设于附近随机点位。植被测量工作在两台相机的中点位置开展。

除PairID（站点对ID）、Grid location（网格位置）以及植被采样日期外，本数据集共包含4种植被变量：
1. CovAll：总植被盖度百分比，计算方式为：从4个方位（cardinal direction，东、南、西、北四个方位）的10米距离处，观测2米高的测杆被植被或结构遮挡的平均百分比。该测杆被划分为20个1分米的分段，数据以遮挡占比超过50%的1分米分段所占百分比进行记录。
2. CovLow：低矮植被盖度百分比，指测杆低于0.5米的区段被植被或结构遮挡的平均百分比。
3. UnderStem_D：单位面积木本茎秆密度，即在3条臂长样带内统计得到的、高度大于1.5米且胸径（dbh, diameter at breast height）小于7.5厘米的木本茎秆总数量，除以33平方米后得到的密度值。样带为平行布设的20米长样带，垂直于样地坡向延伸，且分别穿过实际采样点位，以及该点位上坡与下坡方向各10米处的位置。
4. OverStem_D：单位面积木本茎秆密度，即在与UnderStem_D相同的3条臂长样带内统计得到的、胸径大于7.5厘米的木本茎秆总数量，除以33平方米后得到的密度值。