Forest Inventory of a Northern Hardwood Forest: Bird Area at the Hubbard Brook Experimental Forest, 1981

The forest inventory surveys in the bird area were initiated in 1981 and transects were made permanent in 1991. The inventory is representative of approximately 2.5 km-squared of mid elevation northern hardwood forest. It consists of a total inventory of all trees >=10 cm dbh, within each of four 10 m wide belt transects. The parallel transects are placed approximately 200 m apart and run roughly in an east-west direction for 2200 to 2900 m. In 1991, each live stem >=10 cm dbh was tagged with a unique number. Tree vigor is assessed every two years and diameter is remeasured every ten years. Every two years, new tags are placed on stems that have grown into the 10 cm diameter class. A survey of smaller trees (>=2 to <10 cm dbh) was first taken in 1991 and is resurveyed every ten years. This dataset includes the initial inventory values measured in 1981. The full timeline of tree inventory data for this site is available at https://doi.org/10.6073/pasta/58dfdebfd1b6440510def2394ab92c53 These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.该鸟类监测区域内的森林清查工作始于1981年，其布设的样带于1991年正式确立为永久样带。本次清查范围覆盖约2.5平方千米的中海拔北部硬木林，共布设4条宽度为10米的带状样带，对每条样带内所有胸径（diameter at breast height, dbh）≥10厘米的林木开展全面普查。各平行样带间距约200米，大致沿东西走向延伸，长度介于2200米至2900米之间。1991年，所有胸径≥10厘米的活立木均被赋予唯一识别编号。林木活力每两年开展一次评估，胸径每十年复测一次；每两年会为新长至10厘米胸径径级的林木加装新的识别标签。1991年首次开展了胸径≥2厘米且<10厘米的幼树清查工作，此后每十年复测一次。本数据集包含1981年首次清查测得的初始数据。该样地完整的林木清查数据时间序列可通过以下链接获取：https://doi.org/10.6073/pasta/58dfdebfd1b6440510def2394ab92c53。本数据集作为哈伯德布鲁克生态系统研究（Hubbard Brook Ecosystem Study, HBES）的一部分收集所得。HBES是依托哈伯德布鲁克实验林开展的协作研究项目，该实验林由美国农业部林务局北方研究站（USDA Forest Service, Northern Research Station）运营维护。