Forest inventory surveys were initiated in 1965, repeated in 1977, and repeated at 5 year intervals after that; this data set was collected in summer of 2012. The inventory consists of a total inventory of all trees >=10 cm diameter-at-breast-height (dbh) on the whole of the watershed (13.23 ha), as measured in each of the 208 25 m x 25 m plots. Trees >=2 to <=10 cm dbh were subsampled using a 3 meter wide strip along one edge of each 25 m x 25 m plot. With the addition of tree tags in 2002 on all trees >=10 cm dbh, tracking of individual trees is now possible.
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.