DamQuick: A new method for rapidly assessing residual stand damage during partial timber harvests

The increasing frequency of partial timber harvest prescriptions has created the need for an efficient and accurate method of assessing residual stand damage. In this study, we developed and tested a new sampling method that exploits the general pattern of residual stand damage being concentrated near primary transport routes. The method, termed DamQuick, consists of systematic belt transects located immediately adjacent and parallel to the harvesting operation's extraction corridors. Plot measures of tree wounding are scaled by sampling intensity and a concentration factor to yield stand-level estimates of residual damage. The method was evaluated for a skyline thinning operation in western Oregon. DamQuick damage estimates were compared with actual damage levels obtained from a 100% survey for three thinning treatments - 30, 60, and 100 residual trees/ac. The mean DamQuick estimates were statistically similar to actual stand damage levels (t = 0.366-0.651, P = 0.531-0.725) for all thinning treatments, with mean estimation errors (standard errors) ranging from 0.7% (0.9%) to 2.1% (4.4%). Operationally, DamQuick was easy to implement. The primary transport routes provided ready stand access, which facilitated plot location and establishment.