Field results for line intersect distance sampling of coarse woody debris

Abstract

A growing recognition of the importance of downed woody materials in forest ecosystem processes and global carbon budgets has sharpened the need for efficient sampling strategies that target this resource. Often the aggregate volume, biomass, or carbon content of the downed wood is of primary interest, making recently developed probability proportional-to-volume designs such as line intersect distance sampling (LIDS) of interest. This research presents field results from LIDS and conventional line intersect sampling (LIS) inventories of coarse woody debris (CWD) in three stands in northwestern Montana, USA. Field crews quickly adapted to the distance-limited selection protocol of LIDS, though its variable-length transect design increased data collection times relative to LIS in all three stands. Yet aggregate CWD volumes were estimated more precisely with LIDS, more than offsetting the time differential and rendering LIDS more efficient than LIS for volume estimation given a fixed sampling time or budget. Conversely, LIS generally performed more efficiently than LIDS with regards to the estimation of CWD abundance and aggregate length. Its transect design means that LIDS could be readily integrated into Forest Inventory and Analysis based programs to assess and monitor CWD stocks. However, the utility of LIDS, or of any other sampling strategy, must be determined by the relative importances of the estimable CWD attributes of interest.

Parent Publication

• Forest Inventory and Analysis (FIA) Symposium 2008; October 21-23, 2008; Park City, UT

Citation

Affleck, David L. R. 2009. Field results for line intersect distance sampling of coarse woody debris. In: McWilliams, Will; Moisen, Gretchen; Czaplewski, Ray, comps. Forest Inventory and Analysis (FIA) Symposium 2008; October 21-23, 2008; Park City, UT. Proc. RMRS-P-56CD. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 12 p.