Sampling downed coarse woody debris in fire-prone eucalypt woodlands

Downed coarse woody debris (DCWD) plays an important role in ecosystem processes and should be considered in land management decisions. Unfortunately accurate quantification of its abundance is difficult, due to its patchy distribution. This is especially problematic in woodland ecosystems where DCWD is relatively scarce, unevenly distributed and smaller in size than in other forest types. This study compared the efficacy of the line intersect and strip plot methods to sample properties of DCWD at woodland sites with differing fire histories. Although measures of abundance using the two methods did not differ statistically, the line intersect method had 20% less variability in the data, was quicker to perform and made it easier to locate individual pieces of DCWD than the strip plot method. The results of this study indicate that transects of 100 m or less are insufficient for estimating DCWD volume in woodlands. An acceptable level of precision was reached at approximately 450 m at very recently burnt sites and 700 m at long unburnt sites when only transect length was considered. However when taking both transect length and number of replicates into account, an acceptable level of precision was reached at 500 m when sampling a minimum of 20 sites. It is therefore recommended that pilot studies should be conducted to determine appropriate sampling intensities in previously unsampled areas as DCWD volume estimates are sensitive to the rate at which variance changes with increasing transect length. This is particularly important when there is variation in the disturbance history of the sites. However, if it is not possible to conduct pilot studies, the requirement would be to sample line intersect transects of at least 500 m, at a minimum of 20 sites in woodland systems.