Document: PAU-3-76-17

An indicator of potential stream wood contribution for riparian forests.

RINGOLD, P.L.* ¹, M.BOLLMAN ², J.VAN SICKLE ¹, J.BARKER ² and J.WELTY ³

US EPA, Western Ecology Division, Corvallis, OR 97333 USA ¹
Dynamac Corporation, Corvallis, OR 97333 USA ²
Weyerhaeuser Company, South Federal Way, WA 98003 USA ³

Abstract:
In northwestern Oregon a key function of riparian forests is to provide wood to the stream network. This function is a prominent feature of Federal and State forest practices in the region. Thus, defining indicators which are associated with this function is important for designing and implementing riparian monitoring. This study is based on field observations of 110 riparian forest plots in western Oregon. We compared model predictions of potential stream wood from these 40m by 40m plots to sets of simple field observations. The results showed that tree number and tree basal area were strongly associated with model predictions. The results also examined the effect of the spatial scale of the field measures. Here, the results showed that one component of stream wood (total number of pieces) was strongly associated with model predictions for the full 40 by 40m plot (r² > 0.7 with one woody debris model) even when the field measure was taken over a short distance from the stream (e.g. 5 to 10 m) while for another component - large conifers - model predictions were strongly associated (r² > 0.9) with field measures when the field measure was taken over a greater distance from the stream (e.g. 30 to 40 m). The strength of this association varies slightly with forest structure. It is stronger for forest plots with a uniform distribution of trees and weaker for forest plots with trees which are clustered either towards the stream or away from the stream.

Keywords: Monitoring, Riparian Forests, Stream Wood

This abstract is being presented at: 10:30 AM in session:
RIPARIAN ECOLOGY