Recruitment and function of large woody debris in four California coastal streams.

摘要

Recruitment and function of large woody debris (LWD) was assessed on four central coastal California streams by modifying the California Department of Fish & Game's inventory form to (1) identify trees and LWD to species; (2) separate upslope habitats into perched (edge of bankfull channel), riparian (differentiated stream-dependent vegetation) and upslope zones; (3) separate the channel into lowflow and bankfull zones; and (4) indicate effects of LWD on habitat features. The majority of in-channel LWD was small and not creating backwater or pool habitats. Most hardwood LWD was small-diameter alder and was most abundant in downstream reaches with wide floodplains. Longer, thicker LWD, especially with rootwad attached, was more likely to create pools and backwaters. Most of this LWD was old, weathered redwood which, although scarce, created most in-channel structures, especially in upstream reaches. Most potential LWD recruitment was from small-diameter, perched alders; large conifers are apparently recruited episodically.