Wood abundance in urban and rural streams in northwestern South Carolina.

In streams and rivers, wood from riparian vegetation contributes to habitat complexity and substrates for stream biota, influences channel geomorphology, alters flow, retains sediment and organic matter, and enhances nutrient uptake. A few studies have shown that wood amounts in urban streams may be lower than in rural streams or that wood amounts in streams are inversely related to watershed impervious surface cover (ISC). To determine if these patterns occur more broadly, we compared wood amounts in urban and non-urban streams in the South Carolina Piedmont and Blue Ridge Provinces. We measured wood abundance in 20 streams draining urbanized (15–68% ISC) or non-urbanized (≤ 2.5% ISC) watersheds. Our results did not support the hypothesis that urban streams would have less wood than rural streams, and we found no relationship between wood amounts and watershed ISC. Indeed, one urban stream bordered by large riparian trees had the greatest wood volume of all streams in our study. Instead, large wood amounts were best explained by tree canopy cover and length of unobstructed tree-lined channel upstream. These results suggest that the presence of numerous riparian trees influences wood amounts positively even in urban streams where wood amounts might be expected to be low. [ABSTRACT FROM AUTHOR]