Long-term patterns of hydrologic response after logging in a coastal redwood forest.
| Authors: | Elizabeth Keppeler, Leslie M. Reid, Tom Lisle |
| Year: | 2009 |
| Type: | Miscellaneous Publication |
| Station: | Pacific Southwest Research Station |
| Source: | Proceedings of the Third Interagency Conference on Research in the Watersheds: U.S. Geological Survey Scientific Investigations Report 2009-5049: 265-272 |
Abstract
Experimental watersheds generally provide the only setting in which the more subtle patterns of long-term response to land use activities can be defined. Hydrologic and sediment responses have been monitored for 35 yrs after selective logging and for 16 yrs after clearcut logging of a coastal redwood forest at the Caspar Creek Experimental Watersheds in northwest California. Results show that recovery periods differ for different hydrologic attributes and between the two silvicultural treatments. Total water yield, peakflows, and low flows responded similarly in both settings during the initial post-logging period, but low flows reattained pre-treatment levels more quickly after selective logging. Sediment loads initially recovered relatively quickly after both treatments, but in both cases loads rose once again 10–20 yrs after logging, either because road networks began to fail (South Fork) or because pre-commercial thinning again modified hydrologic conditions (North Fork).
Process-based studies provide the information needed to understand the differing watershed responses. Altered interception after logging provides the primary influence on water yield and peakflow responses, while altered transpiration is largely responsible for the low-flow response. Differences in recovery times between hydrologic attributes and between silvicultural practices may be explained by changes in the relative importance of interception and transpiration and by the long-lasting repercussions of ground disturbance.