Van Sickle, J. 2000. Modeling variable-width riparian buffers, with an application to woody debris recruitment. Pages 107-112, in P.J. Wigington, Jr., and R.L. Beschta, editors, Riparian Ecology and Management in Multi-Land Use Watersheds, Proc. AWRA Specialty Conference, Portland, OR, Aug. 28-31, 2000. WED-00-017
Effective management of riparian areas in watersheds requires that reach-scale knowledge of riparian functioning be carefully "scaled up" to provide models for entire stream networks. Weller et al (1998: Ecological Applications 8, 1156-1169) describe a useful heuristic model for the network-scale average transmission of landscape runoff materials through a variable-width riparian buffer. Their model demonstrates that a variable-width buffer is likely to transmit more runoff materials through a variable-width riparian buffer. Their model demonstrates that a variable-width buffer is likely to transmit more runoff materials, on average, from adjacent landscapes into a stream than would a fixed-width buffer of the same mean width. By extending the Weller et al. (1998) model, I show that analogous results are true for arbitrary distributions of buffer widths and for other riparian functions such as woody debris input and stream shading. I apply the extended model to woody debris recruitment from natural tree-fall in variable-width riparian forest stands. The application suggests that the average number and volume of tree boles falling into a stream network will be overestimated, if the estimate is based on the average width of the network’s riparian stands.