Riparian aquatic interaction simulator (RAIS): a model of riparian forest dynamics for the generation of large woody debris and shade

Streams depend on riparian forests to supply many important functions such as delivery of large woody debris (LWD), organic matter, and nutrients into the aquatic ecosystem and to provide shade to help maintain cool water. Both forests and streams are dynamic, and inputs from the riparian forest are constantly replenished as organic matter and nutrients are processed and transported. Forest stand dynamics have been intensively studied and foresters have developed a good understanding of tree growth and mortality to support commercial forest management. In recent years, the relationships between aquatic functions and adjacent forest stand characteristics have been increasingly quantified by ecologists. Management of riparian forests to protect aquatic functions and water quality has received considerable attention in the Pacific Northwest and elsewhere. For scientific knowledge to be useful to decision-makers, the complex set of riparian relationships, increasingly well understood individually, need to be collectively and objectively linked in a form that can be easily used by scientists and non-scientists alike to develop management strategies for riparian forests. In this paper we describe an analytical system that quantitatively links widely used forest growth forecasting systems for coastal Pacific Northwest forest types to the riparian ecological functions of large woody debris recruitment and shade. The riparian aquatic interaction simulator (RAIS), with its user-friendly interface, allows managers to forecast aquatic functions for up to 300 years. RAIS provides these forecasts over a range of critical input variables and produces realistic estimates of riparian functions when compared with published research. RAIS is available at http://www.weyerhaeuser.com/rais.html (C) 2002 Elsevier Science B.V. All rights reserved.