Roads in Landscape Modeling: A Case Study of a Road Data Layer and Use in the Interior Northwest Landscape Analysis System

Roads are important ecological features of forest landscapes, but their cause-andeffect relationships with other ecosystem components are only recently becoming included in integrated landscape analyses. Simulation models can help us to understand how forested landscapes respond over time to disturbance and socioeconomic factors, and potentially to address the important role roads play in these processes. The inclusion of roads as static or as process components of the landscape modeling, however, presents numerous challenges owing to a general lack of adequate road data and threshold effect information. Roads have been included in several recent landscape analysis efforts in the Pacific Northwest, but not as dynamic components. The Interior Northwest Landscape Analysis System (INLAS) developed a framework for simulation modeling of succession, disturbance, and management activities at the subbasin level. Roads were included in the INLAS project as a static landscape feature. We describe the data, analysis, and applications of road data in the INLAS project. Using the INLAS effort as a case study, we examine the challenges of incorporating roads into multidisciplinary landscape-level analyses. With an emphasis on data requirements, we identify practical and logistic barriers to dynamic modeling of road interactions, and propose a strategy for future studies.