Introduction

Management of diverse landscapes in the interior Pacific Northwest requires consideration of the integrated effects of natural disturbances and management activities on natural resource conditions. The opportunities for managing lands depend on widely varying objectives of owners, vegetation conditions, environmental settings, natural disturbances, and other factors. Likewise, the risks that land managers encounter include natural disturbances, unforeseen consequences of management activities, changing political, social, and economic environments, and others. Land managers and those who influence or set land management policy need to examine the short- and long-term potential effects of different management approaches using methods that: (1) integrate the effects of natural disturbances and management activities on vegetation and resource conditions; (2) consider landscapewide characteristics and trends across all ownerships; (3) maximize the effects of limited budgets and personnel through cooperation across agencies and ownerships; (4) use a modeling approach that is flexible, powerful, easy to understand, and integrative.

A partnership of Federal and State agencies and nongovernment organizations developed a shared effort to generate landscapewide vegetation data, landscape models, and related information. The Interagency Mapping and Assessment Project (IMAP) addresses several landscape assessment and analysis issues, including: (1) limited and declining funds to perform landscape assessments and analyses of potential effects of various management options on resources of interest; (2) an increasing lack of highly skilled people to perform landscape analyses; (3) a desire to avoid conflicting answers to broad questions that cross ownerships and interests; (4) the need for integrated analyses that include many management and natural disturbances across a broad range of ownerships, vegetation conditions, and environments; (5) a consistent basis for monitoring the effectiveness of management activities at achieving policy goals across large landscapes; (6) the desire for relatively simple and understandable approaches to landscape analysis and policy evaluation. Key issues for all these landscape analysis, planning, and assessment activities include, among others, fire risks, forest conditions, wildlife habitats, old forests, and timber products. In addition, policy makers and others want to consider long-term sustainability of landscape resources and conditions given various management approaches.

Landscape simulation models may be used to assist in understanding the potential reaction of large landscapes to various management and policy approaches, (e.g., Bettinger and others 2005, Hann and others 1997, Hemstrom and others 2004, Mladenoff and He 1999, USDA and USDI 2000). Advances in modeling techniques, computer technology, and geographic information systems (GIS) have made it possible to model large landscapes at increasingly finer scales of spatial and temporal resolution (Barrett 2001, Bettinger and others 2005). In much of the Pacific Northwest of North America, resource planning models have focused primarily on conifer succession and management while representing other ecosystem elements as byproducts, (e.g., Alig and others 2000, Johnson and others 1986). Although progress has been made in the formulation of multiobjective goals in landscape simulations (Sessions and others 1999, Wedin 1999), there remain many challenges to building landscape planning models that include all of the important disturbance processes that influence change. The net, synergistic effects of various disturbances, (e.g., drought, fire, insects, and management activities) across a large, ecologically diverse landscape are of particular interest to policy makers, scientists, land managers, and others. Our approach treats vegetation as discrete types and management activities and natural disturbance as transitions among those types to project the long-term net effects of alternative management scenarios across a large landscape, building on the work of Hann and others (1997) and Hemstrom and others (2004). Though we do not specifically include drought and other climatic effects, their impacts are manifest in our annual wildfire and insect probabilities.