Fire and Climatic Variability in the Pacific Northwest: Integrating Science and Management

Project Description

We used existing fire history data from seven watersheds on the Okanogan-Wenatchee and Colville National Forests. Clear differences in fire regimes between the historical period (1650-1900) and the period after initiation of fire suppression in the region (after 1900) were documented.

We acknowledge funding provided by the Joint Fire Science Program under Project JFSP 01-1-6-01.

Purpose and Scope

This project addressed tasks 6 and 7 of the Joint Fire Science Program request for proposals 2001-1 by linking climate to fire regime characteristics and by developing spatially explicit, empirically based tools for predicting fire risks as a function of climatic conditions. We proposed a multi-scale analysis of the relationships between climate and topography and spatio-temporal patterns in historical fire regimes in the Inland Pacific Northwest, using existing fire history data from the Okanogan-Wenatchee and Colville National Forests.

Key Findings

A broad-scale relationship exists between fire occurrence and drought in eastern Washington.

• A quasi-periodic relationship exists between fire occurrence and the El Niño Southern Oscillation and the Pacific Decadal Oscillation.
• The strong link between fire regime and climate was seriously weakened during the 20th century because of fire exclusion and land-use changes.
• With strong evidence for the link between climate and fire regime, researchers expect more fires and surprises in the future with global warming.
• The spatial and temporal complexity of fire occurrence and climate can be shared with a new, user-friendly Web-based approach to GIS-based data delivery and visualization.
• Understanding the measurable impact of climate on fire regime, as well as spatial and temporal forest complexity, is needed for making effective and appropriate management and restoration decisions.

Management Implications

• Managers and planners across the United States, and in particular, in eastern Washington, now have a comprehensive and accessible set of tools and data that have immense explanatory and management power that links climate, fire regime, and spatial and temporal complexity.
• An era of fire exclusion has seriously diminished the link between climate and fire regime in the Inland Northwest, but management decisions will need to account for the re-emergence of the effect of climate on fire regime.
• Climate change will affect fire susceptibility in forests across the West. However, as in eastern Washington, the fire history record provides no analogues to expected greenhouse warming, so we can expect surprises in the future.