Fire History

Context Lack of quantitative observations of extent, frequency, and severity of large historical fires constrains awareness of departure of contemporary conditions from those that demonstrated resistance and resilience to frequent fire and recurring drought. Objectives Compare historical and contemporary fire and forest conditions for a dry forest landscape with few barriers to fire spread.

Western U.S. wildfire area burned has increased dramatically over the last half‐century. How contemporary extent and severity of wildfires compare to the pre‐settlement patterns to which ecosystems are adapted is debated. We compared large wildfires in Pacific Northwest forests from 1984 to 2015 to modeled historic fire regimes.

A major goal of managers in fire-prone forests is restoring historical structure and composition to promote resilience to future drought and disturbance. To accomplish this goal, managers require information about reference conditions in different forest types, as well as tools to determine which individual trees to retain or remove to approximate those reference conditions.

Ecological departure, or how much landscapes have changed from a natural range of variation (NRV), has become a key metric in forest planning and restoration efforts. In this study we define forest restoration need as the specific change in structural stage abundance necessary to move landscapes into the NRV.

We extend a published 9000 yr fire history record from Little Lake, in the Oregon Coast Range, to 35,000 yr and compare it with the established pollen record from the site. The fire history is based on a high-resolution analysis of charcoal preserved in lake sediments, providing a fire history record that spans the Last Glacial Maximum in North America.

High-severity, infrequent fires in forests shape landscape mosaics of stand age and structure for decades to centuries, and forest structure can vary substantially even among same-aged stands. This variability among stand structures can affect landscape-scale carbon and nitrogen cycling, wildlife habitat availability, and vulnerability to subsequent disturbances.

The rain shadow forests of the Olympic Peninsula exemplify a mixed-severity fire regime class in the midst of a highly productive landscape where spatial heterogeneity of fire severity may have significant implications for below and aboveground post-fire recovery.

Context In the interior Northwest, debate over restoring mixed-conifer forests after a century of fire exclusion is hampered by poor understanding of the pattern and causes of spatial variation in historical fire regimes.

A warming climate, fire exclusion, and land cover changes are altering the conditions that produced historical fire regimes and facilitating increased recent wildfire activity in the northwestern United States.

An understanding of how historical fire and structure in dry forests (ponderosa pine, dry mixed conifer) varied across the western United States remains incomplete. Yet, fire strongly affects ecosystem services, and forest restoration programs are underway.