Fire History

Dry forests at low elevations in temperate-zone mountains are commonly hypothesized to be at risk of exceptional rates of severe fire from climatic change and land-use effects. Their setting is fire-prone, they have been altered by land-uses, and fire severity may be increasing. However, where fires were excluded, increased fire could also be hypothesized as restorative of historical fire.

Fire is one of the most important natural disturbance processes in the western United States and ecosystems differ markedly with respect to their ecological and evolutionary relationships with fire.

Wildfire activity in boreal forests is anticipated to increase dramatically, with far-reaching ecological and socioeconomic consequences. Paleorecords are indispensible for elucidating boreal fire regime dynamics under changing climate, because fire return intervals and successional cycles in these ecosystems occur over decadal to centennial timescales.

In parts of central Oregon, coarse-textured pumice substrates limit forest composition to low-density lodgepole pine (Pinus contorta Douglas ex Loudon var. latifolia Engelm. ex S. Watson) with scattered ponderosa pine (Pinus ponderosa Lawson & C. Lawson) and a shrub understory dominated by antelope bitterbrush (Purshia tridentata (Pursh) DC.).

Forest management of dry forests in the western US that historically experienced mixed-severity fire regimes is increasingly focused on landscape-scale restoration.

Rapid and broad-scale forest mortality associated with recent droughts, rising temperature, and insect outbreaks has been observed over western North America (NA). Climate models project additional future warming and increasing drought and water stress for this region.

Wildland fire is an important natural process in many ecosystems. However, fire exclusion has reduced frequency of fire and area burned in many dry forest types, which may affect vegetation structure and composition, and potential fire behavior.

Development owing to population increases over the last 30 years has greatly affected forested lands in the United States. To assess and compare increases in development, we counted changes in the number of structures on a systematic grid of photointerpreted points around public forest land in Washington and Oregon.

The relationship between large fire occurrence and drought has important implications for fire prediction under current and future climates.