fire regimes

Fire is a natural disturbance that is nearly ubiquitous in terrestrial ecosystems. The capacity to burn exists virtually wherever vegetation grows. In some forested landscapes, fire is a principal driver of rapid ecosystem change, resetting succession ( McKenzie et al. 1996a ) and changing wildlife habitat (Cushman et al. 2011 ), hydrology ( Feikema et al.

Projected effects of climate change across many ecosystems globally include more frequent disturbance byfire and reduced plant growth due to warmer (and especially drier) conditions.

Aim Studies of fire activity along environmental gradients have been undertaken, but the results of such studies have yet to be integrated with fire-regime analysis. We characterize fire-regime components along climate gradients and a gradient of human influence.

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.

Warmer and drier climate over the past few decades has brought larger fire sizes and increased annual area burned in forested ecosystems of western North America, and continued increases in annual area burned are expected due to climate change. As warming continues, fires may also increase in severity and produce larger contiguous patches of severely burned areas.

The 2013 Rim Fire, originating on Forest Service land, burned into old-growth forests within Yosemite National Park with relatively restored frequent-fire regimes (¡Ý2 predominantly low and moderate severity burns within the last 35 years).

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

Fire has historically played a fundamental ecological role in many of America’s wildland areas.

Quaking aspen, the most widespread tree species in North America, reproduces primarily by resprouting from roots. In some stands, mortality from fire encourages sprouting and prevents conifers from eventually replacing aspen. In other areas, aspen can form stable communities that do not require fire to regenerate or persist.

During the 21st century, climate-driven changes in fire regimes will be a key agent of change in forests of the U.S. Pacific Northwest (PNW).