Fire

Recent Warming This is an initiative to document and understand the science of recent climate warming in the region and implications for natural resources management. SW CASC researchers from Colorado State University, Scripps Institution of Oceanography at University of California-San Diego, and University of Arizona, and their partners, are identifying the extent to which temperature...

Mature, old-growth forests in the Pacific Northwest provide critical habitat for threatened and endangered species, including the northern spotted owl and marbled murrelet. Dominated by large Douglas-firs and western hemlocks, these established forests range in age from 200 to 1,000 years old. Yet wildfire activity is increasing across western North America, heightening concerns about...

California - one of the nation's most populous states - hosts extensive public lands, crown-jewel national parks, and diverse natural resources. Resource managers in federal, state, tribal, and local agencies face challenges due to environmental changes and extreme events such as severe droughts, heat waves, flood events, massive wildfires, and forest dieback. However, state-of-the-art...

Sagebrush steppe is one of the most widely distributed ecosystems in North America. Found in eleven western states, this important yet fragile ecosystem is dominated by sagebrush, but also contains a diversity of native shrubs, grasses, and flowering plants. It provides critical habitat for wildlife like pronghorn and threatened species such as the greater sage-grouse, and is grazed by...

The Southwest U.S. is experiencing hotter droughts, which are contributing to more frequent, severe wildfires. These droughts also stress vegetation, which can make it more difficult for forests to recover after fire. Forest regeneration in burned areas may be limited because seeds have to travel long distances to recolonize, and when they do arrive, conditions are often unfavorably hot...

The 2017 fire season in California was highly unusual with its late seasonal timing, the areal extent it burned, and its devastation to communities. These fires were associated with extreme winds and were potentially also influenced by unusually dry conditions during several years leading up to the 2017 events. This fire season brought additional attention and emphasized the vital need...

Fire size, frequency, overall area burned, and severity are increasing across many vegetation types in the southwestern U.S. In many cases, large contiguous areas are burning repeatedly at high severity, triggering vegetation type conversions (VTC), where once-dominant coniferous forests fail to return to their pre-fire state, often transitioning to shrub- or grass-dominated systems...

The climate in Hawai‘i is changing, and alterations in rainfall amount and distribution have implications for future vegetation cover, non-native species invasions, watershed function, and fire behavior. As novel ecosystems and climates emerge in Hawai‘i, particularly hotter and drier climates, it is critical that scientists produce locally relevant, timely and actionable science...

In Alaska, increased wildfire activity has been linked to warming temperatures. Summers with extreme wildfire activity threaten life and property, clog the air with smoke, and challenge the state’s wildland firefighters. While the largest fires are often started by lightning and burn in remote areas, these fires require significant resources to fight when they threaten life and property.

As the dominant force that sets the structure and function of most Pacific Northwest forests, fire is likely to be the major catalyst of forest change in a warming climate. Rising temperatures, decreased snowpack, and earlier snowmelt are expected to lead to longer fire seasons, drier fuel, and an increase in the area burned by wildfires in the future. Forest managers therefore need...

In Alaska, recent research has identified particular areas of the state where both a lack of soil moisture and warming temperatures increase the likelihood of wildfire. While this is an important finding, this previous research did not take into account the important role that melting snow, ice, and frozen ground (permafrost) play in replenshing soil moisture in the spring and summer...

In the dry southwestern United States, snowmelt plays a crucial role as a water source for people, vegetation, and wildlife. However, snow droughts significantly lower snow accumulations, disrupting these critical water supplies for local communities and ecosystems. Despite its large influence on land- and water-resource management, snow drought has only recently been properly defined...