Threats to western wildlands can occur over large landscapes and regions without regard for societal or political boundaries. Large, severe wildfires, drought, and insect outbreaks at the multi-state scale have caught the public’s attention recently. Changes in land use, extremes in temperature and precipitation, and air and water pollution are more subtle but insidious disturbance agents. Landscape disturbance generally results from several combined stressors, and can have multiple effects at several spatial and temporal scales. These disturbance agents have the potential for significant, broad-scale effects on wildland ecosystems as well as on human communities that depend on the resources that these wildlands provide.WWETAC supports the development of tools that help land managers better attribute and map valued forest and rangeland resources, predict and map vulnerability of communities and forests to biotic and abiotic stresses, assess the cumulative effects of various management options, and design and assess strategic, cost-effective approaches to land management.
WWETAC assembles and funds teams to conduct integrated landscape assessments. These assessments are used to help managers identify, anticipate, and place the level of disturbances in temporal and landscape contexts. Fuel loading and the resulting level of wildfire exposure is of high importance to land managers and the public alike. A national assessment of the location and frequency of fuels treatments concluded that nearly half of all USFS forested landscapes are in ‘disturbance deficit.’ Wildfire behavior and its transmission is dependent on the acreage, size, shape, and fuel loading of adjacent lands. Wildfire exposure can be reduced through forest-wide management decisions agreed to by the diverse landowners.
Tree mortality from drought and insect outbreaks species have been sufficiently large to equal megafire impacts on the landscape. A forecasting tool for tree mortality from these stressors has been developed for the state of California. A similar approach has been applied to develop a forecast for the states of Washington and Oregon in Region 6 using MODIS satellite imagery. This effort was based on the methods developed for CA, but was not funded by WWETAC. Another tool, FORAD, was developed to rapidly identify tree decline, by species and size class, and source of disturbance (spruce budworm, mountain pine beetle, etc.) using MODIS satellite imagery. Because tree and forest health are essential to resilient systems, a simple, rapid assessment is being developed from whole tree and canopy attributes that are associated with tree growth and vigor, drought stress, and susceptibility to insects and disease. The approach is scalable to the landscape level using a high resolution, multi-spectral imagery.
Over the last three years, significant effort has been devoted to quantifying resource vulnerability to disturbance (wildfire, climate impacts on resources) at the landscape level in the Pacific Northwest (USFS Region 6), and in the southern four National Forests of California (USFS Region 5). The resulting assessment for Region 6 identified counties at greatest risk for socioeconomic impacts resulting from climate change. The assessment for Region 5 is ongoing, and will result in a user-friendly website to explore impacts of concurrent stressors on ecosystem services (water quantity and quality, carbon, biodiversity, recreation) at the landscape level. These biophysical and socio-economic assessments complement regional Adaptation Partnerships supported by the USFS Washington Office Climate Change and Sustainable Operations Office, and can be requested from WWETAC.Links to highlighted studies: