This synthesis integrates recent research concerning socioecological resilience in the Sierra Nevada, southern Cascade Range, and Modoc Plateau. Among the focal topics are forest and fire ecology; soils; aquatic ecosystems; forest carnivores; air quality; and the social, economic, and cultural components of socioecological systems. A central theme is the importance of restoring key ecological processes to mitigate impacts of widespread stressors, including changes in climate, fire deficit and fuel accumulations, air pollution, and pathogens and invasive species.
Water stress represents a common mechanism for many of the primary disturbances affecting forests, and forest management needs to explicitly address the very large physiological demands that vegetation has for water. This study demonstrates how state-of-science ecohydrologic models can be used to explore how different management strategies might improve forest health.
Widespread threats to forests due to drought stress prompt re-thinking of priorities for water management on forest lands. In contrast to the widely held view that forest management should emphasize providing water for downstream uses, we argue that maintaining forest health in the face of environmental change may require focusing on the forests themselves and strategies to reduce their vulnerability to increasing water stress in the context of a changing climate. Management strategies would need to be tailored to specific landscapes but could include: a) thinning; 2) encouraging drought-tolerant species; 3) irrigation; and 4) strategies that make more water available to plants for transpiration. Hydrologic modeling reveals that specific management actions could reduce tree mortality due to drought stress. Adopting water conservation for vegetation as a priority for managing water on forest lands would represent a fundamental change in perspective and potentially involve tradeoffs with other downstream uses of water.
The Water Erosion Prediction Project (WEPP), is a physically-based soil erosion prediction technology. WEPP has a number of customized interfaces developed for common applications such as roads, managed forests, forests following wildfire, and rangelands. It also has a large database of cropland soils and vegetation scenarios. The WEPP model is a distributed parameter, continuous simulation model, and is able to describe a given erosion concern in great detail for an experienced user.
The WEPP model consists of multiple applications that can estimate erosion and sediment processes on hillslopes and small watersheds, taking into account climate, land use, site disturbances, vegetation, and soil properties.