Western Forests and Mountains

Tree-ring science is a component of our interdisciplinary ecological research program that focuses on the effects of climate variability and human land use on forest ecology, fire ecology, and ecohydrology.

Drought, hotter temperatures, and insect outbreaks are affecting dryland ecosystems across the globe. Pinon-juniper (PJ) woodlands are a widespread vegetation type common to drylands of North America, which have been hit particularly hard by a warming climate. Specifically, mass tree die-off events are transforming PJ woodland structure, composition, and distributions. This project aims to...

Forests are a key component of a healthy ecosystem. Management of these resources is vital to their protection as a recreational resource as well as an environmental resource.

Mountain ecosystems are highly sensitive to climate change, and USGS is conducting montane research across the West to help resource managers plan now for the future. Coordination with scientists around the world has led to mountain research networks to expand our understanding of how these ecosystems respond to climate change.

Forests are the dominant land cover along the floodplain of the Upper Mississippi River System. These forests are primarily made up of relatively short-lived and rapidly growing species, such as willow, cottonwood, silver maple, green ash, American elm, but with inclusions of slower growing and longer-lived species, such as oak and hickory species.

Research in our laboratory centers on the ecology and biogeochemistry of forest ecosystems, as well as grassland and riparian systems. We examine how factors such as natural and human disturbances, climate and climate change, succession, and soil fertility shape ecosystem biogeochemistry - and the reciprocal effect of biogeochemical cycles on these and other factors.

Models can be used to investigate changes in ecosystems and disturbance regimes across large landscapes and over long periods of time, i.e., at spatial and temporal scales that are typically not possible or practical using field-based observational or experimental methods. These spatially explicit models can also be used to investigate complex relationships and interactions among various...

This research theme facilitates the sound management and restoration of Pacific Northwest Douglas-fir forests, as well as to refine broader-scale predictions of how temperate forests will function in an increasingly nitrogen-rich world.

This research theme examines the impacts of prescribed fire on plant productivity, soil physical, chemical, and biological characteristics, and nutrient leaching. Results from this research will enable improved decision-making of how to manage fire-prone forests to maintain long-term forest fertility and productivity, especially across wide climate gradients characteristic of the Pacific Northwest...

This research theme coalesces studies of old-growth temperate forests in several major thematic areas including landscape and ecosystem controls on watershed nutrient export, wildfire disturbance legacies on biogeochemical cycling, and the imprint of tree species on soil nutrients in old-growth forests.

Dr. Nathan Stephenson and colleagues seek to determine what changes are occurring in forests, why they are occurring, and what they mean. For example, they have documented a long-term, apparently climatically-induced increase of tree mortality rates in otherwise undisturbed old forests across the western U.S., implying that these forests could become net sources of atmospheric carbon dioxide.

USGS WERC's Dr. Phil van Mantgem and his collaborators are using plot-based methods to describe change and vulnerability to drought in the forests of the western United States. A focus of this work is the installation and maintenance of large (1 ha) monitoring plots. Many other vegetation monitoring strategies are based on small (0.1 ha) plots, which may not be sufficient to detect changes in...