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U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture


The Forest Service Mission is to “Sustain the health, diversity, and productivity of the Nation’s forests and grasslands to meet the needs of present and future generations.”

“The Nation’s forests and grasslands provide clean water, scenic beauty, biodiversity, outdoor recreation, natural resource-based jobs, forest products, renewable energy and carbon sequestration. Climate change is one of the greatest challenges to sustainable management of forests and grasslands and to human well-being that we have ever faced, because rates of change will likely exceed many ecosystems’ capabilities to naturally adapt. Without fully integrating consideration of climate change impacts into planning and actions, the Forest Service can no longer fulfill its mission.” (Forest Service Strategic Framework for Responding to Climate Change (2008)(PDF, 294 KB))

“Climate change is expected to have pronounced ecological consequences in forested ecosystems. Projected impacts encompass a broad range of effects: the evolution of novel plant associations, shifts in the spatial distribution of tree species, redistribution of populations adapted to local climates, and in site index. Several studies, in fact, have been unanimous in predicting widespread disruption of native ecosystems from the change in climate being portrayed by numerous General Circulation Models.” (Crookston and others (2010, p. 1198))

The Climate Extension to the Forest Vegetation Simulator (Climate-FVS) provides forest managers a tool for considering the effects of climate change on forested ecosystems. The original Forest Vegetation Simulator (FVS) components predict performance in the absence of climate change. To accommodate the effects of climate change, Climate-FVS modifies these components rather than replacing them with new climate estimators. In this respect, the primary intrinsic components of FVS and its empirical heritage remain intact. The core tree growth, mortality, and regeneration components in FVS are modeled as functions of site capacity, tree size, and competition. The measures of site capacity rely on direct observations of biological indicators such as site index. In the base FVS model, there is an assumption that site capacity does not change over time. With the introduction of Climate-FVS, there is now the ability to use information regarding climate change to affect site capacity and estimate the effects on tree growth, mortality, and regeneration potential.

Growth is affected when climate conditions at a given location change in relation to the optimal climate conditions within which the species or population is known to grow and thrive. Mortality is affected when the climate in an area changes to become inconsistent with the conditions where species are presently known to survive. Regeneration potential is also limited by changes that cause an area's climate to become inconsistent with the known conditions where species can survive. Conversely, changes that cause an area's climate characteristics to become suitable for a species' survival can lead to successful regeneration of that species. Climate-FVS adjusts FVS to take into account these effects of climate on growth, mortality and regeneration potential.

To compute the magnitude of changes in growth rates, mortality, and regeneration establishment, Climate-FVS requires additional climate and species-viability information beyond that normally required. That input is provided in the form of a file that is described in a draft user’s guide, Climate-FVS Version 2: Users Guide (PDF, 07-06-2015, 1.6M). A web service is available for generating the required input. Users prepare a file of stand locations detailing the stand identification, longitude in decimal degrees, latitude in decimal degrees, and elevation in meters. The website generates climate and species viability information required by Climate-FVS. Visit the Get Climate-FVS Ready Data website for this online service and where additional instructions are posted.

Climate-FVS is currently available for the western half of the conterminous United States; however, work has been initiated to expand Climate-FVS to the eastern half of the United States.

Please contact us if you are interested in trying this extension and need help. We are also very interested in hearing your experience with this new tool.

Climate-FVS Software

The Climate-FVS software is available for download from the Geographic Variant Installer Files web page.

We are also providing Climate-FVS Exercises (.exe, 751K) to introduce the Climate-FVS extension and how to use it.

Climate-FVS Webinar

FVS logoRocky Mountain Research Station logo

The FVS staff partnered with Nicholas Crookston, Rocky Mountain Research Station (RMRS), to present two webinars to introduce users to Climate-FVS. They occurred February 15, 2011, and March 10, 2011. The webinars briefly discussed the FVS model, the scientific underpinnings of Climate-FVS, the appropriate uses of the model, including sources of uncertainties and limitations, and a project level demonstration of Climate-FVS.

View the Climate-FVS Webinar Video…

Further Reading