sen and Tracey Frescino of the RMRS; Thomas Edwards of the U.S. Geological Survey’s Utah Cooperative Fish and Wildlife Research Unit and Department of Wildland Resources at Utah State University; and Niklaus Zimmerman of the Swiss Federal Research Lab in Zurich, Switzerland—to model how climate change may impact PJ woodlands in western North America.
Credit: John D. Shaw
Brown piñon trees in Arizona’s Coconino National Forest (above) fell victim to an insect infestation and drought that struck the region in 2003-04. Although juniper species are more tolerant to extreme weather, piñons barely survive severe high temperatures and drought. In a possible migration to escape rising temperatures, an isolated population of young piñon pines (below) inches northward along a rocky ridge in Utah’s Logan Canyon.
They began by analyzing forest and woodland data collected by the USFS Forest Inventory and Analysis (FIA) Program. To obtain the data, USFSFIA researchers inventory forests and woodlands throughout the U.S., collect data from permanent sample plots approximately every three miles across the nation’s forests, and record the condition of woodlands by noting the species, health, size, growth, mortality, and status of the forests and woodlands. “We collect this subset of data annually so there is a treasure chest of information to draw from,” says Moisen, a research forester. “This inventory data is phenomenal by itself, but we have to integrate it with other data sources to understand [why] things are changing.” To model how the PJ woodlands might change under different climate scenarios, the RMRS team collected data for every PJ woodland tree species on each sample plot and noted which trees were present and which were absent. They compiled a huge forest-woodland data set from 17 states, gathering information on the elements that would determine the potential migration rate of the woodlands. These include “the regeneration rate, mortality rate, and how these elements change at the edges of the distribution compared to the center of the distribution,” says team member Zimmerman. Researchers have also modeled changes 80 years from now, which will help identify and highlight potential areas that offer climactic and environmental conditions conducive to these species (see map on page 49).
What Lies Ahead
Credit: Jacob R. Gibson
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The Wildlife Professional, Fall 2011
Based on their research so far, the team has found that the most sensitive part of the distribution is the “leading edge”—where new populations are occurring, such as the new piñon pine woodlands growing in northern Utah. The conditions for seed germination and establishment require a high quality, narrow subset of environmental conditions, such as “more moisture, more warmth, and other elements more conducive to the growth of saplings,” Edwards says. © The Wildlife Society