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Drought and piñon-juniper woodlands: Changing fuel loads from tree mortality

Status: 
Action
Dates: 
May, 2014 to August, 2015

Skeletons of pinyon pine trees (photo by N.S. Cobb).
Skeletons of pinyon pine trees (photo by N.S. Cobb).
Pinyon-juniper woodlands are one of the most extensive vegetation types in western North America and cover approximately 19 million ha. The American Southwest is characterized by extreme drought conditions accompanied by rising temperatures, causing widespread tree mortality in pinyon-juniper woodlands. This die-off occurred across 1.2 million hectares of the southwestern United States and killed up to 350 million pinyon pines. Widespread tree mortality is an indicator of climate change clearly visible not only to scientists, but also decision makers and the general public.

Widespread pinyon mortality is common across the West (photo by N.S. Cobb).
Widespread pinyon mortality is common across the West (photo by N.S. Cobb).
This research makes significant contributions to understanding mechanisms of tree mortality. Die-offs are significant events for humans and natural systems. Services to humans, biogeochemical cycling, energy fluxes, and wildlife habitat are among the processes severely affected.

The Colorado Plateau and Southern Great Plains continue to experience frequent droughts and high temperatures. On-going research examines whether even drought tolerant junipers may succumb to increased aridity and begin dying at increased rates, potentially significantly altering fire regimes.

These findings will help managers predict how forests will respond to warming and the impacts that will cascade through ecosystems, and provide a better understanding of how climate influences trees.  

Publications

Delph, Robert J. ; Clifford, Michael J. ; Cobb, Neil S. ; Ford, Paulette L. ; Brantley, Sandra L. , 2014
Clifford, Michael J. ; Royer, Patrick D. ; Cobb, Neil S. ; Breshears, David D. ; Ford, Paulette L. , 2013
Floyd, M. Lisa ; Clifford, Michael ; Cob, Neil S. ; Hanna, Dustin ; Delph, Robert ; Ford, Paulette L. ; Turner, Dave , 2009
Floyd, M. Lisa ; Clifford, Michael ; Cob, Neil S. ; Hanna, Dustin ; Delph, Robert ; Ford, Paulette L. ; Turner, Dave , 2009


Project Contact: 

Principal Investigators:
Co-Investigators:
Neil Cobb - Northern Arizona-Department of Biology
Michael Clifford - Desert Research Institute-Division of Earth and Ecosystem Science-Las Vegas

Collaborators:
MIranda Redmond - University of Colorado-Bolder

Funding Contributors:
National Fire Plan-USDA