Implications of precipitation changes on the carbon balance of pinon-juniper ecosystems (with Nate McDowell, LANL and Mike Ryan, USFS, supported by USDA-Forest Service through the Rocky Mountain Research Station).

Mortality associated with drought and bark beetle infestations has recently occurred in 40-95% of piñon-pine ( Pinus edulis ) and 2-25% of juniper ( Juniperus monosperma ) in the southwest USA . The impacts of this mortality on ecosystem carbon sequestration remain unknown. This project will quantify the carbon budget of piñon-juniper ecosystems exposed to precipitation manipulations using the approach of Ryan (2004) via empirical measurements of above and belowground carbon fluxes. These measurements will be utilized within a process based model to develop a more comprehensive understanding of the effects of this mortality on ecosystem structure and function. The study is located in a piñon-juniper woodland on the Sevilleta National Refuge within the Middle Rio Grande watershed and utilizes the treatments imposed by our precipitation manipulation experiment funded by DOE-PER.