The Flagstaff Analytical Laboratory
Rocky Mountain Research Station-Flagstaff, USDA-Forest Service
Southwest Forest Science Complex
2500 S. Pine Knoll Drive
Flagstaff, AZ 86001
Phone: (928) 556-2044

Pinyon-juniper woodlands are a dominant vegetation type within lands administrated by the USDA Forest Service and USDI Bureau of Land Management in southwestern Colorado. The woodlands traditionally have been viewed as having a low risk of wildfires because of the lack of ground cover and the low stand densities associated with the type. However, stand densities are often high and wildfires will occur naturally given conditions of low humidity, high temperature and wind speeds, and an ignition source. The resulting fires destroy dwellings and have had tragic consequences for fire fighters. Pinyon-juniper woodlands are found adjacent to cities, towns, and rural home developments throughout the Southwest. Drought and insect infestations have resulted in high pinyon mortality increasing fuel loadings and risk of severe wildfires. Managers are using mechanical mastication equipment and traditional thinning with piling and burning to reduce fuels/fire risk within wildland-urban-interface areas; however, managers and the public are concerned about the consequences of using wood mastication techniques on the woodland ecosystem soil and vegetation resources. How does the addition of large amounts of woody material affect soil nutrient status and microbial communities? Do the treatments encourage the establishment of non-native invasive species? How do these changes compare to thinning treatment and to untreated conditions? A study is designed to compare soil and vegetation changes among sites within wildland–urban-interface areas treated by a mastication technique using “hydro-mow” equipment or by thinning, and an untreated control. The three treatments will be replicated on three separate sites within the jurisdiction of the Dolores Public Lands Office in southwestern Colorado. Results will be applicable to the immediate Forest Service/BLM lands but will have broader implications since mechanical mastication treatments are currently being applied or planned for other pinyon-juniper interface areas throughout the West.

• Funded by Joint Fire Sciences Program
• Laboratory analyses will include Total C, Total N, Mineralizable N, Phospholipid Fatty Acid (PLFA), Neutral Lipid Fatty Acid and pH.  All analyses will be performed in
  The Flagstaff Analytical Laboratory of the RMRS-Flagstaff.
• For more information, please contact Steve Overby or Gerald Gottfried