Fort Valley Experimental Forest
Contact Information
  • Fort Valley Experimental Forest
  • Forest and Woodland Ecosystems Science Program
  • 2500 S. Pine Knoll Road
  • Flagstaff, Arizona 86001
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About Our EFR


Fort Valley Experimental Forest is located in northern Arizona. The Experimental Forest consists of four disjunct units located within the Coconino National Forest. Click the map to explore the experimental forest in Google Earth.


Precipitation 22 inches per year
Snowfall 80 inches per year
Warmest 98FJuly 5, 1985
Coldest -37FJanuary 12, 1963
Wettest 4.0 inchesAugust 24, 2006


Forester Gustaf Adolph Pearson became the Director of Fort Valley and was the sole scientist on the site in the winter of 1908-09. He lived in this uninsulated cabin first built in 1906 as a forest ranger's cabin. He buried his canned food to keep it from freezing, but the cans froze anyway and the labels came off. Pearson never knew what his meal would contain until he had opened a few cans. The next spring, he built an insulated residence/office now known as the Pearson House.

In August, 1909, Fort Valley served as the site for Ranger Schools to train incoming District 3 rangers. Students learned silvilcuture, camp maintenance, law, grazing, fieldwork, horse care, and office work during the two-week sessions. Two sessions per year were held intermittently until World War II began. A baseball game pitted the Arizona rangers against the New Mexico rangers and included rules that base runners had to remove their spurs and firearms. The camaraderie that developed was as important as the skills learned.

A 1910 test of ponderosa pine's ability to produce resin was led by Forest Service engineer Harold S. Betts who based his research from Fort Valley. The initial response was good enough for more research the following year over a larger area. Results indicated that ponderosa pines produce resin at about 4/5 the quantity of southeastern trees when factors such as length of season are the same. Resin quality is similar and the main problem to developing turpentine operations in northern Arizona was the lack of skilled laborers. The potential existed for a market, but the idea was never pursued.

Pearson and Region 3 silviculturalist T.S. Woolsey, Jr. established permanent sample plots over all the various forest types in the southwest in 1912. They measured, photographed, and inventoried the plots every five years until Pearson's retirement in 1944. NAU forestry professors and students have been remeasuring the plots for the past eight years, providing a ninety-year record of change.

A weather study initiated in 1916 followed biologist C. Hart Merriam study in 1889 when he suggested the lifezones theory based on his work on the San Francisco Peaks. Fort Valley scientists placed weather recording instruments and nurseries at various altitudes. They planted exotic species to see if they would survive and take weather readings weekly. They would leave the Fort Valley station at daybreak with snowshoes strapped on and lunches packed.

By 1927, Fort Valley's scope of operations had grown to include Range studies. Charles K. Cooperrider was the head of this Division. Scientists studied domestic and wildlife grazing damage to tree reproduction and also studied range grasses. Permanent Range Study Plots were established around Region 3 and are still being monitored.