Long Valley Experimental Forest

The LVEF was established in 1936 as a counterpart to the Fort Valley Experimental Forest because of its contrasting limestone/sandstone soils as opposed to basalt-derived clay loam of the Fort Valley Experimental Forest and because it contained some of the best stands of Ponderosa Pine on the Coconino and Sitgreaves National Forests. Today the LVEF comprises some of the last remaining continuous stands of un-harvested ponderosa pine forest in northern Arizona.

Long Valley Experimental Forest has a mean elevation of 2124 meters. It is representative of the largest ecoregions in the national forest. Precipitation is typically higher than the national forest average, except during the early summer months, by up to 2.5 centimeters. Temperatures are typically higher than the national forest average by about one degree. Long Valley is not representative of the hydrological conditions of the Coconino with very little stream length and none of the 245 springs found within the national forest boundary.

There are no facilities within Long Valley Experimental Forest.

Fire return intervals

Researchers at Long Valley have examined fire return intervals. At Limestone Flats Fire Interval Study area, comprising 75 acres in the northeast corner of Long Valley Experimental Forest, researchers have conducted experiments to explore the impacts of burning at certain intervals. Researchers applied burning treatments to the long-term study area—fenced and enclosed by a fire line roughly 16-feet wide—at 1-, 2-, 4-, 6-, 8-, and 10-year intervals. Three plots were set aside as unburned controls. Researchers made various measurements over the years, including fuels, soils, understory and overstory plants. Results are summarized in Fort Valley Experimental Forest-A Century of Research 1908-2008. 

Snowpack effects on northern Arizona forests

Currently, the University of Arizona, in collaboration with USDA-ARS, SRP, and others is seeking to better understand the impact that forest cover has on snowpack in forests of northern Arizona.  Long Valley is an ideal place to study this because of the contrast between the Experimental Forest, which has not been thinned recently, and land to the north, which has recently undergone mechanical forest thinning. Read more about this research in the 2020 publication Forest cover and topography regulate the thin, ephemeral snowpacks of the semiarid Southwest United States.

Other research and treatments

In 1966, researchers clearcut 139 acres in the southeast corner of Long Valley Experimental Forest as part of an effort to remove mistletoe infested trees. Although records show that effort as a clearcut, on-the-ground visits show some residual large old trees.

Researchers included the northwest corner of Long Valley in a Basal Area (BA) study, in which they cut 2.5-acre plots to a basal area of 0, 20, and 40 BA/ac. This study affected 94.6 acres. Although they applied the treatments, the researchers never published results.

In 2009, the Rocky Mountain Research Station and Southwest Regional Office initiated a plan to implement the newly developed Desired Future Conditions (DFC) within an 800-acre portion of Long Valley Experimental that had never been logged. The plan was to use the area for both research and demonstration purposes. Although researchers collected some pre-treatment data on wildlife and overstory forest structure, the treatments were never implemented due to budget constraints.  

In 1937, U.S. Forest Service researchers completed an inventory of all trees greater than 4 inches at breast height within one section (640 acres) of Long Valley. To collect this information, they divided the entire section into 6,400 one-tenth acre plots. For comparison purposes, U.S. Forest Service researchers re-measured all trees greater than 16-inches in 2009, located within a quarter of the original study area. Researchers are currently analyzing the historical and contemporary data.

Two storied canopy including large pre-settlement trees and younger, post-1900 trees.