Background:
Standing dead trees (snags) are considered an integral habitat component of cavity?nesting birds and other wildlife in the coniferous forests of the southwestern United States. The species, size, bark retention, and condition influences the value of a snag as wildlife habitat. Removal of snags has been linked to declines in both diversity and density of cavity-nesting birds and tree roosting bats in southwestern forests. Snags also serve as nesting and perching platforms for numerous raptor species. Conversions of forests from old growth to even aged stands shortens the rotation age from centuries to decades, thereby reducing the size and age of the trees left in the forest. This reduction drastically decreases the amount, size and quality of dead and dying trees available for the future. Currently there are plans to treat the ponderosa pine forests on Camp Navajo using restoration prescriptions that should restore the proper structure and function of the forest community. Forest restoration treatments involve removing accumulated litter and over stocked stands through burning which may alter the type and density of snags. The purpose of this project is to conduct a survey of snags within the ponderosa pine forest on Camp Navajo and permanently mark benchmark snags for future monitoring.

Location:
We inventoried snags throughout the ponderosa pine forest on the western section of Camp Navajo Army National Guard Depot. The area is approximately 10 square miles and is bound by the western property boundary with the U.S. Forest Service and the western boundary of the containment area.

Approach:
We conducted a complete census of snags within the boundaries measuring snag species composition, size (height and diameter), decay class and density. Snags were considered any standing dead trees greater than 4 inches diameter at breast height (dbh) and greater than 7 feet tall, with an angle greater than 45 degrees from the ground. Decay classes are defined as follows: Decay class 1 - snags that have recently died, typically have little decay, and retain their bark, branches and top; Decay class 2 - snags that show some evidence of decay and have lost some bark and branches, and often a portion of the top; and Decay class 3 - snags that have extensive decay, are missing the bark and most of the branches and have a broken top. Decay classes 4 and 5 related to the extent of the decay on large stumps. We recorded woodpecker use, beetle infestation and bark sloughing as a surrogate for bat roost suitability. Each inventoried snag was marked with a uniquely numbered aluminum tag and we permanently marked a representative sample of these for long term monitoring (approx. 50 each) based on size class (4-12, 12-18, 18-24, and > 24 inches dbh) and decay class.

Benefits:
An inventory of currently standing snags will provide biologists with baseline information about snag density and age prior to implementing proposed forest restoration treatments. This study will facilitate the long-term monitoring of snags to assess decay rates and retention rates over time. Through monitoring, we will also gain information about the effects of forest restoration treatments on snag recruitment. This information, combined with wildlife surveys will provide insight to long-term effects that forest restoration may have on wildlife species in the ponderosa pine community.

For more information contact:
Mylea Bayless, Arizona Game and Fish Department, 5000 W. Carefree Highway Phoenix, AZ 85086-5000 .
Phone: (928) 213-9591 E-mail: mbayless@gf.state.az.us

Michael Ingraldi, Ph.D., Arizona Game and Fish Department, 5000 W. Carefree Highway Phoenix, AZ 85086-5000 .
Phone: (928) 523-5625 E-mail: mingraldi@cybertrails.com