Standing dead trees (snags) are considered
an integral habitat component of cavity-nesting
birds and other wildlife in the ponderosa
pine 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 that will result in
the presence of snags in the future.
Oak trees are an important component
of the ponderosa pine forest ecosystem.
These mast-producing trees are a valuable
food, nesting, and denning resource
for numerous wildlife species.
Currently the U.S. Naval Observatory in Flagstaff
is treating approximately 210 acres of ponderosa
pine forest using a 20 foot tree spacing
prescription to reduce fire danger in the
area of the Observatory.
this study, ponderosa pine snags are considered
to be standing dead trees greater than 4
inch diameter at breast height (dbh) and
greater than 7 feet tall, with an angle greater
than 45 degrees from the ground. We located
and measured all ponderosa pine snags on
the Naval Observatory. For each snag we documented
species, size (height and diameter), and
decay class. We also noted woodpecker use,
beetle infestation, and bark sloughing as
a surrogate for bat roost suitability. In
addition we established 30 plots to monitor
long-term oak regeneration. At these plots,
we inventoried all oak stems smaller than
4 inchesat the base within a 30 foot radius.
Thinning the forest may alter the reproductive
response of oaks, as well as the type, longevity,
and density of snags. The purpose of this
project was to collect baseline measurements
of oaks (for example, size distribution,
condition, density, etc.) and conduct a census
of snags within the ponderosa pine forest
on the Naval Observatory. We permanently
marked all snags and oak plots on the installation.
This will facilitate the long-term monitoring
of these snags where each can be sampled
through time to assess decay and retention
rates, and oak regeneration can be monitored
as it relates to the prescribed forest treatment.
For more information
Mylea Bayless, Arizona Game and Fish Department, 5000 W. Carefree Highway Phoenix, AZ 85086-5000
Phone: (928) 213-9591 E-mail: firstname.lastname@example.org
Michael Ingraldi, Ph.D., Arizona Game and Fish Department, 5000 W. Carefree Highway Phoenix, AZ 85086-5000
Phone: (928) 523-5625 E-mail: email@example.com