United States Department of Agriculture, Forest Service
Pacific Southwest Research Station
Sierra Nevada Research Center
Snag (Standing Dead Trees) Demography in Eastside Pine Forests
The Research:
Our understanding of snag (standing dead trees) demographic
patterns, spatial and temporal, as well as whether desired snag
numbers are sustainable, is very limited. To improve our knowledge of snag demographic patterns in eastside pine forests in
Northeastern California, a snag study was initiated in 1988. The
study was also intended to study bird relations with different
snags densities in these pine forests. Twenty-four 5-ha (100 m
x 500 m) plots were selected from approximately 1,000 eastside
pine land management polygons with large trees and at least moderate canopy density on the Modoc and Lassen National Forests
and from suitable areas in Lassen Volcanic National Park.
Objectives:
• Gain a better understanding of the pattern - spatial and
temporal - of snag creation and loss in eastside
pine forests.
• Evaluate cavity nesting bird responses to differing snag
densities.
• Experimentally evaluate the differences between the
decay trajectories of bark beetle killed trees and
girdled trees of different diameters that died at
different times of year.
• Experimentally evaluate the fire effects on trees with no
duff ‘n’ stuff within 1 m of the base of the bole
versus trees with up to 0.5 m of duff ‘n’ stuff
adjacent to the bole.
• Examine the “survival” rates of snags following a prescribed
burn intended to remove large quantities of existing dead
and down material.
• Gain a better understanding of the “lifespans” of dead
trees dying from different mortality agents.
USDA Forest Service
Pacific Southwest Research Station
Sierra Nevada Research Center
Photo: Bill Laudenslayer
Our Mission:
Sierra Nevada Ecosystems are
complex and our knowledge
of them is incomplete. As
a result, the long term outcome of any given land and
resource management strategy
is uncertain. We will provide
assistance to land managers
and policy makers by addressing this management dilemma
through targeted research,
emphasizing an integrated,
ecoregional approach to
examine particular physical,
ecological, and socio-economic issues, across a range of appropriate spatial and temporal
scales specific to each issue.
This unit will represent the
collective research expertise
and interests of scientists
located in Fresno, Davis and
Albany as well as other scientists within the Pacific Southwest Research Station. With
a full spectrum of research,
from long term, fundamental
research to short-term, tactical applications, this Center is
intended to support conservation, restoration, and sustainable utilization of the lands
within the Sierra Nevada
ecoregion.
Application of Research Results:
Managers at Lassen Volcanic National Park are very interested in our findings and
are applying the results to their management activities, especially their prescribed
fire practices. Our findings have been applied to fire salvage questions as well to the
development of criteria for determining which trees to consider for salvage.
Our conclusions from the snag demographics study suggest that snag populations
are reflective of capability of the landscapes to support snags through time and
space. From the cavity nesting bird perspective, a continual flow of dying and dead
trees is necessary to provide a flow of food and potential nesting locations in a landscape.
Some prescribed burns result in large numbers of dead trees shortly following the
burn thus reducing the number of persisting live trees and incipient snags. One
mechanism for reducing mortality is removal of the duff ‘n’ stuff to mineral soil
around the base of the tree but this is expensive, does not save all of the trees.
Other studies suggest such methods may actually cause mortality under certain conditions.
Location:
Northeastern California, Modoc and Lassen National Forests and from suitable areas Lassen Volcanic
National Park.
Photo: Bill Laudenslayer
Photo: Bill Laudenslayer
USDA Forest Service
Pacific Southwest Research Station
Sierra Nevada Research Center
For further inforamation contact:
Dr. Bill Laudenslayer, Research
Ecologist; 530-279-8338
Dr. Peter Stine, Program Manager
Dr. Jim Sedell, Station Director
Pacific Southwest Research Station
www.fs.fed.us/psw/programs/snrc
Albany Location:
800 Buchanan Street
Albany, CA 94710
Mailing Address:
P.O. Box 245
Berkeley, CA 94701
Phone: 510-559-6300
Fax: 510-559-6440
Davis Location:
2121 Second Street
Suite A101
Davis, CA 95616
Phone: 530-759-1700
Fax: 530-747-0241
Fresno Location:
2081 E. Sierra Avenue
Fresno, CA 93710
Phone: 559-323-3200
Fax: 559-297-3355