MANAGEMENT SERIES, NO. 13:
FOREST HEATH FALLACY Science Indicates that
Reduction was not Justified on the Basis of Forest Health
The Pennsylvania Game Commission has attempted to justify
its deer reduction program on three issues – to improve deer
health, forest health, and biodiversity. Deer health was addressed
in the previous DMS No. 12.
Forest Health. A healthy forest is not achieved by
uncontrolled seedling regeneration, but, instead, by accomplishing
two goals: (1) establishing enough seedlings to fully restock
the next generation of commercially harvestable forests, and
(2) providing ample habitat (food and cover) for game and
nongame species of wildlife. Multiple analyses indicate that
blaming deer for destroying forest health is unjustified.
healthy pH-balanced forest soils have the capacity to regenerate
tens-of-thousands of seedlings per acre. A single oak tree
can produce 80,000 acorns per year. Considering that it requires
only about 150-220 six-foot seedlings per acre to fully restock
a forest with 80-120 mature trees per acre, then if it were
not for deer and other wildlife eating excess mast (fruits,
berries, and nuts) and seedlings, the forest could overstock
and suffer from competition for nutrients, water, and sunlight.
Although PGC and foresters demonize deer for eating mast and
seedlings, herbivores provide a vital service toward achieving
a healthy forest.
a U.S. Forest Service survey indicated that Pennsylvania forests
are about 90% fully to moderately stocked. The three predominate
species are red maple (20% of trees), red oak (13%), and black
cherry (12%) – two of which (red oak and black cherry) are
the state's most marketable timber species. This indicates
that Pennsylvania forests have been successfully restocking
themselves throughout the past century.
a 2006 Browse Survey that was conducted by DCNR on over 47,000
plots throughout State Forests concluded that the deer herd
had not been reduced far enough or long enough. However, at
close inspection of the data, the opposite conclusion was
discovered. Surveying all forest tree seedlings from 2"
to 6' tall, 68% were unbrowsed; 22% were lightly browsed (a
combined 90%); another 6% were moderately browsed (accounting
for a combined 96% of tree seedlings); and only 4% of seedlings
were heavily browsed.
Bill Capouillez (PGC's Wildlife Habitat Management Director
and chief forester) stated at a board of commissioners' meeting
that there has been no change in the trends of forest regeneration
after over 10 years of deer herd reduction: "In some
years regeneration is up in a particular WMU, and down the
regarding red oak propagation, according to a Penn State publication,
"Forest hydrologist William Sharpe – who has chronicled
the effects of acid rain in Pennsylvania for several decades
– also has watched as red oaks decline and red maples become
predominant. He maintains that soils in many places have become
too acidic to support adequate growth of red oak. According
to Dr. Sharpe, large mature oaks are dying, and that cannot
be blamed on deer. Penn State research in the 1970s found
that deer actually preferred to browse red maple over red
oak, so Sharpe does not subscribe to the deer hypothesis."
PGC's former chief forester notified commissioners: "I
am concerned AND angered by the mismanagement of the deer
herd in PA under the guise of biodiversity. A feigned lack
of forest regeneration never existed. Research by Penn State
professors show acid rain, rodents, ferns, et. al. have more
impact on a lack of new regeneration than deer. I saw this
happening during my career, repeatedly."
based on the forest health issue, there is no justification
for herd reduction. Nevertheless, foresters continue a relentless
lobbying campaign for increased herd reduction, and PGC continues
to comply with their demands. The biodiversity issue is addressed
in the next Deer Man