of Long Term Research Conducted by the Northeastern Research Station
Effect of Deer Population
Levels on Natural Regeneration of Allegheny Hardwoods
||1) To determine the average deer density which will allow
natural regeneration of desirable Allegheny hardwood timber
species at adequate stocking levels in stands managed under
2) To determine the effects of known herd-size on browse-use
over a range of regeneration conditions in Allegheny Plateau
3) To determine if deer density impacts songbird, small mammal,
shrub and herb communities.
||Warren, McKean, Forest, Elk, and Potter counties in the Allegheny
Plateau of Northwestern Pennsylvania. Hardwood stands in the
large pole-small sawtimber size class, managed on a 100-year
rotation with a 10-year cutting cycle. The 4 sites (replications)
represent the following 4 levels of regeneration potential:
a) poor - less than 30% of the sample quadrats adequately stocked
with desirable tree seedlings.
b) below average - between 30% and 50% of the sample quadrats
adequately stocked with desirable tree seedlings.
c) above average - between 50% and 70% of the sample quadrats
adequately stocked with desirable tree seedlings.
d) good - greater than 70% of the sample quadrats adequately
stocked with desirable tree seedlings.
Desirable commercial woody species typical of Allegheny hardwoods
are sugar maple, red maple, yellow-poplar, white ash, black
cherry, and cucumber. Overstory composition may also include
other commercial species such as beech, eastern hemlock, white
pine, birch, basswood, aspen, butternut, and in transition stands,
oak and hickory. Undesirable woody seedlings are judged on the
basis of their value as deer forage, of their commercial value,
and of their competitive influence on higher value species.
The two most prominent species are beech and striped maple.
At least one site contains an understory dense with plants that
interfere with desirable regeneration such as ferns, grasses,
||Randomized block design with stratified, systematic sampling
from a random start. 4 160-acre fenced blocks, each cross-fenced
to form 4 plots; 1 of 64 acres and 3 of 32 acres are established
and replicated at 4 separate locations across 5 counties on
northwestern PA's Allegheny Plateau. 8 deer were introduced
into each block at a rate of 1 deer per 64 acres, and 1, 2,
and 4 deer in the 3 32-acre plots, thus simulating 10, 20, 40,
and 80 deer per square mile.
Each fenced plot contains a mixture of clear-cut, thinned
and uncut stands along with selected openings resulting from
haul roads and log-landings. The 4 blocks range in regeneration
potential (for desirables) from poor (30% regeneration stocking)
to excellent (70% regeneration stocking). Seedling responses
under the various deer densities were compared using permanently
marked fenced 6' radius sample plots measured just before
deer introduction, during the 5th year, and during the 10th
year after establishment.
In the 11th year of study, evaluation of response of other
communities to deer density was added. Songbirds were censured
at fixed census locations within each silvicultural treatment
within each deer density. Small mammals were censured by live-trapping
on 50-trap grids within each of the deer density x structural
treatments. Herbs and shrubs were tallied by estimating percent
ground cover, by species in May-June, within 30 milacre plots,
located randomly within each deer density x silvicultural
|Likelihood of Locating Study Areas:
||The following is representative of the acreages treated silviculturally
for each plot size:
Cuttings represent the proportions expected under a 100-year
rotation under even-age sustained yield timber management.
The following is representative of the acreages treated with
deer densities per plot:
No. of Deer
Equiv. Deer/Square Mile
||Seedling counts made during tallies of regeneration plots
(0.001 acre each) were by species and height classes: <0.1',
<0.5' to 1', <1', 1' to 3', 3' to 5', <5'. Herbaceous
cover was measured in only the regeneration plots. Not all regeneration
plots were measured at every tally and height classes varied.
|Variables and Sampling Frequency:
||Regeneration plots: 1979 to 1985 annually, 1989.
Independent: soil depth to mottling, parent rock, slope (%),
aspect (azimuth from north), and stand conditions.
Dependent: regeneration stocking per acre in clearcuts, thinnings,
and uncut stands; regeneration stocking of desirable noncommercial
browse species. species richness and abundance of songbirds,
small mammals, herbs and shrubs.
||Plots were located away from fence lines or open trails to
avoid exposing features to abnormal use by the study animals
and potential erroneous data. Data-entry into computer was 100%
cross checked with field sheets.
||Raw data by plot reside on DG and tally sheets are kept with
written instructions and detailed maps to each stand. Annually,
the raw data are transformed using the REGEN1 program in DG
Info. System. Summarized data by plot and by stand reside in
a DG-based program that can output to ASCII text files.
|Global Change Research Applications:
||Studies of Ecosystem Processes
|Publications and Reports:
||Study plan. 1979
Environmental Assessment report. 1979. Coleman Holt.
Establishment report. 1982. David Marquis.
Progress reports. 1983, 1984, 1986. Nancy Tilghman.
The above are office reports of U.S. Department of Agriculture,
Forest Service, Northeastern Forest Experiment Station, Warren,
deCalesta, D.S.; Witmer, G.W. 1990. Drive line census for
deer within fenced enclosures. Res. Paper NE-643. Radnor,
PA: U.S. Department of Agriculture, Forest Service, Northeastern
Forest Experiment Station. 4 p.
deCalesta, D.S. 1991. Modification of the standard deer pellet
group technique. Pennsylvania Acad. Sci. 64: 187.
deCalesta, D.S. 1992. Impact of deer on species diversity
of Allegheny hardwood stands. In: Proceedings, Northeastern
Weed SCI Soc. Abstract. 46: 135.
Witmer, G.W.; deCalesta, D.S. 1992. The need and difficulty
of bringing the Pennsylvania deer herd under control. In:
Proceedings, fifth eastern wildl. damage control. conference.
1991. Ithaca, NY. Ithaca, NY: Cornell Cooperative Extension.
Jones, S.B., deCalesta, D.S.; Chunko, S.E. 1993. Whitetails
are changing our woodlands. Amer. Forests. 99: 20-26.
deCalesta, D.S. 1994. Deer and diversity in Allegheny hardwood
Forests: managing an unlikely challenge. Landscape and Urban
Planning 28: 47-53.
deCalesta, D.S. 1994. Impact of White-Tailed deer on songbirds
within managed forests in Pennsylvania. J. Wildl. Manage.
deCalesta, D.S., and S.L. Stout. 1997. Relative deer density
and sustainability: a conceptual framework for integrating
deer management with ecosystem management. Wild. Soc. Bull.
deCalesta, D.S. 1997. Deer Density and ecosystems management.
pages 267-279. In: McShea, W.J., ed. The science of overabundance:
the ecology of unmanaged deer populations. Smithsonian Inst.
Press. 402 pp.
||Susan Stout, USDA, Forest Service, P.O.
Box 267, Irvine, PA. 16329. (814) 563-1040
||PA. Game Commission; PA. Dept. of Environ.; Resour.; PA. Bureau
of Forestry; Allegheny National Forest; PA. State Univ.; and
various local forest industries and petroleum industries.