Understory Vegetation and
Changes in a Virgin Forest
||To describe changes in tree reproduction, shrubs, and herbs
in the Tionesta Area caused by changes in overstory density,
deer browsing, and other factors.
||expected to continue
||Tionesta Scenic and Research Natural Areas, Allegheny National
Forest, PA. Forest types are hemlock-beech and northern hardwood.
||21 0.001-acre (0.001 ac.) subplots are remeasured on a north-south
|Likelihood of Locating Study Areas:
||The area is near-virginal.
||Field collections for variables are repeated at 10-year intervals,
using the same 21 plots. Overstory density and composition are
measured also. Photographs are used to compare the present understory
with the past, but written records will provide the basis for
comparisons in the future.
|Variables and Sampling Frequency:
||Seedling counts by species and height class: 1972, 1982, 1992.
Ground cover frequency and coverage records by species, and
black-and-white photography collected: 1942, 1947, 1952, 1951,
1962, 1972, 1982, 1992.
Overstory density and composition measured: 1982, 1992.
||Data were field checked and 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:
||Bjorkbom, J.C.; Larson, R.G. 1977. The Tionesta Scenic and
Research Natural Area. Gen. Tech. Rep. NE-31. Upper Darby, PA:
U.S. Department of Agriculture, Forest Service, Northeastern
Forest Experiment Station.
Hough, AF 1965. A twenty-year record of understory vegetation
change in a virgin Pennsylvania forest. Ecology 46: 370-373.
Walters, RS; Nowak, C.A. 1993. Understory vegetation change
on the Tionesta Scenic and Natural Area. In: Proceedings,
20th annual natural areas conference: conservation in working
landscape; 1993 June 22-26; Orono, ME. Orono, ME. Univ. of
||Susan Stout, USDA, Forest Service, P.O.
Box 267, Irvine PA 16329. (814) 563-1040
||Allegheny National Forest, PA.