Regeneration and Growth After
Thinning in Hemlock-Hardwood Stands
||To characterize a) growth of residual trees and stands and
b) regeneration after thinning treatments involving differing
levels of felling unmerchantable hemlock.
||Allegheny National Forest, Marienville Road. Forest type is
||One block of oak-hemlock is fenced and contains 4 2-acre treatment
areas. A 0.6-acre measurement plot is in each treatment area.
All treatments were replicated once inside and once outside
a fence. 12 0.0026 Subplots were established to monitor regeneration.
|Likelihood of Locating Study Areas:
||One of the 4 treatment areas was left uncut as the control
area. The remaining 3 were thinned: 1) conventional shelterwood
cut to 75% residual density, 2) shelterwood cut to 90% residual
density including 20% understory hemlock, 3) shelterwood cut
to 60% residual density with all understory hemlock removed.
||Within each measurement plot, individual hemlock trees with
diameters > 2.5 were measured to the nearest 0.01" at the beginning
of the study (1989) and at 5-year intervals thereafter. At each
measurement period, a subsample of the largest hemlock and hardwood
trees per treatment were assessed for crown class. In each treatment
area, trees from 0.5" to 2.50" d.b.h. were measured on 12 6'
radius plots. Immediately before and 2 and 5 years after treatment,
detailed regeneration data were collected on these plots.
|Variables and Sampling Frequency:
||Stand basal area growth are analyzed using initial basal area,
species composition and relative density as the independent
variables. In the regeneration portion of the study, number
and height of seedlings by species are analyzed for significant
differences between overstory treatments. Herbaceous cover is
also measured in the regeneration plots. 1989, 1991, 1994.
||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:
||none to date
||Susan Stout, USDA, Forest Service, P.O.
Box 267, Irvine PA 16329. (814) 563-1040
||Allegheny National Forest, PA.