Pennsylvania Regeneration and Invasives Research
William H. McWilliams
Northeastern FIA User’s Workshop
April 13, 2004 – Sturbridge, MA
Justification
Study Design and Analysis Techniques
Results
140
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120
1200
100
1000
80
800
60
600
40
400
20
200
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Millions of
Millions
ofTrees
Trees
Structure is Changing: Overstory vs. Understory
Comparison of Composition by Tree Size – Top Ten Species
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Study Team
Goal: Develop Indicators of Regenerative Capacity
for Pennsylvania Forests Using FIA Samples.
Dan Devlin, Stephen L. Sterner
NE RWU 4152: Pat Brose, Harry Steele, Susan Stout
NE RWU 4557: Kurt Gottschalk, Gary Miller
NE RWU 4801: William H. McWilliams, Susan King, Tonya W. Lister,
Brian M. LaPointe, Charles T. Scott, James A. Westfall
Robert White, Lois DeMarco
Todd Bowersox, Jim Finley, Larry McCormick,
Kim Steiner
Designing the Sample – Pilot Study
Goals
FIA Sample
9 Determine how many microplots are
needed to quantify size and composition
of tree-seedling component.
9 Debug other measurement protocols.
An analysis of CV showed that a
single microplot was sufficient.
Designing the Sample – Sub-Paneling
Interpenetrating Sub-Panel of FIA Sample Locations
(collected during leaf-on window, June-August)
Regeneration Sample
1 2
3 4
3 4
5 1
5 1
2 3
1 2
3 4
5 1
3 4
5 1
2 3
Five-Year Panel
Year One
Year Two
Year Three
Year Four
Year Five
Designing the Sample – Three Levels
Sample Location Level
Old 1/5-acre plot
Deer Impact: Record on of five Deer Impact classes:
(after Marquis et al. 1994)
Very Low
Low
Medium
High
Very High
Microplot Level
Condition A =
Forest Land Use
Condition B =
Nonforest Land Use
Site limitations
Dominant Tree: If present, record the species of the
most dominant tree at least 5.0 inches
in diameter.
Subplot Level
Seedling Tally: Count all established seedlings at
least 2” tall by:
Site Limitations
Species
Associated Understory Vegetation: Assign Percent
cover classes to Species/Life Form.
Seedling Source (stump sprout and other)
Stump Sprout
Other Seedling
Competitive oak, hickory, walnut, or butternut seedling
The subplot is also where
we tally Exotic Invasives,
more on this later..
Species/Life Form
Shrubs (FIA’s detailed code)
Vines (FIA’s detailed code)
Fern (Bracken, Hay-Scented, and New York)
Other fern
Grass
Other herbaceous
Height Class
2 inches to 6 inches
6 inches to 1 foot
1 foot to 3 feet
Numbers of seedlings
Percent Cover Class
(after Marquis et al 1994)
3 feet to 5 feet
5 feet to 10 feet
Greater than 10 feet
Analyzing the Results
Canopy-Replacement Species Grouping
Dominants: canopy dominants*
Other High Canopy: add other high-canopy species
Woody: add all other tree species
* all species with at least 2-percent of the State’s
biomass and typically form high canopy
Timber-Based Species Grouping
Desirable: species desired for timber management
Other Commercial: add other commercial species
Woody: add all other tree species
Analysis: applied regeneration guidelines for Pennsylvania and evaluated the
results after screening for plots where the forest floor receives
enough light for seedling development.
Regeneration Study - Results
Percent of Samples Meeting Regeneration Criteria, Timber Group – High Deer:
Desirable
Commercial
36 %
50 %
Interpretation:
Desirable: about two-thirds would likely fail
to regenerate.
Commercial: about half would likely fail.
Woody: over 40 % would likely fail.
Woody
57 %
Regeneration Study – Results – Ecoregion
Plateau
Desirable
28 %
Commercial
Woody
44 %
48 %
Western Broadleaf - West
Desirable
44 %
Commercial
Woody
51 %
61 %
Eastern Broadleaf - East
Desirable
36 %
Central Appalachian
Desirable
37 %
Commercial
54 %
Woody
60 %
Commercial
54 %
Woody
64 %
Exotic Invasive Species - Justification
Chief’s Agenda
Ann Bartuska’s Agenda
Bureau of Forestry
The Nature Conservancy
Morris Arboretum
Exotics Survey – New in 2003
Regeneration Study Plots used to tally
thirty-one species of Exotic Invasive
trees, shrubs, vines, grasses and forbes.
Results are forthcoming:
- Distribution Maps
- Correlation
Future Research Needs
Develop indicators for associated understory vegetation.
Develop an understory vegetation community classification system.
Relate levels of associated understory vegetation to regeneration success.
Incorporate invasive species data.
Analyze results for specific forest types, for example mixed oak.
Explore relationships between overstory and understory composition.
The End