William H. McWilliams
Northeastern FIA User’s Workshop
April 13, 2004 – Sturbridge, MA
Justification
Study Design and Analysis Techniques
Results

Structure is Changing: Overstory vs. Understory
Comparison of Composition by Tree Size – Top Ten Species
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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

Goals
 Determine how many microplots are needed to quantify size and composition of tree-seedling component.
 Debug other measurement protocols.
FIA Sample
An analysis of CV showed that a single microplot was sufficient.

Interpenetrating Sub-Panel of FIA Sample Locations
(collected during leaf-on window, June-August)
Regeneration Sample
Five-Year Panel
Year One
Year Two
Year Three
Year Four
Year Five

Condition A =
Forest Land Use
Old 1/5-acre plot
Condition B =
Nonforest Land Use
Site Limitations
Subplot Level
Associated Understory Vegetation: Assign Percent cover classes to Species/Life Form.
The subplot is also where
Species/Life Form
Vines (FIA’s detailed code)
Other fern
Grass
Other herbaceous
Sample Location Level
Deer Impact: Record on of five Deer Impact classes:
(after Marquis et al. 1994)
Very Low
Low
Medium
High
Very High Microplot Level
Site limitations
Dominant Tree: If present, record the species of the most dominant tree at least 5.0 inches in diameter.
Seedling Tally: Count all established seedlings at least 2” tall by:
Species
Seedling Source (stump sprout and other)
Stump Sprout
Other Seedling
Competitive oak, hickory, walnut, or butternut seedling
Height Class
2 inches to 6 inches
6 inches to 1 foot
1 foot to 3 feet
Numbers of seedlings
3 feet to 5 feet
5 feet to 10 feet
Greater than 10 feet
Percent Cover Class (after Marquis et al 1994)

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 2percent 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 Woody
36 % 50 % 57 %
Interpretation:
Desirable: about two-thirds would likely fail to regenerate.
Commercial: about half would likely fail.
Woody: over 40 % would likely fail.

Regeneration Study – Results – Ecoregion
Plateau
Desirable Commercial Woody
28 % 44 % 48 %
Western Broadleaf - West
Desirable Commercial Woody
44 % 51 % 61 %
Central Appalachian
Desirable Commercial Woody
37 % 54 % 60 %
Eastern Broadleaf - East
Desirable Commercial Woody
36 % 54 % 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.

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