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Exotic species such as privet and honeysuckle are becoming the
dominant species in
the understory of the Arboretum's Hartley Woodlot.
On March 25, 2007, fifteen volunteers joined Dr. Kim Steiner,
the Arboretum director, Samuel Grinstead, research assistant,
and Sarah Melissa Witiak, post-doctoral scholar, for the inaugural
work session of the Arboretum Woodland Restoration Corps (AWRC).
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Source: Michael Hassler
Smooth blue
aster (Aster laevis)
is one of the woodland herbs whose habitat is
disappearing as nonnative species such as garlic-mustard
carpet the forest floor.
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The corps will focus its first efforts on controlling the invasive,
exotic shrubs that are crowding out native species in the understory
of the Arboretum's Hartley Wood, a popular destination for hikers,
bird-watchers, and naturalists that is contiguous with Sunset
Park in the College Heights development of State College, Pennsylvania.
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The outline of the woodlot showing plot locations and density
of invasive plant species. The plot centers are represented
by the grid of points.
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Their work is being guided by Mr. Grinstead, who has developed
a woodland restoration plan for the woodlot, and Ms. Witiak, who
is a volunteer coordinator for the corps.
At an orientation meeting on March 22, Mr. Grinstead explained
to potential volunteers that this 42-acre parcel is a valuable
ecological site. Although there are native pine and hickory trees
growing in the woodlot, seventy-five percent of the larger native
trees are oaks (62 percent white oak, 13 percent black oak), some
of which are more than 200 years old. The stand of oaks that forms
the majority of the forest canopy is, therefore, a remnant of
the typical upland oak forest that grew here before Europeans
arrived.
Because the surrounding land was first farmed, and then developed
as State College and the University expanded, this woodlot is
one of the few remaining natural areas in an urbanizing landscape.
Its tall oaks provide habitat for a variety of native woodland
herbs, ferns, and shrubs, and for wildlife, including Baltimore
orioles, scarlet tanagers, ovenbirds, and rose-breasted grosbeaks.
Unfortunately, shrubs such as privet and honeysuckle, and nonnative
trees such as Norway maple and mazzard cherry, have migrated into
the interior of the woodlot and are crowding out most of the oak
seedlings.
To restore the natural condition of the woodlot, corps members
are being trained to identify and remove the following invasive
species:
- Barberry (Berberis spp. DC.)
- Bush honeysuckles (Lonicera spp. L.)
- European buckthorn (Rhamnus cathartica L.)
- Garlic-mustard (Alliaria petiolata [M. Bieb.] Cavara
& Grande)
- Japanese honeysuckle (Lonicera japonica Thumb.)
- Mazzard cherry (Prunus avium L.)
- Multiflora rose (Rosa multiflora L.)
- Norway maple (Acer platanoides L.)
- Oriental bittersweet (Celastrus orbiculatus Thumb.)
- Privet (Ligustrum spp. L.)
- Russian and autumn olives (Elaeagnus spp.)
Volunteers include members of the community, the University's
student body, Penn State's Master Gardener program, and several
groups on campus, including Eco-Action, the Penn State Student
Chapter of the Society of American Foresters, the Xi Sigma Pi
honorary forestry fraternity, and the Wildlife Society. In three
work sessions, they have already removed dense thickets from approximately
one-half acre along the edge of the woodlot.
After the woodland restoration
corps had cleared exotic shrubs from the plots along the woods'
edge, only a few native trees and shrubs remained. The next step
is to monitor the area to prevent reemergence of the nonnative
species.
Because controlling exotic species in the woodlot will be a long-term
process, there will be an ongoing need for volunteers. Ms. Witiak
plans to schedule monthly work sessions of three to four hours
each through October, and to resume the sessions in March 2008.
Eventually, teams will be formed to monitor the cleared plots
for signs of reemerging exotic species. Where native flora do
not reestablish themselves, the corps will propagate and plant
native species that are indigenous to central Pennsylvania.
The Arboretum is grateful
to those who have helped us to take the first steps in preserving
and restoring this old-growth forest, and we hope that many more
decide to join. Volunteers are welcome to participate in
one or more work sessions.
To learn about future work
sessions, please write to Kate Reeder, Arboretum program assistant,
at kkr1@psu.edu.
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