The Changing Forest on Mt. Nittany
by
MNC Board member Tom Smyth, November 2008
On
a recent sunny Sunday afternoon cars were
parked down around the bend on ML Nittany
Road and the trails were filled with hikers.
As I headed up the Hal White Trail the folks
coming down seemed happy and several remarked
on what a beautiful hike it is and how good
the trails are. And, they were right. That
got me to thinking about how different the
hike was when I first went up in 1955 as
a young faculty member, an advisor to the
Penn State Outing Club (PSOC). Then, the
only trails were apparently old logging
chutes that came steeply down the fall line.
The mountain had been clear cut early in
the 20th century so the forest consisted
of saplings and small pole timber, mostly
sprouts from old stumps, and some seedlings
that had been released by the lumbering.
There was a very small view at what has
since been named the Mike Lynch Overlook.
The hike provided a good physical workout;
we climbed Mt. Nittany "because it
is there", not for the beauty of the
forest or excellent views.
Over
the next several years, with help from some
PSOC members we added a loop trail on top
(now blazed white) partly following old
logging tracks, and cleared several more
outlooks. In the late 1970s Tom Thwaites
and Steve McGuire made the diagonal Hal
White Trail, since modified by additional
switchbacks. The blue trails and outlooks
have been added since the early 1990s. Diagonal
trails have made the ascent less arduous
and reduced trail erosion. The additional
viewpoints have made the hike more rewarding.
Meanwhile,
the forest itself has been maturing and
changing. Sprouts from decaying stumps following
lumbering often become trees with rotten
cores and a reduced life span. Many have
died, providing an opportunity for the survivors
to grow larger. Helpful thinning has also
been provided by several other agents. In
1955 one of my first assignments was to
attend a conference in Carlisle on oak wilt,
a fungus disease mainly spread by leaf hoppers,
possibly by woodpeckers, and through root
grafts. Affected trees may die within a
month or survive up to a year. Oak wilt
killed some trees. The next plague was extensive
defoliation by oak leaf roller caterpillars.
There was some tree mortality directly due
to recurring extensive defoliation and more
due to "oak decline", a loss of
vitality abetted by air pollution, leaving
the trees more susceptible to secondary
attack by other insects and pathogens. Over
the recent decades gypsy moth populations
have increased to damaging levels twice
and have been controlled by aerial spraying,
once with a chemical (Dimilin) and recently
with a bacterial spray. Again there was
some tree mortality.
More
thinning has been caused by other agents.
Lightning strikes are common on or near
the ridge. Heavy snow or ice burdens and
freak winds have brought down a few trees.
Trail compaction by hikers weakens nearby
trees. Campfires scorch the surrounding
forest. A few trees have been cut to block
eroding older trails or provide logs for
water bars and benches. I can recall five
surface fires that cleared out underbrush
but harmed few of the larger trees. Where
trees die, surrounding trees are able to
grow more vigorously. There is also an opportunity
for new trees to have a chance. What these
new trees are depends on what seeds are
present and on environmental conditions,
especially the soil and water.
Most
of the mountains of the ridge-and-valley
province, including most of Mt. Nittany,
are capped with white Tuscarora sandstone
(or quartzite). This breaks down to a white
sand which easily washes away. It is quite
acid, drains rapidly and is unable to bind
more than a minimal amount of plant nutrients.
Most of the useful nutrients on the ridges
are contained within the vegetation, especially
the bark of trees. Thus, harvesting the
trees impoverishes the soil. The trees best
able to survive on these ridges are chestnut
oaks which an tolerate poor acid soil, dry
summers and exposure to the winds. Their
thick bark resists surface fires. Another
tree that withstands these conditions is
pitch pine, but there is very little pitch
pine on the southwest end of Mt. Nittany.
However, there are numerous table mountain
pines, a southern species found here at
the extreme northern limit of its range.
Just below the ridge there are black and
paper birches and red maples. The ground
is covered with lowbush blueberries and
teaberry. The fragrant pink flowers of trailing
arbutus are a bonus in late April.
At
the southwest end of the mountain the ridge
is a little lower and is topped by the older
Bald Eagle sandstone. This brown sandstone
is softer and apparently contains more plant
nutrients because the forest is more diverse.
It must have supported a forest of American
chestnut before the lumbering. The chestnuts
were killed to the ground by chestnut blight
early in the 20th century but the roots
survive and continue to send up shoots There
are many young chestnuts even today, but
they don't grow to a trunk diameter of more
than three or four inches before the blight
attacks and kills them back to the ground.
The forest on this end of the ridge today
contains many pignut hickories, red oaks,
black cherries, service berries and small
sassafras trees. Pink azaleas provide a
fragrant display in mid-May. Teaberry is
very abundant
Lower
on the slopes where the soil is deeper and
moister there are many more red and black
oaks which eventually overtop the chestnut
oaks and they grow larger where the bedrock
is mainly shale. Still lower, near the parking
area and lower boundary of Lion's Paw land
the soil is deeper, richer and moister.
White oak, white ash, shagbark hickory and
black maple are common trees; witch hazel
and viburnums are common shrubs; anemones,
violets and saxifrages and some of the woodland
goldenrods are among the ground cover plants.
Wild grape and Virginia creeper, formerly
rare, are becoming more common and can be
expected to provide food for wildlife in
the future.
The
broad top of the mountain is level to somewhat
dish shaped. Secondary soils have developed
in places. White oak, white pine, black
birch, black cherry and hickory are growing
to larger size and are increasing in numbers.
Where there is enough light blackberry,
huckleberry, lowbush blueberry, and deerberry
are more likely to bear fruit here than
elsewhere on the mountain. This is where
one is most likely to see wild turkey and
grouse.
The
forest today is becoming mature, with some
large trees providing a canopy above smaller
species or younger trees, large shrubs,
small shrubs and ground cover plants. Some
vines are present Chestnut oak will continue
to dominate the crest of the ridge, but
is being replaced mainly by other oaks farther
down. From the progression of sizes of seedling
to sapling trees, it appears that white
ash and shagbark hickory are spreading up
the mountain and pignut hickory out and
down from the southwest top. White pine
has increased on the flat top. The forest
is still not old enough to provide many
den trees for wildlife, but should soon
reach that stage Without fire, pitch and
table mountain pine should continue to die
out without much replacement.
In
summary, the forest on the mountain has
become more interesting and attractive over
the years and the trails are more hiker
friendly. Visitors to the mountain are appreciative.
