1. Pitt Magazine
The Mighty Oak Is Falling by Alan Gintzler
The Mighty Oak Is Falling
Walk through the forests of the eastern United States today, and nature seems
comfortably familiar. Babbling brooks still babble. Trees grow and reach for the sky.
Dried leaves and acorns still litter the forest floor. A deer stands frozen, then darts
majestically away with a wave of white tail.
Take another look. Behind that reassuring sameness lurk ecological changes that will
make the familiar strange indeed. The neighborhood is changing, and not for the better.
The population of America’s eastern deciduous forests is undergoing a slow, catastrophic
change, hard to see, but real. And the stakes are high: the forest itself, as we know it.
It takes a trained eye to see it and a brave voice to say it. In the corridors of learning,
amid floors and shelves strewn with paper, texts, field guides, and yard tools, University
of Pittsburgh Associate Professor Walter P. Carson, an ecologist and evolutionary
biologist, can see the forest for the trees. He’ll tell you that American oaks—red, white,
and scarlet—are in serious decline, along with the food they generate: acorns. And if
something isn’t done to stop this process, the loss of oak trees will ripple through the
food chain bringing declines in the size and diversity of American wildlife.
Carson is researching the phenomenon of “failed oak regeneration.” Oaks, which have
been the dominant tree species in eastern woodlands for 10,000 years, are losing ground
to competitor maples and beech. Vital as food producers for small mammals, birds, deer,
and black bears, as well as suppliers of hardwood for tools, furniture, and interior
construction, oaks are a keystone plant resource. The shape of the forest without them is
unknown.
To a causal observer hiking the eastern forests, the tree canopy appears to be dominated
by the furrowed limbs and toothed leaves of 100-year-old oaks. With old growth
woodlands gone to the logger’s saw, mature oaks still dominate in our second- and third-
growth forests. But walk the forests of Pennsylvania, West Virginia, North Carolina, or
New Jersey, and step on forest floors dominated by red and sugar maple saplings where
oak once ruled. The next generation of oaks is not surviving.
The evidence shows in the underlying layer of vegetation, known as the understory. It is
here where seedlings are generated. Here is where Carson and his research team are
looking and experimenting. Here, a different story is showing itself in a population of oak
offspring that never reaches maturity.
At two sites in West Virginia, Carson and his colleagues have devised on-the-ground
experiments. Their long-term methods, involving thousands of trees, mimic natural and
man-made forces that have shaped forests over time. Preliminary findings show the

2. eastern forests beset to varying degrees by three factors: fire suppression, decreased gaps
in the forest canopy, and over-browsing by deer.
A century of fire suppression has led to shifts in the composition of trees in the forest
understory. Periodic forest fires, caused naturally by lightning or artificially by
indigenous people clearing land for habitat, favored the fire-tolerance of oaks and
hickory. In the absence of fire, maple and beech have overshadowed oak on the forest
floor.
Competition for space is aggravated by other factors. Massive tree falls in old growth
forests opened larger gaps in the canopy than occur today. Maples, more shade-tolerant
than oak, thrive and crowd out sun-worshipping oak tree seedlings.
Carson’s research indicates that deer are perhaps the worst threat to oak regeneration. In
pre-settlement times, 10 or fewer deer populated a square mile. Present-day hunting
restrictions and a lack of natural predators have increased deer populations three- to five-
fold. The problem is that deer love oak for dinner more than they do maple or beech.
Deer are decimating oak seedlings before they can reach the sapling stage for survival.
As research continues, Carson’s findings point to an already full-blown crisis in
America’s eastern forests. Immediate action aimed at reducing the deer population and
the institution of controlled burns seems necessary, though politically unpopular.
Selective cutting and limited clear-cutting also appear necessary but are equally
unpopular in many quarters.
A pastoral hike through the eastern woodland amid birdcalls and chattering squirrels,
towering oaks above and acorns underfoot, seems much the same as always. But for how
long? According to Carson, tough decisions in forest management need to be made
before it’s too late—if it isn’t already too late.
####