Old Growth in the Allegheny 
The Allegheny National Forest contains several tracts of the last remaining old growth forest in the eastern United States, including the 4,100-acre Tionesta Scenic and Research Natural Areas, and the better-known 120-acre Heart's Content Scenic Area. There are also several very small old growth stands within the forest. Just south of the Allegheny lies nearly 2,000 acres of "virgin" forest in Cooks Forest State Park. What is Old Growth? Scientists, foresters, and activists have long debated how to define the term "old growth." Generally, when we think of the term, it conjures up images of 200-foot high, 10-foot diameter trees. But one can find thousand-year-old cedars growing at the top of Canada's Niagara Escarpment that are no taller than a human. The Allegheny Forest Service generally describes old growth as trees older than 111 years. Others consider old growth forests to be only those that have experienced no post-settlement human disturbance. Scientists, however, have been moving toward the use of "old growth characteristics" to delineate old growth areas. Old Growth Characteristics Old Trees: "Old" can vary greatly between tree species, and the definition of "old" is very contentious. A redwood tree can live for thousands of years, whereas an eastern hemlock tree may live for hundreds. "Old" can be defined in one way as greater than 50% of the maximum possible age for a tree. Generally, scientists in the east define "old" as being somewhere between 110 and 150 years. The Niagara Escarpment cedars illustrate that "old" does not necessarily mean "big." The rate at which a tree grows varies greatly in response to site conditions, such as temperature, soil quality, exposure, etc. Commercially-valuable trees: This characteristic is often used in order to determine if a stand has been "high-graded", a term used to describe a form of selective cutting in which only the biggest, most commercially-valuable trees are logged. If an area is entirely devoid of any commercially-valuable trees such as red oak, sugar maple, black cherry, and tuliptree, then thereŐs a high likelihood that it's been high-graded in the past. Uneven-aged canopy: Old growth forests will generally have trees of many different ages and sizes, with a higher density of smaller, younger trees than older, larger trees. This will also lead to stratification of the forest layers into a canopy, midstory, and understory. A forest that has been clearcut or heavily logged at some point will generally only have a few different ages and fewer forest layers. Coarse woody debris: "Coarse woody debris" is a term used to describe large downed wood. Old growth forests should have a significant amount of large (> 4 in. diameter) downed wood. The stems should also vary in size and degree of decay, which shows that the fallen trees are the result of on-going, long-term processes and not the result of one single disturbance. Coarse woody debris provides soil moisture regulation, nutrients, and wildlife habitat. "Nurse logs", or large logs at an advanced stage of decay, provide a concentration of moisture and nutrients for new tree seedings and herbaceous plants. Snags: Standing dead trees are commonly referred to as "snags." Standing dead trees also provide evidence that trees are reaching natural death and not being selectively logged. They are extremely important wildlife habitat (they are used by many cavity nesters such as woodpeckers, barred owls, and some species of bats and small mammals.) They will also eventually fall to become downed wood and nurse logs. Canopy gaps: Small gaps in the forest canopy are caused when one or a small clump of trees falls down. The small gaps provide an area where more sunlight can reach the forest floor, allowing young trees to grow. The canopy gaps also contribute to the multiple layers described above. Pits and mounds: Walking through an older forest, you've no doubt noticed trees that have fallen over with their roots tipped up above the forest floor. As the roots and surrounding soil are pulled out of the ground, a pit is formed. As the roots decay, they form a mound next to the pit. An old growth forest will therefore generally have a "rolling topography" formed from these old pits and mounds, where the trees that formed them have often decayed completely. This type of rolling forest floor is generally absent from human-impacted forests. The process of pit-and-mound formation is important in forest nutrient cycling. Ecosystem stability: In a healthy forest, growth will equal mortality, and because nothing is being removed from the system, the nutrients are generally conserved - input equals output. However, the truth is that no eastern forest is entirely "pristine" or "untouched by man." Forests are impacted by human activities far from their borders. In the Allegheny bioregion, our forests are impacted by acid rain, ground-level ozone and other air pollutants, exotic diseases, climate change, and unnaturally high populations of some native species (e.g. white-tailed deer.) Old growth forests still normally exhibit a more steady-state than younger forests. Presence of older-forest-dependant species: There are many species of plants, mosses, fungi, birds, salamanders, and mammals that are associated with older forests. This means that these species tend to be more common and more abundant in these types of forest. Now that we've defined old growth, why is important? 1. Biodiversity. As stated above, there are many species of plants and animals for which older forests are the primary habitat. If we wish to ensure these species' survival, we must protect the old growth forests they depend upon. 2. Science. Old growth forests allow scientists to study forest processes not affected (or minimally affected) by humans. They also provide a type of "control" against which managed forests can be compared. 3. Human experience and future generations. Simply put, people like to experience old growth forests. What can compare to the feeling of peering up to the top of a 175-foot white pine? We will never see a passenger pigeon, a Carolina parakeet, or, likely, an ivory-billed woodpecker. We have a responsibility to leave the Earth in the same state we inherited it. 4. Ethics. Many people question whether we have the right to annihilate species and entire ecosystems. Some may take the position that these old woods and the plants and wildlife that depend on them have an inherent right to exist, beyond any sort of human utility. Others see old growth forests and the species that inhabitat them in a more theological context; that they are part of Creation and therefore should be allowed to continue to exist. ALLEGHENY WILD! AND OLD GROWTH As part of our Allegheny Wild! proposal, the ADP is seeking to provide additional protections to the old growth forests we have and to allow second growth forests to move toward the old growth characteristics described above. The Allegheny Wild! Alternative would protect the Tionesta old growth tract and a large surrounding buffer as a Wilderness Study Area, in hopes that it will someday become part of the federal Wilderness system. The proposal would also protect nearly 82,000 acres of the Allegheny as old growth management areas, in hopes that they will continue to develop old growth characteristics. References: McCarthy, Brian C. 1995. Eastern Old-Growth Forests. The Ohio Woodland Journal 2:8-10 Old Growth in the Allegheny Tionesta Scenic/Research Natural Areas Description: Located on the eastern side of the Allegheny National Forest, these two areas together comprise the 4,100-acre Tionesta old growth tract - the largest old growth forest between the Adirondacks and the Great Smoky Mountains. This area has been designated an "Important Bird Area" by the Pennsylvania Audubon Society, in part because it contains the largest population of the Swainson's Thrush in Pennsylvania. It also contains the sole population of the Yellow-Bellied Flycatcher in the Allegheny. The forest is primarily composed of American beech and eastern hemlock. Features: The North Country National Scenic Trail passes through the area. The Scenic Area contains a relatively short loop trail accessible from Forest Road 133E. Three major creeks run through the areas - Cherry Run, West Fork Run, and East Fork Run. Current Threats: While the Forest Service has purchased the subsurface rights in the Research Natural Area, the rights below the Scenic Area remain under private ownership. While currently there is little interest in drilling new oil and gas wells in the old growth, it remains a possibility. Dozens of abandoned oil wells are scattered throughout the area, and a major pipeline runs through it. The East Side Timber Sale contains several cutting units near the old growth, including one directly adjacent to the old growth boundary. Beech scale disease, an introduced disease caused by a complex of a scale insect and a fungus, has led to the death of many of the American beech trees. The hemlock wooly adelgid, another introduced pest, has not invaded the Allegheny yet, but remains a threat. Heart's Content Scenic Area Description: While only 100 acres in size, this old growth area is much better known than the larger Tionesta area. The trees at HeartŐs Content tend to be larger than those in Tionesta, due more to site differences than to a difference in age. The forest here also contains a high proportion of eastern white pine, a species nearly absent from the Tionesta old growth. Features: A well-maintained trail runs through the old growth and some of the surrounding woods, providing an easy hike popular with families. Current threats: The biggest problem for these woods is their size. At only 100 acres, the old growth is highly susceptible to outside influences. Deer in particular have heavily impacted the forest. Three major reasons for the overpopulation of deer in the Allegheny are a lack of natural predators, abundant browse due to clearcutting, and antiquated hunting laws. |