European settlers began clearing farms in southeastern Pennsylvania in the 1600s and early 1700s, and gradually pushed up the large river valleys. After the Revolutionary War the rate of settlement increased and most of the farming areas of the state were settled by the mid-1800s. Meanwhile, iron furnaces, tanneries and large lumber companies were acquiring vast forested tracts.
The combination of clearing for farmland and cutting to supply various industries meant that the trees 1n almost all the woodland had been felled by the early 1900s. Thus Pennsylvania has very little old growth forest remaining. Most of what is left exists in scattered small stands, on extremely steep hillsides of the Allegheny Plateau or among the stunted, contorted trees on the steep slopes and ridgetops of the Ridge and Valley region. Those scattered small stands are the result of boundary disputes, economic conditions, inaccessibility, or owners who simply liked big trees.
Most people may have heard of the battles over old growth forests in the western states, and may even have heard that as much as 100,000 acres of Great Smokey Mountains National Park in North Carolina and Tennessee is cloaked in old growth forest. How many know that an even larger acreage of old growth forest is located in New York’s Adirondacks – including a single block of perhaps 45,000 acres that has never been logged?
Those of us who are interested in old forests know that old growth exists throughout all of the eastern states. In Pennsylvania, the largest single old growth tract is about 4,000 acres in the Allegheny National Forest. Many of Pennsylvania’s first state forest natural areas were created to protect old growth stands of hemlock and/or white pine, but almost all of those are relatively small. Unfortunately the remaining old growth oak-hickory and northern hardwood stands appear to have been ignored when the earliest state forest natural areas were created; in fact, some old growth oak stands on state forest land were logged in the 1970s or 80s. In later years a number of large state forest natural areas have been designated, primarily to protect significant watersheds but some do protect additional old growth stands.
Knowing what to look for, those of us who get to wander widely on both public and private land are fortunate enough to occasionally explore forests that have never been logged or grazed. Some of those old growth forests are in small farm woodlots; some are in much larger tracts on public land.
Although it may not be easy to determine whether a stand is truly old growth, all old growth stands share certain characteristics:
A diversity of tree sizes and ages, including some very large trees (20-30 inches in diameter on fertile moist sites);
A substantial number of large standing dead trees;
Numerous large fallen trees on the ground;
Many large gaps in the forest’s canopy;
No sign (cut stumps, old skid trails, roads, stone walls) of human activity.
What’s special about old growth and how does it differ from younger forests?
The diversity of tree sizes and species provides foraging habitat and shelter for a variety of wildlife;
The range of tree heights results in a multi-layered canopy;
Old trees have a branch structure and bark characteristics very different than those on younger trees, creating distinctive habitats;
The fallen trees supply moist habitats and cover for many species;
Standing dead trees offer foraging habitat and shelter for a broad range of wildlife;
Old growth forests have larger trees, a more diverse understory and produce a larger quantity of seed than younger stands.
Some lichens, mosses, fungi and other plants depend on factors that are common in old growth forests but are missing in second growth forests.
Many species of amphibians (especially salamanders) and birds (particularly woodpeckers, warblers and thrushes) are more abundant in old growth forests. Even a number of common species, while not dependent on old growth, benefit from the diversity of food and cover in these old forests.
Unfortunately, many landowners and foresters don’t recognize old growth forests; they may think a tree 18 inches in diameter is “mature”; and may not know, or care, about the significance of old growth forests. In many cases the forest industry, foresters and even some wildlife professionals describe old growth forests as veritable wildlife deserts – when the opposite is actually the case. Those folks are merely justifying cutting old forests to promote their own interests. They see these old forests as nothing more than raw material for a sawmill or a lovely place to build a cabin.
Old growth forests are part of our heritage and are worth as much protection as the most significant historical sites and the grandest monuments.