Eastern Old-Growth Forests
The Ohio Woodland Journal 2:8-10 (1995). Brian C. McCarthy, Ohio University

In recent years, the general public has gained a remarkably heightened awareness regarding the ecology, conservation, and preservation of our natural resources. New technology and increased media coverage have brought biology into the living rooms of most American families. The high profile of the old-growth debate in the Pacific Northwest has generated a renewed interest among Easterners in their old-growth forests.

Historical records and descriptions of the pre-settlement eastern landscape paint a dramatically different picture from that of the present. Colonists of the 1600s were presented with vast stands of large trees and continuous cover. Most historians agree that this country was settled largely because of its enormous timber resource. The needs of a colonist were simple: a roof over one's head, food on the table, and warmth in the cold months. As a result, forests were cleared for settlement, sawtimber, agriculture, and fuelwood. In later years, the surviving forests were exploited for a variety of additional wood products including charcoal, pulp, and turpentine. While the exact dates are arguable, essentially all eastern old-growth was eradicated by the turn of the 20th century.

Today, virtually all old-growth forest that remains in the eastern U.S. consists of small tracts of land (10 to 100 acres) that resulted from surveying errors or private family preservation for the purposes of aesthetics, hunting, or timbering. While these tracts pale in comparison to western old-growth forests, they remain a vitally important resource.

Defining Old-Growth Forest
Perspectives on old-growth forest come largely from three distinctly different groups: environmentalists, foresters, and scientists. Environmentalists frequently refer to old forests as virgin, pristine, and primeval all adjectives which conjure up an image of an ecological entity not touched by the hand of man. Traditional foresters have an altogether different viewpoint: they emphasize the economic and commercial viability of timber, wood products, and forest harvesting. Therefore, they often refer to old forests as decadent, overmature, or senescent in reference to the forest being past the point of economic maturity. Scientists generally refer to old forests as old-growth. All terms are essentially synonymous in meaning and largely reflect the viewpoint of the user. I'll continue to use the term "old-growth" because it best reflects my own perspective, carries the least socio-political baggage, and can be used as a noun as well as an adjective.

Because of the enormous diversity of eastern forests, differences in site quality and environment, and variability in disturbance regimes, a simple, all-encompassing definition of old growth is virtually impossible. If one were to use only the criterion of "no post-settlement human disturbance," then we might have to conclude that there probably is no true old growth in Ohio. However, there are many stands which have had nearly no disturbance and exhibit many of the traits that one would expect to find in an old-growth hardwood forest. There is a growing trend among scientists and agency personnel to emphasize "old-growth characteristics" in defining and delimiting old-growth stands. Many of these characteristics are summarized below and compared schematically with a typical second-growth stand in Figure 1.

Figure 1. Schematic comparison of a mature second-growth forest and an old-growth forest. Note the many structural, compositional, and functional differences between them.

Characteristics of Old-Growth
Forest Trees of Great Age. For a forest to be old-growth, there should be a number of trees of great age. Unfortunately, there is no definitive agreement as to how old constitutes "great age," but a reasonable criterion might be trees exceeding at least 50% of the projected maximum attainable age for that species. Because of small-scale natural disturbances, there may not be any trees at the maximum attainable age at all. Thus, in a typical southeast Ohio mixed-oak forest, trees in excess of 150-200 years old would constitute an old-growth condition. An important point to recognize is that this age need not translate into large diameters, depending upon site quality. Thus, on a very dry, low-quality site, trees may not have the same impressive diameter structure that they would on a moist, high-quality site.

Trees of Commercial Value. The presence of large economically important tree species is usually a good indicator that the area was not selectively cut or highgraded. Candidate old-growth forests should contain canopy specimens (preferably from multiple size classes) of black walnut, black cherry, red oak, white oak, tuliptree, or sugar maple.

Uneven-Aged Canopy Structure. Eastern old-growth forests are generally characterized by trees of all ages and diameters. They typically exhibit a reverse-J age distribution, whereby younger stems are at a much higher density than older stems. The shape of the age distribution often (but not always) parallels that of the diameter distribution. The age/diameter structure is driven largely by small-scale natural disturbances and differential shade tolerance among species.

Downed Logs. Coarse woody debris (stems > 4 inches diameter) should be a prominent component of the forest floor. These downed logs should also be from multiple size classes and in various states of decay, suggesting that they are the result of long-term processes and not one single disturbance event. These logs contain much of the nutrients present in a stand, are important in maintaining forest hydrology, and function as important wildlife habitat.

Standing Snags. Standing dead trees (stems > 4 inches diameter) are another prominent element of the old-growth forest. Snags indicate that trees have reached natural mortality in place and have not been selectively removed. Snags perform many of the same ecological functions as do logs and are a vitally important component of the ecosystem. They are particularly important for a variety of species of wildlife. The optimal number of snags and logs per acre is difficult to estimate because of many variables associated with topography, environment, and soils.

Treefall Gaps. Old-growth stands typically exhibit many small blowdowns of one to several trees. These blowdowns or point disturbances create a heterogeneous overstory and markedly change the understory microenvironment. As a greater and differential pattern of solar radiation reaches the forest floor, advanced regeneration results in a forest with multiple layers (3-5) instead of the 1-2 typically found in an aggrading younger forest.

Pit and Mound Topography. The microtopography of old-growth soil surfaces is often dominated by a rolling topography produced by windthrown trees. When the trees are thrown, their root mat and associated soil is ripped up from the forest floor, creating a pit or depression. As the root ball decays, the soil is loosened and falls into a mound adjacent to the pit. These pits and mounds are important in forest nutrient cycling and understory diversity, but are generally absent from human-disturbed forests.

Undisturbed Soils. Old-growth forests typically have a soil which is high in organic matter, with a thick organic layer and considerable numbers of ferns, mosses, and fungi. Not having experienced heavy logging equipment, horses, dragged logs, or grazing livestock, the soils will not be compacted. Soil macropores (2-4 inches in diameter), formed by the dead decaying roots of old trees, are often present in the upper soil profile.

Ecosystem Stability. Most old-growth forests approximate a dynamic steady-state condition where they ebb and flow around a mean, exhibiting only minor changes. Mortality generally balances growth, and nutrient input is roughly equivalent to nutrient output. Since most of the nutrient capital is maintained in the plants, and they die in situ, nutrients are conserved. It is quite likely that with continued acidification and two or more rotations, many eastern soils will be markedly depleted of nutrients.

Diversity of Plants and Animals. In addition to the above-mentioned abundance of ferns, mosses, and fungi, old-growth forests often have an increased diversity of understory herbs. This may not be the case in some old-growth stands of softwoods because of the decreased light and highly acidified soils, but it is generally the case in most old-growth hardwood forests. In addition to plants, there may be a variety of animals which are associated with old-growth stands because of their structural elements. Certain species of salamanders, soil invertebrates, small mammals, songbirds, and black bear are often found in much greater abundance in old-growth stands compared to younger stands.

Little or No Evidence of Human Disturbance. Stands with obvious signs of human disturbance cannot likely be classified as old growth. Stumps, mechanical bole damage, logging roads ', skid trails, and yarding areas can provide direct evidence of logging. Evidence of livestock grazing might come from tree bole scars left from fencing, or small pens or corral areas for holding roaming stock. Past agricultural or homesite land is generally indicated by old plow furrows, piles or walls of rock, remnants of a house foundation or chimney, an abandoned cistern, or cultivated plant species.

Values of Old Growth
The preservation of old growth is important for a variety of reasons. First, much of what we know about the structure, function, and natural disturbance regimes of forests has been derived from the study of old-growth forests. Ecologists have focused their scientific attention on these forests because they have not been disturbed by humans. They present a remarkable opportunity to understand natural forest processes. Perhaps most important of all are the long-term studies which provide us with a unique database of information about forest dynamics beyond a single career or human lifespan.

Second, in the managed forest landscape of the present, old-growth forests provide a valuable benchmark or "experimental control" against which we can compare our managed lands. In this way, we can evaluate the effects of various forest management practices vs. no management on the flora, fauna, and soils.

Third, eastern old growth functions as a reservoir of biological diversity. These forests may favor unique populations or ecotypes of plants and animals, or they may simply provide a habitat structure that certain animals need and can't find elsewhere in the landscape because old growth is so rare.

Fourth is the heritage value. These forests exist as living museums and present the forests as our forefathers would have experienced them. They provide a remarkable educational tool for historians and social scientists, as well as biologists.

Lastly, there is an ethical consideration. While most scientists are reticent about making these sorts of arguments, preferring to rely on testable hypotheses and experiments to derive factual information, we are left with the question, "Is it appropriate for us [humans] to destroy or modify all of nature?" Should an appropriate land ethic involve "respect for the community as it is"? Thus, we may acknowledge the benefit of timber and wood products, choose to manage much of the forested landscape for human concerns, but set aside substantial tracts where people do not intervene.

Why does the typical Ohio landowner care about all this? At least two reasons come to mind. First, small pockets (5-50 acres) of previously unlogged land continue to be discovered on both public and private lands all the time. The ability to recognize or discover old growth is largely dependent on one's understanding of the definition of old growth and its attributes. Second, a growing number of private landowners are recognizing the non-timber (biological and ecological) values of old growth and are choosing to preserve their forests rather than manage for wood products. Because old growth in the East is so rare and in such short supply, it essentially represents an endangered habitat. As second- and third- growth forests (last logged at the turn of the century) approach maturity, Ohio landowners must decide whether to harvest or preserve. This decision will likely be based on a variety of factors. A better understanding of what old growth is and why it is important will certainly provide a better basis for making such decisions.

Figure 2. Map of Ohio showing publicly accessible old-growth forests (not an inclusive list -- see text for restrictions). The forests are listed by number, with the managing agency in parentheses: 1. Goll Woods (ODNR); 2. Fowler Woods (ODNR); 3. Crall Woods (ODNR); 4.Wadsworth Glen (ODNR); 5. Kyle Woods (ODNR); 6. Dysart Woods (Ohio University); 7.Hawk Woods (Private); 8. Morgan Sisters Woods (Wayne National Forest); 9. California Woods (Cincinnati Recreation Commission); 10. Caldwell Park (Hamilton County Parks); 11. Bowles Woods (Hamilton County Parks); 12. Hueston Woods (ODNR); 13. Davey Woods (ODNR); 14. Gross Woods (ODNR).

Old-Growth Forests in Ohio
Because of its rarity in the landscape, many Ohio landowners are largely unaware of what local old-growth forest is, what it should look like, and how it functions. A good beginning to solving this problem is to visit representative old-growth stands in your region. Figure 2 provides the name, general location, and managing agency of easily accessible old-growth forests in Ohio. Additional information and directions may be attained from the managing agency. The list is not comprehensive. Stands smaller than 25 acres, on private land, or on public land with restricted access have generally been excluded. The above list of old-growth characteristics and Figure I can be used as a reference while touring these forests. Thus, the private landowner can make a more informed decision as the value of their stand and how to manage it. They may choose to "manage" for the old-growth condition by maintaining or enhancing some or all of the above characteristics, just allow "natural management" to take its course, or manage for economic return all have their place in the forested landscape.