How much older forest does each region have?
There aren’t any comprehensive and compatible inventories of older forest for the five regions examined by the NCSSF-sponsored workshops, or for any other forested regions of the United States for that matter, primarily because there are no generally accepted definitions of old growth, older forest, ancient forest, or any of the other names that have been used.
Even when there is agreement on a definition, differences in methodology can produce major discrepancies in inventory results. For example, in 1991 the USDA Forest Service and the Wilderness Society released results of inventories of old-growth forests in the Pacific Northwest and northern California that each organization had performed. They both used a definition of old growth developed in 1986 at the USDA Forest Service Pacific Northwest Research Station. It was based on the number, age, and density of large trees per acre; the characteristics of the forest canopy (the upper layer formed by the crowns of the trees); the number of dead standing trees and fallen logs; the mix of species; and several other criteria. However, the two organizations used different remote-sensing techniques for assessing these characteristics in the forestlands that they surveyed. The Forest Service concluded that there were 4.3 million acres of old-growth forest in the study area, while the Wilderness Society reported 2.0 million acres.
In spite of the difficulty of assessing the amount of older forest in any of the five regions with any precision, it’s possible to offer some broad generalizations about commonalities and differences among them.
It’s clear that older forests are scarce and their future is precarious across the eastern United States. Less than 1 percent of forestland in the Northeast is considered to be old growth. Mature forests with the potential for becoming older forest in a few decades are slightly more abundant, but they are rapidly disappearing. The northern end of the region has more older forest today than southern New England because the land was never farmed and the continuity of forest cover was never broken. However, timber harvesting currently threatens much of this remaining older forest.
The Southeast has even less older forest, according to a 1993 grassroots effort that culminated in the first inventory of old-growth forests in the eastern United States. This inventory identified approximately 425 old-growth sites in southeastern states, ranging from 21 in Mississippi to 67 in Florida. The total area of the identified sites comprises about 0.5 percent of the total forest area in the Southeast.
The percentage is even lower in the Great Lakes region, where no good inventories of older forests have been made, even for public lands, mainly because no consistent definitions of old-growth forests based on habitat or ecosystem type have been developed and accepted. State and federal agencies have worked for years to develop definitions, and a great deal of progress has been made within individual agencies, but the definitions aren’t consistent across the region.
Given those conditions, it’s not surprising that the conservation strategies that came out of the NCSSF-sponsored workshops in the Northeast, Southeast, and Great Lakes regions emphasized growing more older forests.
Older forests are more abundant in the West. As of the mid-1990s, older forest in the Pacific Northwest dominated by trees more than 30 inches in diameter with complex forest canopies was estimated to comprise approximately 6 percent of forestland on all ownerships in western Washington, Oregon, and northern California—3.5 million acres out of a total of 56.8 million. If the definition is broadened to include older forest with a mix of medium- and large-diameter trees and simple as well as complex canopies, that figure increases to about 21 percent. Because of this relative abundance, forest policy in the Pacific Northwest has focused on protecting existing reserves and deciding how to manage them.
Information about the amount of old growth in the Southwest is sketchy, partly because there’s no generally accepted definition of what constitutes old growth, but it’s clear that there’s not much of it. The area of old-growth ponderosa pine in the intermountain Southwest declined by 85 to 90 percent during the last century, mainly from logging. Less than 5 percent of ponderosa pine stands in southern Colorado and New Mexico are classified as old growth, and other parts of the Southwest also lack old trees. Old-growth conservation efforts in the Southwest are focused on how to manage older forests in frequent-fire landscapes.
In spite of the scarcity of older forests across much of our country and the many challenges that face efforts to preserve and restore them, long-term strategies are being developed in all five regions to ensure that these sanctuaries of biodiversity and providers of many other benefits to our society continue to survive in spite of wildfire, fire suppression, invasive species, residential and commercial development, and other threats.
What is each region’s capacity to preserve and/or restore older forest?
The optimum preservation and restoration strategy for older forests is likely to differ by regions and even localities because each region has a different mix of land ownership and because government decision-makers and the public have different goals. However, it seems safe to say that a truly comprehensive strategy will always include a mix of public and private lands and a mix of regulation and incentives.
Even in the Northeast and Southeast, where public land is relatively scarce, public lands can provide an important “backbone” of preserved older forests. Perhaps the best example of how this might work is the “Wildlands and Woodlands” plan for Massachusetts discussed in the “Conservation Tools And Strategies” section of this report.
In general, it’s easier to establish long-term preservation areas and practice long-rotation forestry on public land (rotation length is the number of years between timber harvests). However, incentives should be considered to encourage private forestland owners to apply these strategies, particularly where they can be coupled with ecological services such as watershed protection and carbon sequestration. Other important elements of any old-forest strategy are public involvement that provides mutual education and information exchange among all those affected by the strategy. This should include city dwellers, as they must provide much of the political will and cash to support any strategy.
In the Northeast and Southeast, older forest strategies will depend heavily on private lands and incentive programs, with an important but relatively slight backbone of older forest on public land. In the Great Lakes region, where cooperative effort has a long and relatively successful history, there likely will be a mix of public and private actions. In the Northwest and Southwest, federal lands, and state forests to a lesser but important extent, will provide a robust backbone of older forests with big trees. Important contributions such as restoration of older forests in lowlands and flood plains on private land can be encouraged by carefully crafted incentives and appeals to landowners. The most important element in designing strategies will be to recognize both the dynamic nature of older forests and the extent to which regional culture and society dictate what is possible.
Public lands in the Northeast provide a good opportunity to preserve or restore older forest. Various public lands have diverse mandates, however, and not all of them have the same capacity. Though the 800,000-acre White Mountain National Forest has a long logging history, about 38% of the area is classified as “old.” About 53% of this national forest is off limits to harvesting, and about 25% is in lower elevation forest that will become older forest and old-growth over time.
State-owned forest in Maine administered by the Bureau of Parks and Lands has a multiple-use mandate, but harvesting is much less than growth. These public lands have the capacity to extend rotation length to maintain and restore older forest. Baxter State Park in northern Maine is mostly 60- to 80-year-old second-growth forest, but it will grow into older forest in the next several decades. Because it never went through a grazing/ farming phase, the continuity of forest cover was never broken.
The willingness of state land managers to maintain older forest varies tremendously, and nearly all states lack an explicit process for conserving it (Pennsylvania is a notable exception). In summary, public lands offer the best opportunities to preserve and restore older forest in the Northeast, but there will be a near-term net loss because of trends on private lands.
The first step in a Great Lakes regional old growth conservation framework must be for a regional team to develop consistent definitions for old-growth forests by habitat or ecosystem type. The second step must be to inventory and assess old growth. Setting goals and management plans isn’t possible without knowing what’s there. Ideally, these inventories would include private lands where possible, because much old growth on private lands isn’t protected. Starting with a broad-scale assessment on private lands might encourage a finer scale assessment that could help landowners recognize old-growth opportunities.
Assessments need to consider older forests with the potential for becoming old growth, not just forests that are in ideal old-growth condition now. Inventories and management plans that exclude stands that do not meet exact definitions of old growth will reduce resiliency to catastrophic disturbances. To have old growth in the future, it’s necessary to identify and protect or restore older forests that are nearing old-growth conditions and to sustain a resilient forest landscape by encouraging a wide range of forest types and ages.
In the Southeast, older forests are best sustained by thinking of them as perpetual, with part of the forest being born and part dying (or being harvested) but the forest as a whole never ending. This concept allows for management, including timber harvesting, and allows stands of trees to age with time. Guidelines based on this approach have great potential for conserving older forest in the region.
Given the predominance of federal land and its occurrence in large blocks in the Pacific Northwest, the potential for conserving and restoring old growth in that region is relatively good. However, the story varies by forest type, and it is clear that one-size-fits-all approaches to old growth won’t work.
The capacity to restore old growth in the Southwest depends on two factors: the ability to restore the structure and composition of the ponderosa pine ecosystem by returning fire to it (often preceded by thinning) and the ability to produce old growth from existing stock once it is thinned and exposed to low-intensity fires. This capacity is presently buoyed by fuel-reduction efforts by the federal and state governments and local groups. Public support for forest restoration and fuel-reduction treatments in the Southwest is reasonably high. Residents don’t support old-growth logging, but they generally accept removal of some larger trees as part of restoration and/or fuel-reduction efforts. Most of them have moved beyond the kinds of legal battles that surround old-growth forests in the Pacific Northwest and elsewhere. On the negative side, there is insufficient capacity and financial resources to restore older forests at the pace and scale needed to solve the problem.
This is a chapter from Beyond Old Growth (report).
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