Responses of Northern U.S. Forests
to Environmental Change
Chapter 1: Forest Resources and Conditions
William H. McWilliams, Linda Heath,
Gordon C. Reese, and Thomas L. Schmidt
The northern region contains 23% of the forest area of the
U.S., and 45% of the population. Heavily forested areas are located
near areas of high population density. As a result, forest fragmentation
has become a major issue for the region. Private forest landowners
control 80% of forest land. Most of the private owners are nonindustrial,
owning timberland primarily for recreation and esthetic enjoyment.
Most of the North had been cleared for agriculture or heavily logged
by the mid-1800s. Since then, reestablishment and regrowth of forests
on farmed or logged land has provided the large areas of maturing
forest common today. The region is still gaining forest land from
other uses, primarily agriculture, despite continued development
and fragmentation in some areas.
A major event shaping the species composition of todays forest
was the chestnut blight, which all but eliminated this important
species by mid-20th century. Oaks and other hardwoods replaced this
once-dominant species. Oak-hickory and maple-beech-birch together
account for over 60% of the forest area, with oak-hickory common
in the southern part of the region and maple-beech-birch common
in the northern part of the region. Aspen-birch is common in the
North, particularly in the Lake States. The most northern parts
of Maine and the Lake States contain significant amounts of Spruce-fir.
In terms of timber volume, the North contains 47% of the nations
hardwood volume but only 11% of the nations softwood volume.
Lack of oak regeneration following harvest is considered a major
issue for the region, as loss of oak forests coupled with a major
expansion of red maple results in lower economic value and reduction
of important mast species. Areas of major pest problems include
spruce-fir forests in Maine, heavily damaged by spruce budworm in
the 1980s, and the Allegheny plateau region of Pennsylvania, where
numerous biotic and abiotic agents have caused damage and decline
of sugar maple.
Northern forests contain large reservoirs of carbon, particularly
in abundant maturing forests and forest soils. n the recent past,
forest growth has been more than twice forest removals. Expected
increases in harvesting coupled with slower growth will reduce the
high rate of carbon sequestration over the next 50 years or so.
Location of forestland,
estimated probability of occurrence for oak-hickory forestland.
Probable distribution of oak-hickory
forestland by stand size class, Northern Region (excluding Southern
New England), 1997.
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