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What Is This Indicator, and Why Is It Important?
This indicator reports the percentage of forest lands with
stands in several age classes. Forests of different ages often
provide different goods, services, and values. For example,
woodpeckers and species that need trunk cavities for nesting
find older forests, with their dead trees, a suitable habitat.
Younger forests, with their rapid growth and smaller trees,
provide habitat for species such as the Kirtland’s warbler,
which can only live in forests recently regrown after fire.
What Do the Data Show? Sixty-four percent
of eastern timberlands, where most of the nation’s
timber products are produced (see Timber
Harvest), are less than 60 years old, and about 90%
are less than 100 years old. Most of the nation’s
older timberland stands are in the West––about
35% of western timberlands are more than 100 years old,
with the remainder split between stands that are between
60 and 100 years old and less than 60 years old. Although
not included in this indicator, most of the nation’s
forests in wilderness areas and national parks, which contain
many old stands, are also in the West (see Forest
Management Categories).
Why Can't This Entire Indicator Be Reported at This
Time? Data are currently available only for timberlands.
Data on the age class of forest trees are not available for
national parks and wilderness areas and other forest land
not classified as timberlands. These data will be available
for future reports.
Discussion Forest age structure reflects
historic and current management as well as natural factors.
For example, the high percentage of younger forests in the
eastern United States reflects such factors as the reforestation
of former agricultural land, the management of many private
landholdings for commercial harvesting, and the fact that
very old stands are much less common in the East.
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