Deforestation in the U.S.

A few months back, I was waiting in line at a small store that often tunes its radio in to the Rush Limbaugh show. That being of those occasions, I heard Mr. Limbaugh assert that not only is excessive logging not a problem, but that in fact, the United States has more trees now than it did 300 years ago! He then fielded several calls from listeners who agreed that this was technically true, but wanted to point out that many of those trees would have to be seedlings in replanted clearcuts and therefore Mr. Limbaugh's statement was misleading. Well, I'd like to take this opportunity to point out that Rush was not only misleading, he was also making it up. The present total forested acreage in the United States represents only a fraction of the total in the 17th century, requiring that most of the present acreage be densely covered by extremely young trees in order for Rush's statement to hold true. The difference between current forests and their predecessors becomes even starker when one compares old growth acreage, an important indicator of not only forest health. Consider the following maps:

U.S. areas of virgin forest, 1650

U.S. areas of virgin forest, 1850

U.S. areas of virgin forest, 1926
(Note that most of the virgin forest shown on this map in the Pacific Northwest has since been logged.)

Forests with more diverse plant and animal species resist disease and insects better than less diverse forests. One finds the most biodiversity in old growth forests, while recently logged areas have the least biodiversity. This is usually because they have been replanted with a single commercially valuable species; this is the case with Douglas-fir in Oregon, for example. A disease or insect that targets Douglas-fir could therefore wipe out huge swaths of forest when previously it would have affected only some trees in any given stand.