No Place for Nature
Numerous species of plants and animals require mature forests of relatively large acreage to insure their survival. These species include a variety of birds that spend much of their life in the tropics, but fly to the United States or Canada during the summer months to rear their young. Included are warblers, vireos, tanagers and flycatchers. But migrant birds are not the only species that need mature forests. Many of the less common species of lichens are found only in mature forests. Some are found only in 150 to 200 year old forests, where there is a constant supply of substrate material in various stages of decomposition. The richness of herbaceous plants like ferns, especially those associated with springs or wet areas, are consistently found in greater abundance in older age forests. Large mature forests occur infrequently in the East and old-growth forests, usually considered to be forests over 200 years old, are the rarest type of habitat. Scientists have recommended that "diversity maintenance zones" for species adapted to old-growth conditions be preserved in contiguous blocks of at least 50,000 acres or more.
In the East, this poses problems for species adapted to old growth forests where most forests have been subjected to frequent logging activities. Harvests, on the order of every 20 to 70 years, can remove nutrients from the forest floor faster than natural chemical processes can replace them. Frequent harvests diminish species diversity by depriving the forests of the plants and animals that require a mature forest in which to colonize. Second-growth forests, which are characteristic of most of our Eastern forests, provide habitat for some species, but are not adequate to host populations of the many plants, animals, and organisms that populate mature forests. Finding contiguous blocks of forests approaching 50,000 acres is very difficult in the East, and re-creating such forests is almost impossible when forest management schemes demand continual harvests.
New growth forests are relatively easily re-created, but it is much more difficult and time-consuming to restore old-growth forests. It also requires more forward-looking and enlightened forest managers. We have managed forests in the East for about 100 years, which is not enough time to establish true old-growth forests, but unless we manage for old-growth characteristics, we will never again have any quantity of this type of forest. The very act of managing a forest usually means the primary focus is on producing wood products, which is incompatible with the idea of re-creating mature forests containing rich species diversity.
The largest state forest in Maryland is called the Savage River State Forest. It contains about 54,000 acres, but only half of it is protected from logging. The protected forest is mostly stream buffers and steep slopes, and logging operations are scheduled throughout the other areas. Only about 10,000 acres of this forest is fully protected as a "wildlands", a designation which prohibits logging activities.
Forests being managed in this fashion will never create large "contiguous" blocks of mature forest. Instead, small pieces of mature forest will occur, but these pieces will be fragmented by logging operations and logging roads. Without large tracts of mature forests, much of nature will never have a home.
Bob DeGroot