Forest Calendars: 1995 Editorial

The Future of America's Forests:

A discussion with
Dr. Thomas Bonnicksen Ph.D.

I met Dr. Bonnicksen in Portland, Oregon where he was a technical presenter at the 1994 'Forest Symposium'. Dr. Bonnicksen's research has given him very special insight into many of our nation's forest health, Old-growth and other related issues. What follows has been taken from a article Dr. Bonnicksen prepared for the American Forest & Paper Association's book entitled; Closer Look, An On-The-Ground Investigation Of The Sierra Club's Book, Clearcut.

"Forests cover 1/3 of the United States, but today's forests differ significantly from ancient forests --- and consequently so are the problems associated with managing them properly. Exotic plants, animals and diseases continue to change America's forests. The Asian chestnut blight fungus, for example, eliminated the American chestnut from most eastern forests by 1950. Urbanization and agriculture have also taken their toll, and timber management transformed some ancient forests into managed forests. However, the elimination of Indian burning and the suppression of lightning fires produced the greatest changes. This loss of nature's clearcuts threatens the health and productivity of America's forests.

Without nature's clearcuts, forests throughout America are growing thicker and the mosaic structure that characterized the majority of ancient forests is disappearing. The most dramatic decline in forest health is taking place in national parks, wilderness areas and other forests where timber management is prohibited.

Ancient ponderosa pine savannas in northern Arizona and Wyoming are becoming denser and shading out the grass underneath the trees. The density of mixed-conifer forests in the San Bernadino mountains of southern California increased by 74% in 60 years. Mixed-conifer forests in the Sierra Nevada are being replaced by shade tolerant white fir trees. Sugar maple is taking over northern and eastern hardwood forests. Douglas-fir forests are being replaced by shade tolerant western hemlock in the Northwest and by white fir in the Southwest. Lodgepole pine forests also are being replaced by shade-tolerant spruce and fir in the Rocky Mountains.

Elsewhere in the West, one-seeded juniper is spreading within pinyon-juniper woodlands and replacing grasslands in the Colorado Plateau and southern Rocky Mountain regions of northern Arizona and northern New Mexico. Aspen forests in Arizona and New Mexico decreased by 46% and are rapidly disappearing as a distinctive forest type throughout their range, because of increases in the density of pine and other conifers. Unless something is done now to reverse this deterioration, many forest types will cease to exist within the next 25-50 years.

The decline in forest health is also causing a reduction in wildlife and fish habitat, a decrease in biodiversity and lower water yields. The loss of aspen in the Southwest and throughout the rocky Mountains, especially in Yellowstone National Park, is particularly serious because such forests provide habitat for 77 bird species and 56 species of mammals, including elk. Today's dense forests also are infected with disease and infested with (tree destroying) insects. Tree mortality in the United States increased 34% between 1986 and 1991, and forest growth declined by 2% during the same period. Competition for water, nutrients and sunlight among densely packed trees explains some of the decline.

Increasing tree densities, thickets of understory trees, and the conversion of forests and brushlands mosaics into a continuous cover of highly flammable fuel also makes wildfires larger and more severe, as the Yellowstone fires have shown. These unnaturally large fires increased the size and patches in the forest mosaic, which will drastically increase the destructiveness of future fires.

Housing developments and other structures in forests and brushlands further enhance the chance of disaster. As a result, wildfires in pine forests destroyed 1311 homes between 1985 and 1992 in Florida, Colorado, Idaho, Arizona, California, Oregon and Washington. Fires in California destroyed 3000 homes in 1990 and 1991, and the southern California fires of 1993 destroyed an additional 800 homes and cost $1 billion in property losses. These losses will grow as America's forests and brushlands become thicker.

In Conclusion:

The best hope for America's forests rests on learning from the past and ensuring that professional foresters retain a complete set of silvicultural tools, including clearcutting, to apply what they learn. The deterioration of ancient forests caused by eliminating Indian and lightning fires demonstrates that diverse and healthy forests can only be sustained by active management. Prescribed fires can be used in some cases, but safety concerns and air pollution restrictions will probably prevent widespread and frequent burning.

Science-based timber harvesting is the safest and most efficient way to mimic nature's clearcuts. Timber harvesting has the added advantage of creating jobs, producing wood and generating revenue to pay for management. Ancient forests and nature's clearcuts provide essential lessons for ensuring a productive and sustainable future for America's forests."