Forest Pathology: Unique Features and Prospects

Foresters tend to think of us as pathologists, pathologists think of us as foresters. Both are right-most forest pathologists are professionals in both fields. Many of the unique features of forest pathology are derived from the distinctive characteris­ tics of trees, forests, and man's attitudes toward them. Trees are the largest of all land plants. They cover a larger fraction of the earth's land area than all other crops combined. Unlike most agricultural crops, forest trees do not need man to survive. They are a genetically diverse, climax or subclimax type of vegetation. Forests predominate in most areas of the world where annual rainfall exceeds 600 mm. Most forests are complex mixtures in which the species composition, genetic diversity, spatial distri­ bution, and age-size structure of stands are conditioned primarily by natural selec­ tion and competition. Intensive management and attendant changes in all of the above variables are becoming more common. But even in the mid 1970s only a small fraction of the commercial forest land in the United States has been planted or otherwise artificially regenerated, although in the southern United States, 45% of the slash pine forests are plantations. Eighty species of trees are used commercially in our home state-North Carolina; about 1000 in the world as a whole. Forests provide many values for society in addition to crops of timber. Some forests are managed for wood-based products including such diverse substances as cellophane, rayon, turpentine, or maple sugar. Forest lands also provide water for cities and towns as well as food and habitat for birds, fish, and game. Forests grace the landscape of parks and mountains. They add to the attractiveness of residential