Characteristics of Five Climax Stands in New Hampshire

Analysis of species composition, stand density, and diameter distribution in five climax or old-growth stands in New Hampshire indicates that the northern hardwood climax is characterized by at least 65 to 70 percent tolerant hardwoods, 130 square feet basal area per acre, and "q" ratios (2-inch diameter classes) of 1.3 to 1.4. Climax sprucehemlock have at least 70 percent tolerant softwoods, 180 to 200 square feet basal area per acre, and "q's" of 1.5 to 1.6. In the summer of 1984, prism-plot surveys were made of several old, undisturbed stands in New Hampshire. The purpose was to define the characteristics of climax hardwood and softwood stands to use as baseline information for ecological studies and for refining uneven-age management guidelines. A recent survey of old-growth stands in New Hampshire provided in-depth descriptions of species, structure, dead material, and herbaceous cover (Carbonneau 1986a, b). In this paper, I discuss species composition, diameter distribution (including tree size), and basal area per acre. This information should help foresters decide if a stand is approaching the climax condition. The term "climax," "old-growth," and "virgin" forest are used in different ways. In this study, the objective was to define the characteristics of stands that had attained or were approaching a steady-state condition, the point where species composition and diameter distribution remain essentially constant over long periods of time (a few hundred years). WILLIAM B. LEAK is a research forester, Northeastern Forest Experiment Station, Durham, New Hampshire. Areas The five New Hampshire study areas are characterized briefly in Table 1 . All of the areas supported typical uneven-aged forests containing mixtures of different size trees; distrinct even-aged stands were not evident. The Bowl is a well-known virgin forest on the White Mountain National Forest designated as a Research Natural Area. The northern hardwood stand included in this study is a 2 50-acre tract bordered by the Wiggins Trail and Wonalancet Brook (Leak 1973 and 1974, Martin 1977). Mountain Pond North is a stand of northern hardwoods approximately 100 to 150 acres in size Located in the Saco District, White Mountain National Forest. The Williams Tract is an old stand of northern hardwoods in Stoddard, New Hampshire, that is owned by the Society for the Protection of New Hampshire Forests. Possibly, the area received some light cutting (for softwoods probably) some years back, or experienced some windthrow from the 1938 hurricane or earlier storms. The area examined in this study was a 20to 30-acre stand on the eastern side of the tract. Bartlett Ridge and Bartlett 19 are small areas of softwood (20 acres +) on the Bartlett Experimental Forest, New Hampshire, that were not cut, or very lightly cut, during the logging for softwoods about 1900 or before. These softwood stands contain many large, old trees, but not many snags or logs. Thus, these softwood stands are best described as overmature stands that have not quite reached the climax or old-growth condition; basal areas quite possibly are higher in these stands than in older stands that have begun to experience mortality and blowdown.