| Zusammenfassung: | The distribution of forest communities on Pine Mountain, in the Cumberland Mountains of southeastern Kentucky, is in the main controlled by slope exposure and soil. These are determined by geological structure; the mountain is a monoclinal ridge of strongly dipping strata. The plant communities are treated in sequence along the line of a profile crossing the mountain and along a stream. These are considered in four groups: communities of (A) the southeast or dip slope, (B) the summit, (C) ravines of the dip slope, and (D) the northwest slope. The communities are shown to differ greatly from one another within short distances. Details of forest composition and soil are included as a basis for the discussion. There is shown to be a striking dependence of communities on local factors which are in turn related to geological structure. The community range of forty-five tree species is shown in a table, and the significance of certain species emphasized. Sixteen forest types are considered which are treated as segregates of more complex communities, of which there are four. The mixed mesophytic forest association is considered the most important community of the deciduous forest--the regional climax today and the remnant of an undifferentiated climax from which other simpler climaxes have come. The permanent or relatively permanent character of all the forest communities is interpreted as evidence of the climax or subclimax nature of each. The relation of each to soils is considered. Immature soils support subclimax communities or physiographic climaxes. Mature soils support the regional or true climax communities. All pine, pine-oak, oak and oak-chestnut communities are considered to be subclimax; the mixed mesophytic forest communities (association-segregates) are the true climax communities. These show considerable range in composition and constituent species; sugar maple, basswood and buckeye are the most important indicator species. The admixture of hemlock in a mixed forest does not remove it from the category of a segregate of the mixed mesophytic association. The possible relic nature of one exceptional hemlock forest in which is an unusual group of herbaceous plants, is considered. The recognition of the status of each community is essential to an understanding of deciduous forest climaxes.
|
|---|