Deterioration of sugar maple following logging damage /

The northern hardwood forest comprises about 9 million acres in the Lake States region. Most of this timber is in Upper Michigan and Wisconsin, with lesser amounts in Minnesota, It consists primarily of sugar maple (Acer saccharum Marsh.), yellow birch (Betula alleghaniensis Britt,), basswood (Tilia americana L.), and often eastern hemlock (Tsuga canadensis (L.) Carr.). Although yellow birch is of considerable economic value in this forest type, it is secondary in importance to sugar maple. Only a small part of the area is in old-growth forest, and at the present rate of cutting these stands will soon disappear. However, many tracts of saplings that developed after early logging operations have grown to pole size and now constitute an important area of near- merchantable sawtimber (3). In addition, some areas have been logged on a partial-cut System, leaving rather extensive reserve stands, This system is being applied to a progressively greater extent each year.