Red maple is far more abundant today than when Europeans first arrived in North America. It only contributed minimally to old growth upland forests, and would only form same-species stands in riparian zones. The density of the tree in many of these areas has increased 6- to 7-fold, and this trend seems to be continuing, all of which is due to human factors, mainly continued heavy logging and a recent trend of young, shrubby forests recovering from past human disturbances. Also, the decline of American elm and American chestnut due to introduced diseases has contributed to its spread. Red maple dominates such sites, but largely disappears until it only has a sparse presence by the time a forest is mature. This species is in fact a vital part of forest regeneration in the same way that paper birch is.