The major threats are timber and mineral extraction, conversion to developed lands, fire supression, air pollution, acid precipitation, high densities of deer, and the introductioin of exotic pests and diseases. The logging industry is getting bigger and bigger everyday. There are so many tall trees that are cut down each day. This means that almost all the foliage existing today has regrown after being cut. Younger forests have very few large trees and sparse vegetation and moreover not as biologically diverse as old-growth forests.
Coal mining is another threat.
Many men who worked in coal mines got lung cancer from breathing the black smoke. Just imagine how the animals must feel since they have to breathe the air everyday. Conversion to developed lands has sprawled over the last two decades. Much of the land has been replaced by recreational resorts and second homes. The suburban and urban sprawl has increased the air pollution and acidic precipitation.