• fragmentation
• maintenance of biological diversity
• invasion by non-native species 
• erosion

Remaining old growth forests
Typically, lands unsuitable for cultivation escaped clearing, and most of these occurred near streams. Streams also served as firebreaks, and were therefore typically forested prior to European settlement. Today, most of the forests in the south-central portion of the state are associated with streams.

Secondary growth forest
Much of the increase in forest over the past 25 years came in the form of secondary growth forest. Second growth forests are quite different from native forests. Typically they occur in small, widely spaced plots of land and unless they are managed, are likely to be degraded.