There is some controversy over the management of Plum Creek's timberland, mostly from environmental groups who decry the recent move from Plum Creek as a timber management company into a developer of its land, taking advantage of the much more profitable land values that have occurred for undeveloped land in the late 1990s until the crash in real estate prices. Plum Creek is engaged in a proposal for a large resort and development tract in the Northern Maine Woods, on Moosehead Lake by Greenville, Maine, one of the largest undeveloped forests east of the Mississippi River.