A joint Harvard-Smithsonian study released today in the journal PLOS ONE reveals how much -- and how little -- Northeastern forests have changed after centuries of intensive land use.
A hike through today's woods will reveal the same types of trees that a colonial settler would have encountered 400 years ago. But the similarities end there. Jonathan Thompson, research associate at the Smithsonian Conservation Biology Institute and lead author of the new study, explains, "If you only looked at a tree species list, you'd have the impression that Northeast forests haven't changed. But once you start mapping the trees, and counting them up, a different picture emerges." Thompson adds, "In some ways the forest is completely transformed."
To draw these conclusions, Thompson and his colleagues compared colonial-era tree records to modern US Forest Service data across a 9-state area stretching from Pennsylvania to Maine.
Their results show stark contrasts between pre-colonial forests and today. Maples have exploded across the Northeast, their numbers increasing by more than 20 percent in most towns. Other tree types have declined sharply. Beeches, oaks, and chestnuts show the most pronounced loss -- big trouble, Thompson notes, for wildlife that depend on tree nuts for winter survival.
Pine numbers have shifted more than any other tree type, increasing in some places, decreasing elsewhere. Thompson pins this variability to ecology and economy: "Pine is valuable for timber, but quick to return after cutting. It has a social and environmental dynamism to it."
The nine states in the study share a similar -- and notable -- forest history: during the 18th and 19th centuries, more than half the forestland was cleared for agriculture and cut for timber. Most farms were eventually abandoned, and during the 20th century, forests returned. Today about 80 percent of the Northeast is forested.
Driving the study is a
|Contact: Clarisse Hart|