Today’s forests reflect yesterday’s land use

In the Hudson Valley, our forests have been shaped by human activities, which have often altered and hidden the roles played by natural processes like climate and soil fertility. For thousands of years, we have been manipulating local plant communities.

Native Americans cleared small plots for agriculture and used fire to open woodlands to increase game. European settlers and their descendants had an even greater influence, clearing land until 84 percent of Dutchess County was "improved" by 1915. The opening of the Erie Canal in 1825 sparked a westward movement of settlers and eastward movement of raw materials from the frontier's rich soils. The subsequent human exodus from many Hudson Valley hardscrabble farms resulted in the abandonment of thousands of local acres and their regrowth into forests, which now cover about 60 percent of our region.

Acting as both scientists and detectives, forest ecologists at the Cary Institute of Ecosystem Studies in Millbrook have uncovered an interesting story about how environment and land use history determined the structure and composition of our forests. Like much of our region, Cary's current vegetation was greatly influenced by human activity. In 1875, only about 20 percent of our property was covered in forest. When agriculture ceased during the 1930s, succession unfolded. Today, 43 percent of the property is forested. In effect, more than half of our current forestland was cleared for farming by 1875.

Choices farmers made when working the land more than a century ago are reflected in three forest types on the property today. Steep, rocky slopes that were too poor to farm were never cleared. These sites were the woodlots of yesteryear, where trees were selectively but repeatedly harvested to supply timber, firewood, charcoal or bark for tanning. Today they are forests dominated by chestnut oak (Quercus prinus) and red oak (Q. rubra). Chestnut oak may be more common here today than it was before settlement, as this species readily sprouts from cut stumps.

The other two major forest types found at Cary are associated with abandoned agricultural lands. Less steep but infertile sites were often used as pastureland, and were subject to sprout regeneration of oaks and hickories when abandoned. These stands are currently dominated by white oak (Q. alba), black oak (Q. velutina) and pignut hickory (Carya glabara). Finally, fertile, cultivated fields most often were situated on moister, less rocky sites, which today are dominated by red maple (Acer rubrum), sugar maple (A. saccharum) and white pine (Pinus strobus). These species can be prolific invaders of agricultural lands and may dominate first-generation forests in abandoned fields.

Follow-up studies at Cary and elsewhere have shown that more recent human-caused disturbances are reducing the plant community differences formed from past land use. New pests and diseases, invasive species, excessive browsing by overabundant deer populations, and management decisions such as fire suppression are reshaping today's forest communities. What we see today represents a snapshot in time, not what will comprise future forests.

Interested in learning more about how human practices impact forests past, present and future? View a video presentation "From Forest to Farms, and Back Again: Land Use Change in the Hudson Valley" by Cary Senior Scientist Charles Canham.

Cary Institute of Ecosystem Studies | Millbrook, New York 12545 | Tel (845) 677-5343

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