Global Paleogeology images
The Northeastern U.S. is home to some of the most diverse, and at the same time, continually impacted ecosystems within the United States. From Cape May, New Jersey to Machias, Maine, coastal regions still support rich and productive ecological communities; important marine fisheries, estuaries, pine barrens, cedar swamps and patch matrices of oak-hickory forests. Spreading north toward Canada, the forests of the Northeast, which represent nearly 70% of its land area, grade into large tracts of wild timberland. These Northern Forests sweep east from the Adirondacks in New York, through northern Vermont, New Hampshire and into Maine, encompassing some 26 million acres. Scattered throughout the region are abundant lakes, rivers, ponds, marshes and wetlands. Its grassland communities have long been important habitats for resident and migrant bird species. Quite remarkable for a region that also supports some 15% of the US population.
Change has been a near constant within the region, across many time scales. The Taconic Island chain collided with the proto-North America land mass some 470-450 million years ago, closing the Iapetus Ocean. This added land area to the coastal zone of what is now the Hudson River and helped to form the foundation for the upper Appalachian and Taconic mountains and much of the physical landscape we now see. Multiple glacial periods over the past 25,000 years witnessed the scraping and earth moving actions of over a mile of ice, which rounded the mountains and helped to create the rich, stone-laden soil material that now sustains our abundant vegetation cover. As the last Wisconsin Ice Age glaciers retreated around 11,000 years ago, plant communities advanced again and established niches in the diverse landscape, across gradients of soil fertility, moisture and available light energy. Current theories have early humans arriving shortly after the glacial retreat and they are thought to have managed forests and grasslands for game, using fire as a tool, for centuries, until European settlement 400-500 years ago.
The Human Footprint
The human footprint in the Northeast expanded dramatically from the sixteenth century onward. Resource extraction, agriculture, settlement patterns, transportation and industrial use changed both the composition and integrity of the natural systems. As America solidified into a nation, westward expansion opened available space and opportunities for the densely settled eastern populations, relieving, to an extent, the pressure that humans were placing on Northeast systems. Since 1900, the region has seen a significant natural rebound, as forest lands reoccupy abandoned agricultural sites, water courses and lakes are cleaned and protected, and habitat begins to support faunal populations again.
Ecological systems within the Northeast have been described in a wide variety of ways since Europeans arrived. Early land surveyors referenced
their work in the early colonies by making recognizable marks on “witness trees” and providing a general description of the land’s
composition, content and quality. European names were commonly used for the trees and systems, since that was what those conducting the surveys
were familiar with. By end of the 19th towards the mid 20th century, the US Forest Service and the Society of American Foresters had developed
descriptions of natural areas for what, at that time, were the main feature of interest, namely, timber resources. As the newly forming field of ecology
began to emerge in the 1930’s, researchers such as Frank Egler began to more clearly refine both ecological patterns and processes, and names
for what they observed to be recurring patterns in vegetation communities in seemingly specific niches of the landscape.
Since the 1950’s, the fields of forest, vegetation and ecological region (ecoregions) classification have evolved enormously. In the late 1990’s, a consortium of federal, state and private agencies developed a uniform National Vegetation Classification System. This standardized approach has provided the basis for neighboring political entities and states to commonly map and understand the same structural and compositional vegetation pattern, across artificial boundaries. Increasingly, structure, climate, geology and soils are being added to obvious vegetation patterns, to create characteristic and diagnostic groups of ecological units. Among the more widely used classification systems are those developed by the US Forest Service, the Nature Conservancy, and the World Wildlife Fund. Increasingly, local programs are starting with a particular approach and then refining to greater detail and specificity, based on home range knowledge of particular observations.