Four Centuries of Change in Northeastern United States Forests

Abstract

The northeastern United States is a predominately-forested region that, like most of the eastern U.S., has undergone a 400-year history of intense logging, land clearance for agriculture, and natural reforestation. This setting affords the opportunity to address a major ecological question: How similar are today's forests to those existing prior to European colonization? Working throughout a nine-state region spanning Maine to Pennsylvania, we assembled a comprehensive database of archival land-survey records describing the forests at the time of European colonization. We compared these records to modern forest inventory data and described: (1) the magnitude and attributes of forest compositional change, (2) the geography of change, and (3) the relationships between change and environmental factors and historical land use. We found that with few exceptions, notably the American chestnut, the same taxa that made up the pre-colonial forest still comprise the forest today, despite ample opportunities for species invasion and loss. Nonetheless, there have been dramatic shifts in the relative abundance of forest taxa. The magnitude of change is spatially clustered at local scales (<125 km) but exhibits little evidence of regional-scale gradients. Compositional change is most strongly associated with the historical extent of agricultural clearing. Throughout the region, there has been a broad ecological shift away from late successional taxa, such as beech and hemlock, in favor of early- and mid-successional taxa, such as red maple and poplar. Additionally, the modern forest composition is more homogeneous and less coupled to local climatic controls.

Forest change in the Driftless Area of the Midwest: From a preferred to undesirable future

“…Regional variation in forest composition is often attributed to spatial variation in environmental factors, such as soil moisture, topography, disturbance and climate (Iverson et al, 1997;Fuller et al, 1998;Hessburg et al, 2005;Hanberry et al, 2012), as well as land use history Schulte et al, 2007;Thompson et al, 2013). For example, in our study region, the environmental factors, soil texture, topographic roughness, and distance from waterways, have been found to be associated with pre-settlement tree species cover and vegetation structure (Shea et al, 2014).…”

Transparency, Geomorphology and Mixing Regime Explain Variability in Trends in Lake Temperature and Stratification across Northeastern North America (1975–2014)

“…Similarly, elevation trends indicate a comparable spatial pattern with maximum deepwater trends along the eastern Piedmont. As we move inland from the coast, moving from the west to the eastern edge of the Appalachians, a transition from coastal plain to piedmont and highland physiography is apparent, and this transition is associated with changing ecoregions, increasing elevation, more topographic shading, due to the surrounding terrain, and more temperature variability [58]. In this transition region, we expect maximum change in ice cover duration, mixing regime shifts and wind-driven turbulent mixing, especially for large lakes (e.g., [18]).…”

Tree Diseases as a Cause and Consequence of Interacting Forest Disturbances

“…In the absence of disease, disturbances play a critical role in structuring forest communities at local-to-landscape scales [17,30,39]. Ecological disturbances can alter any component of the disease triangle (Figure 1).…”