The Albemarle Sound watershed stretches 6 million acres along the North Carolina and Virginia borders. “The Sound contains some of the largest areas of bottomland hardwood habitat in the eastern United States,” says U.S. Forest Service Southern Research Station (SRS) research ecologist Anita Rose. “In a variety of ways, both nature and people depend on the services provided by the Sound’s extensive forests.”
Rose is co-author of a new publication that describes the status of the bottomland forests. The study was led by Jean Lorber, a land protection specialist at the Nature Conservancy, and published as an SRS e-Research Paper. The scientists used almost 30 years of data collected by the U.S. Forest Service Forest Inventory and Analysis (FIA) unit to analyze trends in growth, timber harvesting, acreage, size of trees, and other factors such as species composition.
As expected, there were major differences in the composition of forests in floodplains and in swamps or bogs. “The clearest signature was the greater proportion of tupelo and cypress in swamps and bogs compared to floodplains,” says Rose. Floodplain forests tended to have more oaks, ash, sweetgum, and yellow-poplar. Some species, such as oak, were common in both young and old forests. However, younger swamp forests tended to have more loblolly pine, and less tupelo and cypress. The changes in species composition could be temporary, as flood-tolerant species like cypress are favored over time in the flood-prone bottomlands.
A key finding of the study was that the ratio between growth and removals (a measure of sustainability) varied dramatically between 1984 and 2012. This was primarily due to the fluctuations in timber harvesting in response to changes in market conditions.
Other important trends and findings:
- Overall, growth declined substantially between 1985 and 2007, from 79.6 to 33.4 cubic feet per acre per year, recovering somewhat by 2012 to 53.0 cubic feet per acre per year.
- For most of the study period, the total acreage of bottomland forests in the region stayed relatively constant – between 774,000 and 820,000 acres. Currently, bottomland forests cover approximately 800,000 acres of the region.
- Tree volume per acre fluctuated, peaking in 2002 and declining slightly by 2012.
- Most species groups declined by 10 to 20 percent from 1985 to 2012, although ash and oak increased by 41 and 57 percent, respectively.
- Throughout the study years, the number of trees that died or were removed varied dramatically, as did the average growth per year.
While FIA data indicates that the bottomland forests of Albemarle Sound can continue to provide wood products and other valuable services, returning to the level of harvesting practiced in the 2000s could be unsustainable. “In general, our analysis shows that the bottomland forest in and around the Albemarle Sound is a resilient and somewhat stable system,” says Rose. “However, it is not immune to the cumulative effects of human and natural disturbance.”
For more information, email Anita Rose at email@example.com