A soon-to-be-published “status and trends” report on wetlands in the Bay watershed found that about 36,000 acres were destroyed in the Chesapeake Basin during the 1980s, (See the April 1994 Bay Journal).
But many officials in recent months have been pondering the significance of another finding of the federal study — that tens of thousands of additional acres underwent major transformations.
Those areas were changed from one type of wetland to another. Also changed — but to an uncertain degree — was their habitat and functional roles in the environment.
Timber harvesting was the largest single source of change, with about 18,000 acres of forested wetlands being altered into areas dominated by shrubs and other “scrub” vegetation, according to the U.S. Fish and Wildlife Service report which examined wetland “status and trends” in the Bay watershed from 1982-89.
“We don’t have a conversion in the sense that we’re losing a wetland,” said Steve Koehn, associate director of the state Department of Natural Resources’ Forest Service. “It’s being altered from an older successional stage to a younger successional stage. I’m sure a lot of wetlands are being harvested. But are they being lost or destroyed? No.”
Normal forestry activities are largely exempt from wetland regulations.
Overall, the watershed had a 12-fold increase in the rate of forested wetland harvest during the 1980s compared with an earlier study that covered the period 1956-79.
Officials are now trying to determine the ecological — and policy — implications of such large changes in wetland types.
“It’s something that certainly should be tracked,” said Sam Austin, a hydrologist with the Virginia Department of Forestry. “It would be useful to find out how that shift actually changes the function of the wetlands and how permanent that change is.”
The issue raises serious policy questions. Are forestry practices significantly altering wetland functions, such as habitat and hydrology? If so, what should be done to minimize those impacts or restrict or change activities? Would additional regulations spur landowners to stop managing and sell forest land for development?
The Bay Program’s Forestry and Wetlands workgroups are expected to begin exploring the issue and determine what, if anything, should be done.
One thing is clear: large acreages of forested wetland are being cut, changing wetland types for decades.
“When you lose forested wetlands, you’re on the losing end, ecologically,” said Tom Filip, head of the wetlands regulatory section of the Army Corps of Engineers’ Baltimore District. “We believe that in overall ecological value, forested wetlands are one of the most important ecological niches, period, on the landscape.”
Tree root systems, the large amount of organic matter contributed from falling leaves, and the ability of trees to absorb large amounts of nutrients sets forested wetlands apart from others. Filip suggested that about the only way one could convert a forested wetland and come out ahead, ecologically, was if it became a salt marsh — something that is highly unlikely.
Forested wetlands also provide a wide range of important habitats — many of which can be suddenly and dramatically altered when an area is harvested. The question is which alterations are problematic.
“It is kind of an abrupt change, from an ecological standpoint, to have a mature forest and then end up with stumps,” said Bob Zepp of the USF&WS’s Chesapeake Bay Field Office. “If that wetland had a high value for migratory birds, once you take the trees away you’ve destroyed the habitat for those species. At the same time, you may end up increasing the habitat value for frogs and salamanders. So there’s a trade-off.”
But species suddenly displaced by logging are unlikely to be able to move elsewhere because the territories in adjacent woodlands are probably already taken. “If the habitat is suitable, it will be occupied,” Zepp said. “They will try to compete, but one critter will ultimately die out.”
The removal of the trees may also affect hydrology; forested wetlands tend to become wetter after they are harvested. Ruts left from equipment and log dragging can also affect drainage. Sediment loads to local streams may increase.
But despite that, many say it would be more harmful to forested wetlands to prevent or severely restrict tree harvests.
“If we discourage timber cutting here, it might encourage using the land for something else, such as urban development,” Austin said.
Filip, while noting that “it takes years to return it to a forest and get the lost functions back,” agreed that the transformation of forested wetlands into other types should not be viewed as a permanent loss. “I don’t like to see any losses, but that is a conservative use of a resource,” he said. “I have an easier time with that loss than a shopping mall.”
In Maryland, Koehn said that 90 percent of the forest land is privately owned, and many of those people feel they face a “plethora of regulations.” Further restrictions, he said, may lead them to conclude that “it’s less of a regulatory burden to grow houses than it is trees.”
While tree harvests may cause a change in wetland type, the change is not permanent, Koehn said. “I’ve been trained to look at forest land in 100- to 200-year cycles,” he said. “That’s not necessarily the way other people look at land.”
Koehn said much of the forested wetland loss on the Eastern Shore represented the harvests of pine plantations which have been managed for forest products for decades and have been replanted.
Austin and Koehn noted that there has been a steady increase in the demand for forest products in recent years, and with more restrictions being placed on national forests, demand for products from private land is increasing. In Virginia, Austin said, timber harvests have risen about 1.1 percent annually in recent years.
As long as logging is done in a “sustainable” manner, Austin said, the impacts on a wetland can be minimized. But if restrictions prevent harvesting those lands, he and Koehn warned that not only will owners likely sell their property, but the demand for wood and paper will be met from forests in other parts of the world where there are fewer restrictions on logging.
“It’s socially and morally responsible to face those issues here,” Koehn said, and not harvest other nations’ woodlands to “meet our thirst for forest product.”
“It is,” he said, “one of those ‘not-in-my-backyard’ syndromes in a global situation.”
Status and Trends Report Highlights
The soon-to-be-published report, “Recent Wetland Status and Trends in the Chesapeake Watershed,” summarizes the state of wetlands during the study period of 1982-89.
The report, completed by the U.S. Fish and Wildlife Service, found that during that period, the watershed lost about about 0.5 percent of its remaining estuarine wetlands and nearly 2 percent of its remaining nontidal wetlands.
Findings were based on a random statistical analysis of aerial photographs taken from during the study period. The study showed that regulatory programs had slowed the losses of estuarine (tidal salt water) wetlands. Regulatory programs for nontidal wetlands, though, were still being developed during much of the study.
Among the study’s other findings:
- About 1.7 million acres of wetlands existed in the Bay watershed in 1989.
o Forested wetlands were the most common type of nontidal wetlands, covering about 990,000 acres.
- Nearly 2 percent of the total forested wetland acreage was harvested for timber during the study period.
- About 40 percent of the watershed’s wetlands are in Virginia, Maryland has more than 25 percent, Pennsylvania and New York have more than 10 percent each. The rest are in Delaware and West Virginia.
- About 36,000 acres of nontidal wetlands were destroyed during the study period. Most of the losses were the result of pond construction, lake and reservoir construction, and agriculture.
- During the seven-year study, as much wetland area — 2,500 acres — was lost to urban development as during the previous 23-year study period.
- Losses were heaviest in seven identified “hot spots”: Southeastern Virginia; Piedmont Virginia; Eastern Shore of Maryland; Western Delaware; Upper Coastal Plain of Virginia; Western Virginia – the Blue Ridge and Appalachians; and Northeastern Pennsylvania.
A document summarizing the report is being produced by the Bay Program and will be available next year.
For more on the study, see “Bay wetland losses unabated in 1980s,” in the April 1994 Bay Journal.