By C.V. Moore
After severe storm events like those recently experienced in West Virginia, humans aren’t the only ones forced to rearrange and cope with change. Forests react and adapt as well.
Anyone who has been in the woods near the New River Gorge since last month’s mammoth snowstorm, for example, knows that the forest looks radically different than it did before winds and the weight of heavy snow snapped crowns and bowed trees to their breaking point.
And those who walked the ridges before and after this summer’s derecho recall yet another scene change.
In ecology, a “disturbance” refers to an event — like a windstorm, a fire or a clear cut — that causes a dramatic change in an ecosystem.
A “disturbance” might sound like something to avoid, but ecosystems rely on such events, when they occur naturally, to diversify and evolve.
Storms are natural disturbances that break up the uniformity of the forest, creating gaps and patchworks so new species can become established.
All of a sudden, sunlight can reach the forest floor. Mosses, ferns and seedlings can sprout. The craters left by upended tree root systems become ponds where salamanders can live and other animals can drink.
“This is a place of rebirth,” says John Perez, a biologist for the National Park Service.
“It’s an area of a lot of activity because the sun’s energy is there. The seeds are already on the forest floor and when the sun hits it, boom, it’s just like a Chia pet.”
In short, plants and animals take advantage of the new microhabitats formed by a storm’s destruction.
In the relatively unbroken forests that were home to West Virginia’s Native American people, these events would have created healthy opportunities for growth and change.
Now, though, we already have plenty of patchwork in the landscape — whether because of towns, railroads, or mountaintop removal sites — and so the New River Gorge is seen as an important area of unbroken forest, worthy of preservation.
“Natural gaps were always a good thing, generally, because they were a place of rejuvenation,” says Perez. “But in this era, it’s also a place where bad things can get established, like exotic plants. So we need to keep an eye out for those areas so that Japanese knotweed, kudzu and other sun-loving plants can’t get established in an otherwise unbroken forest.”
The flipside of rejuvenation, says Perez, is that some invasive species are a little too good at it. Now, the sun-drenched gaps of the post-storm forest could be overcome by non-native species, which threaten to choke out native varieties.
The park maintains monitoring plots to watch for this kind of dynamic, and they apply herbicides where possible.
In addition, when the storms snap the tops from trees, it’s like opening a wound on skin. Bugs, beetles and other pests can get established. Trees like the eastern hemlock, which are already vulnerable because of the hemlock woolley adelgid — a non-native insect that kills hemlocks — could suffer an even faster decline.
Superstorm Sandy and the summer’s derecho appear to have affected the New River Gorge area in different ways.
Sandy was hard on shallow-rooted species like the Virginia pine, which were easily uprooted by the heavy snow and wind.
Evergreen trees, perhaps because their thick needles were able to catch more snow, were hardest hit — hemlock, pine and spruces snapped or endured broken branches. The weight of the snow also damaged hardwood trees that retained their leaves, or more brittle species like tulip poplars.
On the other hand, in the summer windstorm — which Perez says was far more destructive than Sandy — the biggest, oldest and tallest trees were brought to their stumps.
“The oldest trees in the park came down in the windstorm,” he says. “It appeared to me that it was the biggest trees that had a canopy that could catch a lot of wind, almost like a tent or sail.”
Carnifex Ferry State Park was one of the hardest hit areas by the windstorm, where trees as old as 400 years old blew over.
Some healthy hemlocks in the Fern Creek area also met their demise, though Perez says he was almost glad to see them go by natural causes, rather than slowly dying at the mandibles of the hemlock woolley adelgid.
Down along the river, areas near Stonecliff lay almost flat from the windstorm.
“It was particularly bad right along the edge,” says Perez. “I think we may have had some really high winds in the Gorge. I don't know, really, what was going on in the Gorge, but I would say we almost got some tornadic type winds.
“I even saw sycamores uprooted and snapped off, and that is a tough tree.”
To endure two major storms in less than six months is remarkable, says Perez.
“We’re starting to see a lot of big storms and I think it’s because of a changing climate, possibly. We’re having 100- year storms every 10 years now.”
He has seen and weathered other major “disturbances” in his career as a biologist, including another monumental snowstorm in 1998. But compared to these other events, the derecho was particularly memorable.
“There’s no question it was more than a 100-year event for this state,” he says. “It was one of those storms you probably won't see another one in your life time. At least I hope not.”