Vine threatens trees in East End preserve

The Mashomack Preserve on Shelter Island -- an undeveloped Nature Conservancy property covering a third of the entire town -- is one of Long Island's natural treasures.

But, across hundreds of acres, a slow and nearly invisible battle is taking place there that could change the face of the preserve, causing the death of many of the stately oak and elm trees that give it such a distinctive character.

It's hard to see the problem in the summer because much of it exists in the leafy canopy on top of the trees. But in winter, the telltale signs of an Oriental Bittersweet invasion become visible, and volunteers come out to do battle.

"We call it 'Save the Trees,' " said Nature Conservancy spokeswoman Cindy Belt. "We've called it different things . . . removal of invasive species just left people cold."

Volunteers will, weather permitting, go out to Mashomack next month with loppers, hand saws and clippers and attack the bittersweet, a vine that grows by attaching itself to trees and going up and up, eventually choking the tree and getting so big that the tree eventually collapses from the weight.

About 1,500 acres of the 2,039-acre Mashomack Preserve are forested, but the old-growth oak and elm woods are concentrated in a few hundred acres. So is the Bittersweet, and that's where the volunteers will be going out.

"It's most severe around the visitor's center, maybe 300 or 400 acres," said Mike Scheibel, natural resources manager for the conservancy. "There are places that were cleared for agricultural reasons and left to revegetate on their own . . . that's the areas where Oriental Bittersweet tends to colonize."

The vine is so widespread that the Nature Conservancy -- which has tried to eradicate it for more than a decade -- is rethinking its approach on how to deal with it.

"Are we gaining or losing ground? That's a good question," Scheibel said. "In the past, we've embarked on a lot of control efforts . . . without a whole lot of thought to how much it cost or how long it will take."

The conservancy hopes to have an analytic tool in use this spring to help decide how to deal with a range of invasive species.

Volunteers wage their battle against the bittersweet in the winter for several reasons: The distinctive red and gold berries on the bittersweet are easy to see; the ever-present ticks on Shelter Island are not active; and fewer crowds make it easier to do the work.

The reasons volunteers help vary as well. Tom Damiani, the coordinator of volunteers, has been working at Mashomack for 18 years, and said some just like to come out and spend a few hours in the woods. But there is also a sense of accomplishment.

"Once you do it [cut the vines] you can look back and see it's done," Damiani added. "You see containment . . . you can say 'look what I did. I helped these trees.' If you love nature and the outdoors, you cut the vines and know a tree is not going to die. You've done something good."

More bitter than sweet

Oriental Bittersweet, also known as round-leafed or Asiatic bittersweet:

Is native to eastern Asia, China, Korea and Japan;

Was originally brought to the United States as an ornamental plant around the time of the Civil War;

Is restricted or banned for sale in several states;

Is often spread by birds which eat its brightly-colored seeds in the winter; the seeds germinate in the spring. It can also spread through underground rhizomes, above-ground roots or by sending shoots up from its root system;

Kills trees by growing so large that its leaves cover those on the host tree, preventing photosynthesis. In addition, the vine also girdles the trunk -- literally cutting a ring all around the bark and stopping the flow of nutrients -- and grows so heavy the tree is uprooted;

Interested in volunteering to help eradicate Bittersweet? Call 631-749-1001.