BEETLE BATTLE WAGED

Wonder what those big purple prisms are, hanging from the trees on either side of the highway as you drive through the north country? The 2-foot-long gizmos swaying from branches 15 to 20 feet up — especially visible in St. Lawrence County — aren't bizarre out-of-season Christmas ornaments; they're a powerful surveillance tool in a war you might not know about.

Consider New York's forests through the eyes of state environmental officials, and you'll see them as a battleground.

About 900 million ash trees — almost 8 percent of trees in the state — are under threat as infestations of a tiny, invasive and deadly Asian beetle crop up on all sides.

Emerald ash borer outbreaks have been found nearby in Ohio and Ontario and, last month, in Cattaraugus County in Western New York. Since the beetle was first discovered in Michigan in 2002, 50 million U.S. ash trees have succumbed, according the state Department of Environmental Conservation's Web site.

With the critters closing in, a handful of local, state and federal agencies in New York has teamed up to slow and contain outbreaks, including DEC, the U.S. Department of Agriculture, the state's Department of Agriculture and Markets and its Office of Parks, Recreation and Historic Preservation, and some Indian reservations near outbreak zones.

Joshua M. Payette, a DEC forest health technician, is an intelligence officer in this war, posting surveillance devices and collecting data on enemy positions. Since May, he has traveled the state placing traps for the beetles, including about 188 of the purple prisms in the Cranberry Lake area.

The traps are checked four to five weeks after they're installed, then again four weeks later, when they are removed, he said. That time span covers the season when the beetles are most detectable; the traps lure adult ash borers with their color and with a lure hung inside them that releases a smell like deteriorating ash trees. The bugs then get stuck to the tacky substance, nicknamed "tanglefoot," that's spread across the exterior of the three-sided traps.

The goal was to hang at least one trap in every 1.5 square miles of the state within 100 miles of a known outbreak, Mr. Payette said, with more concentrated in areas considered particularly at risk, like campgrounds and common stops for logging trucks.

The idea behind the extensive monitoring program is that early detection allows DEC to target the right areas for regulation tightening or enforcement, Mr. Payette said.

Outbreaks are seen as more or less inevitable at this point, he said, but slowing and containing them is the goal.

Otherwise, "this could be on par with chestnut blight and Dutch elm disease," Mr. Payette said.

American chestnuts were once a dominant tree in the canopy in eastern North America — and a big industry, too — before an invasive fungus all but eliminated them from the nation's forests in the early decades of the 2th century.

Ironically, ash trees were commonly planted as street trees in municipalities to replace dead Dutch elms.

Emerald ash borers kill their hosts — green, white, black and blue ash trees — when their larvae feed on the plants' cambial tissue, the living part of the tree that conducts water and nutrients, killing it within two to four years, Mr. Payette said.

Along with Ontario, Michigan and New York, the beetle, which faces no effective predators in North America, has appeared in Indiana, Illinois, Maryland, Pennsylvania and West Virginia.

Early infestations are hard to detect, with woodpecker damage one sign a tree may be infested, and later signs of canopy death and atypical sprouting.

The beetles are a powerful predator of ash trees, but their range on their own isn't large, so transport by people, usually through firewood, is the key to their success — and the only hope for their control.

There are inoculations to protect against ash borers, but the treatment can cost hundreds of dollars for a single tree, Mr. Payette said.

DEC already has instituted strict regulations on the transportation of firewood. Firewood cannot be brought into New York state unless it has been heat treated to guard against pests, and untreated firewood may not be transported more than 50 miles from its source.

To be moved at all, it must be labeled. More information is available online.

ON THE NET

DEC firewood regulations: www.dec.ny.gov/animals/

28722.html