Upper Delaware Magazine

Other invasives among us

By MARTY BORKO
Posted 9/23/20

Our story begins in 1904 when the New York Zoological Garden first identified Cryphonectna parasitica, the causative agent of the Chestnut blight. The American chestnut (Castanea dentata) was the …

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Upper Delaware Magazine

Other invasives among us

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Our story begins in 1904 when the New York Zoological Garden first identified Cryphonectna parasitica, the causative agent of the Chestnut blight. The American chestnut (Castanea dentata) was the preferred tree species for log cabins, flooring and railroad ties. Its edible nut was eaten by cattle and hogs on the forest floor as well as roasted for human consumption, often brought into cities by the train car. It did not take long for the tree with a 40-million-year-old evolutionary history to disappear within 40 years, save occasional root sprouts.

In 1930, another fungal disease appeared in Ohio hiding in imported veneer logs. The fungus attacked our American Elm, (Ulmus Americana). The stately elms existed from Texas to Maine and were selected as the trees for cities and college campuses for its large size, form and shade. By 1976, half of the estimated 77 million elms were gone, and today, only a few treated trees exist at all.

In the 1990s, the sap-sucking hemlock woolly adelgid (Adelges tsugae) showed up and began to feed on our hemlock trees (Tsuga canadensis). Our hemlock trees are the dominant evergreens in gorges and headwater streams. These are trout streams and the loss of the hemlocks decreases the shading and thereby increases the stream temperature, making them unfavorable for our native brook trout. The hemlock groves also serve as special nesting habitats for the more uncommon warblers, the blackburnian and the black-throated green.

In 2002, the emerald ash borer (Agrilus planipennis) was discovered in southeast Michigan. It probably came hidden in wooden pallets through the Great Lakes shipping route. This green beetle has very quickly decimated our local ash trees (Fraxinus spp.). Our ash comprised about 15 percent of our hardwood trees and, for all practical purposes, they are gone. They had been used for baseball bats, snowshoes and are the best firewood for those of us who split by hand.

Late this winter, after a successful nesting of great-horned owls in the Carantouan Greenways pine grove at the Wildwood Reserve, I noticed lots of white pine (Pinus strobus) needles on the forest floor—seemingly many more than I could remember before. I checked with the NYS Forest Owners and was referred to the forest entomologist, Mark Whitmore, who identified the condition as white pine needle disease. It is believed that the early loss of needles imperiling the majestic white pine is due to climate change, with our region receiving heavier early spring rains that have been very conducive to fungal attacks on the needles.

Unfortunately, our forest landscape is changing quickly and not for the better. We are the ones responsible. Every time we lose a species, our ecosystem becomes less stable. We have to pay attention and we have got to be aggressive, in particular with respect to climate change. It is real.

Marty Borko is a member of the regional board of New York Forest Owner’s Association, the VP of the Carantouan Greenway and a retired Professor of Biology at Orange County Community College.

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