Warm Weather Puts Trees on Fast Forward

Released: 19-Mar-2012 4:15 PM EDT
Source Newsroom: SUNY College of Environmental Science and Forestry
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Newswise — Unseasonably high temperatures have coaxed pollen from American elm trees, delicate green flowers from spicebush shrubs and a cloud of deep pink flowers from red maples, heralding the unusually early arrival of spring in central New York and reflecting a phenomenon happening across the eastern United States.

Trees and many other plants are developing flowers, and grasses are growing two to three weeks earlier than usual, raising the specter of a long and intense allergy season and concerns about what could happen to fruit crops — both in the forest and the orchard — if the budding fruit has to face a typical late spring frost.

“This warm weather might be really pleasant and some people might find it comforting,” said Dr. Donald J. Leopold, chair of the Department of Environmental and Forest Biology at the SUNY College of Environmental Science and Forestry (ESF) in Syracuse, N.Y. “But when the weather is really altered from typical conditions, there are always winners and losers among all types of both plants and animals. With the many plant and animal species in the East, some will benefit and some will be adversely impacted with these unusually warm conditions.”

Leopold studies woody and herbaceous native and non-native plants; in his 27 years at ESF, he has never seen these species bloom on campus before April 1. The consequences of this early blooming depend on the weather during the next month or so. Temperatures in the low 20s and lower can damage any developing fruit, such as the winged fruits of the silver maple, which are eaten by wildlife. More economically serious would be for apples and other fruit trees to bloom in mid- to late April then be subjected to a killing frost.

The early spring is not good news for allergy sufferers. Leopold said maples, willows, aspens, poplars, and other early spring blooming woody species are major contributors of wind-dispersed pollen that causes allergic reactions so allergy sufferers are likely to notice an early and prolonged allergy season.

A quick walk around the ESF Quad at the center of campus gave Leopold an opportunity to point out an American elm in front of the library that was already producing pollen, a row of spicebush shrubs sporting flowers of various sizes, and a red maple covered with flowers.

Native willow planted in a rooftop demonstration project on ESF’s Illick Hall has also bloomed early. A dogwood known as a Cornelian cherry, which produces fruit that various species of wildlife feed on, was past its blooming peak.

Elsewhere in the region, the silver maples peaked the week of March 12, weeks ahead of their average bloom time; some saucer magnolias are starting to open weeks ahead of their earliest bloom times in Central New York.

Leopold routinely collects twigs over ESF’s spring break to teach his students identification techniques during his fall dendrology course. He said he has never seen the buds as swollen as they are this year.

With temperatures in Syracuse expected to be in the 70s again today (Tuesday, March 20) and into the 80s Wednesday, the cycle is not about to change.

“Things are really going to pop this week,” he said.


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