Green buds and flowers are popping out of tree branches early around campus with the warmer temperatures – an occurrence happening all across the eastern United States.

Researchers at the State University of New York College of Environmental Science and Forestry are studying the consequences of this early bloom.

‘The warmer weather is simply causing trees to flower, leaf out, and in some cases, fruit much earlier,’ said Donald Leopold, a conservation biology professor at ESF, in an email.

But a late frost is just one of many concerns researchers at ESF are looking into.

‘If we get a hard freeze between now and when the leaves and fruits can tolerate cold,’ Leopold said, ‘we’ll have significant damage to the trees.’

The risk of a spring frost damaging the new leaves and flowers is still significantly high. Colin Beier, research associate at the ESF Adirondack Ecological Center, said that though it seems impossible for a frost to still happen, an occurrence is still possible.

Temperatures of 28 degrees and below can significantly damage the new leaves, Leopold said. He added that temperatures tonight and Tuesday morning are currently predicted to reach 23 degrees locally and could be even lower in the hills.

‘This process may stress the trees, making them more vulnerable to insect and pest attacks,’ said John Stella, an assistant professor in the Department of Forest and Natural Resources Management at ESF.

A longer and more intense allergy season is another consequence researchers believe could result from the early blooming. Maples, willows, aspens and poplars are among the trees whose early budding causes them to release pollen that can worsen people’s allergy symptoms, Leopold said.

This is the first time in his 27 years teaching at ESF that he has observed these species of trees blooming before April 1, Leopold said in a March 20 ESF news release.

Pollinators, such as birds and insects, not adjusting fast enough to the early budding may cause trees to produce less or no fruit when they bud early.

‘If the warm temperatures cue the trees earlier but not the pollinators, there may be some mutually negative impacts,’ Stella said.

For example, migrating birds who rely on fruit from trees would not receive the food necessary for breeding if the trees produce fruit faster or slower than usual. Beier said, though, that this is typically not as large of a concern as frost. ‘But in years like this, the lack of pollinators could be a factor,’ he said.

If there is no frost, Beier said, the longer growing season could allow the fruit more time to develop.

To prevent the new leaves and flowers from freezing, people use a variety of methods, including wrapping bags around the sensitive tissues to insulate new buds from cold air, Beier said. But the process is expensive and time consuming.

Beier said there is a lot of ongoing research about the effects of warmer weather on trees and forests. He also said the trees may be able to adapt to the earlier springs, but it will take time.

‘Since trees are long lived and generations are typically centuries-long,’ Beier said, ‘adaptation generally happens slowly in plants.’

smhazlit@syr.edu 

Published on March 25, 2012 at 12:00 pm