MACHIAS, Maine — This long, hot summer has taken its toll on home gardens, green lawns and farmers’ crops, but so far has affected Maine’s trees only minimally, experts say. The fall foliage should be as beautiful as ever, they say.
“Things are looking pretty good overall,” said William Ostrofsky, a pathologist with the Maine Forest Service of the Department of Conservation, on Monday.
Rainfall has been lower than normal throughout Maine, with the central part of the state facing drought conditions.
“Paper birch and yellow birch are already turning color in central Maine because of the lack of water,” Ostrofsky said, referring to the Dover-Foxcroft and Guilford area.
“We are particularly concerned about the Piscataquis River Valley,” said William Livingston, associate professor of forest resources at the University of Maine, on Monday. The river is at an all-time low, he said, indicating that little water is moving through the forest.
“The higher temperatures won’t hurt the trees as long as there is rain,” he said.
Livingston researches the information passed on by rings inside trees. “I can look back and definitely identify years of dryness,” he said. But he added that usually drought wouldn’t hurt the trees unless it is combined with a second stressor, such as insect infestations.
Livingston said he is far more concerned about the warmer winters and the impact that has on insect populations.
“Warmer winters aren’t halting the insects,” he said.
For example, the balsam woolly adelgid, once spotted only along the coast, has spread through Washington County all the way to U.S. Route 9.
“Before World War II, temperatures dropped below minus 25 degrees Fahrenheit at least several times a year,” Livingston said. “Since World War II, that only happens about once every five years.”
The lack of pine cones in some areas of the state is cyclical, he said. “Two years ago, for example, we had a huge amount of white pine cones. That won’t happen now for another few years,” he said.
Ostrofsky said many problems were exacerbated last year by the overabundance of rain. Tar leaf spot, which affects the leaves of Norway maples, was rampant last year, but incidents and severity of outbreaks are way down this year, he said.
Ostrofsky said that in the early spring, a fungus was causing pine needles to turn yellow and brown and then fall off white pine trees around the state.
But the fungal infections were caused by last year’s wet spring and summer, “not this year’s conditions,” he said. The infections have not increased the mortality rate of the pines.
“There really is nothing out there of real concern right now,” Ostrofsky said. “And there is nothing that should impact the fall coloration.”
Ostrofsky said the fall colors are triggered by waning daylight, and the early leafing of Maine’s trees this year plays no role.
“I think the hardwoods are in good condition for fall coloration,” he said. He expected the fall leaf-peeping season to begin peaking during the last week in September and the first week of October.
“Overall, statewide, the trees are looking pretty good,” he said.