Wet, Cool Summer Hurt Trees

Ricky Kemery points to a red maple tree on the campus of Indiana University-Purdue University Fort Wayne.

On one side, the tree sports bright orange and yellow leaves, but on the other, there are only clusters of bare branches, as if the wind has selectively blown the leaves away.

It’s an example, he says, of a tree under stress.

This year, as the region enters the traditional season for flaming foliage, the maple has lots of company.

“People are having lots of problems with their trees because of the weather we’ve been having,” says Kemery, horticulture educator for Purdue University’s Extension Service in Fort Wayne.

In other words, the area’s unusually wet and cool summer has sapped many trees’ ability to cope.

“You might say we’re seeing a sort of spike in problems,” Kemery says.

But, he says, owners of ailing trees can get professional help this week, when the extension service will have its sixth annual Northeast Indiana Landscape and Turf seminar.

Traditionally geared to professional arborists and landscapers, who receive continuing education credits for attending, the seminar Friday features a three-hour morning session on what’s been troubling trees and shrubs.

The session will be presented by Kemery along with Gary Moughler, a gypsy moth specialist with the state Department of Natural Resources, and Jodi Ellis and Dr. Cliff Sadof, of the department of entomology at Purdue University in West Lafayette. Sadof is an expert on the emerald ash borer, recently found to have invaded the state.

Although trees can be stressed by drought, Kemery says, they also can be damaged by too much rain, particularly in Indiana, where clay soils can hold large amounts of moisture.

“Diseases in trees and shrubs are primarily fungal in nature and related to too much water,” he says.

Michael Sabones, meteorologist-in-charge of the northern Indiana office of the National Weather Service in Syracuse, says the Fort Wayne area has had more than its share of water from above lately.

This summer was the sixth-wettest June, July and August since records began to be kept about 100 years ago, Sabones says. Rainfall between the beginning of May and the end of August was more than seven inches, which was more than 50 percent, above average.

Temperatures, meanwhile, made the months the fourth-coolest on record, judging by daily averages. They averaged more than two degrees below normal for June and July and four degrees below normal for August, he says.

Among the tree diseases helped along by the odd weather, Kemery says, is a condition called verticillium wilt, caused by a fungus. The disease affects maples and redbuds.

“We’ve seen a lot of that this year. It clogs up the pipes of the tree under the bark up to the top of the tree, and the tree can’t get water,” Kemery says. “It wilts the leaves, and the branches die back, and in some cases, it will kill the tree.”

The tell-tale sign is streaking in the sapwood, he says.

Root rot and root stress, propelled by flooding and saturated soils, also have attacked hardwood trees this summer, including ashes and maples, he says.

“If trees and shrubs are standing in water, the roots still need oxygen, and they don’t get it,” Kemery says.

The maple on campus with the asymmetrical foliage is probably suffering root stress, he says.

“When you see a top part of the tree looking like that, or there’s dead branches, it means the trouble is in the root zone,” he says.

Root rot, which can attack spruce and white pine, has been particularly hard on arborvitae shrubs and yews commonly used around homes, he says.

The shrubs’ needles brown and branches die from the disease, Kemery says.

Jeff Ford, owner of J&A Tree Care in Fort Wayne, says he’s also been seeing weather-related tree disease in evergreens.

“I’ve noticed a lot of white pines have died this year,” he says, noting that the species is intolerant of flooding.

“Since they store almost all their energy in their needles, if it’s extremely wet or dry for a period of time, they completely shut down,” he says. The hallmark is needles that turn light green.

A fungal condition called needle cast has hit spruce trees, Ford adds, leaving football-shaped black spots on the needles in its wake.

“I think it’s because it’s been cool,” he says.

Still the news on trees is not all bad.

Both gypsy moth defoliation and damage caused by the newly discovered emerald ash borer have been kept in check, say the experts who will speak on those topics at the seminar.

Sadov says the borer apparently has not spread beyond its two known Indiana sites.

“These ash borers attack trees under stress due to lack of rain, and we had a lot of rain, at least early in the season,” Sadov says.

“We could see an increase of borer problems next year,” he says, because the weather started to dry out in September, when the weather service reported rainfall was about an inch below normal.

Moughler says gypsy moths also have been kept in check by this summer’s weather.

“From what I’ve seen so far, the numbers seem somewhat down,” says Moughler, who keeps track of moths caught in traps. “We had some slight defoliation, but the treatments this year have done very well.”

Treatments might have been aided by a fungus that attacks moths.

“I did see it in a few places,” he says.

To make trees, including ashes, less susceptible to damage, Kemery suggests they be thoroughly watered in the coming weeks. Trees need to go into winter with well-hydrated roots, he says.

“We had all this rain and people think it’s enough, but it doesn’t work that way,” Kemery says. “We actually went from flooding to drought in about three weeks’ time, and it’s tough, tough, tough on plants.”

Kemery says diseases and other problems of trees can take weeks, months and even years to show up. But, by learning the signs, homeowners can improve their chances of figuring out problems.