OREGON STATE UNIVERSITY

Street trees often neglected, says OSU expert

08/04/1998

CORVALLIS - You don't have to actually hug trees, but it would be nice to occasionally check on their well being - especially the ones right in front of your house.

Many trees along city streets are dying a slow death because people often treat them as if they were established, eternal things rather than something that is alive and interacting with the environment, according to Melodie Putnam, a plant pathologist with the Oregon State University Extension Service.

"It is sort of a 'telephone pole' phenomenon," explained Putnam, who is the chief diagnostician at OSU's Plant Disease Clinic. "People tend to regard street trees as objects that were just stuck in the ground and don't need to be cared for."

In reality, street trees planted along a curb line are especially stressed because they generally have cramped roots and poor aeration. And, since they are outside of most people's lawns, these curb-side trees don't get watered with the regularity of a lawn or vegetable garden, she said.

Even Oregon's wet springs are not enough to carry a tree through the state's hot, dry summers. Since most of their root system is in the top 12 inches of soil, a tree's roots can dry up quickly during the summer months.

"Just because they still have leaves on them, doesn't mean the trees are doing well," she emphasized. "Trees don't usually turn brown and die all at once, but you can easily see the results of 10 years of neglect.

"You shouldn't be able to look through a healthy tree and see the blue sky on the other side," Putnam added.

Other common signs of stress are a thinning canopy, smaller-than- normal leaves, branch die-back and premature fall coloration, she says.

In addition to regular summer watering, removing dead branches can help keep your trees healthy, she pointed out. Dead wood tends to attract pests and fungal diseases that could spread to the rest of the tree.

"It's easy to take for granted how valuable trees are," Putnam said. "They increase property value and provide shade from the heat. Or, if you want to look at it another way, the cost of removing a dead tree can be $500 or more."