Atlanta’s crashing trees predictable, arborists say

A towering oak can be a welcome sight to behold — until it crashes into your house.

The old Atlanta neighborhood of Grant Park, riddled with huge oaks, regularly sees roofing crews repairing tree-wrought damage — such as the one tree that took out parts of two houses on Broyles Street this spring. The park itself has been the scene of more than a half-dozen crashing trees this spring and that’s not counting the “hazard” trees that city arborists removed before they fell on their own.

Arborists say the damage was predictable — a hangover from several years of drought that weakened towering hardwoods and that was then coupled with rain-drenched soil and high winds.

“Grant Park has a lot of overmature trees — trees that have been around a long time,” said Tyler Baxter, a certified arborist with Baxter Tree Service. “They are really ominous looking — they have really large crowns.

“When the soil becomes really saturated, those trees are prone to come down. The roots can’t hang on to the soil.”

Trees are crashing all over metro Atlanta. Arborists — and even tree-hugging advocates — say that homeowners have to weigh the beauty, shade and environmental benefits a tree provides with the risk it imposes.

“The vast majority of our trees are on private property,” said Nina Cramer, president of Trees Sandy Springs. “People have to take responsibility and have the trees on their property assessed. We recommend that they have an arborist come out at least every five years. … I had a tree that looked healthy on the outside but was diseased on the inside.”

Baxter and Mark Livingston, a certified arborist from Arborguard Tree Specialists, recommend having an assessment done every year — saying that preliminary inspections are often free of charge. They provided advice to homeowners.

Q: Why do more trees seem to be falling this year?

A: A three- year drought weakened root systems, which generally aren’t deeper than eight inches in the soil, causing the roots to contract and making the tree too big for its “root plate.” The drought has also encouraged pests such as insects that attact trees, and fungus that attack healthy roots. That combined with a saturated soil and high winds has caused a lot of trees to tumble.

Q: Are there any warning signs that a particular tree has diseased roots and more likely to fall?

A: Big mushrooms growing around the base of the tree might signal root rot. Dead branches or dead limb tips — more evident to the trained eye — indicates disease. Again, an arborist can see signs of “root flare” at the base of the tree, which indicates root problems. An arborist can check to see if the tree is hollow with a simple test of thumping it with a rubber mallet and listening.

Q: What can be done to treat unhealthy trees or make trees less likely to fall?

A: Pruning the canopy and lowering the crown can reduce “the sail effect” so that branches don’t catch as much wind — in essence allowing air passages through the branches. Homeowners should consult an aborist before doing heavy pruning because if the sap is running, the pruning can damage or kill the tree. One of the cheap tactics to keep a tree healthy is to mulch around the base. Arborist can also treat trees by injecting beneficial organisms beneath the base to help restore roots.