Daily photo by Gary Lloyd|
Decatur Beautification Department workers remove the remains of an oak tree limb that fell Friday morning at Third Street and Seventh Avenue Northwest.
Rainfall burdens parched trees
By Paul Huggins
Recent regular rainfall may seem like medicine to trees parched from the worst drought in a century, but the precipitation actually has caused widespread destruction.
Many have experienced a condition called sudden limb drop, whereby the tree limbs break and fall because of the sudden weight of water in what were lighter, drier branches.
Decatur has received 3.13 inches of rain since July 1. Since then, the Decatur Landscape and Beautification Department has responded to 33 calls of fallen limbs or trees.
Busy cleanup time
The past two weeks has been the busiest cleanup time since Hurricanes Katrina and Ivan, said Linda Eubanks, landscape and beautification director.
Billy Rye, the city's urban forester, explained that sudden limb drop is a common condition when regular rainfall follows a summer drought. Willow and water oaks are especially susceptible.
Trees constantly draw water from their roots up to their leaves, an action called transpiration. The branches act as a straw. Transpiration slows during a drought, but suddenly quickens after rainfall, he said.
The branches suddenly have more water weight than the branch is accustomed to, putting excess stress on weakened parts, Rye said.
"If there's an area in the tree that's particularly weak, that limb is going to fail," he said.
The good news is that sudden limb drop usually ends after a couple weeks of rain because any weak points quickly get exposed, Rye said.
Unfortunately, there's not much that can be done to avoid the problem, other than pruning to lighten long horizontal branches, which is time consuming and expensive.
Rye said the best prevention of sudden limb drop is healthy, ongoing tree management, such as pruning, fertilizing and watering.
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