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Irma-killed ‘zombie trees’ pose threat

By Staff | Aug 16, 2018

Residents across all of Southwest Florida are still feeling the effects of Hurricane Irma that blew through almost one year ago.

In its wake, among many, many things, have been trees and vegetation destroyed by 100-plus mph winds, torrential downpours and lightning strikes.

Occasionally, trees may appear to be healthy, but are really dying inside. These trees are sometimes referred to as “zombie trees.”

These “zombie trees” can be quite hazardous, especially if in the vicinity of a house or building.

Dan Powell, arborist and district manager for The Davey Tree Expert Company in Naples, said it could take up to a month or more to see the effects of a decaying tree, especially after a storm such as Irma.

“High winds take moisture out of leaves and needles on trees, called wind desiccation,” he said. “In Florida specifically, the wind can blow salt all over, which creates more dryness and stress.”

Davey Tree Experts removed at least 5,000 dead trees across Southwest Florida after Irma.

Some of the things to look for on a tree to identify if it may be losing life, are cracks, decaying of wood, leaf loss and a lack of re-foliation after a storm.

“Depending on the severity of stress, your tree should have regained some growth in around 30 days; if they don’t, that’s an issue,” Powell said.

Other causes can be secondary invaders such as insects and borers.

Borers burrow into tree trunks and plant stems, eating their way through vital structural components of a tree.

They can be beetles, months, or larval stages of other insects.

Along with hurricane force winds and pesky insects, an over-saturation of water can also lead to a tree’s death.

“The length of time the water sits on the root zone can deplete oxygen to the tree, sometimes called ‘wet feet,'” said Powell. “It can’t move energy. The soil is saturated. In the case of Irma, we had severe rain prior to the storm and the soil was already saturated. Combine that with 130-plus mph winds, it caused uprooting.”

Powell said his crew found trees with 30-foot root plates that were pulled from the ground.

“The trees were huge,” he told.

The guideline used by Powell is that if 30 percent of the trunk is decayed, they would recommend it comes down, particularly near a target like a school or building.

“Trees such as the Cuban laurel, banyan trees and ficus took a beating during Irma,” said Powell. “Especially those that weren’t pruned well.”

Another major cause of tree damage during Irma were lightning strikes Powell said.

Palm trees looked as if they had exploded, and stronger, hardwood trees were left with staggering cracks down the middle.

Some trees can survive these strikes, though usually weakened internally and susceptible for future decay, you just need to monitor its growth following the event.

Poor maintenance of trees prior to big weather occurrences can lead to a higher possibility of damage or death.

“Proper pruning and trimming of trees helps a lot. It gives more air the opportunity to flow through the crown of the tree,” Powell said.

Other steps you can take to prepare your tree is to mulch around the trunk or base.

“Proper mulching can help. It wakes up the soil to mulch around the base,” he advised.

People can often overlook the trees in their area, more notably the condition of those trees.

“People don’t always look up, they really should,” Powell said.

Being unaware of “zombie” or already clearly dead trees can be a costly mistake.

A few months back, two journalists were killed by falling trees during post-storm coverage in South Carolina.

Powell’s team took part in Storm Restoration Pruning after Irma, where they inspected trees across Lee County, among others, to check for limbs that could compromise trees and to keep as many energy-producing leaves as they could.

If you are in need of tree removal, or are unsure about the status of your tree, Powell said to call a Tree Care Industry Association accredited company, such as Davey, or a International Society of Arboriculture certified arborist.

For inquiries to Davey about tree removal or services, call 866-244-8014 or visit www.davey.com/local-offices/southwest-florida-tree-service/.

Connect with this reporter on Twitter: @haddad_cj