Even trees need protection from a storm

by Donica Kaneshiro | Sept. 20, 2021

Back when I was a kid, every time a hurricane was coming, my grandma used to worry about a branch from the huge mango tree in the front yard damaging her Kaimuki home.

I remember her seeking out a tree trimmer to thin out the canopy to lessen the chances of wind damage.

It turns out that grandma’s attempt at hurricane prep was misguided. Fortunately, no damaging winds ever battered the tree, but it’s a misconception that many people still hold today.

Desireé Page, Hawaiian Electric system arborist, explained that it’s impossible to predict which trees will become an issue in high winds without visible signs of structural weakness.

“When you start getting high winds and you start getting strange wind patterns, such as swirling… and trees and branches are exposed to forces that they have not grown to sustain, in extreme weather, even healthy branches will fail, and whole trees,” Page said.

However, preemptively pruning trees to prevent wind damage is counterproductive, she said.

“Research has shown that leaves, twigs, and branches actually act as force dissipators,” Page said. “And if you thin them out preemptively to try to prevent whole tree failure in a wind event, what actually ends up happening is you make it more likely because the trunk itself ends up facing more wind force.”

Instead, year-round preventative maintenance is a more effective plan both in your yard and for Hawaiian Electric crews who inspect trees daily for structural defects and dead wood, while pruning trees to keep lines clear. (Read this blog to learn more about how our Vegetation Management crews train branches to grow away from power lines.)

“So when storms happen, we’re already prepared,” Desiree said.

Once a storm is on the way, Page recommends checking around your house and yard to make sure loose branches and gardening tools are cleaned up and secured. “Just make sure there’s nothing that can become a projectile,” she said.

In recent years, invasive Albizia trees have been the source of a lot of damage during storms in the islands.

Albizia trees grow about 12 to up to 20 feet a year, so you get really long branches with weak attachments, Page said.

“So as soon as they go into seed or it starts to rain, whenever a little weight is added to the end of the branch, the whole branches fail and it’s very destructive,” she said.

Page said she highly recommends that people become familiar with what Albizia looks like when it’s small and get rid of these trees as soon as they take root, as well as removing larger Albizia trees.

“The longer it’s there, the higher your chances are of having a serious failure that leads to some serious damage,” she said.

“But ultimately, when you hear a storm is coming, when we know for sure and it’s time to bunker down, it’s time to start boarding up your windows. Not worrying so much about the tree because the chances of you being able to prevent whatever could happen in those moments is little,” Page said.

Once the storm has passed, don’t try to clean up storm damage around lines. It’s impossible to know which lines may be energized, so you should treat all lines as if they are conducting electricity.

If there is a tree or a branch in contact with lines, call Hawaiian Electric at:

• Oahu: 1–855–304–1212 (toll free)
• Maui: (808) 871–7777
• Molokai and Lanai: 1–877–871–8461 (toll free)
• Hawaii Island: (808) 969–6666

Hurricane season runs through Nov. 30, so now is the time to consult with a certified arborist if you are concerned about a tree in your yard.

An expert may have been able to give grandma better trimming advice and peace of mind about her mango tree when storms approached.

Donica Kaneshiro is a communications consultant at Hawaiian Electric Company.