Hawaiian Electric takes on threat of albizia trees

Oahu dodged a bullet when Hurricane Douglas skirted the island by just 30 miles on July 26 in a last-minute shift in course.

Memories have dimmed since Tropical Storm Iselle paralyzed the Puna district on the Big Island in 2014, taking nearly three weeks for power to be restored to 30,000 residents.

Iselle’s hurricane force slowed to tropical storm status on Aug. 7, 2014 when it struck Hawaii island, snapping hundreds of albizia trees like matchsticks. The massive canopy trees crashed into houses, knocked out power lines, blocked roadways with their thick trunks and trapped many residents.

In the months following Iselle’s devastating blow and through 2015, property owners across the island chain scrambled to remove albizias and other potentially hazardous trees that threatened homes and other structures, overhead lines and roadways in preparation for the next hurricane season.

But is Oahu ready for 70 mph tropical-storm-force winds, let alone a Category 1 hurricane with 74 to 95 mph winds? Have its residents been lulled into complacency with so many misses?

Iselle’s lessons

Hawaiian Electric learned a large lesson from Iselle.

“We’ve learned that albizia trees are a real threat,” Hawaiian Electric spokeswoman Shannon Tangonan said. “Tropical Storm Iselle caused significant damage to homes and infrastructure in the Puna district.”

“Fallen albizia trees and branches on power lines caused extended outages for many customers. Hawaiian Electric on Hawaii island worked with our partners to clear trees, assess damage, rebuild and repair damaged infrastructure, and restore power in less than three weeks.”

“We’ve put more resources into the Hawaii island vegetation management, especially after Iselle,” Tangonan said.

In 2019, Hawaiian Electric spent about $18.6 million on trimming or removing more than 360,000 trees across its five-island territory. It uses multiple private contractors to perform the work.

For 2020, it allocated $9.8 million for Oahu alone.

Hawaiian Electric also works closely with the Department of Transportation, which is responsible for maintaining trees along highways and freeways.

In August, the DOT was tackling several areas on Oahu, including the H-3 freeway, Vineyard Boulevard, Fort Weaver Road and the Likelike, Pali and Kalanianaole highways.

Hawaiian Electric has been working with Hawaii County and the state, including the Big Island Invasive Species Committee, to chip away at the problem, not only where invasive albizias are visible to the public, but in the forests and over mountains where power lines cross.

Greg Chun, who oversees Hawaiian Electric’s vegetation management, says the company partnered with the DOT to clear a lot of the main thoroughfares. “That allowed us to push back the canopy cover so that there’s basically no overhang in a lot of the big, main roadways. … They had to spend so much time to just cut a way to get in to the roadway.”

“For Oahu, we don’t have necessarily the same issues widespread,” Chun said.

“It’s localized in some areas,” Chun said, referring to the albizias. “We do what we can as far as albizias. We clear the ones near our lines, of course. We’re trying to reduce the future ones by cutting down the keikis before they get too big in places where we can.”

He noted the albizias are prolific. “It’s a double-edged sword,” Chun said. “If you cut a large one down, and you open up an area that once was seeded, now you have sunlight hitting these areas with hundreds of latent seeds. It starts that whole process again. Hopefully, if we try to get to the young ones, we slow that process down.”

Damage to electrical equipment can range from an overhanging limb that breaks, requiring removing a branch and a quick repair and restoration of power.

“It could be where the entire tree fails, and if it breaks the lines or damages the pole, we’re looking at an all-day affair for that one tree,” Chun said. “But multiply that across the island in the event of a storm and you can understand the magnitude of what we’re looking at.”

For Hawaii island. “It’s improved, but they’re still dealing with albizias. It’s always going to be a problem, but it’s more management.”

Is Oahu ready?

In comparison to the Big Island, Hawaiian Electric does more with regard to their lines on Oahu. “We do a lot more on a larger scale,” Chun said. “We can actually cut trees down in a lot of these cases when they’re small or medium sized. We’re not going to spend a lot of resources to remove just a few large trees.

“We make the best use of our resources and cover as much ground as possible. We remove all sorts of species that could potentially affect power lines crossing the mountains.”

As for Oahu’s hurricane readiness, Chun says, “We’re as good as we can be. We can’t really predict hurricane-force winds. The damage would be fairly extensive, not just on trees, but everything. To the extent possible, I think we’re fairly well positioned.”

The DOT has “been pretty active on the Pali, Likelike and the H-2,” Chun said. “They’ve killed a bunch of albizias” using herbicide.

Although it does not specifically target albizias, which are more prevalent on Hawaii Island, the power company says that the worst areas on Oahu are in Central Oahu and parts of Manoa and Palolo.

“Trimming and removal of trees near our power lines is a priority for Hawaiian Electric,” Tangonan said. “Year-round vegetation management protects our infrastructure and prevents outages. But our island grids are not storm-proof, no matter how much maintenance is done throughout the year.”

The company does not accelerate its schedule prior to or during hurricane season.

“(Our) most effective defense against storm damage is to consistently prune trees away from the lines throughout the year,” Tangonan said. “Jumping from spot to spot in an effort to predict where storm damage might occur would be less efficient.”

On Oahu, its trimming efforts are focused mainly in urban areas, but it also maintains rural and wooded areas and challenging areas where the lines cross over the Koolau Range and elsewhere.

Oahu’s residential areas have a variety of species of fruit and ornamental trees that could pose problems to electrical lines. In rural areas it’s a mishmash, which includes ironwood, Java plum, African tulip and octopus trees, Chun said.

Lot owners responsible

While Hawaiian Electric carries much of the burden of maintaining the overhead power lines, government and private property owners — big and small — are ultimately responsible for the trees and vegetation that could fall onto or grow into and entangle lines.

The company calls it “a shared responsibility between property owners and Hawaiian Electric.”

Chun encourages property owners to maintain their trees and vegetation or to remove them. “Once it gets too large, it’s almost too late,” he said.

The company does not advise customers to prune trees near their lines but encourages them to hire a line clearance-qualified contractor to do the work.

“Hawaiian Electric gets involved only when a tree is not maintained and grows into our lines, requiring maintenance to prevent outages,” it says.

“More likely than not, we will not take care of large, large trees,” Chun said. “We would not spend a lot of our resources with one albizia tree. That means we have less resources available to take care of the rest of the island.”

“We’re aware of many of the large trees,” he said. “I don’t see we can promise much.”

The City and County of Honolulu also maintains trees on its properties, along city streets and in its parks.

City Department of Parks and Recreation spokesman Nate Serota said the city will not address problem trees on private property such as albizias, which could pose a threat. Property owners are responsible.

However, during a tropical cyclone, city crews would be ready to respond to emergencies to clear trees and branches obstructing city roads, he said.

Act 13, which addresses albizia hazards on privately owned vacant property and was enacted in 2019, permits a property owner or agent to enter adjacent, vacant privately owned property with albizia to control the trees before they become hazardous.

BIG ISLAND EXPERT OFFERS ADVICE ON REMOVAL OF ALBIZIA TREES

Bill Buckley, the Big Island Invasive Species Council’s forest response program coordinator, addressed an online audience recently about albizias, which have brittle branches and shallow root systems and tend to fall over or break in wind events.

He reminded his audience how Iselle caused the invasive trees to block emergency access and cost the county in multi-millions of dollars almost entirely due to albizias, he said.

They grow 10 to 15 feet a year, and their seeds, which have wings, move well, are lightweight and tiny and are dispersed by the wind.

He pointed to an area near Wailuku that had just a few patches of the trees in 1993. In 16 years, they had multiplied into a forest covering 35 acres.

The Council’s approach is to have the electric company, the county and DOT pay arborists to trim back hazardous trees.

Then the Council and its volunteers move in and employ a “hack and squirt” method to remove the non-hazardous trees — those that no longer or do not pose a threat to infrastructure.

With a few chops of a hatchet and small applications of an herbicide, the trees defoliate, die and do not return, he said.

Extreme care and forethought should be used when applying this method. Once a tree is treated, it will begin to die, and will eventually drop its branches onto whatever is below such as a fence, house or power lines.

Arborists and contractors do not want to work under and around dying trees because they can be a hazard, Buckley warns.