After back-to-back summer fires, Kula community tries to ‘wipe out’ invasive wattle and restore landscape

KULA — Standing at the edge of a gulch in Kula where a wildfire ripped through on Aug. 8, 2023, the same day another fire destroyed much of Lahaina, Dave Albright surveyed the clusters of black wattle trees lining the steep banks. 

“Welcome to Australia,” he said. 

The invasive tree native to the Land Down Under has proliferated across Kula since its introduction to the islands more than a century ago — and especially in the gulch where several homes along the ridge burned down in 2023. The wattle is a fire-adapted tree that sucks up all the moisture in an area, taking water away from other plants. It also burns well and makes for long, slow-smoldering firewood.

Now, after back-to-back summers of major fires that burned more than 1,000 acres and 26 structures in 2023 and nearly 600 acres in 2024, a local nonprofit is working to clear a buffer between homes and newly grown stands of wattle before the dry summer season arrives. 

Sara Tekula, executive director of the Kula Community Watershed Alliance that’s spearheading the “Wipe Out Wattle” initiative this month, said it’s about more than just reducing the threat of fire. She said it’s about bringing back a landscape where native species can thrive once again.

“There’s an ecological identity of Kula. Right now, it’s Australian,” Tekula said. “You turn it back to Hawai‘i, the trees become sponges in the landscape. They hold the water. They tell fire, ‘Yeah, good luck.’ It doesn’t mean there won’t be fires. It just won’t be like what we had.”

WATTLE OVERSTAYS ITS WELCOME

On a recent cloudy afternoon in Kula, Ian Sherman stretched a long, weighty pole saw over the edge of the Pōhakuokalā Gulch to reach the leafy branches of a young black wattle tree, one of dozens that have regrown since the fire. While hooked securely into a harness to brace himself on the steep slope, Sherman carefully cut down the tree a couple feet at a time, leaving the stump to keep the soil stable. 

Sherman, a conservation guide with zipline operator Skyline Hawai‘i, is on the front lines of the effort to create a buffer between dozens of homeowners and the wattle trees that helped fuel the 2023 major Upcountry fire. The project is focused on 15 acres of gulch terrain along the border of 46 burned properties. 

“We’re trying to reduce a fire hazard by cutting the trees away from the homes that are here,” said fellow conservation guide Elena Pray, who kept a watchful eye on Sherman. 

Skyline Manager Joe Imhoff, Tekula’s husband and the project manager for the watershed alliance, said about 20 property owners on the north side of the gulch have signed up for wattle clearing, and crew members worked on seven or eight properties last week. He’s hoping to get even more property owners on board. Now is the time — these wattle trees are younger, and most haven’t developed the seed-bearing flowers that will make them even harder to root out.

“There’s a lot more of a future risk if we don’t do anything right now,” Imhoff said. “Because the wattle forest that’s going to grow back is going to be way, way, way more dense than the wattle forest that burned.” 

Like many invasive species, black wattle was brought to Hawai‘i in hopes that it would prove useful before it started taking over the landscape. 

In the late 1800s, there was lots of interest in planting wattle as a shortage of European tanning materials drove the search for alternatives to the valonia oak. In Hawai‘i, Australia and South Africa, wattle was seen as a quick way to get large profits, and “a considerable amount of seed was secured and distributed throughout the islands, so that now there is hardly a district where full-grown specimens of this tree can not be found,” stated a 1906 report by the Hawai‘i Agricultural Experiment Station.

Now considered a noxious weed in Hawai‘i, black wattle has become so widespread that it’s no longer a target of the Maui Invasive Species Committee, which has to put its resources toward invasive species that it can control, said Lissa Strohecker, public relations specialist with the committee. However, the experts still recommend that property owners keep it in check.

The tree is adapted to fire and grows fast, with hardy roots and “a fairly long-lived seed bank” that has allowed it to come back strong in the Kula burn zone, Strohecker said. In fact, the seeds “readily germinate after fire,” according to the Hawai‘i Invasive Species Council. 

Steve Anderson was an ecologist for more than 30 years with the National Park Service, including Haleakalā National Park. On the balcony of his home, which survived even though his neighbor’s home did not, Anderson said that the gulch used to be lined with kikuyu grass, but as axis deer chewed it down, wattle took over. 

Wattle likes disturbance, which is why it grows so well on the steep, rockfall-prone slopes, Anderson said. It pushes out other species by putting a chemical in the soil that prevents other plants from growing around it, and by using up all the water in the area, unlike native species such as koa that help direct moisture back into the earth. The tree also contains a resin, essentially its own fuel, that helps it burn, Anderson said.

The Olinda and Kula fires had some of the worst soil burn severity compared to the other fires that broke out on Maui and Hawai‘i island that same day. According to a September 2023 report by multiple federal agencies and the state, 16 of the 330 burned acres in Kula and and 14 of the 1,486 burned acres in Olinda experienced high soil burn severity. The fire burned deep into the volcanic-ash derived soils and left some areas with no cohesion or strength. By comparison, the much more destructive Lahaina fire had 1 acre with high soil burn severity. 

Tekula said that much of the burn scar in 2023 “was just pure wattle forest.” She remembers hiking through the incinerated remains of trees that “felt like hot talcum powder.”

When the flames had died down and residents were accounted for, the community started thinking about rehabilitating the land and stopping wattle from taking over again. On Aug. 30, 2023, Tekula and about 40 others impacted by the fire gathered at Skyline’s zipline property on the slopes of Haleakalā where the company has spent years pushing out invasive species. 

When Skyline first opened on Maui in 2002, there was only one native tree on the property, and wattle and eucalyptus dominated the forest, Imhoff said. In 2008, he started coordinating the company’s conservation efforts, and “I basically planted as many trees as he would let me buy with a company credit card.”

Schoolkids, church groups and other volunteers helped plant more than 28,000 trees over time, Imhoff said. When they ran out of space for native plants, he got a chainsaw and started cutting down the invasive trees, using the logs to stabilize the soil and the branches as mulch to suppress the weeds.

Encouraging signs began to emerge. In 2015, Imhoff spotted an ‘apapane, a native honeycreeper, drinking nectar from a sandalwood tree they’d planted. In 2023, there was a new spring bubbling up from the ground in the absence of the thirsty wattle trees. 

To date, Imhoff estimated they’ve restored about 15 acres to 100% native forest. During the pandemic as tourism halted, Skyline’s crew members were trained in conservation and invasive species removal and now contract out their services to the community.

When the group of residents visited Skyline after the fire, Imhoff took them through trees planted five, 10 and 15 years ago to show what the burn areas of Kula could look like if replanted and cared for properly. 

Under canopies of native koa trees, ʻōhiʻa, sandalwood and ‘a‘ali‘i, the Kula Community Watershed Alliance was born. 

“I’ll never forget the feeling driving home that day of excited butterflies,” Tekula said. 

ROOM FOR THE NATIVE PLANTS

With a team of advisers that included Anderson, and a council of neighbors led by Albright, the alliance took on four main objectives: stabilize, protect, restore and maintain the area in the burn zones and beyond. 

This involves putting wood chips and other erosion barriers into the soil, installing fencing around the burn scar, reducing fire risks like wattle, partnering with homeowners to do “early and often” maintenance of the landscape, and growing native plants from local nurseries with Kula genetics that are meant to thrive in the area.

“We want to be as true to what was here before as we possibly could be,” Tekula said. 

Their first project helped stabilize the hillside of the Kula Sandalwoods Cafe and Inn, whose property was damaged by the fire. The alliance removed the fallen trees, mulched them and spread the chips onto the landscape to help prevent soil from “just sheeting off” during heavy rainfall, Tekula said. As the chips decompose, they also help rebuild the soil. On the steep hillside, the family that owns the cafe and inn planted a new sandalwood tree.

The watershed alliance is backed by $300,000 from the U.S. Forest Service for fuels reduction and planting shaded greenbreaks, with $25,000 being used for the current work; $25,000 in matching funds from HydroFlask, which is going towards invasive species removal and watershed restoration and is part of a larger, $80,000 two-year grant; and $5,000 from the Hawai’i Wildfire Management Organization for community wildfire mitigation.

The federal government also has a project to clear gulches from burnt debris and dead or dying trees, but project delays have left some residents frustrated, including David Chevalier, who said he’s lost “huge swaths of soil” to major rainstorms since the fire. He is currently setting aside a portion of his land as a test plot for stabilizing soil with logs, mulch and native plants.

Putting more plants in the ground is a key part of the long-term vision for Kula. The alliance has been providing seeds to local residents to help grow native trees that can be replanted in the burn zone one day. They hope to open a nursery soon that will allow them to store trays of seeds, lend tools to the community, and grow everything from sun-loving plants like koa to darker, understory plants like ferns.

Some of those seeds made it to the Kula property of Albright and his wife Pam, who brought home plants to foster after a seed-collecting walk with the alliance in December. That soon grew to hundreds of koa plants, and the couple was working with 10 native species at one point. Some of their koa trees have already been planted back into Kula’s landscape. 

“There’s a process, and it takes time,” Dave Albright said. “It’d be nice if we could just fix this tomorrow, but it took a hundred years to screw this up. … It’s going to take a while to fix it.” 

Once the wattle trees are cleared along the gulch, Tekula said they will start putting plants in the soil. They’re waiting for the summer to pass so they can plant the trees right before the rainy season and give them the the best chance at survival. 

“It’s hard and we’re fighting all these crazy battles with invasives and with red tape and all these things, but the alternative is not OK,” Tekula said. “And every little bit that we get to succeed and get to come see things growing makes it all worth it.”

Imhoff said one of the most important lessons he’s learned from years of restoring native forest is to “kilo,” to really observe the land and have patience, he said. He learned the hard way what can happen if he rushed to put plants in the ground before the soil was stable. But, he said, if you chip away at it, eventually the work gets a little easier every year. The weed control takes less effort. The wattle regrowth slows. And, eventually, the native species can take over again. 

“If we’re going to do it right, we have to continuously bring in resources to make it a successful reality that’ll benefit future generations,” Imhoff said. “So once you start, you’re committed.”