Defending the Watershed

"What we’re protecting right now is miniscule compared to what needs to be protected. We have big plans and aspirations, but without improving the technology, it’s a pipe dream.”

Trae Menard
Hawai'i Director of Forest Conservation

By Matt Vale

Ultimately this is a war. We are fighting a war against invasive species,” says Trae Menard, director of forest conservation for The Nature Conservancy of Hawai‘i.

Menard is faced with protecting the Conservancy’s 7,050-acre Wainiha Preserve, a crucial buffer zone one valley over from the precious heart of Kauai’s watershed, one of the wettest spots on earth and the primary source of the island’s freshwater supply: the 12,000-acre Alaka‘i wilderness. The Alaka‘i is among the most biologically diverse areas in the world, but also among the most threatened: amid other dangers, a non-native Australian tree fern invasion approaches up neighboring valleys, displacing native forest.

Tree ferns spread like wildfire, sending spores up to seven miles on prevailing winds blowing into the Alaka‘i. It’s extreme, rugged pali country, accessible only by helicopter — impossible to manage with ordinary boots-and-shovel conservation. Mere gardening can’t help the Alaka‘i, Menard says; we need “gardening 5.0.”

His strategies range from the sublime to the ridiculous: working with scientists and engineers, he’s developed innovative, remote-controlled, camera-monitored traps for feral pigs, a revolutionary aerial mapping technology to detect weeds across entire watersheds — and to remove invasive plants with precision, a low-toxicity herbicide delivered via a helicopter-mounted “stinger.” The absurdity isn’t lost on Menard. “It’s nuts, man.”

Conservation Warrior

These aren’t just Hawai‘i-specific strategies; Menard’s real goal is to develop technologies with global application. It’s all part of the Hawai‘i Conservancy’s new scientific raison d’être that Menard’s been central in shaping.

"We’re using our preserves as proving grounds to test and develop new technologies that will help everybody manage much bigger areas across the state, across the nation," he says. "So that is now our niche for Hawai‘i  — technology development.” Menard’s group is a think-tank and living laboratory, making watershed-level conservation possible worldwide, in any ecosystem threatened by invasives.

Menard’s innovating spirit comes from a passion for results: “When I was starting out my career, working in the field, I was constantly asking myself — ‘What impact am I having? Are we actually controlling this weed; are we actually improving this ecosystem?’”

Ever since, he’s been working towards protecting entire landscapes: since 2003, he’s led an alliance of Kaua‘i forest landowners whose mission is to protect the island’s 143,000-acre watershed. When he realized the severity of the tree fern infestation, he began using the Conservancy’s Wainiha Preserve as testing grounds for tide-turning technologies.

It’s a passion for the macrocosm: “What we’re protecting right now is miniscule compared to what needs to be protected," he says. "We have big plans and aspirations, but without improving the technology, it’s a pipe dream.” And to protect the Alaka‘i, Menard had to find a way to detect and remove Australian tree fern.

That got Menard and his team thinking: “Hey — we need a better way to map and monitor these ecosystems.” In 2006, they approached Resource Mapping Hawai‘i with their goal: to produce a photograph-based map detailed enough to identify individual weeds over thousands of acres of radical, cloudy terrain. It had to be done quickly and repeatedly to check their progress. And it had to be cheap.

“The mapping experts told me, ‘Well that’s impossible. There’s no way you can do that. There’s nobody in the world who can do that.’ And I said, ‘well…we need to do that.’”

High-tech Breakthrough

Photographing the forest landscape from the air, existing satellite technology could produce .5m sq. /pixel maps—“wholly inadequate,” Menard laughs: even the largest trees are unidentifiable, grey-green blocks. The challenge is orthorectifying: syncing 2D images with 3D computer models of Wainiha’s extreme topography. Menard’s pilot studies sharpened the technology to 7cm sq. /pixel. “But we still couldn’t see; it’s got to be better than 7cm.”

After two years, the team at Resource Mapping made a breakthrough — 2cm sq. /pixel. But Menard is insatiable: “Even 2cm resolution wasn’t good enough for the small-leafed [weed] species we’re after.” Since then, they’ve worked with an Israeli aerial imaging system developer to orthorectify images faster and quadruple image detail again—to 1cm sq./pixel.

Menard’s work hasn’t just helped the Alaka‘i—it’s pushed image-based aerial mapping technology to sharpen by 2,500 times. Throughout statewide studies, the team’s testing how well they can identify even shadowed plants on the forest floor. Besides Australian tree fern, Menard’s group can map kahili ginger, African tulip tree and Chinese albizia—they can collect the exact coordinates of every visible weed.

Controlling the Australian tree fern infestation was the next challenge. Given Kauai’s radical terrain, conventional ground-based methods such as walking and climbing to each individual tree fern were impossible, and broadcast spraying herbicide from a helicopter was out of the question; aside from harmful chemical runoff, weeds are often surrounded by healthy native forest. Kaua‘i needed what Menard calls “surgical weed control — individual by individual — but at scale.”

Herbicide Solution 

Using an ultra-low volume herbicide solution that can kill tree ferns with a minute application, Menard and his team developed an applicator system that hangs on a cable below the helicopter with a nozzle assembly protected from the rotor wash by an inverted cone. The pilot simply flies to each tree fern, places the nozzle directly in the center of the fern, squirts a tiny dose of herbicide and moves on to the next tree. The system, which delivers a precise and lethal application of herbicide, has been dubbed the “stinger.”

“The combination of the mapping technology with precise herbicide application at scale — it’s a comprehensive way to find, control, and monitor weeds in remote, inaccessible forests,” says Menard. They’re killing more weeds, faster, cheaper and with less manpower. And they can quickly remap to monitor how well the native forest recovers.

“There’s no system in the world that can do what we’re doing. And if we use it right, we can actually win.” Already, the “stinger” has eliminated more than 4,000 invasive tree ferns, about 90% of the infestation mapped in Wainiha; they’ve halted, even reversed the weeds’ spread into the Alaka‘i. Next, they’ll take on Lumaha‘i Valley — a tree fern hotbed.

And, more innovations are on the way: Menard’s Kaua‘i team is working with several companies to develop remote-controlled pig traps monitored by motion-sensing cameras. To make it all possible, they’ve contracted a telecommunications group to cheaply extend their cellular network coverage with small, mobile repeaters for Wainiha’s summits. “From our office, we’d be able to monitor the Alaka‘i, Wainiha Valley.”

The results reach far; his technologies promise application across the globe. It’s the radical, Menardian notion that we truly can, with enough labor and wit, bring imperiled ecosystems back.

“People say, ‘there’s no way you can map individual plants across a whole watershed — that’s impossible.’ We say, ‘Well, maybe not.’”



Stay Updated

Learn about the places you love and find out how you can help by signing up for Nature eNews.

I'm already on the list Read our privacy policy

Thank you for joining our online community!

We'll be in touch soon with more Nature Conservancy news, updates, and exciting stories.