To Build a Fence

Protecting Maui’s native forests takes grit, determination and a lot of digging
Story by Kyle Ellison. Photos by Matt McDonald.

High on the slopes above Launiupoko, Daniel Tanaka is crouched in a ravine, eating poi from a bag. The bright orange shirt he donned this morning is drenched with sweat, and he’s managed to find a patch of shade to escape the relentless sun.

It’s lunchtime for the Mauna Kahalawai Watershed Partnership’s fence-building team, who for the past three hours have been hiking through brush and pounding posts into the dirt. It’s grueling work that involves a forty-five-pound post pounder, and hammering the posts leaves their fingers bruised and their muscles knotted. The rock drill and generator required to make post holes in rocky sections rattles their bones, but it’s all in a day’s work when you’re fighting to protect West Maui’s native forests.

Above three thousand feet on Mauna Kahalawai, a.k.a. the West Maui Mountains, a diverse and comparatively intact native ecosystem helps to capture water from the clouds and keep it in the ground. The summit, Pu’u Kukui, is one of the world’s wettest spots, with rainfall totals that annually average just shy of four hundred inches. All that water feeds sixteen streams and fifty-three smaller channels, accounting for over twenty-five billion gallons of water each year.

Considering that Maui gets 77 percent of its municipal water from this area, these fence teams are doing important—one might say critical—work, because protecting the forests means protecting the water. When introduced ungulates—hoofed animals like pigs, goat and deer—roam these slopes freely, they destroy native forest by uprooting plants and spreading invasive weeds. These introduced plants, like strawberry guava, clidemia and tibouchina, will thin out the understory, contribute to runoff and prevent the water-shed from absorbing moisture. Even as far back as 1876, when Hawai’i’s King David Kalākaua signed the Act for the Protection and Preservation of Woods and Forests, people realized that hooves destroy forests —and that fences could keep them out.

That led to the creation of forest reserves over the course of the 1890s, and the prominence of proverbs relating to rain.”Hahai no ka ua i ka ululā’au,” goes one of them, “The rain follows the forest.” Although Hawai’i’s foresters understood the importance of protecting native habitat even then, they invested more energy in the fledgling timber industry than in conservation. Timber never took off in the Islands, and decades would pass before Island foresters shifted their focus toward protecting what’s already there: Hawai’i’s indigenous plants. 

Since the Mauna Kahalawai Watershed Partnership’s founding in 1998, the team has built over twenty-three miles of fence in West Maui’s forests. Creatively using the natural landscape (and trying to think like a pig), they strategically build fences along ridgelines and gulches where any ungulates, hikers or, recently, dirt bikers might enter the watershed. That often means walking for multiple days doing transects high in the mountains and trekking along ridges just a few feet wide, where in case of an accident help is miles away. It means clipping into harnesses and rappelling down valleys to build fences at hair-raising angles, and commuting to work in a helicopter that might—or might not—pick them back up.

There are only two ways to reach the job site on these remote areas of the mountain: by air or, more often, on foot.

If a storm rolls in when they’re up on the mountain and conditions are too poor for flying, they’ll need to hike their way out or hunker down for the night. A foot could punch through a rotting log infested with wasps, or at lower elevations they could bushwhack through thorns from invasive kiawe and blackberry. They could fall in a hole covered by uluhe ferns, stumble upon illicit drug camps or shiver for days in a sodden high-altitude field station. Then there’s the constant threat of falling boulders. That’s something that crew member Kainoa Marchello recently experienced, when a bowling ball-size rock missed his face by inches. 

Marchello trained in rappelling and ropes on O’ahu, but aside from his skill with a carabiner and line, he can rattle off the names of dozens of native Hawaiian plants. He knows all the names of invasives as well (both Latin and common), and at the team’s base yard in Olowalu, he lists about six or seven different seeds that could turn his boots from comfortable footwear to a catastrophic biohazard. The day prior, Marchello and a few of his fellow crew members had checked some fence lines in a remote area on the ridges above Kahakuloa. There are invasive plants on one side of the mountain that aren’t yet found on the other, so to ensure they don’t become a vector for transporting clusters of seeds, the team methodically decontaminate their gear. 

On the “decon” day between the Kahakuloa assignment and the trip up to Launiupoko, Marchello removes all the laces from his boots, which he cleans with a wire brush. He completely empties and cleans out his backpack, sprays his boots with isopropyl alcohol and repeats the procedure for any piece of gear that could potentially transport seeds.

To install the fences, crewmembers spend hours hauling supplies up the mountain, and then more hours pounding the posts into the ground.

The rest of Marchello’s crew, meanwhile, is power-washing the metal fences that the following day will be wrapped in a sling load and flown up the mountain by helicopter. Even though the fences are new, they’ve been shipped from parts of the Mainland, New Zealand and Hawai‘i Island, where the seeds and spores of foreign species could have made the trip along with them.

The fence is made of galvanized steel, which should last about twenty-five years, and each section of five-foot-tall fence weighs close to seventy-four pounds. The squares in the mesh are only four inches wide—so no baby piglet can squeeze through them—and a wire apron is laid on the ground so larger pigs can’t dig under.

Deer, however, can easily clear a five-foot fence. Two decades ago, when many of the forest reserve’s existing fences were placed on the mountain, four-foot sections were more than tall enough. But axis deer, which are legion across much of the rest of Maui, have recently been spreading westward—and that’s why Kama has the saw. 

Wearing a flame-retardant suit, Kamakani Palolo hops on the fence pile while holding a circular saw and proceeds to cut some fences in half amid a flurry of sparks. These two-and-a-half-foot sections will be affixed to the top of the five-foot fences, creating an effective barrier for deer. The good news is that pigs, goats and feral cattle have largely been cleared from the watershed, and the original four-foot fences are the reason they haven’t returned.

Fencing around the reserve is being heightened to over seven feet to keep out the axis deer that can easily clear the older, shorter sections. 

After the metal is cleaned and cut, next comes the math—calculating how much the crew can haul in the next day. They’ll have to load it on a trailer, then tow it up-hill to a landing zone where they’ll break it into piles less than seven hundred pounds, which is the maximum the helicopter can carry. They’ll mark each pile with bright pink flagging so the helicopter pilot knows which side of the fencing to set on the ground, and drops will be made every seventy-five feet for a total of six hundred feet of fence. You can see why the crew’s unofficial motto is “Pick it up, put it down, then pick it back up again.”

In an area with flat, friendly terrain, the team might be able to construct one hundred meters of fence in two days. When there are rocks that need drilling or cliffs that need rappelling, that distance could take a month. Given all the prep and variables, every meter of fence requires three to four hours of manpower on average. While the work itself is exceptionally physical—“The farther you build,” says field supervisor John, “the farther you hike the next day”—what’s perhaps more impressive is the observational skill the crew develops over time. They’re geologists who can tell which rocks are best for postholes; at other times they’re geographers, hiking through stands of head-high ferns with tablets in Ziploc bags, navigating by waypoints on Google Earth. Mainly, though, they’re stewards, both environmental and cultural, who develop relationships with some of the island’s most isolated spots.

Spend a day with the team in the field and they’ll tell you names of mountain peaks you didn’t even know had names, and excitedly stop every couple hundred feet to discuss a plant on the path. This watershed they’re working to protect is habitat for 147 rare species of plants—forty-nine of which are endangered—and there are more than two dozen plants with fewer than fifty individuals known to remain in the wild. One of those, Stenogyne kauaulaensis, is a flowering mint found in Kaua’ula—a steep, shaded valley in West Maui not far from the spot above Launiupoko that the team is currently fencing. Another, Cyanea kauaulaensis, is a recently discovered lobelia from the same valley. At last count it’s estimated there are only fifteen plants in the wild. These and around ninety-five other rare species are protected above the fence lines, and in the native montane bogs on the highest reaches of the mountains, there are over a dozen more plant species found nowhere else on earth.

Teams have performed measurements along narrow ridgelines and plotted thousands of waypoints in areas where very few people have ventured. These coordinates are crucial for locating fence lines that have been swallowed by the forest.

Hobdy’s naupaka is a plant named for Bob Hobdy, a retired Hawai’i forester who discovered numerous previously unknown plants over his decades-long career. In discussing the long-term effectiveness of fences, Hobdy says, “If you catch things early enough, the natural stuff can really come back in a pretty dominant way. But if you get there too late, it might never recover.” If you can protect the top of the mountain, you can “stop things,” he says, which is why the fence teams start at the peak and gradually work their way down.

The most sensitive areas toward the top of the mountain were fenced years ago, and the crews have worked their way down the slopes to the point where they’re now building a boundary fence like the one above Launiupoko. That elevation, around one thousand feet, has essentially succumbed to invasive grasses, although a few native species, like wiliwili, are still putting up a fight. 

Even on days when they’re just checking fences for breaks, corrosion and erosion, the team will hike downhill from the point where they exited the chopper. A single clidemia fruit, for example, can hold over two hundred seeds, which the team could easily get on their boots and inadvertently move up the mountain. 

Of the nearly fifty-thousand acres that the partnership manages, only about 20 percent is free of invasives—nearly all of it at the top. Entry to these areas, as you can imagine, is reserved for researchers and conservationists who carry the requisite knowledge to move through that sensitive environment without damaging it. “I’ve been doing this for thirteen years,” says Tanaka, “and I’m still going places I’ve never been before, just some really amazing spots.”

What’s more important to them than the privilege of seeing these protected places, though, is their sense that they’re preserving them for the future. “The work these guys are doing,” says Hobdy, “is really a big deal. For the higher spots it’s absolutely critical. There’s a lot of really cool stuff up there.”  HH