Why Hawaii Is Burning Its Massive Mangrove Trees

The mangrove forest in He’eia, Hawaii.
The mangrove forest in He’eia, Hawaii.
Photo: Courtesy of Kanekoa Kukea-Shultz

All over the world, from Florida to Thailand, efforts are underway to restore mangrove forests. These ecosystem have been in serious decline for the last 10 years, and sea level rise is set to threaten them further. In Hawaii, however, heavy efforts are underway to eradicate the trees.

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In fact, the islands might be the only place where ecologists are trying to permanently remove mangroves. They’re invasive here—and they’re pushing out native flora and fauna that have called these islands home for much longer than the mangrove has.

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Seeing the towering trees along the eastern coast of Oahu in He‘eia, Hawaii, for the first time, was an awe-inspiring experience. While the tallest mangroves exist in the African country of Gabon and along the Pacific coast of Colombia, Hawaii’s red mangroves are definitely impressive.

But that doesn’t mean that the mangroves belong there. In fact, these trees came over in the early 1900s with the sugar industry, which hoped they’d help retain sediment during the heavy rains. Sediment retention is kind of the mangroves’ thing elsewhere, but that hasn’t necessarily been the case in Hawaii. Some research has shown that in the Hawaiian ecosystem, the trees function differently, sometimes even releasing additional sediment into the water, said Rob Toonen, a researcher at the Hawaii Institute of Marine Biology, to Earther.

“The belief that they are helping to trap sediments is simply that: a belief and not a fact,” said Toonen in an email.

Now, the trees dominate the ecosystem in this part of Oahu, and in other parts of Hawaii, from the Big Island to Maui.

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In He‘eia, groups have been working since the ’70s to restore native wetlands. But removing invasive mangroves has really ramped up since last year as part of a greater effort to restore the region’s estuary system. None of the researchers or community leaders I spoke with were familiar with any other effort anywhere in the world to get rid of mangroves.

“To my knowledge, every other place in the world dealing with mangroves, they’re trying to restore, not remove them,” said Kawika Winter, the reserve manager for the Heʻeia National Estuarine Research Reserve where this work is taking place, to Earther.

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How the area looked before the towering mangroves existed.
How the area looked before the towering mangroves existed.
Photo: Courtesy of Kanekoa Kukea-Shultz

As Ken Krauss, a research ecologist with the Wetland and Aquatic Research Center at the U.S. Geological Survey explains, the mangroves cause a host of problems in a region where Hawaiians are working to restore traditional methods of food production and bring ecosystems back to what they were like before the colonial period.

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“[The trees] sort of degrade native Hawaiian artifacts like fish ponds and break up the rocks
,” Krauss told Earther. These invasive organisms also keep native bird species like the Hawaiian stilt from nesting in the wetlands.

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And so in He‘eia, the mangroves are now being burned and chopped down. The tops and bottoms are burnt while the middle chunk is recovered. That way, all that biomass isn’t spewing dirty emissions into the air, either.

The community groups collaborating with the National Oceanic and Atmospheric Administration on this effort still have a ways to go to bring the system back to what it was, but they hope that the region will be mangrove-free within the next few years.

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The removal process in progress.
The removal process in progress.
Photo: Courtesy of Kanekoa Kukea-Shultz

As for the wood that get removed? Workers are recovering it to sell. They’re not letting the trees go to waste.

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In the mangroves’ place, the community is planting taro and native wetland shrubs instead to help feed residents and filter sediment the way the land traditionally has. That way, local birds and other fauna can return.

Just because something is beautiful doesn’t mean it’s necessary. Sometimes, beauty can be destructive.

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Yessenia Funes is climate editor at Atmos Magazine. She loves Earther forever.

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DISCUSSION

dnapl
Dense non aqueous phase liquid

Let’s dig a bit deeper, shall we?

The Hawaiian islands are pretty much a built environment controlled mostly by special interest and extremely wealthy folks, depending on the island at this point in time. And of course mother nature lets everyone know we’re all her bitches every so often. The islands have a who’s who of tech titans owning lion’s shares of several islands. Hell, even Bette Midler is a major landowner from maybe all that Beaches royalties money. And of course major food group families still own shitloads of the land, thusly giving Hawaii a political structure not too different than say Iowa or Illinois. Just hipper in appearance given the whole surfing and tropical paradise thing. And Hawaii interest groups have much cooler marketing -say from nonprofit environmental communications outlets funded by big donors interests’ like Grist. Big money also funds a lot of research to get their “right answer.” Even academics can become whores.

Invasive species can either fuck things up or eventually fall in line with ecological system equilibrium. Given 7.4 billion people and climate change, pretty much every native ecological system will be getting fucked up, if it already isn’t.

Industrial agriculture companies planting mangroves 100 years ago is not necessarily less impactful to the existing native ecology than a flock of birds driven off course during a storm and taking a dump full of mangrove seeds on the shores a million years ago.

Here’s a nice paper from USFS published in the 1990s on this topic:

Mangroves as alien species: the case of Hawaii

The paper’s conclusion: on balance, they’re doing more good than bad. Further study is needed.

For some reason I’m getting triggered on who it is that doesn’t like mangroves. It’s like the age old argument of landscape architecture for resorts and golf courses. It would be better to design in natural riparian vegetation, like cattail, instead of manicured lawns up to the water’s edge. The paying customers however likes the look of the manicured lawn for ball retrieval and wedding party photoshoots. The customer is always right.