Fight for the forest

At the very end of Manoa Road, after the paved asphalt narrows and fades as it meanders into the lush valley, sits an unassuming greenhouse where university researchers are working to revive hundreds of native plants on the brink of extinction.

“Most of what’s in here are actually extremely rare species — critically endangered species that are federally listed as endangered or state listed as endangered. And a lot of them actually have less than 50 individual plants remaining in the wild,” said Marian Chau, who manages the Seed Conservation Laboratory at Lyon Arboretum, a research unit of the University of Hawaii.

The newest arrival to the greenhouse: ohia lehua seedlings.

Considered vital to the health of Hawaii’s native forests and highly regarded in Hawaiian culture, the trees are under attack on Hawaii island by a newly identified fungal disease dubbed rapid ohia death. Officials say the disease, which can kill off a tree within a few weeks, has the potential to wipe out ohia trees statewide.

The trees — often studded year-round with vibrant red blossoms — cover more than 1 million acres of native forests. State officials said last month that the aggressive disease had spread to 34,000 acres of ohia forest on Hawaii island, more than double the acreage researchers had estimated earlier using satellite images collected in 2014.

“What’s at stake is basically our native forest in Hawaii,” J.B. Friday, a forester with UH-Manoa’s College of Tropical Agriculture and Human Resources, said in an email.

“Ohia comprises about half the forest area in Hawaii. All the other forest trees such as koa, mamane, naio, kiawe, eucalyptus, and koa haole together comprise the other half,” he said. “More importantly, the native ohia forests protect our most important watersheds, especially at the higher elevations where we have more rainfall. No one knows the effects if we have large-scale mortality of ohia but it can’t be good.”

Sheila Conant, a retired UH-Manoa biology professor, added that small native forest birds like the iiwi and the apapane get all of their food in the ohia forest — from nectar in the flowers to insects and other invertebrates in the leaves, branches and bark of ohia trees.

Friday said pesticides aren’t a viable option to kill this disease.

“It is not practical or environmentally possible to manage large-scale forest diseases such as this one through the application of pesticides,” he said. “No one is going to fly crop dusters over the forest spraying fungicide. In the short term, we are trying to limit the spread of the disease by public outreach. In the long term, the best hope is to find multiple resistant strains of ohia to restore forests in high-quality native ecosystems.”

That’s where Chau’s laboratory wants to help.

Chau and seed lab technician Tim Kroessig are working to protect ohia species through a method known as seed-banking, or preserving seeds for future use. The program already has in storage 12 million seeds representing more than 500 mostly rare species.

“Rapid ohia death is a serious threat but we’re hopeful we’ll be able to use these seeds for restoration once the threat has passed or by using resistant seeds in reforestation efforts,” said Chau, who earned her doctorate in botany from UH.

In general, the process involves drying down seeds to 5 percent to 8 percent moisture content, then heat-sealing them into foil packets that are then stored in a freezer or refrigerator, where they can remain healthy for at least a couple of decades.

“We’re probably looking at millions of seeds that would be in storage,” Chau said of the ohia project. The tree produces tiny crescent-shaped seeds — about 10,000 could fit in the palm of your hand — in little pods.

This weekend, Chau launched an online crowdfunding campaign at gofundme.com/ohialove with the aim of raising $35,000 for the effort. The Seed Conservation Lab’s work, part of the arboretum’s Hawaiian Rare Plant Program, is funded mostly through federal, state and private grants. The university covers its facilities and utilities, but doesn’t provide funding for personnel and supplies.

Funds raised would be used to collect seeds from Hawaii island, from areas at risk and from populations or individual trees that might be resistant to the disease, Chau said. (It’s not clear if the fungus infects the plant’s seeds, but all seeds will be treated before being brought back to Oahu.) The funds also would cover costs to collect ohia seeds on Oahu, which is home to three endemic species of the tree, as well as storage and viability testing.

“Seed banking is a really efficient and effective way to store a lot of genetic diversity of a plant,” Chau said. “That’s why we want to use this method to do our part to help to conserve ohia during this crisis. Hopefully if we preserve that genetic variation, and we preserve enough of it, then the plants that we plant out in the future will have more adaptability to these types of threats.”

The threat poses not only environmental and ecological dangers but cultural risks as well.

UH-Hilo Hawaiian studies professor Kalena Silva said ohia lehua is respected in Hawaiian culture for its spiritual, physical and cultural aspects.

“It really is an extremely important part of traditional Hawaiian thinking and perspectives,” Silva said. “Up until our very day, we see the value of the ohia lehua through the many songs — some of them ancient, some of them modern — that have to do with not only the beauty of the ohia lehua, but the importance of the tree itself.”

Silva said the plant’s name also appears in the names that Hawaiians have for different winds and rains. “For example, the famous rain of Hilo is the ua kani lehua — the rain that makes the lehua sound as it falls on the flowers and the leaves,” he said.

“Almost everywhere you look, we see how important it is to Hawaiians,” Silva added. “So the idea that there is something that might decimate the population of lehua in the wild or that might completely obliterate the lehua is unthinkable. It’s just impossible, really, to think about a Hawaiian culture without the ohia lehua.”