Hybrid planting, partnerships drive success in tropical forest restoration in Hawaiʻi

By Thomas Milligan (USAEC)June 7, 2024

Microhabitats
1 / 6 Show Caption + Hide Caption – The Hawaii Army National Gaurd environmental conservation personnel work with the University of Hawaii Hilo to develop hybrid ecosystem microhabitats within restoration plots. These microhabitats mimic the habitat requirements needed for the outplanting of the endangered Cyrtandra nanawaleensis plant within the Keaukaha Military Reservation forest. Hybrid ecosystems provide a greater degree of ecosystem resiliency and improve odds for recovery. (Photo Credit: U.S. Army Photo) VIEW ORIGINAL
Training area for Soldiers and landing zone for helicopters
2 / 6 Show Caption + Hide Caption – This 20-acre training area for soldiers and landing zone for helicopters was once full of invasive grasses, shrubs, and trees making the area unusable for military training. This site is now maintained in-house by the Hawaii Army National Guard environmental conservation team allowing for multi-use training. (Photo Credit: U.S. Army Photo) VIEW ORIGINAL
Training Sites
3 / 6 Show Caption + Hide Caption – Areas once cleared by contractors, and goat/sheep grazing are now maintained in-house by the Hawaii Army National Guard environmental conservation team with the use of mechanical clearing, which reduces the spread of invasive species, the use of pesticides, and costs. The restoration work, in terms of reforestation, native plant propagation, and clearance of invasive species, has direct benefits to the HI ARNG training mission. All of these activities, conducted in concert, create open forest understories that can be used for land navigation and other dismounted training; without the NRC program’s efforts, much of these training sites would be so overgrown as to be impassable. (Photo Credit: U.S. Army Photo) VIEW ORIGINAL
Hawaiian hawk
4 / 6 Show Caption + Hide Caption – State-listed endangered Hawaiian hawk (Buteo solitarius) perched on a tree branch located along a restoration corridor developed by the Hawaii Army National Guard environmental conservation for training. The Hawaiian hawk was delisted as an endangered species in 2021 (though still a state-listed species), but the Natural Resources Conservation Program continues to protect habitat for the bird and is assisting U.S. Geological Survey in a five-year monitoring program. Reforestation and invasive vegetation control directly benefit the rare and unique wildlife that depend upon HI ARNG installation habitats. (Photo Credit: U.S. Army Photo) VIEW ORIGINAL
Tree Planting
5 / 6 Show Caption + Hide Caption – Polynesian introduced kukui tree (Aleurites moluccana) out-planted by University of Hawaii Hilo student volunteers on Earth Day. More than 2,000 trees have been out planted at Hawaii Army National Guard training sites since 2022. Through partnership with One Trillion Trees, the Natural Resources Conservation Program and HI ARNG have also been positioned to provide knowledge and literacy around forest stewardship for the broader community. (Photo Credit: U.S. Army Photo) VIEW ORIGINAL
Cllimate-resilient hybrid forests
6 / 6 Show Caption + Hide Caption – A variety of endemic and Polynesian-introduced trees out-planted within restoration areas at Keaukaha Military Reservation. The kukui (Aleurites moluccana) tree, a Polynesian-introduced tree, is the official tree of the State of Hawaii for its variety of uses and the symbol of enlightenment. These plantings are part of the broader implementation of a project to establish climate resilient hybrid forests on the islands, with a blend of native, endemic, and Polynesian species that will achieve carbon sequestration goals. (Photo Credit: U.S. Army Photo) VIEW ORIGINAL

Battling direct threats to fragile native ecosystems while simultaneously working with partners on ambitious replanting projects are just two of the programmatic successes of the Hawaiʻi Army National Guard and its Natural Resources Conservation team.

The HI ARNG NRC team was awarded the Secretary of the Army Environmental Awards Program Natural Resources Conservation, small installation category for this work and for exemplary conservation efforts.

Craig Blaisdell, HI ARNG natural resources supervisor who oversees the NRC program, said that in all, the HI ARNG has more than 1,300 acres of tropical environment training areas and facilities, and that this acreage has improved ecosystem vitality, but also added land available for training purposes. Blaisdell said while the training areas include many diverse ecosystems, the main challenge in each has a common thread.

“Throughout all the training sites the most consistent challenge has been eradicating invasive and non-native species that continually threaten precarious ecosystems and impede training access, while simultaneously reestablishing thriving forest systems,” Blaisdell said. “To that end, our NRC program has implemented a multi-faceted approach that has focused on hybrid habitat creation over the past two years. As a result, among training lands where every acre is precious, the HIARNG is achieving holistic benefits at the ecosystem level that enhance training capabilities.”

“I am very proud of the work and accomplishments of our Hawaiʻi Army National Guard’s NRC team,” said Brig. Gen. Stephen Logan, HI ARNG commander. “By eradicating invasive plants and establishing resilient hybrid forests, we’re protecting the native ecosystem and preserving our training area. It’s a true win-win that adds value to our overall readiness.”

Blaisdell said that using multi-faceted approaches is necessary in the complex tropical environment, and the team has embraced the approach. The hybrid planting focuses on establishing resilient hybrid forests on the islands, with a blend of native endemic, indigenous, and Polynesian introduced species that will achieve carbon sequestration goals. Scientists at the University of Hawaiʻi, Institute of Pacific Islands Forestry USDA Forest Service, and Stanford University were instrumental in developing the hybrid approach, which HI ARNG began implementing two years ago.

This replanting program is part of HI ARNG’s cooperation with the One Trillion Trees project, an international effort designed to help battle climate change. In addition, the NRC is using these hybrid planting strategies to deal with the extensive loss of the native ‘ōhi‘a trees to disease -- replacing the threatened native species with a more sustainable ecosystem of plants.

Blaisdell said the NRC team joined several partners in the Liko Nā Pilina project (which translates to budding of new relationships) to help track and battle the Rapid ʻŌhiʻa Death (ROD) fungal disease, a threat to native ‘ōhi‘a trees and the tropical canopy they help to create. The team, working with the university and Liko Nā Pilina partners, created a propagation program growing trees for out planting at the installation and achieved 90% survival rates one year after planting and increased seedling recruitment by the native species.

“University of Hawaiʻi researchers and students assist with the propagation and planting of seedlings for the installation and maintenance of restored forest stands. The U.S. Forest Service and U.S. Geological Survey have assisted in monitoring for the ‘ōhi‘a disease and in addressing the invasive species impacts that occur,” Blaisdell said. “These close working relationships help maintain the HI ARNG’s regulatory compliance as well.”

Another group of invasive species that pose a threat at the installation are plants like the longthorn kiawe, albizia and miconia, which can cause habitat degradation for the endangered Hawaiian hoary bat and native bird species. The invasive plant species crowd out the natural habitat and vegetation that these native species rely on.

“The Big Island Invasive Species Committee and the Kauaʻi Invasive Species Committee have been critical partners in targeting these invasive species and preserving habitat,” said Blaisdell, adding that these partnerships and others will be reflected in a five-year update of the installation’s Integrated Natural Resources Management Plan that will begin next year to build on the success of past efforts.

“The invasive species and ‘ōhi‘a preservation proactive programs have allowed us to monitor the ecosystem and after many years of concerted effort, we have been able to wind down the intensity of invasive plant eradication,” Blaisdell said, "including a major reduction in the use of pesticides needed to control the invasive species.”

“Hawaiʻi Army National Guard has a beautiful tropical setting, and our Natural Resources Conservation team has built both the plans and the relationship to protect and preserve the ecosystem, which in turn has created more land availability for military training opportunities,” Blaisdell said.