MAKUA MILITARY RESERVATION, Hawaii -- In spite of the damp weather forecast, 10 O'ahu residents gave up a Saturday (Sept. 27) to help control invasive weeds in Kahanahiki, the northern Ahupua'a (traditional Hawaiian land division) of Makua Valley.
The native forest of Kahanahiki is home to several endangered species, including the haha, or Cyanea superb subsp. Superba, a plant that nearly went extinct in 1995. Fortunately, before the last five Cyanea died-off, staff from the O'ahu Army Natural Resources Program (OANRP), Directorate of Public Works, U.S. Army Garrison-Hawaii, were able to collect fruit from these plants, and later grow new Cyanea from the seed in the OANRP nurseries.
Today, hundreds of Cyanea have been returned to the Kahanahiki forest as staff and volunteers work to stabilize this fragile species by improving habitat and removing threats.
-- National Public Lands Day Honoree
The task for Saturday's group was to control the invasive downy wood fern, Cyclosorus dentatus, an aggressive fern that has begun to blanket the slopes around the endangered Cyanea. The weeding took place on the 21st Annual National Public Lands Day, the largest single-day volunteer effort for public lands in the U.S.
The project was selected as a recipient of a National Public Lands Day, Department of Defense Legacy Award, and staff from the OANRP used the award money to purchase new volunteer tools to support long-term restoration goals for this critical habitat.
-- Fieldwork
Like most days in the conservation field, the day began with a hike. Staff and volunteers traversed along a rugged, hot, mountain ridge trail for thirty minutes, transporting heavy packs filled with weeding tools, before dropping down into the shady gulch habitat of the Cyanea. The temperature difference and scenery change from ridge to valley was dramatic. The blazing sun from above filtered out through a multitude of tree layers, including a canopy of sixty-foot tall koa and kukui trees, shorter-statured mamaki (a native nettle tree), giant tree ferns (Hapu'u), and the stunningly beautiful Cyanea in full bloom.
"When you descend into the gulch and suddenly see the ten-to-fifteen-foot-tall endangered Cyanea," said Roy Kikuta, a regular volunteer with OANRP, "it just takes your breath away."
As Kikuta and many other volunteers took time to photograph the ivory blooms of the Cyanea, the group's collective gasp could be heard with the sudden appearance of the state insect, the native Kamehameha butterfly (Vanessa tameamea). Camera lenses quickly shifted focus to capture images of this beautiful red and black insect as it hovered around the numerous mamaki trees (the primary host plants for the Kamehameha butterfly).
"This area is wonderful," exclaimed Mokul?'ia resident, Kelly Perry. "The native plants, the Cyanea, the native butterfly -- it feels like an ecosystem.
These days, few people get to see native Hawaiian animals and plants interacting and we are seeing Kamehameha butterflies landing on mamaki before our eyes!"
Once the excitement over the butterflies died down, OANRP staff spent time orienting the volunteers to a few target weed species in the area. Handsaws and pruners were handed out and weeding goals were outlined for the day.
Controlling the invasive downy wood fern proved to be the most challenging of tasks. Volunteers were shown how to clip each frond from the plant's long rhizome (horizontal stem) and how to then apply small drops of herbicide to each cut along the rhizome.
The work was tedious and required a lot of focused attention. Look away for a second and the stem that was just cut becomes invisible, lost in the leaf litter of the forest. Untreated stems (without herbicide) grow back … which cancels out the weeding efforts. Volunteers worked as a steady wave of weeders across the sloping terrain, clearing approximately 250 square meters of dense weeds in three-and-a-half hours.
"It was gratifying to see the amount of area we covered," commented Perry. "Even though the weeding was very detailed, we were really able to accomplish a lot because we had so many people working together."
-- Become a volunteer
The Oahu Army Natural Resources Program staff leads monthly volunteer service trips to protect rare and endangered plants and animals on Army-managed lands. All trips are open to the general public on a first-come, first-served basis.
For more information on volunteer service trips, contact the Environmental Outreach Specialists, U.S. Army Garrison-Hawaii's O'ahu Army Natural Resource Program at (808) 656-7741.
(Note: Welch is an environmental outreach specialist with DPW's O'ahu Army Natural Resources Program.)
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