Kaʻū News Briefs December 6, 2023

Koa art by Joan Yoshioka

KOA, MEANING BRAVE, BOLD, FEARLESS, is Plant of the Month for the last Lāʻau Letters of 2023, written by Jody Rosam with illustration by Joan Yoshioka. Here is La'u Letters, Native Plants of Ka'u:
    I wanted to share a familiar friend, Koa (meaning brave, bold, fearless, courage, and warrior) to bring you strength in the upcoming year. E ola Koa!  Description:  Koa is another one of our endemic Fabulous Fabaceae, and is the second most common tree species in Hawaiʻi (second to ʻōhiʻa). In rich volcanic ash soils, koa can grow to impressive heights of 100 feet or more. In fact, a koa tree in Kapuʻa Ahupuaʻa was measured at 115 feet tall with a crown spread of 93 feet!
    Did you know that mature koa trees do not have true leaves? When they are young, koa produces compound leaves composed of many small leaflets, but as they mature, they form the flat sickle-shaped leaf-like structures we are all familiar with seeing. Those are actually phyllodes, which are a modified petiole (the stalk that attaches the leaf blade to the stem). This is a unique adaptation, because petioles are able to twist the leaves in order to face the sun. In the case of koa, the vertically-flattened arrangement of the phyllodes optimizes their exposure to sunlight (and photosynthesis) throughout the canopy.
    The bark of koa is typically light gray, and is sometimes covered on one side by a bright orange lichen. The white flowers form in small, round heads and give way to seed pods containing many dark brown hard seeds. If you look closely at seeds in a pod, you can even notice the piko where it is attached to the pod. Have you ever walked through a koa forest and smelled a garlicky smell? That is the smell of the busy rhizobia or soil bacteria that live in root nodules fixing nitrogen! These rhizobia have the power to convert atmospheric nitrogen (N2), which is difficult for plants to uptake, into a usable form of ammonia (NH3). Cool symbiotic relationship, right?
    Uses: Commercially, koa is one of the most valued (and most expensive) woods in the world, which is why a sustainable harvesting method is crucial to perpetuating koa’s survival. Historically, one of the most well-known uses for koa was in canoe making. However, the process of selecting and harvesting the koa 

Young koa trees. Photo from state Department of Land & Natural Resources

tree for this purpose was intricate and ceremonial (please read about it). I kū mau mau! In addition to canoes, the fine red wood was once used for hale (houses), hoe (paddles), papa heʻe nalu (surfboards), and ʻumeke lāʻau (calabashes) to name a few, and is now used in woodworking to make exquisite furniture and ʻukulele. The bark can be used to make a red dye for kapa and the leaves can be strung into lei.
    Koa’s medicinal uses are plenty, including reducing fever, pūhō (abscesses), ʻeha māui (bruises), and haki (bone breaks). Habitat: Generally speaking, koa can be found on all of the main Hawaiian Islands except Kahoʻolawe and Niʻihau. It is able to grow at elevations between 150 - 7,000 feet in dry and mesic environments, though the greatest concentrations of koa are between 3,000 - 6,000 feet. In Kaʻū, you can find koa growing in every ahupuaʻa mauka of about 1,000 feet elevation.
    Growing and Purchasing: Koa keiki are often available at local plant sales, however, it should be noted that koa does vary greatly from one location to another. For this reason, as well as when you purchase any native species, please try and be aware of the source of your plant and keep them planted on your property and do not plant purchased trees out into the wild, as the genetic variation of our wild plant populations is critical to their survival. Koa are happiest when planted in full sun, and once they are established, they can handle periods of drought and high winds. Plant them 30-40 feet apart to accommodate their future crown spans in an area with plenty of sunshine. Do your best to keep the base of the tree weed-free, as koa does not like being weed whipped or bumped with a mower, and keep pruning to a minimum. Consider companion planting with a friend like ʻaʻaliʻi, māmaki, or ʻiliahi. Kūlia! 

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Mauna Loa and Hilina Pali Roads are open. NPS photo

MAUNA LOA AND HILINA PALI ROADS HAVE REOPENED for vehicles, for access to their overlooks in Hawai'i Volcanoes National Park. "Currently, there is no imminent wildfire threat in the area," says the Park posting. "While we are happy that the road is again open, it is essential to remain informed. Dry conditions and invasive plant species have heightened the risk of wildfires in Hawai'i. Increased fire events and the presence of flammable grasses pose a real threat to the cherished ecosystems in Hawai'i. Let's all stay vigilant and #RecreateResponsibly to protect our natural treasures."