Welcome to the Invasive Informant, sponsored by Kauaʻi Invasive Species Committee. KISC works across Kauaʻi to prevent, control, or eliminate the most threatening invasive plant and animal species in order to preserve Kauaʻi’s native biodiversity and minimize adverse ecological, agricultural, economical, and cultural impacts.
This month, we take a look at ʻōhiʻa, Hawaiiʻs state endemic tree and the most abundant tree in the forest.
A native ʻōhiʻa forest is more than just a collection of plants. It’s home to native birds, beetles, butterflies, damselflies, and tree snails. Many co-evolved with the forest, creating symbiotic relationships.
Nā Manu Nahele
One of the most well-known mutually beneficial relationships is that between ʻōhiʻa and nā manu nahele, our native forest birds. ʻŌhiʻa provides nectar in their fireworks of lehua, blossoms, and as ʻiʻiwi and ʻapapane hop from lehua to lehua, slurping away, they help pollinate ʻōhiʻa.
Acrobatic ʻakikiki creep up and down the tree in search of insects while ʻakekeʻe use their cross-bill to pry open ʻōhiʻa flower and leaf buds for insects.
ʻŌhiʻa serve as a living growing medium for native lichen and mosses, material nā manu nahele use to line their nests. Nests they build in the limbs of ʻōhiʻa.
Rapid ʻŌhiʻa Death
ʻŌhiʻa can grow a hundred feet tall and live hundreds of years. But a fungal disease known as “Rapid ʻŌhiʻa Death” is killing Hawaiʻiʻs most abundant native tree. ʻŌhi‘a are infected through open wounds, possibly due to peeling bark, torn roots, or broken branches.
Microscopic fungal pathogens enter the wound and the fungus grows inside the tree, preventing the flow of water. The first external symptom is the sudden browning of the leaf canopy. There is no known cure, and after a few months, the tree dies.
Help Save ʻŌhiʻa
Because the fungus moves around the island in mud, brushing mud off footwear and gear before and after entering the forest, then, spraying with isopropyl rubbing alcohol, can help stop the spread of Rapid ʻŌhiʻa Death.
And, remember, when we save ʻōhiʻa, we save our nā manu nahele. And when we save nā manu, we save ʻōhiʻa.
Join us at Kukui Grove as we celebrate Hawaiian Honeycreepers on Saturday, August 12, from 10:00 a.m. to 2:00 p.m.