One of the great pleasures of visiting Kaua‘i is hiking through a native Hawaiian forest. Owing to its extreme isolation from continental influences, the Hawaiian Islands have become home to more than a thousand plant species over the past million years, which evolved from fewer
than 300 founding species. Carried by wind, water and wings, these first plants found their way to
the islands as seeds and spores before the arrival of the first human settlers less than 2,000 years ago.
Hawai‘i’s first native plants originated from Asia, Australia, the Americas and other Pacific Islands.
They evolved in isolation over millennia, free of competition from other more aggressive plants,
destructive animals and human activities like agriculture, forestry or collecting. When the first humans
arrived from the Marquesas Islands and later Tahiti and Samoa, they found islands that rose to great
volcanic peaks like Mauna Kea and Mauna Loa on Hawai‘i Island, but also lower level mountains like
Kaua‘i’s Kawaikini and Wai‘ale‘ale.
These smaller mountains supported forests of large trees and, in Kaua‘i’s case, a diverse swamp
network where plants found nowhere else on earth, not even on the other Hawaiian islands, created
a rich habitat for birds and insects that co-evolved with plants equally unique and limited to Kaua‘i.
Today, over a thousand years after first being settled and 234 years after the arrival of Captain
Cook and the deluge of humanity (and animals and aggressive non-native plants) that followed, these
high elevation wet forests are the last refuge for Hawaiian flora and fauna that represent Hawai‘i’s
irreplaceable natural legacy.
Walking amongst these plants, admiring the stately ‘öhi‘a lehua (Metrosideros polymorpha) trees
that dominate Kaua‘i’s wet forests and the vibrant green mosaic of ferns, mosses and liverworts found
growing in open swaths and shady recesses, it’s valuable to pause and consider the remarkable beauty
and fragility of these important Hawaiian ecosystems.
Kaua‘i’s wet forests found in Köke‘e State Park and near the Alaka‘i Swamp are home to endemic
plants like the yellow-bloomed Scaevola glabra, filmy ferns, sedges, lichens and a number of melicopes
(in the Citrus family) and lobelias (Bellflower family). These forests contain beautiful trees like ‘ölapa
(Cheirodendron trigynum), the tiny red berry-filled pükiawe bush (Leptecophylla tameiameiae) and
Hawai‘i’s three native species of orchid so rare, it’s unlikely you will see them.
Many of these plants are endangered and subject to damage from invasive non-native plants like
Himalayan gingers, blackberry bushes and Australian tree fern, just to name a few. Feral goats, deer,
wild pigs and rats cause more damage, and humans can irrevocably impact Hawai‘i’s forests with the
litter we drop, the plants we pick and the seeds we spread—no matter how unintentional.
But it is important to preserve Kaua‘i’s high elevation forests and the Alaka‘i Swamp, as these
locations serve as a giant “sponge” for the entire island. Rain and cloud moisture are captured by
plants, absorbed by the earth and filtered to the lower elevations, ultimately feeding and nourishing
the entire island.
In order to gain a better appreciation of Kaua‘i’s wet forests and to help preserve and enjoy them
safely, Kaua‘i Traveler spoke with botanists and field collectors from the National Tropical Botanical
Garden and Hawai‘i’s Plant Extinction Prevention program to seek what advice they had.