A Guide to Identifying Trees While Hiking: Na Pali Coast, Kauai, Hawaii

Ohia Lehua (Metrosideros polymorpha)

The ʻōhiʻa lehua tree is often found in the mountain regions, including lava fields, rainforests, and bogs along the trail. In fact, it grows easily on lava and is often the first plant to establish itself on new lava flows. They provide critical habitat for numerous native Hawaiian species, including birds like the honeycreeper. The Ohia's leaves have a leathery texture and varying colors from silver green to dark green. It is well-known for its distinctive lehua flowers, which come in various colors of yellow, salmon, pink, or white, but the most common is scarlet red. The flowers are made up of clusters of stamens that create a fluffy appearance that contrast nicely against the green foliage.  The wood from the tree is used for kapa cloth beaters, pounding poi and building structures. 

Koa (Acacia koa)

Koa is the second most common tree and the largest native tree in the Hawaiian Islands, reaching heights of 82 feet. It can often be found in higher elevations along the trail. The koa tree produces pale-yellow or cream flowers arranged in spherical clusters.  The flowers have numerous long stamens which give the flower clusters a fuzzy appearance. Koa trees can flower at various times throughout the year, but flowering often peaks during the winter and spring months in Hawaii. After pollination, the flowers develop into long, flat seed pods, which can grow up to 6 inches long.  Koa flowers attract a variety of pollinators, including bees and other insects. The hardwood is highly prized with a rich, varied grain and a range of colors from golden to deep reddish brown.  Due to its beauty, koa wood is one of the most expensive woods in the world. Conservation efforts are in place to protect this unique species. 

Black bamboo (Phyllostachys nigra)

There are various species of bamboo that may be present along the more forested areas in the valley. A notable and eye-catching species is black bamboo. This species typically grows to about 20-30 feet tall, with long, green, lance-shaped leaves which contrast beautifully amongst the black stems (culms). When young, black bamboo starts green and matures into a deep ebony hue over the course of about two years. The culms are often used in construction, furniture making, and crafts. They are strong, durable and flexible. Black bamboo is also used to make musical instruments.  Their unique appearances make for great photographic subjects.

Hala (Pandanus tectorius)

Common in coastal and wetland areas, Hala trees can be seen near the trailhead at Ke'e Beach and along the trail in wetter sections. The Hala tree has distinctive aerial roots that provide support and stability, allowing it to withstand coastal winds and sandy soils. The leaves are arranged in a spiral pattern around the trunk, giving it an architectural and umbrella-like canopy.  Its leaves, known as lau Hala, are traditionally used for weaving various items like mats, baskets, and hats.  The male flowers, called hīnano, are surrounded by very fragrant bracts.  The fruit of the Hala tree resembles a pineapple and is made up of numerous segments called keys or phalanges. The fruit can vary in color from green to yellow to reddish-orange when ripe. The fruit segments are edible and can be consumed raw or cooked.  Hala trees provide habitat and food for various wildlife species, including birds, insects, and crabs. 

Kukui (Aleurites moluccanus)

The kukui tree, also known as the candlenut tree, is the state tree of Hawaii. It has large, pale-green leaves and can grow up to 50-80 feet tall with a broad, spreading canopy. The small, white, and fragrant flowers grow in clusters, and the fruit is a round, green drupe that turns brown as it matures. The kukui tree's extensive root system helps stabilize soil and prevent erosion, while its flowers and fruit provide food for various birds and insects. The oily kernels of the kukui nut were historically used as a source of light, earning the tree its nickname "candlenut tree."