Makiki trail, Puu Uallakaa State Park, Oahu, HI

Forest trail in the foothills near Honolulu

I get it, when folks go on vacation they want to relax. Our jobs and homelives are often stressful and full of obligations. Most people coming to Hawaii as a tourist want a comfortable place to stay, somewhere near a safe clean beach, and with easy access to good places to eat. But in order to provide these amenities for thousands of travelers at any one time means the built environment has to replace the natural environment. Don't expect a quiet tropical beach in the Waikiki neighborhood of Honolulu.

My partner and I have found a bit of an antidote for the overcrowding on the beach: head for the hills. The Hawaiian Islands have some wonderful hiking trails where the natural environment is largely preserved. Sure, there are lots of invasive plants and trees, an ancient Hawaiian wouldn't hardly recognize the place. But still, the hills are all jungle-y, green, and lush.

Most of the state parks are free, and many provide basic services and nicely marked trails. We chose the Makiki Valley trail in Puu Uallakaa State Park because it was accessible by city bus from our hotel in Honolulu - about a 30 minute bus ride each way.

Strangler fig, aka banyan tree, aka Ficus benghalensis

Banyon/strangler fig next to the trail

Being so close to the city of Honolulu it is not surprising there are many introduced invasive plants. Ficus trees are mostly native to India, but they thrives in the warm subtropical climate of Hawaii. Ficus benghalensis is the most most common species in Hawaii. But, there are about 1000 other species of ficus trees in addition to F. benghalensis; and many of them display the 'strangler' style of growth by vining around the trunk of a nurse-tree and eventually entombing the nurse and causing its demise.

There are examples of this tree that have become famous in Hawaii. For example a large banyan tree grew in the middle Hula Bar and Lei Stand in Honolulu (now gone). The large tree formed the "roof" over the seating area of the bar and restaurant. Another vast tree covered the area the size of a city block in Lahaina. It survived - only just barely - the great fire of Lahaina in 2023. The tree in this photo is a mere young shrimp in comparison.

I've read that the ficus tree was introduced to Hawaii in the mid-1880s. At some point a fungus carried on the ficus trees has infected and nearly wiped out the native Ohia trees in mountainous area. Invasive plants may look benign, but they can be quite damaging.

African tulip tree

African tulip tree

The tulip tree (Spathodea campanulata) is said to be one of the most invasive trees in the Hawaiian landscape. Known for their large blowsy orange blossoms, the tree was introduced in the 1870s by Dr. Wm Hildebrand, a famous botanist and royal physician. In the 1930's more the 30-thousand of them were planted in a re-forestation effort. The trees have grown to crowd out native trees along streams in many of the valleys, on most of the islands. They are shade tolerant, grow quickly up to 6 feet per year, and their seeds spread easily in the wind.

Eucalyptus trees

Trail through a eucalyptus grove

Another tree that was introduced in the reforestation effort is the eucalyptus tree. It grows fast, reaching a large size. The wood also has some commercial uses. There are 500 species of the tree, mostly confined to Australia originally. But they have been introduced to subtropical areas around the world. Eucalyptus robusta is common in Hawaii.

Epiphytes

There are thousands of native and non-native plants that live off of the ground and up in the trees and shrubs of the Hawaiian landscape. Lichens, mosses, and orchids are included in the category of epiphytic plants. One of the most commonly noticed epiphytes is the staghorn fern (Platycerium superbum), native to Australia. This plant has been naturalized into the forests of Hawaii and is remarkable for its size. It is easy to notice these large plants growing on the boughs of trees.

Staghorn ferns growing on a koa trunk.

Monarch or laua'a fern

Microsorum scolopendria is a fern common throughout the Pacific rim. It was introduced to Hawaii in the 1910s and has rapidly spread through the Islands. Many people will recognize this fern as it is often used in flower arrangements, adding greenery and texture.

Laua'e fern, admixed with asparagus fern