THE RAINFOREST

Rainforests are Earth’s oldest living ecosystems. Though it only covers 6% of the Earth’s surface, rainforests are incredibly diverse and complex, home to more than half of the world’s plant and animal species. Tropical rainforests are mainly located between the latitudes of Tropic of Cancer and the Tropic of Capricorn. Tropical rainforests are found in Central and South America, western and central Africa, western India, Southeast Asia, the island of New Guinea, and Australia.

TYPICAL RAINFOREST LAYERS

Most rainforests are structured in four layers: emergent, canopy, understory, and forest floor. Each layer has unique characteristics based on differing levels of water, sunlight, and air circulation:

Emergent layer: This layer gets the most sunlight. Colorful birds and butterflies fly above the trees. Small mammals swing through the branches.

Canopy layer: Only a few rays of sunlight shine through this layer. Many small mammals such as sloths and monkeys, and birds such as owls and toucans, live here.

Understory layer: This layer is home to many plant and animal species. With a lot of shade in this layer, snakes, amphibians, bats and all types of plants thrive here.

Forest-floor layer: The lowest layer in the rainforest. Leaves from the layers above block the sunlight making this layer dark and damp. Insects and rodents move around on the dirt floor.

Image by Bruno Kelly for Reuters

Hawaii's tropical rainforest

Hawaii’s tropical rainforests vary in elevations. Moist to wet forests are commonly found on the windward lowland, montane areas on larger islands and mountain tops of smaller islands. They cover an area of 6,700 km² (2,600 sq mi).

Tropical moist forests of Hawai’i occur as mixed mesic forests (about 750–1,250 m elevation), rain forests (found above mixed mesic forests up to 1,700 m), wet shrublands, and bogs in swampy areas. There are forty-eight different forest types found in the Hawaiian Islands.

Native Hawaii rainforest consists of 3 layers:

Canopy layer: Dominated by ohia lehua and acacia koa.

Understory layer: Consists of a variety of smaller trees and shrubs.

Forest-floor layer: Consists mostly of ferns (hapu’u) and berries.

Image by randy fujimoto for maui no ka oi magazine

THE EVER-CHANGING CLIMATE

RAINFORESTS TODAY

Due to human presence, lowland and foothill moist forests have been largely eliminated. There is degradation from feral ungulates (plant-eating 4-footed hoofed mammals), development, and recreational activities in montane forests. Introduced weed and tree species, avian malaria, invasive ants, rats, frogs, toads, pigs, goats, and cats all modify native habitats and harm threatened wildlife populations.

PHOTO: National Geographic

WHY RAIN IS NECESSARY

The hot, wet weather of the rainforest helps to add water to the atmosphere. It accomplishes this through the many different plants and trees releasing water from their leaves into the air. The moisture from the leaves is then absorbed, or soaked up, into the air. In turn, it can lead to the forming of rain clouds. The clouds then release the moisture in the form of rain. This cycle occurs over and over and over again. This ongoing process helps the rainforests stay healthy and green — which means that the plants can grow, animals can eat and so the ecosystem of the rainforest is in balance.

PHOTO: Ryan Aguilar, Hawaii Department of Land and Natural Resources

HAWAII'S RAIN THROUGH THE DECADES

Isolated in the Pacific Ocean, the Hawaiian Islands’ freshwater resources are limited, and understanding the impacts of changes in climate on the freshwater supply is crucial. From 1920 to 2012, over 90% of the state experienced drying trends, with Hawai‘i Island, and in particular the western part of the island, experiencing the largest significant long-term declines in annual and dry season rainfall.

The western part of Hawai’i Island had constant annual rain precipitation and dry season trends. While other in regions, drying trends were significant, especially in recent decades.

CHART: Rainfall Atlas of Hawai’i, Geography Department – University of Hawaii at Mānoa

BIG ISLAND'S TROPICAL RAINFOREST

The Hāmākua Coast is one of the most beautiful stretches of scenery on the island. This wet region boasts lush tropical rainforests, stunning waterfalls and tranquil green valleys.

Rainfall in Hāmākua Coast can reach up to 300 inches per year, the wettest part of the Big Island. Over 2,500 species of plants found the Garden thrive in this climate.

The Trade Winds direct weather patterns. The wind blows from high-pressure zones in the north Pacific that pump cool, moist wind onto the island’s eastern and northeastern slopes.

Most of Hawaii’s fresh water comes from aquifers, which are layers of rock and soil underground that collect water after rainfall.

HTBG IN THE RAINFOREST

Over the years, the Garden has developed into a living classroom where photographers, botanists, gardeners, scientists, and nature lovers gather. With more than 2,500 species of plants and trees spread across 17 acres, guests meander through nature trails streams, waterfalls, and ocean views.

Today HTBG has grown from one man’s vision into a world class destination for nature lovers and conservationists. HTBG is a living seed bank for plants that are now extinct in the wild. Join us in our commitment for education in tropical plant life, preservations, sustainability, and history.

Etlingera elatior (Torch ginger)

Heliconia rostrata

Bulbophyllum dearei

Breadfruit

Bulbophyllum corolliferum

Stanhopea connata

Lauae fern

Etlingera venusta (Malay Rose)

Elaeocarpus angustifolius

Orthosiphon aristatus (Cat Whiskers)

Medinilla cummingii (Chandelier tree)

Coelogyne rochussenii