About The Mauna

West Maui, Maui Komohana, is home to many important historical and sacred sites in Hawaiian culture. The Partnership aims to maintain the protection of these areas for future generations and to help visitors understand the significance of these sites of cultural heritage.

A relatively modern Hawaiian name for the West Maui Mountains, “Kahālāwai” is interpreted as the House of Water, the Meeting Place of Waters, or the place where heaven and earth meet. Other names include "Hale Mahina" meaning House of the Moon, after Hina the lunar goddess, and “Mauna ʻEʻeka” after ʻEke Crater which rises to the north of the summit of Puʻu Kukui.

The West Maui Watershed has horizontal bands of vegetation communities, arranged by elevation zone. Ancient Hawaiians had long ago recognized these horizontal land divisions as having their own spiritual and practical purposes.

Mauna Kahālāwai is an eroded volcano characterized by narrow knife ridges, steep slopes, and deep valleys. With a great elevation range and highly variegated terrain, Mauna Kahālāwai is home to a wide range of microclimates and vegetation communities. Examples include montane wet forest and shrublands, mesic forests and shrublands, lowland forests and shrublands, wet cliffs, and dry cliffs. With such varied habitats, West Maui is home to a diverse array of native species, including at least 18 plant species that are endemic to this mountain in particular! Read on to learn more about each elevation zone.

THE PRISTINE CORE:  Summit (5,788 ft.) to 2,800 ft.
Near the Puʻu Kukui summit at 5,788 feet, the landscape is dominated by montane bogs, and wet, windswept shrublands which extend downward to more mesic forests and shrublands. These lands are relatively pristine with few invasive species occurring in otherwise intact native forests.

Notable rare species that grow in this unique environment include ʻōhiʻa lehua (Metrosideros polymorpha), Viola mauiensis, Lobelia gloriamontis, Hawaiian damsel flies (Megalagrion spp.), and others. Kiʻowaiokihawahine (translated as “the pond of the moʻo goddess Kihawahine”; also known as Violet Lake) represents a little-known ecosystem found only on Maui and Hawai’i. This example of a Hawaiian Montane Lake is approximately 10 feet by 20 feet in size and is found within the Puʻu Kukui Watershed Preserve in the northwestern region of the West Maui watershed.

Other unusual ecosystems include Mauna ʻEke, a magmatic dome formed during the later years of the West Maui volcano. This plateau-like region is pocketed with deep sinkholes, bogs of standing water, and stunted yet pristine vegetation. Unique species here include the ʻEke Silversword (Argyroxiphium caliginis), hinihina (Geranium humile), and koʻokoʻolau (Bidens conjuncta), as well as miniaturized giants like ʻōhiʻa lehua (Metrosideros polymorpha var. pseudorugosa).

TRANSITION ZONE:  2,800 ft. to 2,000 ft.
Moving down the mountain slopes, other vegetation communities include koa (Acacia koa) forest, lama (Diospyros sandwicensis) forest, diverse mesic forest with several dominant native tree species, and a variety of native shrubland types. Uluhe (Dicranopteris linearis) ferns are common in these areas, and shrubs like pūkiawe (Leptecophylla tameiameiae) and kanawao (Broussaisia arguta) are frequently seen as well.

In this mid-elevation band there is a mixture of native and invasive species.  This is the key battleground where we work to hold the line against alien invaders and hopefully gain ground over time.  Below 2,800 feet elevation the vegetation transitions from native-dominated into more alien-dominated vegetation with non-native trees such as strawberry guava (Psidium cattleyanum),  ironwood (Casuarina spp.), Koster’s curse (Clidemia hirta), parasol leaf tree (Macaranga tanarius), and others becoming increasingly prominent in a mixed native and alien canopy. Invasive species will gain more ground in this zone and spread upslope unless we are afforded the chance to do our work of maintaining fence lines, controlling feral animals, and fighting invasive weeds.

RARE NATIVE, ALIEN DOMINATED ZONE: Below 2,000 ft.

While this area may be dominated by alien plants, there are still pockets of rare individual plants and plant communities. Naturalized alien vegetation such as common guava and strawberry guava (Psidium guajava and P. cattleyanum, respectively) and Java plum (Syzygium cumini) dominate in this zone, with the exception of small native forest and shrubland stands. 

At the bottom edge of the watershed, plantings of introduced trees such as eucalyptus, Cook and Norfolk pines (Araucaria spp.), silky oak (Grevillea robusta), and naturalized alien vegetation occupy the lowest slopes. Small and sometime rare assemblages of native forest and shrubland stands such as wiliwili (Erythrina sandwicensis), ʻaʻaliʻi (Dodonaea viscosa), and naio (Myoporum sandwicense) occur in these lower slopes, giving us hope for future restoration.

Other Organizations and Helpful Resources

East Maui Watershed Partnership (EMWP) - The first Watershed Partnership established in Hawaiʻi, an alliance of Federal, State, and private landowners driven to protect 100,000 acres of native forests and watersheds on windward Haleakalā

Firewise - Community-driven wildfire protection

Hawaii Association of Watershed Partnerships (HAWP) - Ten watershed partnerships across the State of Hawaii protect over 2 million acres of vital forested watersheds

Hawaii Wildfire Management Organization (HWMO) - Working to protect Hawaii's precious resources from destruction by wildfire

Hawaii Ecosystems at Risk (HEAR) - Invasive species information for Hawaii and the Pacific

Leeward Haleakala Watershed Restoration Partnership (LHWRP) - Maui’s third Watershed Partnership, an alliance of public and private landowners driven to protect 43,000 acres of native dryland forests of leeward Haleakalā

Maui Invasive Species Committee (MISC) - Protecting Maui Island from the most threatening invasive species

Plants of Hawaii - Extensive photo database of native and invasive species in Hawaii, compiled by Forest & Kim Starr

What is a watershed?

A watershed is a geographic area such as a mountain or valley that collects rain water and drains to a common outlet like a river, an aquifer, or the ocean. Topography--the shape of the land--influences how water moves toward the ocean via rivers, streams, or via movement underground.

In Hawai'i, every ahupuaʻa is essentially its own watershed, being comprised of a valley and stream system that supports all life within its boundaries. The most robust watersheds--the most fertile ahupuaʻa--are those that are densely vegetated by native forests. With their many layers of canopy and sub-canopy trees, understory shrubs, ferns, groundcovers, and mosses, our native forests are giant living sponges that soak up rainfall and catch moisture from passing clouds. The rainwater and fog drip that our forests collect serve to recharge our aquifers and feed our streams, thus providing a dependable source of clean water for our islands.

The West Maui Watershed

The watershed vegetation of Mauna Kahālāwai, the West Maui Mountains, is a fabric of thousands of native plants, birds, snails, insects and other invertebrates. Each of these native Hawaiian species has value as a source of unique genetic information. Many plants are still used today for lei, hula, tapa and tapa dyes, medicine, cordage, and other practices. Native species are central to Hawaiian culture and therefore critical for its preservation and perpetuation.

Hawaii Association of Watershed Partnerships

Established in 2003, HAWP is led by representatives from each of the 10 watershed partnerships in Hawaii.  The mission of  HAWP is to increase the effective management and protection of mauka (upper elevation) watershed areas by raising the capacity of Watershed Partnerships, facilitating sharing of watershed management expertise, building public support for protecting watershed values, and developing sustainable funding sources.

A Giant Living Sponge

Millions of years of evolution have made the Hawaiian forest highly efficient at capturing and retaining water.

Generally speaking, the more complex the structure of a forest, the more enhanced its watershed functions. 

The Hawaiian rain forest, with its multi-layered structure - tall canopy, secondary trees, shrubs and fern layers, ground-hugging mosses and leaf litter - act like a giant sponge, absorbing water and allowing it to drip slowly underground and into streams.

Even without rain, the forest can pull moisture from passing clouds.  In Hawaiʻi, this interception can push water capture above and beyond total annual rainfall by as much as 30 percent.

A Conserver of Water

The Hawaiian rain forest is a great conserver of water.  The tall, closed canopy shades out the sun, resulting in less water lost to evaporation and transpiration.   The dense vegetation also blocks wind, which would otherwise pull moisture from the land.

The many layers of vegetation blunt the erosive effects of rain, and once saturated, buffer the release of stored water, reducing immediate flow in wetter times, maintaining it in dry.  Long after rain subsides, the forest delivers fresh water for human use.

A Reef Saver

There is a direct correlation in Hawaii between the health of our forested watersheds and the health of our reefs and beaches.

Without a healthy forest to anchor the soil and temper the erosive effects of heavy rain, large amounts of sediment wash off our steep mountains and into the ocean, polluting streams, destroying coral reefs, and degrading coastal fishing resources.

Drought and Flood Defense

Perhaps the greatest value of the thousands of native species in the West Maui Watershed is the function they perform together, as parts of a complex, natural ecosystem.

The balance achieved among these species over the millennia has produced forests that can best weather the typical cycles of drought and flood in the region, and are uniquely adapted to the climate and soils of the mountain.

Because of the buffering effects of the forest, our human communities enjoy a more comfortable climate with a lowered risk of extreme conditions.