Managing Environmental Diversity for Sustainable Human Communities: Lessons from East Maui, Hawai‘i, USA - Island Futures: Conservation and Development Across the Asia-Pacific Region - page 90

Stones used by Hawaiians to construct agricultural terraces, waterways, and building
foundations were cleared starting in the mid-nineteenth century for sugar cane and
pineapple plantations and in the mid-twentieth century for commercial ranching.
Pasture and woodlands have replaced most of the Polynesian cultural landscape in
this zone.
Alien tree species introduced in the modern period dominate coastal and lowland
woodlands as high as 500 m and pose a serious threat to the native montane rainforest.
Disturbance of native vegetation and introduction of alien species, both intentionally
and accidentally, have created conditions that favor aggressive alien species.
Lowland Zone (Sea Level - ~1,000 m)
The lowland zone poses major problems for the long-term preservation of native
rainforest habitat above 1,200 m. Habitat destruction and regular disturbances for
agriculture and settlement since the pre-contact period have created conditions for
the contemporary domination of alien species, which thrive in the wet and warm
conditions of the lower montane rainforests in this zone. Feral pigs and alien birds
disperse many of the common alien species introduced since the nineteenth century,
the most invasive of which is strawberry guava ( Psidium cattleianum ). Dispersion
of strawberry guava has led to native habitat loss and the extirpation of several
indigenous and endemic plant and animal species. In addition to strawberry guava,
introduced grasses form thick mats under native forests and inhibit the growth of
native seedlings, posing a threat to the native forest.
Montane Zone (~1,000 - ~2,000 m)
The influence of Haleakala on local climate is dramatic and is particularly apparent
in the montane rainforest. The lower range of the forest receives abundant precipita-
tion from rain and fog drip in a cloud forest, conditions that support 35 m-tall trees
and a thick undergrowth of shrubs and ferns. At the base of the inversion layer, at
approximately 1,900 m, where cold air encounters rising warm air, trade winds
condense moisture and form a band of clouds on the windward slopes.
In contrast to the alien-dominated lower montane forests, the montane rainforest
is a refuge for indigenous and endemic species of plants and animals, including
more than 89 known species of ferns, 290 species of flowering plants, and four
endangered forest birds (National Park Service 1989 ). Tropical montane rainforests
are wet and cool, and the 1,000 m lower elevational boundary coincides with the
average lifting condensation level caused by the orographic effect. The multi-
layered forest is dominated by an upper canopy of koa ( Acacia koa ) toward a domi-
nant ohi'a ( Metrosideros polymorpha ) forest as elevation increases. An understory
of tree ferns and epiphytic ferns grows on moss-laden tree branches, and the forest
floor is vegetated with mosses, sedges, and ferns.