american samoa - University of Hawaii at Manoa

incrme (aloalo tai) may also be common,
particularly if the site is very near the ocean.
Another shrub, Alyxia stellata (nau), is also
sometimes common.
Vines are not common in this type of lowland
forest, probably because of the dry soil and salty
winds from the nearby sea. The most frequent
species is probably the trunk climber Epipremnum
pinnatum. Other species present include Hoya
australis (fue selela), Mucuna gigantea, and
Ipomoea macrantha. Epiphytes are also relatively
sparse for the same reasons. The most frequent
species are Asplenium nidus, Davallia solida, and
Davallia epiphylla, all of which are ferns, and the
orchid Dendrobium dactylodes.
c. Ridge Lowland Forest - This is the forest on
the upper portion of the ridges and slopes, ranging
from about 200 to 350 m elevation, but sometimes
lower. This forest has indistinct boundaries because
it blends into coastal lowland forest below it and
montane forest community above it. It corresponds
to the "mixed lowland forest" described for Ta'u
(Whistler 1992b), the "asi ridge forest" of American
Samoa (Whistler 1980), the "mafoa ridge forest" of
'Upolu, Western Samoa (Ollier et al. 1979), and the
"asi forest" and "tamanu forest" of Savai'i and
'Upolu (Chandler et a[. 1978). It probably covers
the majority of the park, but the western half of the
area has recently been disturbed by hurricanes and
human activities (Fig. 20).
Ridge lowland forest is not a monodominant
community, and any one of several trees may
prevail at a particular site. The seven most
characteristic canopy trees in the forest on Tutuila
are shown in Table 1. The four canopy species
averaged between 12 and 16% relative dominance.
The first species, Syzygium inophylloides (asi), is
also the dominant of the lowland forest of Ta'u
(Whistler 1992b). Calophyllum neo-ebudicum
(tamanu) is common throughout the archipelago in
lowland forest of ridges, as is Canarium vitiense
(ma'ali). Buchanania merrillii (no Samoan name)
finds its greatest abundance on Tutuila; it is absent
from Manu'a, and is uncommon in Western Samoa.
The subcanopy trees may sometimes be
dominant, but they are not as tall nor as big (in girth
or dbh) as the other species. Diospyros samoensis is
a dominant tree of lowland forest of coastal ridges,
and becomes progressively less important with
increasing elevation. Myristica fatua (Samoan
nutmeg, 'atone) is typical of most types of lowland
forest, but at higher elevation on ridges it is often
replaced by Myristica hypargyraea (also called
'atone). Canarium harveyi (mafoa) may be a
modern introduction to Samoa, since it was not
recorded in the islands before 1920; consequently, it
may actually be a canopy tree that has not been in
Samoa long enough to grow into the huge size
characteristic of older native trees.
Table 1: Relative dominance (%) of characteristic trees of the lowIand forest of interior
ridges of the Tutuila park.
CANOPY SPECIES
PLOTS AVERAGE
5 6 7 8 9
Syzygium inophy No ides 16 11 22 25 4 16
Calophyllum neo-ebudicum 11 13 17 3 12 13
Canarium vitiense 8 7 12 11 2 5 13
Buchanaria merrillii 1 3 1 11 - 18 12
SlJBCANOPY SPECIES
Diospyros samoensis
Canarium harveyi
Myristica fatua