american samoa - University of Hawaii at Manoa

harvcyana (laupata), Morinda citrifolia (Indian
mulberry, nonu), and Kleinhovia hospita (fu'afu'a).
Less common, but still typical species, include
7'rema cannabina (magele) and Melochia aristata
(ma'o). Vegetation dominated by any combination
of these species is probably on land that was in culti-
vation in the last decade or two (with the exception
of "disclimax" vegetation on steep slopes, discussed
below).
Another indicator species is Hibiscus tiliaceus
(beach hibiscus, fau). This tree is one of the most
adaptable species in Samoa, where it is common in
disturbed lowland and littoral forest, on the margins
of mangrove swamps, on talus slopes, and along
streams. The tree is very useful, since its wood is
widely used for firewood, artifacts (such as canoe
outriggers and the sticks used for making fire by
friction), and light construction. The bark is also
useful for making cordage of a temporary or perma-
nent nature.
Hibiscus does not seem to have good dispersal
ability, since the fruits and seeds are not wind- or
bird-dispersed. It probably gets around by being
planted (since it is so useful) or may spread slowly
from adjacent areas where the trees are present. It is
often found in what otherwise appears to be undis-
turbed ridge lowland forest. It seems to be able to
persist for long periods of time, but is probably
eventually shaded out when the secondary forest
canopy closes. Its presence in these situations may
indicate that the area was disturbed long ago for
inland villages or plantations. A dense stand of this
along Alava Ridge east of the TV transmitter is
probably related to the presence of an ancient trail
li-om Vatia village to Pago Pago Bay. The presence
of Hibiscus on steep talus slopes is probably natural,
since this type of "disclimax vegetation" is in a
continual state of disturbance due to landslips and
rock falls. Another tree with somewhat similar
distribution, ecological needs, and stature as
Hibiscus is Kleinhovia hospita (fu'afu'a) mentioned
above. but this is less common than Hibiscus.
Cocos nucifera (coconut, niu) is another good
indicator tree of past disturbance. Although it is
rarely found very far inland in native vegetation, its
presence in significant numbers in secondary forest
is an almost certain indicator of a former plantation.
It is not able to compete with inland species in these
habitats. It is also probably unable to naturally
compete with littoral forest trees, and its presence
along uninhabited coast is usually an indication that
it was planted there. Other trees, such as the inland
species Paraserianthes falcataria (tamalini),
Flueggeaflexuosa (poumuli), and Erythrina subum-
brans (dadap, gatae palagi), do not readily spread,
and are indicators of more recent disturbance, since
they are all of modem introduction.
A number of native canopy species are also indi-
cators of past disturbance-from both natural and
human causes. The most common of these is Rhus
taitensis (tavai). This tree often forms monodomi-
nant forests, particularly on the western half of the
island. Apparently the tree, which has readily
dispersed seeds (in small succulent fruits), germi-
nates mostly in bright sunlight, because seedlings
and saplings are common in areas where native
forest has recently been cleared for agriculture, and
possibly also when forests are flattened by hurri-
canes. Seedlings in closed-canopy forest are un-
common. Thus forests dominated by Rhus are most
likely areas once extensively disturbed decades
earlier (the tree probably lives for decades, and per-
haps more than a century, since individuals of nearly
2 m dbh have been recorded (Whistler 1980).
A species with similar ecological needs and life
history as Rhus is Alphitonia zizyphoides (toi),
which is sometimes a co-dominant species with
Rhus. Other species that likewise indicate past
major disturbance are Pometia pinnata (tava),
which, however, is not found within the park,
Neonauclea forsteri (afa), Cananga odorata
(ilangilang, moso'oi), and Bischofia javanica ('o'a).
Two other secondary forest species, Elattostachys
falcata (taputo'i) and Macaranga stipulosa (lau
fatu), are probably more indicative of "gap replace-
ment" and are not useful as indications or major
disturbance to the vegetation. Seedlings of Elatto-
stachys are often common in lowland forest, but
adult trees are not, indicating that they may only
mature if a canopy gap appears while they are a
seedling or sapling; if no gap is forthcoming, the
seedlings and saplings die. Of the secondary species
noted above, all have small seeds, except Pometia
pinnata. Pometia, however, is the dominant tree in
one kind of lowland forest-that found on relatively
recent lava flows.