american samoa - University of Hawaii at Manoa

Although Mauga-o-Tula lacks some of the chara-
cteristic montane scrub species of other trachyte
plugs, such as Matafao and Pioa, it still can be be
classified as montane scrub because of the dominance
of Metrosideros trees and by the ground cover
dominated by Dicranopleris.
Secondary Vegetation
Secondary vegetation includes all those plant
communities that are in a state of relatively rapid
change in structure and species composition brought
about by some kind of disturbance. The disturbance
can be natural, as from hurricanes and landslides, or it
can be caused by the activities of man, such as the
clearing of forests for plantations and villages. Until
the arrival of the first Polynesian settlers perhaps 3000
years ago, all disturbance was natural. Nowadays,
however, it is most often caused by the activities of
man.
Three secondary vegetation communities are
recognized below. They are successional, i. e., over
time after a disturbance, the first one, managed land
vegetation, evolves into the second one, secondary
scrub, and this in turn evolves into the third one,
secondary forest. Species dominating disturbed
vegetation have some characteristics in common:
(I) they are relatively fast growing; (2) they have
mostly small, readily dispersed seeds; (3) they are
intolerant to shade and disappear when the large
primary forest trees, or other secondary species, shade
them out. The species of the first community,
managed land vegetation, are mostly aliens, i.e.,
non-native, but those of the other two are mostly
indigenous (but not endemic) species.
The three communities are described below. They
are basically the same as those included in the report
for the Ta'u unit of the Park (Whistler 1992b), altho-
ugh a few of the species are different (Ta'u has fewer
species).
8. Managed Land Vegetation
Managed land comprises those areas that are
actively managed by man, and includes villages,
plantations, pastures, roads, and airports. The managed
land within the park comprises only villages,
plantations, and roads (and roadsides). Although the
village of Vatia, which is surrounded by the park, is
excluded from the park itself by a 200 ft elevation
boundary line, there are several houses in Amalau
Valley (possibly only four) above and below the
road, and thus the land around these structures fit
into the village category. The TV transmitter atop
Mt. Alava and the area around a house along the
Alava Ridge road, belong here as well.
The plantations in the park are found mostly
around the village of Vatia above the 200 ft
elevational line (Fig. 27), perhaps some on the
slope to the west of Afono, and some patches
below and north of the Alava Ridge road. The
most commonly cultivated plants in plantations
(and villages) are coconuts, taro, and bananas.
When coconut plantations are abandoned, the
coconuts may persist for many decades, but
eventually disappear because they do not compete
well reproductively with rainforest trees. Taro and
bananas are usually grown only for one or a few
times on a piece of land cut out of the forest, after
which the plot is abandoned to fallow. It is then
rapidly overgrown with herbaceous weeds, and
eventually by shrubs and small trees, at which time
it is classified as secondary scrub (discussed
below).
Paved roads obviously have no vegetation, but
their margins can be classified as managed land.
The only paved road within the park runs from
Afono to Vatia, and its margins are periodically
cut or sprayed with herbicide. The road cut along
this and other roads probably also would be cla-
ssified as managed land, at least until they become
vegetated with forest or scrub.
The only other road within the park is the dirt
road running from Fagasa Pass to the TV trans-
mitter-the Alava Ridge road. It is passable only
by means of 4-wheel drive vehicles because of
erosion and mud puddles, but a family travels it
regularly by truck to their house located part way
along the road. The managed land vegetation of
this road consists of the low plants on the road
itself, the taller weedy plants along the margins,
and the plants on the roadcuts along its route.
Nearly all the plants found on managed land are
introduced species. Before the arrival of the
Europeans, the weeds introduced by the
Polynesians and a few native species shared
dominance. Now, however, most of the weeds,
including the most dominant species, are modern
introductions-mostly from tropical America.
Because of the competition of these more recently