FAUNA AND FLORA O F MANGROVE SWAMPS
105
I n the ever-wet of Malaya and Indonesia a ceriops zone is not well
marked but, rather, species of Ceriops occur within a bruguiera forest
or, as in Sabah and peninsular Thailand, in association with Rhizophora
spp. where these form well-developed and mature virgin forests. Under
these circumstances C . tagak reaches tree dimensions of upwards of 10 m
and some 20 cm in diameter at the base of the trunk above the
buttresses. Trees of this size are mentioned by Watson (1028) without
his being explicit as to where they may be found. I n regions of intermediate rainfall and on soils which are well drained, dense thickets of
C. tagal follow the landward fringe at a level immersed by all spring
tides, i.e. at the lower levels of Watson’s class (iv) and the upper levels
of his class (iii) (Figs. 16 and 19). Within these thickets all stages of
development from newly germinated seedlings through saplings to
mature small trees may be found in almost pure stands. I n Australia
the most common associate is Bruguiera exaristata. OccasionaI trees of
Avicennia marina, B. gymnorhiza, Xylocarpus granatum and X . moluccensis also occur ; Xcyphiphora hydrophyllacea occurred in this zone
along the Hinchinbrook channel. I n eastern Africa only A . marina
and B. gymnorhiza are present as associates. The trees of Ceriops are
always taller a t the lower margins : where they merge with the trees in
the zone of bruguiera forests they reach similar heights to the adjacent
bruguiera trees which, in turn, are not so tall as those farther downward.
C. Zone of bruguiera forests
Watson recognized three types of bruguiera forest, dominated
respectively by B. cylindrica, B. parvijlora and B. gymnorhiza.
Forests of B. cylindrica are characteristically developed on stiff,
bIue clay soils with a shallow humus layer and a well-marked surface
drainage but no creeks. I n Malaya such forests occur along the long
stretches of the western coastline which lie between the major rivers
(Fig. 17). These forests of B. cytindrica develop behind a seaward
fringe of Avicenniu marina (= A. intermedia). The purity of these
stands as seen today may be the result of thinning out other species.
The soil surface is almost level and few animals were seen, these were
mainly small sesarmas (personal observation).
B. parvijlora is essentially an opportunist species and not popular
with foresters because its timber is said to be inferior to that of other
species. I n Australia (Macnae, 1966) and in Burma (Rogers, quoted by
Watson, 1928) this species is also opportunist and tall groves occur in
areas which have formerly been cleared (Fig. 20). I n Malaya, too, it
frequently takes over an area which has been cleared and may then act
105
I n the ever-wet of Malaya and Indonesia a ceriops zone is not well
marked but, rather, species of Ceriops occur within a bruguiera forest
or, as in Sabah and peninsular Thailand, in association with Rhizophora
spp. where these form well-developed and mature virgin forests. Under
these circumstances C . tagak reaches tree dimensions of upwards of 10 m
and some 20 cm in diameter at the base of the trunk above the
buttresses. Trees of this size are mentioned by Watson (1028) without
his being explicit as to where they may be found. I n regions of intermediate rainfall and on soils which are well drained, dense thickets of
C. tagal follow the landward fringe at a level immersed by all spring
tides, i.e. at the lower levels of Watson’s class (iv) and the upper levels
of his class (iii) (Figs. 16 and 19). Within these thickets all stages of
development from newly germinated seedlings through saplings to
mature small trees may be found in almost pure stands. I n Australia
the most common associate is Bruguiera exaristata. OccasionaI trees of
Avicennia marina, B. gymnorhiza, Xylocarpus granatum and X . moluccensis also occur ; Xcyphiphora hydrophyllacea occurred in this zone
along the Hinchinbrook channel. I n eastern Africa only A . marina
and B. gymnorhiza are present as associates. The trees of Ceriops are
always taller a t the lower margins : where they merge with the trees in
the zone of bruguiera forests they reach similar heights to the adjacent
bruguiera trees which, in turn, are not so tall as those farther downward.
C. Zone of bruguiera forests
Watson recognized three types of bruguiera forest, dominated
respectively by B. cylindrica, B. parvijlora and B. gymnorhiza.
Forests of B. cylindrica are characteristically developed on stiff,
bIue clay soils with a shallow humus layer and a well-marked surface
drainage but no creeks. I n Malaya such forests occur along the long
stretches of the western coastline which lie between the major rivers
(Fig. 17). These forests of B. cytindrica develop behind a seaward
fringe of Avicenniu marina (= A. intermedia). The purity of these
stands as seen today may be the result of thinning out other species.
The soil surface is almost level and few animals were seen, these were
mainly small sesarmas (personal observation).
B. parvijlora is essentially an opportunist species and not popular
with foresters because its timber is said to be inferior to that of other
species. I n Australia (Macnae, 1966) and in Burma (Rogers, quoted by
Watson, 1928) this species is also opportunist and tall groves occur in
areas which have formerly been cleared (Fig. 20). I n Malaya, too, it
frequently takes over an area which has been cleared and may then act