Api-api
tree
Avicennia sp.
Family Avicenniaceae
Api-api trees are among the more common mangrove trees that can be
seen on Chek Jawa.
Pencil-like Roots: An Api-api
tree can be identified by its pencil-like pneumatophores that help
the tree to breathe air. To about 30cm long, these roots stick out
from the ground at regular intervals from long shallow underground
cable roots that spread out from the trunk to stabilise the tree.
Along these cable roots, anchoring roots grow downwards. From these
anchoring roots emerge finer roots that absorb nutrients.
Dealing with Salt: Api-api has
the highest salt tolerance of mangrove trees. Instead of excluding
most of the salt in seawater at the root level, Api-api simply absorbs
the salts. Thus, its sap is salty, at about one-tenth that of sea
water. The salt is then secreted on the leaves through special pores,
to be removed by rain or wind. Sometimes, the salt can be seen as
a white crystalline layer on the upper surface of the leaf. You can
taste the salt on the leaf surface!
Api-api seedlings: Api-api has
small yellow flowers, several together, forming a cross-shaped inflorescence.
The fruit is a small leathery capsule containing one seed. While the
seed does germinate on the mother tree, the growing shoot does not
penetrate the seed coat while the fruit is still on the tree (thus
this is called cryptovivipary). The shoot and roots only appear after
the fruit falls off. And these grow best in water of the right temperature
and salinity.
There are three species of Api-api on Chek Jawa.
Api-api ludat (Avicennia officinalis)
has thick waxy leaves with rounded tips and edges that are slightly
curled down. They look a little like chinese soup spoons. The leaves
are shiny green above and slightly hairy underneath.
Api-api bulu (Avicennia rumphiana)
has leaves with rounded tips that are hairy underneath. Its fruits
are furry too!
Api-api putih (Avicennia alba)
has longer narrower leaves with pointed tips and white undersides.
Role in the habitat: Being able
to tolerate saltwater, Api-api seedling are among the first mangrove
trees to colonise extremely soft, newly formed mud and sandbanks which
are regularly flooded by seawater. As the seedlings grow, they produce
an extensive network of underground cable roots which help to anchor
mud. Thus the trees stabilise the shores, preventing erosion and allowing
colonisation by other plants and animals.
Human uses: Api-api is well used
by traditional coastal communities. The fruits of some Api-api species
are eaten and the leaves may be used as cattle fodder. Api-api flowers
produce lots of nectar and fragrance to attract insect pollinators.
Thus, Api-api produces some of the best honey of the mangrove trees.
The timber is also used to make boats, houses, wharves. Tannin from
the bark and roots is used for tanning leather. Various parts of the
Api-api tree may be used in traditional medicine to treat skin ailments,
as a contraceptive and other tonics. Api-api makes poor firewood as
it smoulders when burnt. However, this makes it useful for smoking
fish. 'Api' means 'fire' in Malay. Api-api species regenerate branches
easily from their trunk. So it is possible to harvest branches without
hurting the tree and maintain mangroves for such harvests (called
coppicing). Api-api is among the few used in replanting mangroves
to protect coastlines (the others are Perepat and Bakau).
Status and threats: Api-api ludat
(Avicennia officinalis) is considered rare in Singapore. The
other Api-api species are more commonly seen in our mangroves. However,
mangroves as a habitat is threatened particularly on the mainland
by development, reclamation and other destructive human activities. |
|
Pencil-like
pneumatophores
Api-api
ludat
A. officinalis
Leaves and flower
Salt crystals on leaf
Flowers
Api-api putih
A. alba 
Leaves
Flowers
Api-api bulu
A. rumphiana
Leaves and fruits |
