Banyan
VulcanSpirit
Richard & Alison Brunstrom
Thu 29 Aug 2013 12:51
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The banyan is a common forest giant here in
Vanuatu. The original banyan from India, Ficus benghalensis, can grow
absolutely huge. In fact according to the Guiness Book of Records it's the
world's biggest tree with one individual covering 19000 square metres or about
eight acres! Interestingly the name comes from the Gujerati for merchant,
'banya' - it is the tree under whose shade business was done.
The species found in Vanuatu is Ficus
microcarpa. Not quite as grand, but equally interesting. It is a
true fig, related to the edible fig, and as with all figs, pollinated by a
wasp, with the seeds spead by birds. The seed germinated on an existing forest
tree and grows initially as an epiphyte ie. a plant using another as a support.
It puts down aerial roots which strengthen and multiply, eventually overwhelming
the host tree and killing it; for this reason they are known as strangler figs.
The structure is amazing. A thicket of twisted and interlocking roots which
suddenly meet in a crown about 10-15 metres in the air and generate an entirely
different structure of huge branches above. These giant branches send
down aerial roots which thicken and become props, and enable the tree to spread
laterally.
Because these are forest giants they are quite
difficult to photograph in their entirety. Here is a small one to show the
structure:
 you can see above the form of the young adult tree.
The 'trunk' of matted roots is a hollow where the strangled host tree used to
be, and the crown is developing but without large prop roots allowing sideways
spread, yet.
Looking up at developing aerial roots n an older
tree. These are 10-15m long and some will grow into thick trunks in their own
right:
 The Vanuatans use banyan tree to provide roof beams
for their houses. The area around a selected tree is cleared; choice young
individual aerial roots are then pegged out under tension like tent guy ropes,
and left to grow. Some years later you have a strong thick utterly straight
unknotted timber pole, long and strong enough to support a large roof. The only
work required is to cut it to length. I have seen one in a hall that was a
single piece of timber 30m long. Here is a young tree being used in this manner.
Very clever.
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