P36
WILLIAM MACNAE
Silvicultural rotation is designed to produce the maximum economic
yield of the tree of choice. I n Malaya two types of forest are under
management. I n Selangor and states to the southward, Bruguiera
cylindrica is exploited. I n Perak, where the mangals are much more
extensive, the species of Rhixophora are exploited. The former is used
directly as firewood, because it is easily split, or as poles for scaffolding,
etc. The latter are used for charcoal production.
Because of the nature of the forest B. cylindricu is more easily
cxtracted. The forests are relatively narrow and lie parallel to the
coastline, and an arterial road runs immediately behind them. Extraction canals are dug at right angles to the road and at convenient
distances apart, and loading stations built where these impinge on the
road. The canals divide the forest into strips and these strips are cut
out by rotation when the trees reach an economic size. Regeneration of
a cleared strip is rapid and complete and the strip is then thinned
periodically, the thinnings being sold as fishing stakes, fencing stakes
and for other similar purposes.
Management of the very extensive mangals of the Matang in Perak
is not so simple. I n these forests trees of one or other of the two species
of Rhizophoru are felled, cut up into lengths, which must be convenient
both for easy carrying and for easy stacking within the kiln of the
charcoal burner. The larger trees are unpopular, and the most popular
size of tree has a girth a t the height of the last prop root of around
50 cm (20 in). Management is designed to produce an ample supply of
trees of these dimensions.
Silviculture in this and other similar areas depends on various
factors of which the most important are the accessibility of the forest
and consequent ease of removal of timber, and then the ease and degree.
of cover by regeneration, either natural or encouraged by planting
Mangrove timber is all heavy, and will not float in water, so it has to be
carried and hauled out manually. It has been calculated and found in
practice that a rotation based on a forty-year cycle will provide trees of
a size suitable for the demands of the charcoal burners.
I n an undisturbed rhizophora forest the trees are close together,
giving long clean stems and a continuous canopy. Younger trees and
other species form several storeys beneath. In early stages of exploitation those younger trees which have reached the preferred size are cut
out. The older trees remain as standards and provide seedlings for
regeneration. This elementary " selection " system has disadvantages,
mainly as the result of damage to younger trees. I n Malaya a variation,
known as the " shelter wood " system, is used. Under this system all
younger trees are cut out leaving the older trees t o give a complete
WILLIAM MACNAE
Silvicultural rotation is designed to produce the maximum economic
yield of the tree of choice. I n Malaya two types of forest are under
management. I n Selangor and states to the southward, Bruguiera
cylindrica is exploited. I n Perak, where the mangals are much more
extensive, the species of Rhixophora are exploited. The former is used
directly as firewood, because it is easily split, or as poles for scaffolding,
etc. The latter are used for charcoal production.
Because of the nature of the forest B. cylindricu is more easily
cxtracted. The forests are relatively narrow and lie parallel to the
coastline, and an arterial road runs immediately behind them. Extraction canals are dug at right angles to the road and at convenient
distances apart, and loading stations built where these impinge on the
road. The canals divide the forest into strips and these strips are cut
out by rotation when the trees reach an economic size. Regeneration of
a cleared strip is rapid and complete and the strip is then thinned
periodically, the thinnings being sold as fishing stakes, fencing stakes
and for other similar purposes.
Management of the very extensive mangals of the Matang in Perak
is not so simple. I n these forests trees of one or other of the two species
of Rhizophoru are felled, cut up into lengths, which must be convenient
both for easy carrying and for easy stacking within the kiln of the
charcoal burner. The larger trees are unpopular, and the most popular
size of tree has a girth a t the height of the last prop root of around
50 cm (20 in). Management is designed to produce an ample supply of
trees of these dimensions.
Silviculture in this and other similar areas depends on various
factors of which the most important are the accessibility of the forest
and consequent ease of removal of timber, and then the ease and degree.
of cover by regeneration, either natural or encouraged by planting
Mangrove timber is all heavy, and will not float in water, so it has to be
carried and hauled out manually. It has been calculated and found in
practice that a rotation based on a forty-year cycle will provide trees of
a size suitable for the demands of the charcoal burners.
I n an undisturbed rhizophora forest the trees are close together,
giving long clean stems and a continuous canopy. Younger trees and
other species form several storeys beneath. In early stages of exploitation those younger trees which have reached the preferred size are cut
out. The older trees remain as standards and provide seedlings for
regeneration. This elementary " selection " system has disadvantages,
mainly as the result of damage to younger trees. I n Malaya a variation,
known as the " shelter wood " system, is used. Under this system all
younger trees are cut out leaving the older trees t o give a complete