A review of dipterocarps - Center for International Forestry Research
A review of dipterocarps - Center for International Forestry Research
A review of dipterocarps - Center for International Forestry Research
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Seed Handling 75<br />
Table 1. Likely periods <strong>for</strong> flowering and seed production <strong>of</strong> important Dryobalanops, Dipterocarpus, Shorea, and Anisoptera<br />
species (Krishnapillay, unpublished).<br />
Species<br />
Over the last 25 years various authors have reported<br />
detailed phenological records. Studies include those <strong>of</strong><br />
Burgess (1972), Cockburn (1975) and Ng (1981, 1984)<br />
<strong>for</strong> the Malaysian aseasonal <strong>for</strong>est, and Sukwong et al.<br />
(1975) <strong>for</strong> the dry <strong>for</strong>est <strong>of</strong> Thailand. In Table 1, there is<br />
a general summary <strong>for</strong> the important timber species <strong>of</strong><br />
Peninsular Malaysia.<br />
The infrequency and irregularity <strong>of</strong> dipterocarp<br />
flowering and fruiting in the aseasonal areas have already<br />
been referred to above. A further feature is that flowering<br />
tends to be gregarious and may be limited or may extend<br />
throughout an entire region.<br />
Flower and seed surveys indicate:<br />
1. whether flowering is scattered and confined to<br />
particular species or whether it is a mast flowering;<br />
2. whether the amount <strong>of</strong> seeds available is sufficient to<br />
meet seed collection requirements;<br />
3. whether the crop is sound or has been attacked by<br />
pests or insects; and<br />
4. the time when the seeds will mature.<br />
The natural trigger <strong>for</strong> mast flowering and fruiting<br />
among <strong>dipterocarps</strong> has been sought by looking <strong>for</strong><br />
associations with several factors. Foxworthy (1932) and<br />
Months<br />
J F M A M J J A S O N D<br />
many others suggested an association between flowering<br />
and strong droughts but Wood (1956) disputed the<br />
conclusion. Ng (1981) suggested that a dry spell<br />
preceding leaf flush accompanied by a rising gradient <strong>of</strong><br />
daily sunshine induces flowering. Again, Ashton et al.<br />
(1988) proposed that the environmental trigger is a<br />
protracted low night temperature over a period <strong>of</strong> about<br />
3-4 days. However, experimental evidence is required<br />
to establish cause and effect. The matter is further<br />
discussed in the Seed Physiology chapter.<br />
Seed Procurement<br />
Frequency<br />
Dryobalanops aromatica x x x x x x x x x x x biennial<br />
Dryobalanops oblongifolia x x x x x x x x x x biennial<br />
Shorea leprosula x x x x x x x 3-4 years<br />
Shorea parvifolia x x x x x x x 3-4 years<br />
Dipterocarpus baudii x x x x x x x annual<br />
Dipterocarpus costulatus x x x x x x x 4-5 years<br />
Anisoptera scaphula x x x x 4-5 years<br />
Anisoptera laevis x x x x 4-5 years<br />
Dipterocarpus kerrii x x x x 4-5 years<br />
Shorea macrophylla x x x x x x x x x x x x annual<br />
Shorea macroptera x x x x x 3-4 years<br />
Shorea ovalis x x x x x x x 3-4 years<br />
Shorea platyclados x x x x x 3-4 years<br />
Shorea acuminata x x x x x x x 2-3 years<br />
Shorea bracteolata x x x x x x x 2-3 years<br />
Shorea curtisii x x x x x 3-4 years<br />
Current research on artificial regeneration has been<br />
<strong>review</strong>ed by Mok (1994), whilst Barnard (1950) and<br />
Appanah and Weinland (1993) outline some procedures<br />
that have been used to procure dipterocarp seeds <strong>for</strong><br />
planting programmes. A more detailed procurement<br />
procedure is needed. At present, most methods involve<br />
collection <strong>of</strong> seeds on an ad hoc basis or the collection<br />
<strong>of</strong> wildings. Seed procurement should involve planning,<br />
collection, transporting, processing, testing, temporary<br />
storage and nursery facilities. A general description <strong>of</strong>