A review of dipterocarps - Center for International Forestry Research

Seed Handling 79
Table 2. (continued) Seed (fruit) weight and size indicators at harvest.
Species Mean seeds per kilo Mean length (mm) Mean width (mm)
Dryobalanops rappa 1400 17 9
Shorea faguetiana 1400 n/a n/a
Shorea laevis 1600 14 9
Anisoptera marginata 1800 10 10
Shorea leprosula 1800 16 10
Shorea affinis 1900 n/a n/a
Shorea leptoderma 1900 n/a n/a
Shorea ovata 1900 n/a n/a
Dipterocarpus intricatus 2800 20 17
Cotylelobium burckii 2900 10 10
Cotylelobium melanoxylon 2900 9 8
Shorea obtusa 2900 n/a n/a
Hopea dryobalanoides 4000 10 7
Vatica odorata ssp. odorata 4000 8 7
Hopea parviflora 4100 7 6
Shorea guiso 4200 11 6
Hopea odorata 5300 8 6
Hopea foxworthyi 5500 8 5
Hopea ferrea 5800 n/a n/a
Hopea mengerawan 6300 10 4
Hopea nigra 9000 8 5
Vatica mangachapoi 17000 5 5
Monotes kerstingii* 45000 n/a n/a
*: Assessment refers to seeds inside the fruit.
to germinate they can be saved by storing in rigid
containers lined with moist newspaper or other absorbent
materials to keep them moist during transit.
Size Considerations
There is a large range in sizes of dipterocarp seeds (Table
2) which implies that different handling procedures may
be needed for moist seed of particular size ranges. For
example, smaller seeds (< 2 g) would benefit from the
inclusion of packing material to increase the size of air
spaces between the seeds. Crumpled newspapers and
polystyrene chips have been used for this purpose.
Seed Processing
The fruit of dipterocarp species, which is the unit
employed for handling, is generally referred to as the
‘seed’. Removal of calyx lobes (‘wings’) by manual
abscission is carried out for all physiology types. This
enables easier sowing and better contact of the seeds with
the soil.
Factors which should be considered in the drying of
OLDA seeds for storage are described in the summary
at the end of the chapter.
Insect infestation can be a major problem in the
handling of seed, especially in the genus Dipterocarpus
(Table 3, Prasad and Jalil 1987, Eungwijarnpanya and
Hedlin 1984); sometimes 100% of individual seedlots are
rendered useless. Methods to reduce this problem are
required and would be best supported by studies on insect
behaviour. Some studies have already been carried out
on recalcitrant material of the rain forest (Toy et al.
1992, Toy and Toy 1992); extension of such studies to
include seasonal-climate species would be advantageous.
Further discussion of infestation problems can be found
in Chapter 7.
Methods for Storage of Dipterocarp
Seeds
In the past half century, various methods of storage have
been proposed for recalcitrant dipterocarp seeds and,