A review of dipterocarps - Center for International Forestry Research

Plantations 156
and no longer in need of special protection or special
tending, but only routine cleaning, thinning and pruning
(definition according to Ford-Robertson 1983).
Species Choice
Up to now, little systematic species elimination work
has been done on plantation species with the exception
of Shorea robusta, around which a complete silvicultural
and agri-silvicultural system has developed. Anderson
(1975) proposed Shorea spp. of the pinanga group (e.g.,
Shorea macrophylla, S. pinanga and S. stenoptera) as
an agricultural crop. Jha et al. (1991) have discussed the
selection and evaluation of suitable tree species and food
crops for agro-forestry systems which include Shorea
robusta.
In the Malaysian context Wyatt-Smith (1963b)
presented a list of species with promise for plantation
establishment. They were selected on the basis of 16
criteria, for example, fruiting frequence, seed viability,
collection and nursery handling, fast, early height growth,
natural bole form, self-pruning capacity, timber
properties, etc. The species proposed were: Anisoptera
laevis, A. scaphula, Dipterocarpus baudii, D.
costulatus, D. grandiflorus, D. kerrii, D. verrucosus,
Dryobalanops aromatica, D. oblongifolia, Hopea
odorata, Shorea acuminata, S. curtisii, S. leprosula,
S. macrophylla, S. macroptera, S. ovalis, S. parvifolia,
S. pauciflora and S. platyclados.
Recently, an assessment of the dipterocarp
plantation stands at the Forest Research Institute
Malaysia was carried out in the field and from
phenological and plantation records (Zuhaidi and
Weinland 1994, Appanah and Weinland 1996). The
indicators used were: overall diameter growth rate, initial
height growth rate, stem shape, seedling adaptation phase,
natural pruning capacity, cutting propagation capacity, site
specificity, natural regeneration capacity within the
rotation age, susceptibility to diseases and mode of
growth. The result was that the dipterocarp species
differed considerably in some aspects, especially in
growth form, mode of growth, site specificity and natural
regeneration capacity. In the case of undesirable mode
of growth, the species was nevertheless considered
suitable for planting, if the deficiency could be corrected
by simple silvicultural means. As a result, 15 dipterocarp
species were chosen for immediate inclusion into
plantation programmes (Anisoptera laevis, A. scaphula,
Dipterocarpus baudii, D. costulatus, D. kerrii,
Dryobalanops aromatica, D. oblongifolia, Hopea
odorata, Shorea acuminata, S. leprosula, S.
macroptera, S. macrophylla, S. parvifolia, S.
platyclados and S. ovalis), and 2 species (S. bracteolata
and S. curtisii) were considered promising, but were not
included because of lack of sufficient information and
doubtful field characteristics. For the Bornean part of
Malaysia species could be added, such as Parashorea
malaanonan, Shorea fallax and S. smithiana, and for
Indonesia Dryobalanops lanceolata, Shorea laevis, S.
macrophylla and S. selanica. The most common
plantation species in the Philippines are Dipterocarpus
grandiflorus, Shorea almon, S. contorta, S. guiso, S.
polysperma and S. squamata (e.g., Assidao 1950,
Cacanindin 1983, Abalus et al. 1991). Systematic
species/provenance elimination trials are urgently
needed, particularly in relation to the more pronounced
seasonality following the extensive removal of natural
forests in many regions of the humid tropics.
Planting Stock Production
Seed
Much effort has been invested in developing methods
for seed production, collection and handling. Generally,
dipterocarps fruit at irregular intervals and with varying
seed yield. On top of that, seed viability declines. This
field is reviewed in Chapter 4. Tompsett (1991) has
reviewed the storage aspects of dipterocarp seeds. Much
is also known about germination (e.g., Caguioa 1938,
Jensen 1971, Tixier 1973, Chai 1973, Masano 1988a, b,
Ng and Mat Asri 1991, and others), the effect of
harvesting time and sowing interval on germination
(Haque et al. 1985), the effect of fruit ripeness upon
germination and seedling growth of Shorea ovalis
(Kosasih 1987), the effect of fruit collection time on
the germination of Dryobalanops aromatica (Barnard
1954), the effect of seed size on germination of Shorea
contorta (Basada 1979), the effect of wing colour on
the germination of Shorea pinanga and S. stenoptera
(Masano 1988b) and the effect of tree girth on seed
viability and germination of Shorea robusta (Yadav et
al.1986). Overall, the storage/germination/viability
aspects are sufficiently covered.
There is definitely a lack of information on the seed
yield from trees and stands (quantity of seeds during a
normal seed year). Such information is only available for
Shorea robusta (Jain 1962, Sharma 1981). In Peninsular