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