A review of dipterocarps - Center for International Forestry Research

Plantations 155
dipterocarps when inoculated with Scleroderma
columnare. One dipterocarp species (Shorea pinanga)
showed better results when inoculated with Russula
amatic. Inoculation techniques for nurseries are
described for example by Bakshi (1980), Khemnark
(1980), Smits (1987) and Tacon et al. (1988).
Mycorrhizal research has yielded practical incoculation
techniques for nurseries.
Site requirements of dipterocarp species have only
been examined systematically for Shorea robusta (e.g.,
by Yadav and Mathur 1962, Bhatnagar 1966). Butt and
Sia (1982) and Ting (1986) touch on the problem in their
evaluation for reforestation and rehabilitation projects
in Sarawak, however, assignment of species to site was
not based on species-adaptation trials. Most of the
information has still to be obtained from species
compilations (e.g., Foxworthy 1932, Symington 1974,
Smitinand et al. 1980, Ashton 1982) which contain
information on the natural habitat of the species, from
which in many cases generalised inferences to the site
requirements under plantation conditions can be made.
A systematic approach to this problem through species
adaptation trials is urgently needed. Such trials would
include the species most likely to be used for plantation
programmes. Field operations before and during planting
site operation change site conditions, foremost the soilphysical
structure so site management with low negative
impact is important for the success of a plantation. Dabral
et al. (1984) reported impaired rooting behaviour of
Shorea robusta in compacted soil. Kamaruzaman (1988)
showed that bulk densities in crawler tractor tracks
declined to 1.52 g cm -3 , at which rooting is severely
impaired. Gupta (1955) investigated compaction,
erodibility and other soil-morphological features in
Shorea robusta forests and taungya plantations. In the
latter, cultivation and continued exposure had caused hard
pans to develop which resulted in reduced seepage and
increased erodibility.
When planting a species the silvicultural characters
of the trees should be known. Stand density regimes
depend on a clear understanding of the growth form,
which is the characteristic shape, posture, and mode of
growth of a tree (Ford-Robertson 1983). Troup (1980)
describes silvicultural characters of 22 dipterocarp
species besides Shorea robusta. Additional work
includes that of Kadambi (1954, 1957), but, these reports
cover only a small percentage of the total species of
dipterocarps. Dipterocarp species differ considerably in
terms of crown structure, branching habit, growth
dynamics etc. Hallé and Ng (1981) worked on crown
architecture, especially reiteration and aggregation.
Zuhaidi and Weinland (1994) and Appanah and Weinland
(1993) give information on growth form of some
commercially important dipterocarp species for planting
and mention the species: Anisoptera laevis, A. scaphula,
Dryobalanops aromatica, D. oblongifolia, Hopea
odorata, Shorea acuminata, S. leprosula, S.
macroptera, S. macrophylla, S. parvifolia, S.
platyclados and S. ovalis. Information on speciesspecific
growth dynamics, which is required for the
design of species mixtures, is contained, e.g., in Howard
(1925), Edwards and Mead (1930), Griffith and Bakshi
Sant Ram (1943), Mathauda (1953b, 1955), Ng and Tang
(1974), Rai (1979, 1981a, b, 1989), Masano et al.
(1987), Primack et al. (1989), Zuhaidi et al. (1994).
Within the group of the fast-growing light hardwoods
(e.g., Shorea leprosula, S. parvifolia, S. ovalis and S.
macrophylla) important differences between species in
growth dynamics seem to exist (e.g., Wyatt-Smith 1963b,
Zuhaidi and Weinland 1994, Zuhaidi et al. 1994).
The following characters of a tree species to be
planted should be known to the practising silviculturist:
(i) control of side branch development by the leader shoot
(apical dominance), (ii) phototropic sensitivity
(phototropism), (iii) self-pruning capacity, (iv) type of
branch formation, and (v) growth rates and growth
dynamics.
In conclusion, there is a pressing need to build up
information on the silvical and silvicultural properties
(stress tolerance, growth form, mode of growth) of a
defined set of the most promising species for plantations
and on the site requirements (site adaptation) using
standardised methods.
Stand Regeneration and Establishment
Regeneration of a forest is the renewal of a tree crop,
whether by natural or artificial means. Renewal by selfsown
seed is termed ‘natural regeneration’, by sowing
or planting ‘artificial regeneration’. Formation of stands
means all the operations contributing to the creation of
a new crop up to the stage where it is considered
established, i.e. from seed procurement, as for a nursery,
to early tending. Establishment is the process of
developing a crop to the stage at which the young trees
may be considered established, i.e. safe from normal
adverse influences e.g., drought, weeds or browsing,