A review of dipterocarps - Center for International Forestry Research

Plantations 160
‘Predictive Test for Apical Dominance’. The test has not
yet been established for dipterocarps.
Some research has been carried out on tissue culture
of dipterocarps. Linington (1991) grew seedlings in vitro
from embryos of Dipterocarpus alatus and D.
intricatus. Other in vitro experiments were carried out
by Smits and Struycken (1983) on leaf fragments of
Shorea curtisii, which formed callus and roots but no
shoots, and on nodal explants of Shorea obtusa with
axillary buds, which formed lateral shoots but no roots.
Suspension cultures of embryonic axes of Shorea
roxburghii, which eventually formed whole plantlets,
were carried out (Scott et al. 1988). Umboh et al. (1988)
described the rejuvenation of adult trees and a three step
bud culture for Shorea pinanga. Moura-Costa (1993)
describes trials in tissue culture techniques for in vitro
propagation of Dipterocarpus intricatus which were
successful. No commercially feasible procedure has
been developed and tissue culture cannot be introduced
on an operational scale at this stage.
Darus and Rasip (1990) carried out both intra and
inter-species splice grafting of Dipterocarpus baudii,
Shorea parvifolia, S. leprosula and S. roxburghii. It was
successful and grafts grew faster than single-rooted
seedlings. Chaudhari (1963) tested air-layering in
Shorea robusta and found that it is more successful if
carried out in the months of July and August (midmonsoon)
when there is a full flush of green, healthy
leaves. Zabala (1986) successfully carried out airlayering
of Anisoptera thurifera and Shorea contorta
but was unsuccessful with Hopea foxworthyi, H. plagata
and Dipterocarpus grandiflorus. Air layering was
successful in Shorea palembanica and Vatica pauciflora
(Hallé and Kamil 1981) and in Shorea selanica (Harahap
1972). Rashid and Serjuddoula (1986) rooted branches
from 5 to 10-year old saplings and 50 to 80-year old
trees of Dipterocarpus turbinatus using air-layering.
Rooting was better on branches from old trees.
Planting stock production of the commercially most
important dipterocarp species, whether from seeds or
from cuttings, has largely been solved.
Stump plants
Stumping is used to rejuvenate over-aged planting stock
and in some cases, for example, Tectona grandis, it is
applied as a method of multiplication of the planting
stock. The use of stumped plants started early. Watson
(1931/1932d) found that Dipterocarpus spp. can be
successfully stumped. Hodgson (1937a) showed that
Dipterocarpus baudii, Shorea curtisii and S.
macroptera can be stumped, but it was unsuccessful with
Dryobalanops aromatica, S. leprosula and S.
pauciflora. Barnard (1956) tested stumping of
Dipterocarpus baudii, Dryobalanops aromatica,
Hopea helferi, Neobalanocarpus heimii, Shorea
assamica, S. foxworthyi, S. pauciflora and S. sumatrana.
The stumping was carried out by pruning all side roots
close to the tap root, which itself was cut to 23 cm from
the collar. The shoot was cut to 14 cm from the collar.
Stumping of most species was promising but
Dryobalanops aromatica failed and the success of
Dipterocarpus baudii was uncertain. Sasaki (1980a)
found that bare-root stock of Shorea talura successfully
transplanted after stripping off all the leaves and cutting
back the leader and the tap root. In 1985, a stumping trial
was carried out with Dryobalanops lanceolata in East
Kalimantan, Indonesia, which was highly successful
(Diana 1987). A trial with 2 year old bare-rooted stump
plants of Shorea robusta carried out in West Bengal was
also successful (Anon. 1959). Pande (1960) found
Shorea spp. can be stumped and he carried out some
experiments comparing stumped plants with ball
transplants and basket plants. Basket plants did best.
Landon (1948b) compared stumped plants of
Dryobalanops aromatica with potted seedlings and the
performance of potted seedlings was superior. Pande
(1960) obtained a similar result for Shorea robusta
when survival and growth performance of bare-rooted
stump plants were inferior to ball-rooted transplants and
container plants.
Hormone treatment for growth stimulation of stump
plants was investigated by Masano and Omon (1985),
Omon and Masano (1986), Srivastava et al. (1986) and
Siagian et al. (1989a) but results were inconclusive.
Mori (1981) investigated the effect of starch reserves
in the stem on survival and growth of stumped bare-root
transplants of 16 dipterocarp species. Some species
showed high mortality after stump planting, e.g., Shorea
curtisii, S. ovalis, Hopea nervosa, H. beccariana.
Stimulation of root and shoot growth by growth
regulators or fertilisers was unsuccessful in various
species and some species survival and initial growth were
directly related to starch reserves before planting.
Planting site
The positive role of an initial shelter for the newly planted
dipterocarp trees is beyond doubt (e.g., Wyatt-Smith
1947, Chakravarti 1948, Landon 1948b, Ardikoesoema