A review of dipterocarps - Center for International Forestry Research

Plantations 158
able to store them in polythene plastic bags for several
months without loss of viability. The effect of hormone
application on the storage of potted seedlings has been
investigated by Siagian et al. (1989b) for Shorea selanica.
Dabral and Ghei (1961) applied gibbelleric acid to the
shoots of Shorea robusta seedlings but failed to boost
root development and growth.
There has been some systematic research on
fertilisation of nursery planting stock. An early
investigation into morphological symptoms of mineral
deficiencies of nursery stock of Shorea robusta was
carried out by Kaul et al. (1966). Deficiencies in N, P,
K, Ca and Mg caused marked symptoms in both shoot
and root development. Deficiencies in N, P and Mg
affected height increment especially, while root
development was affected by deficiencies in all minerals.
Bruzon (1978, 1982) investigated the optimal NPK
(14:14:14) fertilisation of Shorea contorta nursery
seedlings of an average height of 15 cm grown in a
mixture of potting medium and forest soil. The seedlings
were fertilised (control, 2, 4, 6 and 8g) three times at an
interval of approximately one month. The survival was
best in the unfertilised control and with applications of
2g and 4g per seedling. Height and diameter growth were
best in the 2g, 4g and 6g treatments. Survival was
significantly reduced with application of 4 and 8g of
fertiliser. Fertilisation with 2g NPK per plant is
recommended. Bhatnagar (1978) tested the nutritional
requirements of Dipterocarpus macrocarpus seedlings.
For 1 year the potted seedlings were fertilised every two
weeks with 450 and 900 mg NPK solution. Achieved
height and dry weight were greatest with N and P at 900
mg application and K at 450 mg application.
Sundralingam (1983) investigated the best height growth
response of below 1-year old Dryobalanops aromatica
and D. oblongifolia seedlings by fertilising the seedlings
in a shaded nursery with 50 mg P 2 O 5 (as superphosphate)
and 300 mg N (applied as ammonium sulphate at 2-month
intervals) per plant. The height growth was reduced to
that of the control plants when the amount of phosphorus
was doubled. In another experiment Sundralingam et al.
(1985) tested the nitrogen and phosphorus requirements
of Shorea ovalis seedlings in sand culture by fertilising
seedlings with various dosages at 2-4 week intervals.
After 8 months it was found that the optimal N dosage
was 80 mg/plant per application and the optimal P dosage
4 mg/plant per application.
Another method to boost performance is through
mycorrhizal inoculation. Garbaye (1989) reviewed the
literature on natural and controlled mycorrhizal infection
in tropical plantations including dipterocarp plantations.
Santoso (1988, 1989, 1991) tested inocula of Boletus,
Russula (3 species) and Scleroderma spp. on 45-day old
seedlings of Hopea odorata, Shorea compressa, S.
pinanga, S. stenoptera and Vatica sumatrana and after
6 months growth parameters such as diameter, dry weight
of leaves, stems and roots were increased. Responses
were best in Hopea odorata, Shorea stenoptera and
Vatica sumatrana with Scleroderma spp., while
responses of S. pinanga were best with Russula (species
2). Santoso et al. (1989) found that under the same
experimental conditions as above all inocula increased
the accumulation of micro-nutrients (Fe, Mn, Cu, Zn and
Al) in leaves, stems and roots of the seedlings. Turner et
al. (1993) investigated the effect of fertiliser application
on mycorrhizal infection. NPK (combined N, P 2 O 5 and
K 2 O) was applied at a rate of 10g m -2 to potted Shorea
macroptera seedlings (potting medium: forest soil). In
fertilised pots ectomycorrhizal infection was increased
but the correlation between extent of infection and
growth was closer in unfertilised seedlings, suggesting
that seedlings may only be responsive to fertiliser
addition when grown at very low nutrient availabilities.
Mycorrhizal infection may be important under such
conditions. Smits (1982, 1987, 1993) pointed out the
importance of mycorrhizal infection in nurseries and
described controlled inoculation
Wilding planting stock
‘A wilding is a naturally-grown, in contrast to a nurseryraised
seedling, sometimes used in forest planting when
nursery stock is scarce’ (Ford-Robertson 1983).
Wildings were frequently used in the past and various
trials have been carried out with them.
Wildings have been successfully used for planting
places lacking natural regeneration. Capellan (1961)
tested the possibilities of Parashorea plicata and Shorea
contorta wildings as planting stock and P. plicata had
better survival than S. contorta. Barnard (1954) mentions
that wildings of Shorea macrophylla, S. multiflora,
Dipterocarpus baudii and Neobalanocarpus heimii
were successfully planted. Gill (1970), while reviewing
experimental enrichment planting work in West Malaysia,
found that transplanting bare-rooted wildings of
Anisoptera laevis, Shorea curtisii, S. leprosula, S.