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 162<br />
Qureshi et al. (1968) investigated the effect <strong>of</strong> soil<br />
working and weeding on the growth and establishment<br />
<strong>of</strong> Shorea robusta plantations.<br />
A common practice is to establish dipterocarp<br />
plantations by line planting into <strong>for</strong>est vegetation. Ådjers<br />
et al. (1995) have investigated the effect <strong>of</strong> line width,<br />
direction and maintenance on survival and per<strong>for</strong>mance<br />
<strong>of</strong> Shorea johorensis, S. leprosula and S. parvifolia. Line<br />
direction had little effect on survival or growth, although<br />
SE-NW line direction was best <strong>for</strong> S. johorensis. Line<br />
width did not affect survival, but effect on growth was<br />
significant. Line widths used were 1, 2 and 3 m. In the<br />
control, the seedlings were planted under the <strong>for</strong>est canopy<br />
without opening it above the planting line. Horizontal<br />
line maintenance was better than vertical line maintenance<br />
and growth <strong>of</strong> S. johorensis and S. parvifolia benefitted<br />
from it. Survival was not affected. Omon (1986) tested<br />
the strip width to be cut into secondary <strong>for</strong>est <strong>for</strong> optimal<br />
growth <strong>of</strong> planted Shorea ovalis seedlings. He found that<br />
strips 1 m wide were the best <strong>for</strong> survival and<br />
per<strong>for</strong>mance.<br />
Planting patterns in the context <strong>of</strong> underplanting were<br />
discussed by Tang and Chew (1980). Shorea parvifolia<br />
was underplanted in two patterns: (i) line planting, and<br />
(ii) group planting in groups <strong>of</strong> 4-6 trees at final spacing.<br />
Six months later the tree crowns overshadowing the<br />
planting lines or the planting patches were removed.<br />
Differences in growth were not significant, however,<br />
survival was higher <strong>for</strong> the group planting. The authors<br />
recommend removal <strong>of</strong> overhead shade after 6 months<br />
and underplanting as group planting. Abalus et al. (1991)<br />
recommend groups planted at a spacing <strong>of</strong> 10 x 10 m.<br />
In an underplanting trial at Agumbe in Karnataka,<br />
India, Vateria indica seedlings were planted in 1962 and<br />
observed until 1978. Those growing under lateral shade<br />
with sufficient light had grown to an average height <strong>of</strong><br />
over 5 m in 16 years while those which had no light<br />
reaching them had survived but had grown only about<br />
5 cm (Rai, personal communication).<br />
Planting Techniques<br />
Outside India, Indonesia and Malaysia no large-scale<br />
plantations <strong>of</strong> dipterocarp species exist. Although<br />
experimental <strong>for</strong>ests have been established in several<br />
regions in<strong>for</strong>mation on the establishment techniques is<br />
scarce. The most complete account <strong>of</strong> artificial<br />
regeneration in the Malaysian context is by Barnard<br />
(1956). Agpaoa et al. (1976) give an overview <strong>of</strong> the<br />
planting techniques in the Philippines context. Most <strong>of</strong><br />
the in<strong>for</strong>mation on planting techniques is contained in<br />
instructions <strong>of</strong> <strong>for</strong>est services or <strong>of</strong> companies, and thus<br />
not always readily available. Planting techniques have<br />
been worked out very well <strong>for</strong> tropical conditions and<br />
the basics are generally valid irrespective <strong>of</strong> region,<br />
species or site.<br />
Planting methods can be classified into: (1) planting<br />
<strong>of</strong> potted seedlings or transplants, (2) planting <strong>of</strong> bareroot<br />
seedlings or transplants, and (3) planting <strong>of</strong> stumps.<br />
Normally, <strong>dipterocarps</strong> are planted as potted seedlings,<br />
when they are about 9 months old and about 25-30 cm<br />
tall. Size or age <strong>of</strong> planting stock has been investigated<br />
by various researchers. In general, potted seedlings had<br />
better survival (e.g., Barnard 1954, Cerna and Abarquez<br />
1959). The planting holes are usually prepared to a depth<br />
<strong>of</strong> 25 cm. The seedling or transplant is removed from the<br />
container (polythene bag) with the earthball undamaged.<br />
If broken, the beneficial effect <strong>of</strong> planting seedlings or<br />
transplants with undamaged roots is lost. Different pot<br />
types were used in the past, e.g., bamboo pots, veneer<br />
pots, tin cans. However, a plastic bag <strong>of</strong> 500 cc content<br />
(e.g., 10 cm x 15 cm and 6.3 cm diameter) is the bag size<br />
commonly used. Barnard (1954) tested different sizes <strong>of</strong><br />
bamboo pots and larger pots gave better survival. A trial<br />
on varying pot sizes using Shorea polysperma was carried<br />
out by Bruzon and Serna (1980) and height development<br />
in 8 cm diameter pots was best. When planting, the upper<br />
part <strong>of</strong> the earthball should be slightly below the soil<br />
surface <strong>for</strong> successful establishment, and never above it.<br />
Depth <strong>of</strong> planting was investigated, e.g., by Shrubshall<br />
(1940), and Walton (1938) who <strong>for</strong> Dryobalanops<br />
oblongifolia found deep planting (collar 5 cm below<br />
surface) gave the best results and shallow planting caused<br />
75% mortality. Shrubshall (1940) also reported deep<br />
planting gave the best results. Earth is firmly placed<br />
around the plant to close the air spaces and finally, the<br />
young plants are mulched with organic material to<br />
prevent desiccation and overheating <strong>of</strong> the soil. Bareroot<br />
seedlings can be planted in two ways: hole-planted<br />
as in potted plants; and notch-planted. In notch planting a<br />
cone- or wedge-shape hole is made with a spade or a<br />
hoe. The roots <strong>of</strong> the plant are placed into the hole to the<br />
required depth and the soil firmed around the plant.<br />
Barnard and Setten (1955) reported on the comparison<br />
<strong>of</strong> planting trials <strong>of</strong> Dryobalanops oblongifolia in<br />
prepared planting patches and in notches. The<br />
per<strong>for</strong>mance <strong>of</strong> two types <strong>of</strong> seedlings were compared: