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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Seed Handling 76<br />
the basic activities involved in seed procurement is given<br />
below. If a large collection region is monitored, some<br />
seeding may be found every year; in practice, however,<br />
logistical and other problems make annual collection from<br />
aseasonal regions difficult.<br />
Planning<br />
When trees start fruiting, procurement planning has to<br />
be initiated immediately so that good-quality planting<br />
material can be obtained. The period between collection<br />
and storage or sowing should be as short as possible to<br />
reduce the chance <strong>of</strong> seed deterioration. Transport and<br />
processing should be carefully planned and, when<br />
necessary, the nursery advised so that germination space<br />
is available.<br />
Collection<br />
The choice <strong>of</strong> collection technique <strong>for</strong> <strong>for</strong>est tree seed is<br />
dependent on many factors, including the way the tree<br />
disperses its seeds or fruits. For recalcitrant-seeded<br />
dipterocarp species collecting seeds directly from the tree<br />
crown by climbing has several advantages. These are:<br />
a) mature seeds can be selectively collected;<br />
b) seed from each mother tree can be kept separate when<br />
the need arises;<br />
c) potential losses to insect and animal interference can<br />
be minimised; and<br />
d) damage incurred after falling onto the ground, such<br />
as that resulting from desiccation and ageing, can be<br />
limited.<br />
Generally, collections <strong>of</strong> seeds should be made from<br />
healthy trees that have good shape and <strong>for</strong>m, avoiding<br />
trees that are obviously diseased. Inclusion <strong>of</strong> immature<br />
seeds and seeds that have been lying on the ground <strong>for</strong><br />
some time should be minimised. Various methods <strong>of</strong><br />
collection used by the seed collection team at the Forest<br />
<strong>Research</strong> Institute Malaysia (FRIM) are described below<br />
along with their advantages and limitations. The methods<br />
can be divided into two main types. Firstly, those that do<br />
not involve climbing, the overall operation being confined<br />
to the ground (Methods 1-3). Secondly, those involving<br />
an element <strong>of</strong> tree climbing (Methods 4-5).<br />
Factors to be considered <strong>for</strong> harvesting in the<br />
aseasonal zones are given in the summary at the end <strong>of</strong><br />
the chapter.<br />
1. Ground collection<br />
Ground collection does not require employment <strong>of</strong> staff<br />
possessing both tree climbing skills and the ability to<br />
collect seed efficiently; the cost is thus reduced.<br />
Nevertheless, this method necessitates good preparation:<br />
trees must be selected and marked; and all vegetation,<br />
debris and old or premature seeds below the trees must<br />
be cleared. Proper supervision <strong>of</strong> collection is also<br />
necessary. The limitations <strong>of</strong> this method are:<br />
a) seed collection is protracted;<br />
b) collections have to be made daily until most <strong>of</strong> the<br />
seeds have fallen;<br />
c) there is competition with mammals, birds and insects;<br />
d) fungal problems, seed deterioration and premature<br />
germination are encountered; and<br />
e) ground cover surrounding the tree is destroyed.<br />
2. Collection using nets or canvas<br />
With this method, nets or canvas are laid under the tree.<br />
This procedure is desirable in that undergrowth is not<br />
destroyed. The limitations <strong>of</strong> this method are:<br />
a) it is not suitable under dense undergrowth; and<br />
b) daily collections <strong>of</strong> fallen seeds need to be made.<br />
3. Shaking <strong>of</strong> seed-bearing branches<br />
This method is referred to as the ‘fishing line’ method. A<br />
local home-made catapult is used to shoot a singlefilament<br />
fishing line, attached to a lead weight, over<br />
smaller branches <strong>of</strong> the tree from which seed is to be<br />
collected. A polythene rope is then pulled over the branch<br />
and back down to the ground using the fishing line; the<br />
rope is then pulled vigorously to shake down the seeds.<br />
The method is suitable <strong>for</strong> small trees and <strong>for</strong> those<br />
standing in the open. The limitations <strong>of</strong> this method are:<br />
a) it cannot be used with very tall trees, which may be<br />
the ones possessing the best genotypes;<br />
b) a clear view <strong>of</strong> the terminal branches is required <strong>for</strong><br />
the lead weight to be aimed accurately;<br />
c) it usually requires several attempts be<strong>for</strong>e the line is<br />
satisfactorily positioned on the right branch; and<br />
d) the lead weight and line are not fully controllable and<br />
minor injuries may sometimes be experienced by the<br />
operator.<br />
4. Free climbing<br />
This method is employed by pr<strong>of</strong>essional tree climbers.<br />
It involves the use <strong>of</strong> a neighbouring smaller tree <strong>for</strong> the<br />
initial ascent, after which the climber crosses to the main<br />
seed tree at a height where the bole is small enough to<br />
hold safely and ascend the tree. The climber cuts <strong>of</strong>f and