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 77<br />
drops down small branches bearing the seeds. The<br />
limitations <strong>of</strong> this method are:<br />
a) a suitable smaller proximal tree (or group <strong>of</strong> trees) is<br />
required;<br />
b) it is very strenuous and time consuming which limits<br />
the number <strong>of</strong> trees that can be worked on per day;<br />
and<br />
c) it is dangerous.<br />
5. Methods <strong>of</strong> climbing using equipment<br />
With the following three methods climbing gear is used<br />
to gain access to the canopy making the overall procedures<br />
much safer.<br />
a) Tree bicycle<br />
Trees can be climbed without causing serious damage to<br />
the tree trunk. The equipment consists <strong>of</strong> two unequally<br />
long bearing pieces with rests <strong>for</strong> the feet. Flexible steel<br />
bands are positioned around the tree trunk at the far end<br />
<strong>of</strong> the bearing pieces,. By a bicycling motion the tree<br />
climber ascends the tree moving the steel bands upwards<br />
parallel to the tree axis. During this procedure the climber<br />
wears a security belt with ropes fastened around the tree.<br />
The equipment <strong>of</strong>fers a com<strong>for</strong>table and safe basis <strong>for</strong><br />
standing during working in the crown. This method is<br />
not suitable, however, <strong>for</strong> trees that have branches on the<br />
bole. Also, use is limited to those trees having a girth that<br />
can be easily encircled by the fastening ropes.<br />
b) Climbing using spurs<br />
With this method the climber uses a pair <strong>of</strong> spurs fastened<br />
under his shoes in addition to the security belt and<br />
fastening ropes which were mentioned above <strong>for</strong> the<br />
bicycle method. The climber uses the spurs by pricking<br />
its spikes into the tree bark to secure a foothold <strong>for</strong> every<br />
upward movement. The holes made by the climbing spurs<br />
are vulnerable to fungal, viral and bacterial attack, a<br />
problem which is aggravated if trees are <strong>of</strong>ten climbed in<br />
this way. It is thus advisable that, if this method is<br />
employed, an interval <strong>of</strong> at least a year should be allowed<br />
be<strong>for</strong>e a further collection is made; healing <strong>of</strong> the<br />
damaged parts on the trunk can then occur. As is the case<br />
<strong>for</strong> the tree bicycle method, the circumference must not<br />
be too large.<br />
c) ‘Roping up’ method<br />
In this method a line is shot up into the crown over two<br />
or more strong branches. The climbing rope is then drawn<br />
up over the branches and, on return to ground level, the<br />
free end is fastened at the base <strong>of</strong> the trunk. The climber<br />
then uses the rope to pull himself up using a shoemore.<br />
This method can be used whatever the girth <strong>of</strong> the trunk<br />
and does not damage the tree.<br />
A combination <strong>of</strong> elements from different methods<br />
may be necessary; <strong>for</strong> example, it may be desirable to<br />
combine the laying-nets as in Method 2 with the shaking<br />
element <strong>of</strong> Method 3.<br />
Seed Transportation<br />
The length <strong>of</strong> time between collection <strong>of</strong> moist<br />
dipterocarp seed and its arrival at the seed centre is<br />
crucial in determining viability. Transport should be<br />
carefully planned to minimise delay; staff in the nursery<br />
or seed store should be advised <strong>of</strong> the schedule so that<br />
seed can be handled immediately on receipt.<br />
Methods <strong>for</strong> transport <strong>of</strong> OLDA seeds collected in<br />
the dry condition are given in the summary at the end <strong>of</strong><br />
the chapter. The following points are relevant in relation<br />
to the transport <strong>of</strong> moist dipterocarp seeds.<br />
Ventilation and Moisture Content<br />
Moist dipterocarp seeds respire intensively and so require<br />
good ventilation. If large quantities are closely packed,<br />
the seeds become anaerobic, physiological breakdown<br />
takes place, fungal growth takes hold and overheating<br />
occurs; these changes accelerate deterioration <strong>of</strong> the seed.<br />
Recalcitrant-seeded species will deteriorate rapidly if their<br />
moisture content is reduced significantly; ventilation must<br />
be provided, but without drying the seed.<br />
If plastic bags are used to contain the seeds, their tops<br />
should either be left open and folded over or they should<br />
be tied and small holes made in their sides. Hessian or<br />
jute bags with a loose weave are also suitable <strong>for</strong> transport.<br />
Desiccation is more likely to occur if transport is in open<br />
vehicles; air movement may accelerate the process.<br />
Temperature<br />
Temperatures below 16 o C or above 32 o C should be<br />
strictly avoided <strong>for</strong> moist, recalcitrant seeds. Good<br />
ventilation reduces heat build-up from respiration. Seeds<br />
should be shaded from direct sunlight at all times during<br />
transport.<br />
Long Journeys<br />
Ef<strong>for</strong>ts must be made to dispatch the seeds to their<br />
destination within two days <strong>of</strong> collection. If seeds begin