A review of dipterocarps - Center for International Forestry Research

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