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โครงการหนังสออเล็กทรอนกสด้านการเกษตร เฉลมพระเกียรตพระบาทสมเด็จพระเจ้าอยู่หัว
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TEAK IN MEKONG
and form of forest produce available. managing the natural forests in Myanmar
Occasionally, TSWC and HSWC overlap since 1856. It involves adoption of a felling
when non-teak hardwoods are also cycle of 30 years, prescription of
extracted in TSWC. Both working circles exploitable sizes of trees, girdling of teak,
are worked under the Myanmar Selection selection making of other hardwoods,
System (MSS). The working circles consist felling of less valuable trees interfering
of a group of reserves, which are further with the growth of teak, thinning of
divided into felling series for the congested teak stands, enumeration of
convenience of working according to the future yield trees down to fixed sizes, and
drainage and the geographical situation. fixing annual allowable cuts (AACs) for
Again, they are sub-divided into teak and other hardwoods. Simple coppice
compartments on maps as well as on the or coppice with standards systems are also
ground; these are the basic management applied in the local supply forest reserves.
units. As for local supply reserves, annual Under MSS, only mature trees are selected
coupes are the basic management units. and harvested. Harvesting of trees is
They are similar to compartments, except regulated based on annual growth and
that they are marked only on maps and are controlled by girth limits prescribed
not permanently demarcated on the ground. species–wise. Felling of exploitable trees is
Teak extraction is organized under the within the bounds of carefully calculated
TSWC which includes all teak bearing forests.
Annual Allowable Cut (AAC). Fixing
Notwithstanding ever-increasing pressures AACs, therefore, accords the increment of
on the forest resources for both domestic individual tree species, which has taken
and export requirements, the forest place over the course of 30-year felling
management in Myanmar has always cycle. AAC is thus a tool that ensures the
adhered to the principles of sustainable harvest of timber yield on a sustained basis.
forest management (SFM). It is manifested AACs for teak and for non-teak other
by the wealth of the forest resources hardwoods are periodically revised and
Myanmar is still endowed with. Myanmar fixed based on the updated information.
Selection System, has been the principal Annual yield is estimated as
forest management system applied in
1
CI − ∗
= + 2
LP
where ARR = annual rate of recruitment of Class II trees to Class I; CI = original no. of trees
in Class I; FC = felling cycle (i.e., 30 years); and LP = decided period to liquidate original CI
trees (usually 60 years).
The MSS is not a true Selection system. It well aware that silvicultural techniques are
is a Stratified Uniform or Girth-limit sometimes highly site-specific. Now, the
system (Dawkins et al., 1998) by which all unsuitability of the MSS is evidenced by the
commercial species including teak above deteriorating stand structure, reduced
minimum felling girths are harvested at growing stock and declining composition of
each felling cycle. The MSS has been being teak, the principal species the whole
applied in Myanmar practically to all types management system of Myanmar virtually
of natural forests with virtually blanket has been targeted (Kyaw, 2002). The extent
silvicultural prescriptions, although it is of the natural teak forests is shrinking, the
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