To manage and preserve one of the regional important forest types and
the native tree species in a relatively minimized human disturbed forest,
and/or in a forest fragmentation in a seasonally dry forest type, long-term
dynamics of a deciduous dipterocarp forest was investigated to gain the
basic information for formulating an alternative future management guideline.
Four stands of deciduous dipterocarp forest were monitored for their
changes with time in stand structure, species composition, species
diversity, tree death, recruitment and growth over 17 years in a well
preserved forest area of the Sakaerat Biosphere Reserves, Nakorn Ratchasima
Province, Northeastern Thailand.
Each stand composing of different leading tree species was repeatedly
censussed in each 1 ha permanent plot at approximately 1 year interval
during 1984 to 2001. All trees with DBH 4.5 cm were marked, numbering
tagged, DBH measured, species identified, death trees and trees grew to
reach the DBH fixed size at 4.5 cm in each census year counted. Stand
structure in terms of stratification, size distribution and crown cover
were initially investigated in all 4 stands. Their stratifications were
observed to be 2-3 crown layers and size structure followed a negative
exponential form. The stands were largely opened with large crown opening
(gap) and less lateral crown overlapping. Stand density and stand basal
area demonstrated moderately dense and less basal area coverage as
contrasted to other forest types. Number of tree species ranged from 32 to
37 and being dominated by most dipterocarp tree species followed by some
other families and notably some legumes. Based on their ecological
importance value indices, they were classified into 4 different community
association types.
Over 17 years monitoring, trees undergone changed with death exceeded
recruitment although the total stand density, number of species and basal
area increased considerably but size structure of trees in each stand was
not drastically changed. The major leading tree species could be maintained
in 3 stands while in another one stand some associated leading tree species
changed. Leguminous tree species were found to be relatively success in
recruitment in the 4 stands. Growth of tree was remarkably rapid for those
considered to be the pioneer tree species and those belonging to legume
tree group while the dipterocarp tree group was less changed over the
period of 17 years. With this relatively good control of stands under the
biosphere reserve scheme, this forest community might provide a good sample
for future stand prescription in forest management and conservation of
local tree species in the future national forest management that local
inhabitant will be involved as the manager of community forest in the region.
Coordinator: Prof. Isamu Yamada (Ext. 7310)
21st Century COE Program
-Aiming for COE of Integrated Area Studies-