this phenomenon arises from
the fact that early successional species, which occupy a secondary
forest stand in the first one to three decades, disappear as intermediate
successional species take over, while trees that are planted in
plantation forests at the same time as early successional tree species
persist to maturity thereby ending up with larger stems. Thus,
the two forest types may have had fairly similar tree species in this
tropical forest, but those in the old-growth secondary forest were
relatively younger and hence had smaller stem DBH. The results
indicated also that mixed indigenous plantation forest had a significantly
larger proportion of individual trees with high wood specific
gravity than old-growth secondary forest. This can be attributed
to the fact that tree species in the mixed indigenous plantation
were selected based on their superior wood attributes (KFS,
2010), while those in the old-growth secondary forest recruited
naturally. Thus, the mixed plantation ended up with more individual
trees with high wood specific gravity, which significantly
increased its mean wood specific gravity compared to the oldgrowth
secondary forest where the same tree species were represented
but with a lower population.