The results of a sensitivity analysis of the “biodiversity rotation
age” to the carbon price showed that the “biodiversity rotation age”
and the bird density remained constant as the carbon price went
up, but the NPV increased. The results suggested that the increase in
the carbon price had no effect on the biodiversity rotation age (since
MVPwas binding), but led to a higher economic return to forest owners.
This research has suggested that the inclusion of the biodiversity
component (MVP ha−1 of birds) into the optimization model induced
a longer rotation age compared to the carbon rotation age for
E. urophylla. The optimal biodiversity rotation age (when the MVP
ha−1 was 50) was between 10 and 11 years. The average NPV was
11.46 million VND ha−1 (674.12 USD ha−1). This result for the
incorporation of biodiversity preservation resulting in lengthening
of the optimal rotation age, was similar to the findings by Koskela
et al. (2007).