Most tropical rainforest tree species depends on forest gaps for their successful
regeneration. Evaluation on the gap or canopy openness provides an indicator on the
forest development stages. This paper reported on the canopy openness (CO) of three
study plots at (1-, 9-, 18-year old) rehabilitated forest sites and one study plot at natural
regenerating secondary forest (± 22-year old) in UPM-Mitsubishi Corporation Forest
Rehabilitation Project, Universiti Putra Malaysia Bintulu Sarawak Campus (UPMKB).
Plot of 20 x 20 m was established where dendrometric parameters were collected
while Delta-T Device HemiView system was used to take the hemispherical photograph
and field observation information were used to assess the CO. Qualitative analysis of
the photographs suggested there were three stages of forest growth namely gap,
building and mature stand development phases. These also helped the interpretation
of the quantitative analysis in relation to forest dynamics. Hemispherical photographs
were used for quantitative analysis of the CO. CO showed statistical significant
differences among study plots which recorded a range of 3-78%. Rapid analysis of CO
on the hemispherical photographs with information from the dendrometric
measurement had assisted in assessing the forest stand development. The canopy
openness was dependent on the age of the rehabilitated forest. Overall, the study plots
were in the different stages of stand development.