Tree Diversity and Timber Resources Assessment in Secondary Forests of Quirino Forest Landscape Project, Philippines

This is a part of baseline data gathering for a short-term project in 12 barangays referred as Quirino Forest Landscape (QFL). The study assessed trees’ diversity, biophysical attributes, utilization values and ecological importance. Quadrat sampling was performed to gather abundance and biometric data of trees with diameter at breast height of 15cm and greater. Data analysis employed alpha diversity indices, distance and similarity measures, carbon-based allometric equations, stand-stock table and other tools. Secondary information and first-hand accounts were used to gather ecological and utilization values. Diversity was very high, highly heterogeneous, and very complex. Diffun was found to have the most contiguous tree assemblage; Cabarroguis and Aglipay share more species than with Maddela and Diffun. Analysis of photographed canopies revealed mean canopy closure is 77.41%. Close to half of individual trees fall under 40cm and 50cm dbh classes, implying QFL is secondary forest. Trees have aboveground stored Carbon of 642.87tons/ha or 1.26tons/tree. The area host five premium timbers, 10 Philippine Mahogany timbers, Rosewoods, 15 Furniture/Construction, and 95 underutilized species. Slightly more than a third (33.60%) of sampled canopy trees (43 species total) require conservation effort, White Lauan (Shorea contorta) is the most critical. To control further damage, measures to prevent further forest cover loss must be instituted to understand and sustain ecosystem functions.

Keywords: Secondary Forest, biodiversity, importance value, carbon storage, cabarroguis, Quirino Forest Landscape