Rapid Recovery of tree diversity over forest structure in post-kaingin secondary forests in the upland Philippines

The Philippines is one of the few countries that is, entirety, both a biodiversity hotspot and a mega-diversity country, placing it amongst the top priority hotspots for global conservation. Kaingin – the local term for shifting cultivation, is a widespread land-use in forest-agriculture frontiers in upland areas of the country, and regarded as one of the key drivers of deforestation and forest degradation. Whilst kaingin is not yet a recognised land-use, it is still the mainstay of livelihoods to millions of upland rural farmers in the Philippines. We investigated the conservation value of post-kaingin secondary forests in an upland area of Philippines along a fallow gradient. Fallow areas that have been abandoned for less than 5 years, 6-10 years, 11-20 years and 21-30 years were identified and inventoried following a modified Gentry plot approach. Tree diversity, species composition and forest structure parameters were measured, and recovery rate of diversity and forest structure parameters were compared with that of undisturbed forests. Altogether, 2918 tree individuals were measured from 100 transects of 250m2 size. 131 tree species belonging to 86 genera and 46 families were identified, with 10 species being listed as critically endangered globally. Species richness was significantly (p