Biodiversity and ecosystem carbon budget in the upland landscapes following shifting cultivation by small-holder kaingin farmers in the Philippines

Shifting cultivation, locally known as kaingin, is one of the common forest uses in upland Philippines. Despite efforts by the Philippines government to ban this practice, kaingin systems play an important role in the food security of small-holder farmers. We conducted an exploratory survey in Leyte province across fallow kaingin areas of four distinct categories (i.e. 0–5; 5–10; 10–20; and 20–30 years) and in secondary forests without any kaingin history. A transect method was followed, and 20 transects of 50 m × 5 m were established along each fallow category and in forests where we recorded tree diversity, standing biomass, biomass in dead/dying/burnt woods, biomass of leaf litter/woody debris/ undergrowths and in fine roots. Study reveals that fallow areas of older age embrace a considerable amount of tree diversity and carbon comparable to secondary forests. The contribution of small diameter trees and dead/dying/burnt woods were however prominent in carbon budget of young kaingin areas where large diameter trees have the largest share in secondary forests. Greater understanding of the pattern and processes of biodiversity and carbon pool in kaingin landscapes could be useful to restore the degraded upland areas more efficiently, and could help develop possible mechanisms to reward small-holder farmers to avoid this age-old practice