title: Tropical secondary forests regenerating after shifting cultivation in the Philippines uplands are important carbon sinks.
abstract: In the tropics, shifting cultivation has long been attributed to large scale forest degradation, and remains a major source of uncertainty in forest carbon accounting. In the Philippines, shifting cultivation, locally known as kaingin, is a major land-use in upland areas. We measured the distribution and recovery of aboveground biomass carbon along a fallow gradient in post-kaingin secondary forests in an upland area in the Philippines. We found significantly higher carbon in the aboveground total biomass and living woody biomass in old-growth forest, while coarse dead wood biomass carbon was higher in the new fallow sites. For young through to the oldest fallow secondary forests, there was a progressive recovery of biomass carbon evident. Multivariate analysis indicates patch size as an influential factor in explaining the variation in biomass carbon recovery in secondary forests after shifting cultivation. Our study indicates secondary forests after shifting cultivation are substantial carbon sinks and that this capacity to store carbon increases with abandonment age. Large trees contribute most to aboveground biomass. A better understanding of the relative contribution of different biomass sources in aboveground total forest biomass, however, is necessary to fully capture the value of such landscapes from forest management, restoration and conservation perspectives.
authors.affiliation: Tropical Forestry Group, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD 4072, Australia.|Tropical Forests and People Research Centre, University of the Sunshine Coast, Maroochydore DC, QLD 4558, Australia.
authors.forename: Sharif A
authors.initials: SA
authors.lastname: Mukul
authors.affiliation: Tropical Forestry Group, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD 4072, Australia.|Tropical Forests and People Research Centre, University of the Sunshine Coast, Maroochydore DC, QLD 4558, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Herbohn
authors.affiliation: School of Earth, Environmental and Biological Sciences, Faculty of Science and Engineering, Queensland University of Technology, Brisbane, QLD 4001, Australia.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Firn
mesh_terms: D000383:Agriculture; D018533:Biomass; D002244:Carbon / Q000378:metabolism*; D057965:Carbon Sequestration; D003247:Conservation of Natural Resources; D065928:Forests; D010679:Philippines; D014197:Trees / Q000254:growth & development* / Q000378:metabolism*
chemical_list: D002244:Carbon