Unlocking the potential of fast-growing species from Indonesia: durability and sorption aspects

Abstract

Social or community-managed forestry has been promoted as an inclusive way of mitigating climate change, under the UNFCCC’s REDD+ programme (Reducing Emissions from Deforestation and forest Degradation). Fast-growing wood species are little used as a community forestry resource in South-East Asia, although their potential could help to meet the surge in demand for sawn timber. In 2016, the Government of Indonesia aimed to hand over concession rights to 12.7 million hectares for community forestry, and support at the national level is currently strong. Although there is high demand for commercial plantation-grown species such as sengon (Paraserianthes falcataria L. Nielsen) and jabon (Anthocephalus cadamba Roxb.), the potential of other species, such as acacia (Acacia mangium Willd.), deserves to be explored. Paulownia (Paulownia tomentosa (Thunb.) Steud.) was also used in this study. Physiologically, fast-growing wood species differ from long-rotation hardwoods in their quality, i.e. their resistance to biodeterioration. In this study, the natural durability of the aforementioned fast-growing species was investigated by laboratory testing, using basidiomycete monocultures. Wood specimens were incubated with brown rot (Coniophora puteana) and white rot (Trametes versicolor) fungi for 16 weeks. Parameters such as mass loss, surface hardness, sorption properties, and anatomical characteristics after exposure to the fungi were determined. Sorption measurement times at high temperature were faster with lower hysteresis. Different relative humidity levels affected the changes in the total vessel area. The fast-growing wood species A. cadamba, P. falcataria, and P. tomentosa were classified as not very durable to non-durable, except for A. mangium, which was classified as durable. The data for specimens exposed to C. puteana were found to be highly variable. The remaining axial hardness of wood specimens incubated with T. versicolor was lower compared to C. Putanea. EDX observation (energy-dispersive X-ray spectroscopy) showed K as the major cation in decayed specimens.