BENDING PROPERTIES OF HARDWOOD TIMBERS FROM SECONDARY FOREST IN PAPUA NEW GUINEA

Abstract

The wood processing industry is one of the key economic sectors of Papua New Guinea (PNG), generating significant income from export earnings. It has the potential to meet PNG’s socioeconomic needs in the long term if managed in a sustainable way. Currently, most timber harvesting is heavily concentrated within the secondary (regrowth) forest. The transition from primary forest timber to secondary growth timber poses various challenges. Secondary growth timber differs in properties and processing characteristics from the same species from virgin, primary forest. Thus, wood processing companies require technical information of the differences to facilitate the transition and to optimise the processing of this newly available resource. Therefore, a collaborative research was undertaken by the University of Melbourne and PNG University of Technology with the aim of creating a basic catalogue of PNG secondary forest timber characteristics. This paper describes the first stage of the study, which aims to determine wood density and bending properties [modulus of elasticity (MOE) and modulus of rupture (MOR)] of 10 selected hardwood timbers from secondary forest in PNG. These timbers are available for the timber industry for processing. Test results revealed that the properties of timbers from the secondary forest differed substantially from those of the primary forest. There was high degree of variability between and within species with regard to density, MOE and MOR. Statistically, the degree of variability of MOE was moderately distributed within species than between species. The variability of MOR was greater between species than within species. Preliminary data provided a foundation for further studies using laboratory test assessments and would allow enhancing the application of PNG timbers for continued development of the timber processing industry.