Machinability of 28-year old plantation-grown Eucalyptus globoidea timber

Abstract

Eucalyptus globoidea is an emerging plantation species in New Zealand. Its naturally durable heartwood has potential to be used for solid wood outdoor products such as garden furniture, playground equipment, or decking. Good machinability of a timber is essential for solid wood processing but was unknown for E. globoidea. This study showed that E. globoidea heartwood machined equally well or better than Pinus radiata in planing, boring, mortising, grooving, edging, and turning. Sanding the higher density E. globoidea (air-dry density 723 kg/m3) was more difficult than the lower density P. radiata (air-dry density 461 kg/m3) but possible at lower sanding depth. Within species, density was not a relevant factor of machining grades. Defect types determining the machine scores were identified so processing strategies for improved outcomes could be devised, for example avoiding exit points for grooving and boring. The results will give forest growers confidence in investing in E. globoidea plantations as no new processing machinery is needed for the well-established P. radiata wood processing industry to work with this timber.