Collapse and physical properties of native and pre-steamed Eucalyptus camaldulensis and Eucalyptus saligna wood from Tunisia

Eucalyptus is the second major wood species used for Tunisian reforestation since 1957, and they are found around the country in several arboretums. Eucalyptus may be an interesting raw material to the Tunisian wood industry. The main obstacle to its industrial exploitation is its natural propensity to incur internal checking, collapse and a high transverse shrinkage during industrial drying process. This study focused on the physical and mechanical properties of reforested Eucalytus saligna and Eucalyptus camaldulensis from the north west of Tunisia. Moisture content, densities, shrinkages and mechanical properties were determined. Then, the impact of pre-steaming on the physical properties of modified wood was investigated. The results showed that both Eucalyptus possess low dimensional stability and mechanical properties compared to other Eucalyptusspecies from Tunisia, Morocco, Australia and Brazil. These wood characteristics were mainly due to their low density and sensitivity to collapse reactions, occurred during drying. Pre-steaming process reduced Eucalyptswood moisture content, changing the wood permeability and resulting in a residual collapse recovery and a decrease in wood shrinkage. Pre-steaming treated E. camaldulensis and E. saligna wood could be valuable as furniture and/or structural material without being submitted to moisture content variation.

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