While there is an increasing volume of data for the impregnation and curing of timber using dimethylol dihydroxyethyleneurea (DMDHEU) on species such as Scots Pine, Beech, Slash Pine and Spotted gum, there is limited information available on the impact of the modification process on the performance of Pinus radiata (referred to hence forth as Radiata pine). The variability within material and species can play a key role in modification and subsequent performance of a wood product. In New Zealand and Australia, Radiata pine is the primary source of available softwood. However, sapwood of Radiata pine is perishable, and heartwood is moderately durable. Therefore modification or the chemical treatment of Radiata pine is required for timber to be used outside. In this study we compared the physical, mechanical and biological properties of DMDHEU modified Radiata pine to other modified species. In collaboration with Gottingen University, Germany, TimTechChem and Scion (New Zealand Forest Research Institute), a number of large scale trials were conducted to modify Radiata pine. A significant amount of laboratory analyses and on-going field trials undertaken in New Zealand on Radiata pine confirm several distinct advantages for the use of DMDHEU. These include increased dimensional stability, decreased swelling and shrinkage, increased hardness and increased resistance to biological degradation. These proven benefits, together with an increase in customer expectations for timber products with this type of performance and sustainability make DMDHEU a commercial reality in Australasia.

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