Screening Corewood of Pine for Wood Properties

Conventional breeding requires long breeding cycles which limits selection intensity due to large tree sizes and high costs associated with assessing properties. In contrast very early selection offers a short cycle and assesses corewood which is the poorest wood in the tree. Young Pinus radiata trees were deliberately leant to produce separately opposite wood (OW) and compression wood (CW). The two distinct wood types were evaluated for dynamic modulus of elasticity, basic density, longitudinal shrinkage and volumetric shrinkage. A subset was also characterised for microfibril angle and mechanical properties using dynamic mechanical analyser to understand property–structure relationships in OW and CW. The wood properties of the two wood types differ significantly. We observed, for example, higher stiffness and density of CW which implies that selection in a nominally vertical stem would inadvertently result in a biased selection in favour of trees that happened to have abundant CW. This is avoided by focusing on the properties of OW in leant stems.