Understanding the failure mechanism of wood loaded in compression parallel to the grain has been
shown to be an important parameter in the design of timber beams strengthened with fibre-reinforced
plastics (FRP). In this paper, a constitutive relationship for wood under uniaxial compression load parallel
to the grain was determined experimentally. Several parameters, such as silviculture, moisture content
and radial position in the log in relation to the pith from where the specimen was sawn, were considered.
Small clear-wood specimens were used. The strain localisation in the failure region (kinkband) was mon-
itored using the digital image correlation method. The results show that silviculture and moisture con-
tent are two very important parameters which influence the compression failure mechanism.
Furthermore, there is a significant difference in behaviour between specimens from the juvenile region
of the log and specimens from mature wood. Based on experimental results, two numerical models were
built, considering either a global or a local constitutive relationship. It was demonstrated that both
numerical models yield accurate results and that, depending on the experimental equipment available,
a constitutive relationship could be extracted and used as input in these numerical models.