Visual and machine grading of small diameter machined round Pinus sylvestris and Pinus nigra subsp. salzmannii wood from mature Spanish forests

The results of previous studies using conifer species are not applicable to small diameter round timber from mature forests, given their small diameter and higher density than samples from forests of intermediate age, clearings, selective loggings or thinning. This work establishes a visual classification methodology for structural machined round wood, giving a strength class of C27. This is applicable to small diameter machined round wood of the Scots pine (Pinus sylvestris) and Austrian pine (Pinus nigra subsp. Salzmannii) species from mature Spanish forests. Analytical equations are also supplied that make it possible to obtain the MOE and MOR by the conjoint use of non-destructive methods and the measurement of certain singularities in the wood.