Resin pocket was the only defect type whose frequency was significantly higher in boards from pruned butt logs than in boards from unpruned logs (Table 2).
Resin pocket was the only defect type whose average size was larger in boards from pruned butt logs.
Generally, all defects except resin pockets were less frequent in boards from pruned logs.
Intergrown knots, partially intergrown knots, loose knots/holes, spike knots, pith, bark pockets/blemishes, resin pockets, needle flecks, and wane were identified as separate defect categories.
Frequency of resin pockets was highest in boards from pruned logs (0.
The visual grading technique for wood quality assessment is based on measurement of the singularities and characteristics present in timber pieces, such as: knot size, slope of grain, presence of pith, splits and checks size, bark and resin pockets length, etc.
The main reasons for the rejection of pieces center on bark pocket length, knot size, and resin pockets length, at 20.
As a consequence of the analysis of the graded material, a new group defined by size and a modification of the specifications of the standard dealing with the size of knots and bark and resin pockets is proposed.
Intergrown knots, partially intergrown knots, loose knots/holes, spike knots, bark pockets/blemishes, resin pockets, needle flecks, and wane were classified as separate defect categories.
Finally, analyses were carried out in which all knot types were grouped in one single category and resin pockets, bark pockets and blemishes were grouped into another.
The incidence of spike knots and resin pockets was impossible to predict using tree characteristics included in the analysis.