Variation in treatability of Scots pine sapwood: a survey of 25 different northern European locations

The treatability of Scots pine sapwood sampled from 25 locations in northern Europe, which was impregnated with an experimental furfuryl alcohol mix, was studied. A large variation in treatability was found between stands. The treatability was affected by anatomical properties of the trees and therefore also by the immediate climate, the sociological position of the tree in the stand, growth increments and on-stand competition. With the models applied, most parts of the differences in treatability between stands could be explained, while the treatability variation between trees within a stand remained mostly unexplained. Wider annual rings and higher latewood contents were found to increase the treatability. Models that included data on growth conditions and climate explain more of the variation in treatability, indicating that also other anatomical properties are influencing the treatability. Tree attributes and growth conditions that reduce annual ring width and latewood content decreased the treatability. Trees growing under warmer conditions and developing larger growth increments were easier to impregnate. Wood from trees growing near the timberline and under environmental conditions impairing wood growth was more difficult to treat.