Natural and thermally modified paulownia wood from northern Italy plantations: sawing yield, sawn-timber quality, properties and durability

The growing interest in cultivating paulownia highlights the need for the characterization of its wood from a technological perspective. Sawing yield and board appearance, physical and mechanical properties and the effect of thermal modification on mechanical properties and durability of paulownia from three plantations were evaluated. A 1-metre-long-trunk section was used to prepare small-clear specimens of natural and thermally modified wood. Paulownia, due to its cylindric shape, achieved a high sawing yield (57%), but a significant limitation was the hollow pith, which affected 41% of the boards. Late pruning was also identified as a major issue, leading to the rapid development of large knots. Only 44% of the boards were classified as first quality according to the European Standard EN 975-2:2005. In terms of physical properties, one of the primary characteristics of paulownia wood is its lightness, with a measured density of approximately 220 kg m−3. The low density contributed to very low shrinkage coefficients but resulted in low mechanical performance, which was further reduced by thermal modification. Both natural and thermally modified wood were found to be nondurable. Uses that do not demand high mechanical properties but instead leverage on its lightness could be the most suitable.