Evaluation of the durability of the exterior siding products made with trembling aspen lumber in terms of colour change

Trembling aspen (Populus tremuloides) is a fast-growing and widely distributed species in Canada, but its uses in non-structural wood products are limited. This study was aimed at evaluating the feasibility of using aspen lumber for producing wood siding products and their durability in terms of colour change (ΔE). Both short-term natural exposure and artificial accelerated weathering tests were conducted on the aspen wood sidings produced and pressure-treated on a production line. The spruce-pine-fir (S-P-F) sidings were used as control. It was found that (1) both short-term natural and artificial accelerated weathering tests resulted in an increase in average ΔE of the siding specimens, exhibiting surface greying and darkening. (2) Finished trembling aspen siding specimens consistently exhibited greater colour stability than finished S-P-F ones. (3) Both finished trembling aspen and S-P-F siding specimens had smaller ΔE values than unfinished ones, suggesting the finishing employed in this study effectively protected surface colour.