A comparative study on the degradation of fir (Abies alba mill.) and beech (Fagus sylvatica L.) in UC3.

The paper presents a comparative investigation of fir (Abies alba) and beech (Fagus sylvatica) degradation after 7 years exposure in outdoors, above ground conditions (UC3), in a modified L-joint test. It refers only to the complex degradation of untreated samples revealed by non- destructive and destructive evaluation. Almost a similar degradation of fir and beech was observed by non-destructive evaluation of exposed faces and tenons. In contrast, destructive evaluation of the longitudinally sliced samples highlighted distinct differences between the two wood species. Inner biological degradation of beech was far more advanced than for fir, revealing its lower natural durability compared to fir, even in these out of soil contact conditions. Therefore, utilisation of beech in UC3 applications should be carefully considered alongside adequate efficient treatments.