Stem damages caused by heart rot and large poplar borer on hybrid and European aspen

Solid wood production of hybrid aspen requires relative longer rotation periods, thus increasing risk of wood damages by pests and diseases. We compared damages by heart rot and poplar borer of 48 years old hybrid ( Michx. × L.) and European aspen in a progeny trial located in Eastern part of Latvia. Trees were harvested and rot patches and galleries were recorded and measured at a stump level. The number of galleries had positive relation on number of patches and total area of rot. The susceptibility of the rot and poplar borer was similar for both hybrid and European aspen. Yet, some differences among families were detected. No effect of pathogens damage was observed on the tree growth. Larger trees had smaller proportion and incidence of rot and galleries per unit of area as well as wider outer rot-free wood layer.