Protection of stored roundwood: methods, efficacy of protective measures, and quality losses

The forestry and timber industry is increasingly confronted with large quantities of calamity round wood, which must be stored for longer periods of time and needs to be protected from losses of quality. This review provides an overview of today’s and potential future storage methods. Results from German recently completed and ongoing research projects on storage of round wood under foil, in-ground, dry and standing storage are presented and the different methods are evaluated against the background of the current framework conditions. Wet storage allows several years of conservation, but is not sustainable due to the decreasing availability of water and soil contamination due to washouts. Foil storage using the “Baden-Württemberg method” is more reliable but also more expensive than the “Swiss method” due to the complete exclusion of oxygen. Both methods have limitations with respect to the storage of logs from beetle infested trees. Earth storage is a new approach with successful oxygen reduction, but further research regarding the wood moisture is required. Leaving dead trees in the forest on stock, so called “standing storage” preserves wood by drying, but there is currently a lack of scientific findings. Live storage, in which the root ball of thrown trees remains on the trunk, preserves the wood quality over a vegetation period. “Calamity wood dry storage”, a special form of dry storage, is used for storage of bark beetle infested Norway spruce from months up to years.