During the autumn of 2000 and early spring of 2001 disfiguring fungi attacked many wood coated surfaces outdoors in mid and south Sweden. Unusual weather conditions for the period with relative high temperatures and relative humidity are believed to be partly responsible for the massive disfigurement of coated wood caused by moulds, blue stain fungi and algae. On the other hand, some paint formulations might not perform well under these conditions, especially if the biocide content has been changed over time to meet current Swedish regulations. Many experts claim that the global weather is changing towards a warmer climate. If that is true, Sweden will have the same climate as Holland in 10-20 years. Sweden is very restrictive when it comes to the use of biocides. This will certainly have an impact on the performance of surface coatings outdoors in the future. The question is if we should optimise formulations that are already commercial or if we need new concepts on how to make wood surface coatings for outdoor use. The ultimate goal for Sweden would be to combine EVIRONMENTALY FRIENDLY (without fungicides?) with RESISTANCE DURING SERVICE LIFE. Although we know quite a few things about the biology of moulds and blue stain fungi (specially Aureobasidium pullulans) there are still many questions regarding how to avoid blue stain on coated wood that should be explored. These may lead to new concepts for coating formulation. More research is needed to assure the sustainable use of wood surface coating outdoors.

Dr. Stig L. Bardage SLU Department of Wood Science P.O. Box 7008 750 07 Uppsala SWEDEN

• fungi: molds in buildings
• wood, lumber, timber