The environmental discussion in Sweden has lead to an increasing use of naturally durable domestic wood species and wood treated according to alternative methods for use above ground. A number of these alternatives have been tested according to field- and laboratory tests and compared to wood treated with preservatives for above ground use. Seven untreated wood species, four alternative wood treatments labelled as environmentally friendly and four wood preservatives are included in the study and as references CCA-treated and untreated pine sapwood were used. The best results against wood decaying organisms were obtained with acetylated wood and heat treated wood. Among the tested naturally durable wood species pine heartwood from Gotland (a pine very rich in wood extractives) and oak were the best, but none of these were as good as acetylated wood or preservative treated wood. After 14 months testing against mould and blue stain, preservative treated wood was less attacked than any other tested material. Among the untreated wood species oak and pine heartwood from Gotland were the best and among the alternative treatments heat treated spruce was the best.

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