After severe storms timber is often wasted because it cannot be processed before being damaged by fungi and insects and excess oftimber can flood the market causing economic problems. Effective storage of sawlogs is therefore essential. However, this often involves water storage causing problems in environmentally sensitive sites. 'Vater storage also leads to bacterial attack ofthe wood which increases its porosity. A method receiving current interest relies on the exclusion of oxygen by wrapping stacks in plastic film. This method has been shown to be effective on certain species, particularly Norway spruce, in Germany. In this study the method was restricted to Pinus sylvestris in the UK. which is far more susceptible to sapstain. In previous work the oxygen exclusion relied on a perfect seal being maintained during storage. Combining wrapping with biological control micro-organisms and with a strain ofSaccharomyces cerevisiae was also tested. Sapstain development, oxygen and carbon dioxide levels were monitored in laboratory and field tests. In the laboratory, airtight containers were developed using gas piping to test variables prior to field trials. In field trials. wrapping resulted in almost complete control ofbluestain fungi in Pinus sylvestris. 'After over four months storage, in both field trials, the stain on wrapped timber was less than 1 % compared to over 33% in control stacks. In all wrapped stacks the COl levels increased and the 0, concentration decreased, reaching zero within about 14 days. The addition ofyeast aided the depletion ofoxygen and the increase in carbon dioxide in wrapped stacks, although it had no significant effect on stain development. Further trials with even simpler wrapping systems are needed to fully assess the additive effect ofusing Yeasts to help maintain low oxygen levels under such conditions.