Temperature and gas evolution during large scale outside storage of wood chips

The temperature and gas concentrations in a newly established pine-wood debris pile of 20 mx15 mx6 m in dimensions (approximately 400 tons of fresh weight material) were monitored for 150 days. Temperature was measured at ten different positions within the pile, while concentrations of CO(2), O(2), CO and CH(4) were taken at four different representative locations. The pile was characterized by a strong temperature increase within the first 10-12 days of storage. Results of the gas analysis in this period suggest that the temperature increase was caused by microbial processes. In particular, reduced oxygen concentration and almost complete absence of methane indicate mainly aerobic respiration processes. Effects of weather conditions on the temperature/gas distribution and time evolution are also discussed in the paper.