AbstractsBiology & Animal Science

Wet storage (sprinkling) of wood offers valuable protection against drying out and biological attack, but at the same time there are disadvantages to be considered. Negative effects in the forms of reduction in wood quality and the environmental impact of log yard run-off must be minimised in order to make wet storage effective. In the work underlying this thesis, the effect of different sprinkling water qualities on changes in wood properties during storage was studied. A new method for treating log yard run-off by using it to irrigate soil-plant systems was also evaluated. Sprinkling experiments were conducted both indoors and outdoors in which the effects of sprinkling on the wood quality of Norway spruce (Picea abies) pulpwood piles were examined. Soil-plant systems with willows (Salix schwerinii x Salix viminalis), alder (Alnus glutinosa) and couchgrass (Elymus repens) were irrigated with Norway spruce log yard run-off and evaluated both in lysimeters and in the field (couchgrass) for their purification capacity. Sprinkling water quality, in terms of salinity, did not affect the inorganic content of wood during storage. Brackish waters can be used without increasing the risk for raising the inorganic contents. Neither did sprinkling with fresh or recycled water affect wood brightness. Factors other than those studied determine the optimal wet storage regime. The composition of different log yard run-offs is very different, but they are all rich in oxygen-consuming organic material. Irrigation of soil-plant systems purifies log yard run-off even at very high irrigation intensities and is a convenient method for practical use. The irrigation intensity, rather than the soil type or plant species, is the major factor for the efficiency since lower intensities lead to both better purification and greater possibilities for long-term sustainability.