MIGRATION OF LOW-MOLECULAR SUGARS AND NITROGENOUS COMPOUNDS IN PINUS-SYLVESTRIS L DURING KILN AND AIR-DRYING

Redistribution of water soluble sugars and nitrogenous compounds in wood during drying improves the nutritious basis for the colonisation of wood by microoganisms. The effect of two kiln drying schedules and air drying on migration of low-molecular sugars and nitrogenous compounds in wood of Scots pine (Pinus sylvestris L.) was studied. During the kiln and air drying samples at different moisture content and depths in the planks were taken and chemically analysed. The two kiln drying schedules were found to result in a different sugar redistribution, the faster drying giving a higher sugar enrichment. The lowest sugar and nitrogen gradients were observed during air drying. Redistribution of sugars during kiln drying is influenced by transport processes as well as sugar conversion as a result of chemical interactions, while redistribution during air drying is caused mainly by transport processes. Eventual transport of soluble substances below fiber saturation point is discussed.