Treatability of waterstored poles of Norway spruce by sap-displacement and pressure treatment with Boliden K33 and creosote
P Moltesen, E Borsholt, B Bang
Poles of windthrown Norway spruce were stored in bark under water sprinklers for 11-20 months or fully submerged in a lake for 3 years (tab. 1 and 2). Water content after storage is shown in fig. 1 and 8. Treatment with Boliden K33 by sap-displacement (open tank suction) gave a poor result. The Danish requirements of delivery claim a penetration of 20 mm and a net retention of 12 kg/m³ in outer 20 mm sapwood. According to that 22% of the poles stored for 11 months, 53% of those stored for 20 months under water sprinklers and 67% of those waterstored for 3 years were rejected compared with 11% in both control series (tab. 3 and 4). There was no correlation between water content in outer sapwood before treatment and penetration/retention neither for stored nor for unstored poles (fig. 2-7 and 9-10). Pressure treatment (full-cell) of water stored poles with Boliden K33 after air-drying to app. 28% gave a similar poor result (tab 5) while pressure treatment (Rueping) of water stored poles with creosote gave very good penetration as well as retention (tab. 6). The hypothesis is put forward, that the main reason for the unsatisfactory result of the treatment with Boliden K33 might be coagulation of the bacterial slime when mixed with the salt blocking the pathways for the liquid, although the membranes in the tori and the parenchymatic cells are supposed to have been partly destroyed by the bacteria.
Keywords: BOLIDEN K33; CCA; CREOSOTE; PICEA ABIES; POLES; WATER STORAGE; TREATABILITY; RETENTION; SAP-DISPLACEMENT; PRESSURE TREATMENT; RUEPING PROCESS