Improvement of fir-wood permeability caused by bacteria action

This article focuses on the improvement of permeability brought about by anaerobic bacteria on fir poles. Poles, each 6 meters long, were divided into three equal groups. In first group there were poles which had been exposed to air drying immediately after felling. The poles from second and third group had been submerged in the water of Lake Bajer after felling for one and two months respectively. After that, they were also exposed to air drying. Following air drying, small log samples were sawn from each pole, those to be used in the investigation of the improved permeability of firwood. The logs were exposed to full-cell pressure impregnation by anorganic salts (CCB salts). Investigation has shown that the increased permeability is observed only in the sapwood of the submerged poles, while the heartwood remained impermeable. The average sapwood permeability of the poles submerged for two months (10.69) has become 3.9 times bigger than that of the nonsubmerged poles (2.74 darcys). The value for the poles submerged for one month was 8.71 darcys, i. e. 3.17 limes higher than for tl1e nonsubmerged poles. The increased permeability, observed on the submerged poles sapwood has been additionally attested by increased retention and increased penetration of waterborne salts. The average retention of waterborne salts observed in the one-month and the two-month submergence group was 73% and 75% higher, respectively, that the average retention observed in nonsubmerged poles. At the same time, the average lateral penetration of waterborne salts in the sapwood of the submerged poles (50.35 mm for the two-month and 50.53 mm for the one-month submergence group) was 5.52, that is 5.54 times higher than the average lateral penetration in nonsubmerged poles (9.12 mm). The axial penetration in the one- and two-month submergence group reached 2.5 meters from the end to the middle of the poles, which is significantly more than the same penetration observed in nonsubmerged poles (maximum 0.05 meters from the end to the middle). The crushing strength (testing in compression parallel to grain) on the sapwood of the poles submerged far one and two months showed no significant reduction.