Water retention of beech shavings heat-treated at lower temperatures

Water retention after 2 hours and 24 hours of soaking in water was determined for beech shavings subjected to heat treatment at temperatures of 120°C, 140°C and 160°C for 2 hours, 4 hours, 6 hours and 8 hours in order to reduce the equilibrium moisture content (EMC) of the wood shavings for use in wood based composites. EMC was determined after 14 days of air conditioning at 23°C and 55% relative humidity. The measured values were compared with the sample dried at 103°C. Water retention was determined after 15 min of centrifugation at 1400 rev.min-1 for a more objective assessment of the wood’s ability to retain water in the cell lumens. The results showed that heat treatment reduces the EMC of beech shavings heat-treated at 160°C for 8 hours in the given conditions from 8.7% to 6.19%. The reduction of EMC at lower temperature was not sufficient enough, especially in the shorter treatment duration of up to 6 hours. In parallel, the reduction of water retention from 65.53% to 47.79% was caused by heat treatment for 8 hours at 160°C.

Quality of beech, birch and oak wood from stands growing on post-agricultural lands

This study assessed the quality of birch, beech, and oak for timber production on former agricultural land. All sample plots for the selected species had the same forest habitat type. All measured trees had already reached the age of felling. Thus, beech was over 120 years old, birch was over 70 years old, and oak was over 140 years old. On each plot, the same morphological features were measured for all trees: diameter at breast height, tree height, height of the first dead branch, height of the first live branch, and crown base. Based on collected data the length and percentage of the trunk suitable for industrial purposes were calculated. In general birch and beech trees from former agricultural land were higher, but had thinner trunks, when in oak reverse observation were noticed. Tree trunks from former agricultural lands have app. 7% shorter knots-free trunk section. The bigger different between forest and former agricultural land was noticed in case of the oak – 14%, then beech – 5% and birch – 1%. Considering the morphological characteristics of the trees and quality indicators, we showed that all species could be used for the afforestation of former agricultural lands to produce high-quality wood for future industrial purposes. However, it should be noticed, that in general calculated standing volume was lower on former agricultural land.