Influence of phenolic compounds in heartwood of Silver fir (Abies alba Mill.) on the equilibrium moisture content

Experiments were undertaken to differentiate between sapwood and uncolored (light) heartwood of Silver fir (Abies alba Mill.). Paired samples of sapwood and heartwood were removed from five randomly selected healthy trees without wetwood, aged over 170 years, and (a) the percent of extractives, (b) the amount of total soluble phenols and (c) the equilibrium moisture content (EMC) at three relative humidities (RH) were determined. The percentage of extractives and the amount of total soluble phenols in the heartwood were significantly higher and EMC lower than in the sapwood. The effect of extractives on the EMC was most marked in the upper range of the RH.