Air drying of logs from an Eucalyptus urophylla clone for carbonization use

Wood drying is one of various stages in the carbonization process, therefore proper monitoring is key to improving yield and obtaining quality charcoal. Prior to being subjected to carbonization by charcoal production plants and once trees have been felled, logs are piled up by the roadside or close to carbonization furnaces and left air drying for 90 days until an optimal 30% moisture content is reached. This work aims to evaluate air drying of logs from an Eucalyptus urophylla clone for carbonization use, analyzing moisture reduction over time and also the influence of log diameter and bark. Logs with and without bark were used, 6.0cm to 21.0cm in diameter, 3.60m in length, with average basic density of 0.496 g/cm³, obtained from a commercial stand of Eucalyptus urophylla at age 8 years. Air drying log piles were arranged outdoors in Paraopeba, Minas Gerais State, Brazil and monitoring consisted of periodic log weighing for a period of 80 days. At the end of the experiment, higher rates of moisture loss were observed in the three initial weeks. Moisture in logs without bark (54%) and with bark (50%) was close after 80 drying days, with a higher level of moisture reduction being observed for logs without bark. Bark influence on moisture loss was more pronounced in the first three weeks. Moisture reduction varied in intensity as a function of log diameter. After 80 days, the highest level of moisture reduction was observed in logs without bark: 65% for logs larger in diameter and 80% for logs smaller in diameter. As regards logs with bark, results were 56% and 75% respectively.