http://worldcat.org/entity/work/id/369979043

Heat-treatment options and heating times for ash firewood

Because of the potential risk associated with moving firewood infested with emerald ash borer, the interstate movement of all hardwood firewood is currently restricted under Federal quarantine. Communities and firewood producers are now faced with decisions on how to treat firewood for interstate commerce. New regulations for heat sterilization of ash firewood require holding a core temperature of 160 °F for 75 min, much higher than the current international heating standard for treating solid wood packaging. The present study evaluated different heat-treatment options for various firewood operations and developed heat-treating schedules and heating time tables. We first conducted laboratory heating experiments using green and air-dried ash firewood and obtained heating time data for different heating schemes. Mathematical models were developed to estimate heating times for heating conditions not tested in the experiment. Heating time tables were developed for a series of heating temperatures and initial wood temperatures. Our field heat-treatment trial in a commercial dry-kiln facility indicated a significant difference in heating times between the laboratory kiln runs and the field kiln run. Although the size of kiln could have contributed to the increase of heating times in the field trial, the type of kiln and heat sources are the main factors that control the heating rate and result in differences in heating times. More field heat-treatment trials at different types of kiln facilities (steam, hot water, and direct fire) should be conducted in the future to calibrate the heating time tables developed through the laboratory experiments.

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