Apparently, an ongoing debate rages; is it best to stack firewood bark up or bark down? While Norwegians seem evenly split 50/50 on the topic, some say it is all semantics and still others are evaluating the psychology of a person based on which way their firewood is stacked, the direction of the bark really does make a difference.
When stored outdoors, wood stacked bark side down can allow for moisture to collect in a u-shaped trough. The moisture retention will delay the drying process while accelerating decay mechanisms. Wood stacked outdoors with the bark up, at least on the very top row, will protect lower rows from weather. Many people have sheds or other structures solely for the purpose of firewood storage; having a roof over your wood proves advantageous because even moderate precipitation can affect wood. In this case, the bark up vs. bark down debate becomes inconsequential. As long as there is airflow in the wood shelter drying will occur considerably faster than it would outside.
Inside or out stacking a row of smaller logs perpendicular to the first row of firewood allows for superior airflow and reduces the potential for bacterial and fungal growth which can occur due to close proximity with the ground. The question also arises as to whether exposure outside will cause eventual photo-degradation and if so, does it affect the wood’s thermal output (BTUs-British Thermal Units). Evidently, ultra-violet light will degrade lignin which does produce higher BTU output than other wood components, but this doesn’t greatly affect the total thermal output.
So, when all is said and done, it seems the answer to the bark up/bark down debate is: it depends. Indoors, where airflow can be the deciding factor, bark up or bark down is truly a matter of choice. When stacking firewood outside variable factors will include placement, covering, proximity to ground, regional climate conditions as well as ease of handling; bark down storage may make wood easier pick off the pile.
For more information on the do’s and don’ts of firewood, how it compares to other products for heating your home and more about forest products visit the USDA’s Forest Products Laboratory website: http://www.fpl.fs.fed.us/index.php.