Be considerate of our environment and only use dry wood. The first BImschV (First Ordinance for the Implementation of the Federal Immission Control Act) prescribes a maximum wood moisture content of 25 percent. However, the optimum water content is lower: Between 15 and 20 percent residual moisture is ideal and enables efficient combustion. If the firewood is moister, this can lead to a higher pollutant load, damage to the chimney and a lower calorific value.
You can determine the moisture content with a wood moisture meter.