From time immemorial, firewood has been a very important source of energy for mankind. Later in history, wood for energy decreased its importance because of other more convenient and cheaper sources, mainly fossil fuels. Today, focus is again on use of forests as a producer of energy with main drivers being climate change, shortage and increasing prices of fossil fuel sources, and safety in energy supplies. However, intensive use of forest biomass is qu- tioned since fundamental ecological processes may be influenced negatively thus making up a trade-off with the benefits of using an...