Forests are a source of renewable energy.
Energy wood refers to wood harvested from forests and used for energy generation in power plants and households. Using wood-based material in energy production is an important element of the renewable energy sources portfolio. Energy wood can be used as a substitute for fossil fuels. When sustainably sourced, energy wood has a significant potential to combat climate change.
Energy wood comes from logging residues – branches and tree tops - and stumps. Energy wood is harvested from forests after a final felling, before forest regeneration activities. Timber that can be used as pulpwood or logs is not used for energy production. Harvesting energy wood improves material efficiency of wood use.
Logging site properties define where energy wood can be harvested. It cannot be harvested from sites with poor nutrient content in the soil; instead, suitable sites are fertile with higher levels of nutrients for vital forest growth. When harvesting tree stumps, there are concerns beyond site fertility. Stumps are not collected from important groundwater areas or from steep slopes in order to protect water quality and prevent soil erosion.
When energy wood is harvested, not all logging residues or stumps are taken away. At least one-third of logging residues, evenly distributed over the harvesting area, are left on site to maintain soil nutrient balance. This also promotes biodiversity as some species use small diameter decaying wood or dead stumps and root systems during their lifecycle.
Logging residues are first dried on the logging site. This enables nutrient-rich needles to drop off preventing nutrient loss from the site. Collecting only residues that are no longer “green” also helps improve the energy content of biomass per weight unit. Logging residues and stumps are dried further in roadside storages before transporting them to power plants. The drier the biomass is, the cleaner it gets when soil particles drop off, resulting in better energy output during the burning process.
Planting is the starting point for new forest growth.
Deadwood is one of the key elements for biodiversity.