Ecological restrictions in forest biomass extraction for a sustainable renewable energy production.

Renewable Energy Sources investments are scaling up across the Mediterranean region. The small scale utilization of the forest biomass for bioenergy purposes could boost the socio-economic benefits in a decentralized level, tackle the energy poverty and reduce the forest fire risk. This research contributes to a more sustainable use of the forest biomass for bioenergy purposes. From plant tissues analysis was proven that both macronutrients and micronutrients are being allocated differently between the aboveground biomass parts. This knowledge of content differentiation and distribution of nutrients in aboveground biomass contributed to the creation of hierarchy content of significance and protection of those parts. The foliage is the main carrier of the macronutrients. The bark of the stem and the foliage are the main carriers of the micronutrients. Thus, foliage extraction should be strictly prevented. In addition, the stem should be extracted without the bark. The leaves and the stem bark are vital ecosystem's residues. Further analyses reveal remarkable knowledge for the integration of suitable silvicultural treatments for ecological managing of coppice forests, for the sustainability criteria of forest energy harvesting and the ecosystems' nutrient balance. Accordingly, practical implications are presented. The ecological restrictions of the present research can shape an ecological and modern legislation framework as regards the forest biomass extraction for energy purposes in Greece and enhance in parallel the forest management policy in the Mediterranean region. Finally, future challenges are presented. Image 1 • Nutrients' mean content is differentiated among the aboveground biomass' parts. • Foliage is the main carrier of the macronutrients in trees' aboveground biomass. • Foliage extraction should be prevented as leaves are vital ecosystem's residues. • Stem bark and foliage are main carriers of micronutrients in aboveground biomass. • Stem should be extracted without bark, as stem bark is vital ecosystem's residue. [ABSTRACT FROM AUTHOR]