Background European policy includes several items that target the carbon-neutral sources of energy in particular to reduce the dependency on fossil fuels and combat the climate change [1]. Wood biomass is considered to fulfil many of these targets as it is considered carbon-neutral [2] and it is applicable feedstock for many bioenergy applications. It is also abundantly available in many parts of Europe, especially in Nordic countries such as Finland [3]. There are many parallel initiatives to study the properties, growth and sustainable cultivation of forest biomass for energy, chemical and material applications under the national bioeconomy strategy [4,5]. Among the forest species under study in the Nordic countries, Silver birch (Betula pendula) is an interesting species: presents a large spatial distribution, reaching the northernmost areas, it is a native species and presents potential high yield rates. In this context, this study focuses on bioenergy potential of a common Scandinavian hardwood silver birch in its natural genotypes in terms of biomass yield, energy content, chemistry and general potential as short rotation coppice for bioenergy applications. Experimental and aim of the study A multi-site common garden experiment was established in 2010 in three locations: southern (60°N), central (62°N) and northern (67°N) Finland. These reciprocal transplant experiments represent 26 randomly selected silver birch genotypes from a latitudinal cline from 60°N to 67°44'N (i.e. from southern Finland to the northernmost known silver birch stand). Contrary to many previous experiments, the material has been clonally produced. This study discusses results obtained from the central garden (Joensuu at 62°37'N, 29°49'E) harvest in August 2015. We have measured the tree growth (biomass yield) and complemented the growth data with calorimetric energy content and the chemical and elemental composition from stem wood and branches. The appearance and green weight of trees differed significantly, the highest aboveground biomass yield being 24.28 kg and the lowest a mere 0.44 kg (for branches and leaves 9.8 kg and 0.02, for stem wood 14.72 and 0.26, respectively). The significant differences in biomass yield and bioenergy potential between the tree origins (genetic background) are discussed with the implications they have on valorization of the Nordic silver birch in bioenergy applications. Selected cases will also be analyzed in more detail for the applicability for pyrolysis bio-oils production.
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