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ABSTRACT
The chemical composition and fibre characteristics of branch wood of hardwood species namely European beech (Fagus sylvatica L.), common oak (Quercus Robur L.), common hornbeam (Carpinus betulus L.), sycamore maple (Acer pseudoplatanus L.), black locust (Robinia pseudoacacia L.), silver birch (Betula pendula L.), European ash (Fraxinus excelsior L.), black poplar (Populus nigra L.), black alder (Alnus glutinosa L.), white willow (Salix alba L.), small-leaved lime (Tilia cordata Mill.) and royal paulownia (Paulownia tomentosa (Thunb.) Steud.) were determined. The branch wood of the examined tree species differed in the content of ash (0.44-0.86%), extractives soluble in dichloromethane and hot water (2.9-10.63%), Klason lignin (15.3-23.7%), acid-soluble lignin (1.78-3.53%), polysaccharides glucan (40.6-48.9%), xylan (16.7-25.3%), mannan (0.8-1.8%), galactan (0.5-1.1%) and arabinan (0.3-1.4%). The concentrations of inorganic elements (Ca, K, Mg, Na, P, Fe, Mn, Si, Zn, Cu) in the ash of the branch wood varied depending on the tree species. Differences in the fibre coarseness (4.15-8.52 mg/100 m), but more differences in the arithmetic average fibre length (0.4-1.20 mm) and the weighted average fibre length (0.51-1.45 mm) were found. Branch wood of common hornbeam, European ash, European beech and silver birch had a high content of polysaccharides and a lower content of Klason lignin, which is advantageous for the production of biofuels and for the pulping process. In addition, branch wood of these species has longer fibres with lower coarseness, which is advantageous in terms of pulp and paper quality.
Key words: branch wood, hardwood species, polysaccharides, lignin, extractives, ash, fibre length, fibre coarseness.
INTRODUCTION
Wood is best defined as a three-dimensional biopolymer composite composed of an interconnected network of cellulose, hemicelluloses and lignin with minor amounts of extractives, and inorganics. It is a highly variable and complex material that has inherent variability among species, within species, and also within a tree (Zobel and van Buijtenen 1989, Lindström 2001, Martin et al. 2010, Krishna et al. 2017, Tarelkin et al. 2019).
Generally, anatomical and chemical properties are the features that are often used to identify the species of woods. Utilization of these biomass resources is critically dependant on the in-depth knowledge of their morphological and chemical characteristics. The study of chemical characteristics of wood is important to exploit the potential utilization of wood such as that for...