The chemical composition of silver birch (Betula pendula Roth.) wood in Poland depending on forest stand location and forest habitat type

We report on the most extensive study to date in Poland concerning the variability in the chemical composition of silver birch (Betula pendula Roth.) wood depending on the forest habitat type and the location of the forest stand. The research was carried out in 12 forest districts, on two habitat types where silver birch forest stands predominate in respect of coverage area and merchantable volume. Chemical composition analysis was performed on 51 samples from 306 test trees aged approximately 30, 50 and 70 years. In the examined sample material, the sum of the main chemical components for individual locations varied from 89.26 to 91.57%. The content of substances soluble in water and ethanol ranged from 2.30 to 4.03%, and the ash content was measured at between 0.09 and 0.25%. The results showed that the location had a significant influence on the contents of substances soluble in cold water (p = 0.0015), hot water (p = 0.0005), ethanol (p < 0.0001) and 1% NaOH (p = 0.0014), as well as on the contents of cellulose (p = 0.04), lignin (p = 0.002), pentosans (p = 0.04) and ash (p < 0.0001) and on the pH value (p < 0.0001). Notable influence of location on the contents of secondary constituents of birch wood, especially those extractable with water and ethanol, was recorded for the test plots in north-eastern Poland. The obtained results may form a basis for assessment of the industrial utility of birch wood, as well as the optimisation of traditional methods of utilisation and the development of new such methods that are ecological and sustainable.