Assessment of scots pine (Pinus sylvestris L.) annual tree ring structure response to air relative humidity

Correlation analysis methods were used to evaluate the effect of relative humidity on the width of annual rings and the proportion of late wood in Scots pine climatypes of different geographical origin tested in the forest-steppe of the Novosibirsk Region and the southern taiga of the Krasnoyarsk Territory. The most significant correlations of wood structure features with relative humidity over certain periods based on average monthly data have been identified and shown. The main differences between climatypes have been identified in terms of the dynamics of the annual ring width, the relationship of the wood structure with certain time intervals during the growing season. Despite the same age of reaching the maxima of the annual ring width in the forest-steppe, differences between climatypes in correlations with relative humidity were revealed in these conditions. In the southern taiga, on the contrary, with the equally significant influence of relative humidity from May and June on the width of the annual ring, there is a different character of its dynamics, which is expressed not only in different maxima of growth, but also in the different nature of the radial growth recovery after the dry conditions in 2003.