The tree-ring width and interval trend values as indicators of sensitivity to temperature and precipitation in different provenances of European larch.

Abstract

The study assessed the sensitivity of 20 provenances of European larch (Larix decidua Mill.) growing at provenance experimental trials located in lowland (Siemianice) and upland (Bliżyn) climate in Central Poland to air temperature and precipitation, including drought. The measure of the tree' sensitivity was their radial growth reactions, i.e. changes in the radial growth in years 1971-2015. We found that rainwater supplies in a soil stored in autumn of the previous year, length of the growing season and thermal conditions in its beginning, as well as thermal and moisture conditions of the year of tree ring formation had a significant impact on the wood volume formed by the larches, regardless of their origin and climatic region in which they grew. The degree of homogeneity of tree' radial growth reactions to precipitation deficit and high temperature was the lowest in a warmer and drier climate in the lowlands in Central Poland. Larch provenances with the lowest and the highest values of drought resilience components (resistance, recovery, resilience, relative resilience of radial growth) originated in different regions of Poland. Greater resistance to drought was observed in larch provenances growing at the trial located in the uplands. The relative resilience index seems to be the most helpful in predicting the future radial growth reactions of the studied provenances, and consequently their viability and survival, as this index showed the highest variability among trees of a given provenance and was most often significantly different between pairs of provenances.