Adaptacja wybranych pochodzeń modrzewia europejskiego do klimatu nizin centralnej Polski

The study evaluated the sensitivity of European larch (Larix decidua) of two provenances to thermo−pluvial conditions on the provenance plot located in Sękocin Stary (52°05‵ N, 20°51‵ E, 125 m a.s.l.). The studied larches originated from Pelplin (lowland, northern Poland, 50 m a.s.l.) and Szczytna (upland, southern Poland, 525 m a.s.l.). The trees of both provenances differed in terms of their quantitative and qualitative breeding characteristics. The trees originated from different climatic regions whose climate was also different from the climate of the provenance plot. Values of the size of the radial increments measured at cores extracted from the trees were the measure of their sensitivity to the climatic factor. The cluster and principal component analyses were used to classify the trees according to their features of the short−term rhythm of the radial increments. The response function and pointer years analyses were used to evaluate climate−growth relationships. The results of the study show the trees of both provenances have similar sensitivity to the thermo−pluvial conditions in the previous September, the temperature in March and the precipitation in May of the year of tree−ring formation. The larches of Pelplin provenance, in contrast to the trees of Szczytna provenance, were sensitive to the low temperature in February and the low precipitation in the growing season. These features could be one of the causes of the lower incremental abilities of the trees of Pelplin provenance. The larches of Szczytna provenance had higher frost tolerance in February and drought tolerance in summer.