Effect of climatic factors on height increment of Scots pine in experimental plantation in Kalsnava, Latvia

Relationships between height growth of Scots pine in two experimental plantations (local provenance and diallel hybridization experiment) in eastern part of Latvia and climatic factors was determined by dendrochronological techniques. Similarity of high frequency variation of annual height increment (HI) between trees in each plantation was determined by PCA. Effects of climatic factors were determined by correlation analysis. For each plantation two groups of trees were distinguished. These groups showed slight differences in high-frequency variation HI. Height growth of trees from diallel hybridization experiment was sensitive to temperature in early spring and precipitation in dormant period; however, differences in significant climatic factors were observed between groups. Groups distinguished for local provenance experiment differed by mean HI. Both groups showed sensitivity to temperature in May and precipitation in previous July and September; however, fast growing trees showed higher correlation coefficients and additional sensitivity to summer and seasonal amounts of precipitation. As the distinguished groups consisting of trees from different origin or with hybridization patterns, thus the differences in height-growth-climate relationships apparently might be related with individuality of tree growth or different functional traits of trees.