Climate and annual ring growth of black spruce in some Alberta peatlands

Abstract

The long-term relationship between climate and tree-ring growth in black spruce (Picea mariana (Mill.) B.S.P.) was determined in two peatland sites near Slave Lake, Alberta. At each site, 15 dominant – codominant black spruce were sampled for tree-ring growth at 30 cm height. The tree-ring indices for each site were related to precipitation and temperature data from Slave Lake. It was found that (i) tree-ring indices were positively correlated with June – August precipitation of the current year and of the 1st and 2nd years prior to the current year; (ii) June – August maximum temperatures of the current year and of the 1st and 2nd years prior to the current year were negatively correlated with tree-ring indices; (iii) tree-ring indices had a positive linear correlation with the June – August minimum temperature of the current year and polynomial correlations with June – August minimum temperatures of the 1st and 2nd years prior to the current year; and (iv) summer precipitation values greater than 325 mm probably had a negative impact upon the tree-ring growth. Maximum and minimum temperatures, however, were intercorrelated with precipitation. Key words: dendrochronology, climate, tree rings, peatlands, mire.