Dendrochronological and Palynological Observations on Populus balsamifera in Northern Alaska, U.S.A.

Abstract

Sexual and clonal reproduction is occurring in a stand of Populus balsamifera on the Alaskan North Slope. Both even-aged and gradually expanding clones were observed. Trees attain ages in excess of 230 yr, but are slender due to slow diametrical growth (1.4 to 2.5 mm yr-1). A tree-ring chronology developed using 16 trees exhibited higher mean sensitivity (0.48) and lower first-order autocorrelation (0.43) than other high-latitude chronologies. Ring-width indices were most higly correlated with June temperature (r = 0.50). This species may be useful in expanding the array of climatically sensitive tree-ring sites in the Arctic. Moss polster samples in the vicinity of the stand indicate that although abundant Populas pollen is produced, little is found in surface samples > 30 m from the trees. It is suggested that Populus balsamifera was considerably more abundant in Beringia during the early Holocene due to warm early summer temperatures and widespread substrates favorable for its growth.