ESTIMATING ECESIS FOR TREE-RING DATING OF MORAINES - A COMPARATIVE-STUDY FROM THE CANADIAN CORDILLERA

Studies from glacier forefields in the Canadian Cordillera report that conifers ecize in ca. 5 to 60 yr. Comparative studies of four methods of ecesis determination in two glacier forefields in British Columbia indicate that the traditional approach of sampling trees on small dated surfaces may produce ecesis estimates that are too large. Results from sampling on transects running orthogonal to moraines, interpolating surface age between fixed points based on historical photographs, provided improved estimates of ecesis by enlarging the area and range of environments sampled. Although both the traditional and transect techniques may give comparable results in well-vegetated forefields, the transect technique is recommended as a better estimate of ecesis in sparsely vegetated terrain.