RETROSPECTIVE ANALYSIS OF GROWTH AND REPRODUCTION IN CASSIOPE TETRAGONA AND RELATIONS TO CLIMATE IN THE CANADIAN HIGH ARCTIC

Techniques of retrospective growth analysis, adapted from dendrochrono logy, were applied to Cassiope tetragona, an evergreen dwarf-shrub, sa mpled at Alexandra Fiord, Ellesmere Island, Canada. A new method of de limiting annual growth increments through patterns in leaf node placem ent along a stem was utilized. Chronologies of mean annual stem elonga tion leaf production, and flower production were developed, and estima tes of these parameters agree with those obtained for other arctic pop ulations of C. tetragona. Stem elongation and leaf production were pos itively correlated in the same year. Flower production was positively correlated with growth in the previous year, but negatively correlated with growth in the same year. This pattern was interpreted as the eff ects of resource allocation strategies, namely, the preemption of with in-plant resources by flower production once flowering is initiated. A ll chronologies were significantly correlated with climate records fro m Alexandra Fiord and Eureka, Ellesmere Island, with the majority of s ignificant correlations occurring with June and July temperatures. Flo wer production appeared to be most sensitive to variations in summer t emperatures, and climate response functions which included previous gr owth explained up to 84% of the variation in the flowering chronology. Unstandardized leaf and flower number chronologies were used to provi de an independent test of the climate transfer function presented in H avstrom et al. (1995). The results indicate that C. tetragona may be u sed successfully to generate proxy climate data, although use of stand ardized chronologies is recommended. Two predictive models for July te mperatures at Alexandra Fiord, based on standardized chronologies, are presented to provide future opportunities for verification and applic ation of this technique.