Variability in height growth, survival and nursery carryover effect of Betula papyrifera provenances

Abstract

Eleven paper birch (Betula papyrifera Marsh.) provenances from a single geographic region in northern Idaho and four geographic regions in British Columbia (BC) were studied to determine whether morphometric variability was due to species' genetics, growing environment, or their interaction. Seedlings were grown at three nurseries in BC and Idaho and planted in a randomised single-tree interlocking block design at Skimikin (50°47′) and Red Rock (53°45′) common gardens in BC. Geographic variation in birch height growth was regulated by genetics and a complex interaction with environmental factors. Growth does not follow latitudinal, longitudinal or elevational clines although provenances at the southern garden showed better height growth compared to the northern garden. Greater percentages of seedling mortality were observed at the northern garden compared to provenances planted at the southern garden. Birch height growth was significantly influenced by nursery displacement effects up to four years after establishment. The safe range of southward seed-transfer distance may be as much as 5°, and beyond this limit a detrimental effect likely occurs. Collectively, these results suggest that a provenance best suited to one environment might not be the best for another environment. However, these findings will be useful in understanding the genecology of paper birch when establishing operational seed-transfer guidelines in BC.