Genecology of 20 paper birch (Betula papyrifera Marsh.) provenances from British Columbia and northern Idaho.

Paper birch is an ecologically valuable species with a broad geographic distribution and increasingly valuable commercial attributes. Its diversity, versatility and enduring nature make it an ideal candidate for a selective breeding program. However, an understanding of the genecology of the species and an understanding of the potential impacts of climate change will be fundamental to its success. The objectives of the trail were to determine if the phenotypic variability observed in paper birch for certain traits was due to genetics, the growing environment or an interaction between the two. Traits examined were bud flush (phenological) and height growth (morphological). Whether or not nursery practices were a factor was also examined. Twenty provenances of paper birch were collected from five regions in British Columbia (BC) and northern Idaho. Seedlings were grown at three nurseries in BC and Idaho and planted in a randomized single tree interlocking block design in three common gardens in BC and Idaho. Geographic variation in the timing of bud burst in paper birch is under genetic and environmental control. It follows climatic clines based on latitude, longitude and elevation. The signal for the onset of spring bud flush is determined by an interaction between air and soil temperature and photoperiod. Long distance displacement of provenances from their site of origin can lead to detrimental abiotic and biotic effects such as frost or pest damage. Differences in stock handling among nurseries and nursery displacement effects also influenced the growth and survival of some provenances. This information will be useful when developing seed zones and seed transfer guidelines for paper birch in BC. It will also help mitigate the potential impacts of climate change and will be beneficial if a selective breeding program is established.