| Abstract: | Six provenances of both Pseudotsuga menziesii (Mirb.) Franco and Pinus contorta Dougl. from a range of locations in the interior of British Columbia between latitudes 49° and 58° were grown for 80 days in controlled environment chambers programmed to provide daylengths comparable with those at either latitude 48°, or latitude 58°, during the period from mid‐June to early September. Neither shoot : root ratio nor whole plant dry weight of P. menziesii were affected by photoperiod. However, P. contorta seedlings, which unlike P. menziesii set bud during the experiment, had a greater dry weight and a higher shoot:root ratio (p<0.05) under longer daylengths. The results appear relevant to the interpretation of effects of cross‐latitudinal provenance transfer on plantation productivity. |
