Eco‐physiological potential of jack pine (Pinus banksiana) for assisted northward migration: interactions among photoperiod, [CO2] and moisture stress

Climate change will cause northward shifts of climate envelopes for boreal plants, however, the different photoperiod and soil moisture regimes at higher latitudes will likely influence the success of species migrations (natural and assisted). The objective of this study was to assess the effects of photoperiod regime and its interactions with soil moisture and carbon dioxide concentration ([CO2]) on the morpho‐physiological processes in jack pine Pinus banksiana. One‐year old seedlings were exposed to two [CO2] (400 and 950 μmol mol–1), two soil moistures (60–70% and 30–40% of field water capacity) and three photoperiod regimes (photoperiods at seed origin, 5° and 10° north of the seed origin) in environment controlled greenhouses. The impacts of photoperiod, soil moisture and elevated [CO2] on growth and physiological processes in the seedlings were examined. The results suggest that the response of jack pine to climate change will be complex under the interactive effects of northward migration associated longer photoperiod, soil moisture stress and elevated [CO2]. The longer photoperiod associated with higher latitudes under elevated [CO2] significantly advanced the budburst at both high and low soil moisture regimes, which may likely increase the risk of late spring frosts damage prior to and during budburst. The interactive effects of longer photoperiod and low soil moisture significantly increased the water use efficiency under elevated [CO2]. However, the significant 2‐ and 3‐way interactions suggest that drought and longer photoperiods with northward migration will limit the positive effects of elevated [CO2] on growth and physiological processes in the species. These results might have important implications in assisted migration/seed transfer of the species following climate change.