摘要
Trees have adapted to their local climates, but with changes in the climate, they may currently or in the near future occupy climates that are sub-optimal for growth and survival. The goal of current reforestation is therefore to establish a new generation of trees with growth adapted to the future climate(s). Here, we present preliminary data of a study assessing the effects of seed source and transfer potential of white birch populations. Seeds from twenty-five white birch (Betula papyrifera Marsh.) populations collected acrossCanadawere grown in the greenhouse and observed for emergence time, germination and growth. The seedlings were later planted in a common garden. After one year, the seedlings were measured for height, root-collar diameter (RCD) and survival rate and average volume per seedling calculated. Transfer functions were used to estimate the climatic distance from which populations may be transferred to the test site. There was a significant effect of population on all growth variables. Initial height was positively correlated with 1-year height and survival. Germination rate negatively correlated with emergence time. Principal component analysis showed effects of seed origin on performances of the populations in the common garden. Summer temperature was the best predictor of the transfer distance.
Trees have adapted to their local climates, but with changes in the climate, they may currently or in the near future occupy climates that are sub-optimal for growth and survival. The goal of current reforestation is therefore to establish a new generation of trees with growth adapted to the future climate(s). Here, we present preliminary data of a study assessing the effects of seed source and transfer potential of white birch populations. Seeds from twenty-five white birch (Betula papyrifera Marsh.) populations collected acrossCanadawere grown in the greenhouse and observed for emergence time, germination and growth. The seedlings were later planted in a common garden. After one year, the seedlings were measured for height, root-collar diameter (RCD) and survival rate and average volume per seedling calculated. Transfer functions were used to estimate the climatic distance from which populations may be transferred to the test site. There was a significant effect of population on all growth variables. Initial height was positively correlated with 1-year height and survival. Germination rate negatively correlated with emergence time. Principal component analysis showed effects of seed origin on performances of the populations in the common garden. Summer temperature was the best predictor of the transfer distance.
