The increase of atmospheric greenhouse gas resulting from human activities could significantly alter the global climate during this century. The natural rates of migration of forest ecosystems are struggling to keep pace with rapidly changing climatic conditions. Assisted migration of plants, namely the moving of species or tree populations to places where future climate conditions will be more favorable, has been proposed as a strategy to reduce the impact of climate change on forest ecosystems. The main objective of this study was to quantify the efficiency of tree provenance displacement in terms of survival, growth rate, nutrient status and carbon isotopic composition, a proxy of plant water-use efficiency, of four tree species in Québec's (Canada) boreal forest. Assisted migration was also combined to the creation of carbon sinks by the afforestation of boreal open woodlands (OWs), which are common in this territory. OWs are also drought-prone lands, precursory habitats for future climatic conditions in the boreal forest. The experimental design was planted in 2014 with different provenances of Larix laricina, Pinus banksiana, Picea mariana and Picea glauca. Survival and growth measurements were made during two years after planting. Tree foliage was also collected for nutrient status and carbon isotopic composition analyses.
Results/Conclusions
Survival rates did not differ significantly between species, nor between provenances. Relative growth rates (RGR) did not differ at the species level, though the RGR of one provenance of P. banksiana was significantly greater than the local provenance (control) (p<0.0001). Preliminary results on carbon isotopic composition did not suggest any significant differences between species or provenances (p>0.05). These early findings provide no evidence that there is an impact of the displacement of provenances for three of the four species, though a single provenance of P. banksiana did differ compared to the control provenance. This suggests that this provenance that was displaced northerly by 425 km, seems already able to acclimate to the northern boreal forest – and relatively harsh – conditions. This study could provide forest managers with new information about assisted migration in boreal OWs, the acclimatization of species to climate change, altogether contributing to the future health and productivity of forests. Repeated measures on the same trees may provide more evidence over next years.