this study examined the height growth and survival responses of selected 16 black spruce (picea mariana (mill.)) seed sources originating from across ontario, quebec, minnesota, wisconsin, and michigan in an assisted migration trial located near thunder bay, ontario. survival and growth responses varied significantly among the black spruce seed sources growing at the test site. seed sources originating from northern minnesota had a greater survival and mean productivity index when compared to ontario seed sources, excluding the seed source from the algoma forest which had the highest survival percentage and productivity index among all seed sources. the local seed source originating from the lakehead forest performed below average for both survival and productivity index, suggesting that local seed sources may not be the best suited for planting in future climatic scenarios for this region. climate variables identified as significant predictors of black spruce growth and survival included mean annual temperature, mean summer precipitation, and frost-free period. this study further supports the hypothesis that southern seed sources may be better suited for the future reforestation of northern regions. the identification of adapted seed sources to areas of optimum growth and survival will assist reforestation programmes under changing