Seedlings in Ontario have traditionally been regenerated annually using seed sources that fall within the same seed zone as the planting site. However, this seed selection strategy may not be ideal under rapid climate change. The purpose of this research is to determine the most suitable seed replantation strategy for black spruce (Picea mariana) and white pine (Pinus strobus) in Ontario under climate change. A unique universal response function (URF) was developed to determine the optimal climatic conditions for each potential seed source and potential reforestation sites across the province. The findings indicate that black spruce and white pine are adapted to grow best at site mean annual temperature (MAT) of 4-60C and 120C, respectively. To examine the economic gains and losses associated with various seed movement strategies, the net present value for each planting site or seed selection was evaluated using the Faustman model. At the example of Hearst, Ontario for black spruce and North Bay, Ontario for white pine, choosing a planting site or seed source from the optimal climatic regions (rather than the local replantation) results in an NPV that is $2-$17/ ha higher for black spruce and $64-$122/ha higher for white pine.