The question is not: Is this the best time for transplantation? but: tips for successfull transplantation?. If I had to do it, I would first prepare carefully the new place. Then I would make sure that the rootball of the tree is well watered. Then using the proper tools (spade, shovel,.....) try to dislodge carefully the tree, with a lot of patience going around the trunk and keeping as much soil with the rootball as you can manage to transport. Finally install the tree at its new location watering generously throught the spring and summer. The climate in SW France is not too different from BC (if anything, warmer) and if I had to do this transplantation at this time the probability of success (that depends on the time the tree has been at its current location) for a tree with 5 years or less in its location is about 90%. Gomero
Preparation consists of merely digging wide, shallow planting hole--no amendments. Generally, best moving method is one that gets largest amount of roots, with specimens of much size this is often barerooting rather than moving with intact soil ball. Trimming roots down to get manageable soil ball soon gets to a point where it is counterproductive, many balled-in-burlap plants in nurseries have most of the roots cut off. This method is used anyway, in commercial practice because the stock is going to be out of the ground for more than a matter of minutes--unlike a home garden transplanting operation, where the plant can be hustled from the old site to the new one, as well as kept hosed down. Another problem with soil balls is that the texture of the soil in the ball may not be the same as in the new location, causing problems with movement of water into and out of the soil ball, same as with liberally amended small planting holes. However, due to timing in this instance (new leaves present or soon will be), if this is a small specimen and soil texture in new location similar to old it would probably be best to try for an intact soil ball.
I'd say its one and the same, timing is essential for a successful transplantation. Our birches come into the Nursery bare root in late autumn, we then pot them (quite often pruning the roots, and you'd be surprised just how much root you can remove) 6-10 feet high birches are no problem, they root quite happily through the winter.....bigger plants than that and im affraid i could'nt say.
