In article .com,
"Ornata" writes:
| I have several seedlings of Betula albosinensis and Betula utilis, and
| I would like to try growing some of them as multi-stemmed trees. I
| understand that this can be achieved by pruning them to the ground,
| after which multiple stems are thrown up. Could anybody help, please,
| with the following questions?

I am not an expert, but the following are fairly general answers:

| 1) At what stage in the tree's development should it be done, e.g.
| how old, or at what thickness of stem?

Any time after it has produced a couple of 'nodes' (for most
broad-leaved trees, that is leaf-stem attachments), from which it
might branch. You may need to repeat it on the more vigorous shoot,
to balance them and to get the requisite number of stems.

| 2) When would be the best time of year to do it? I know birches can
| bleed a lot of sap.

Not from late winter to midsummer, certainly. I would do it after
leaf fall and before the end of January (in Cambridge).

| 3) Does this method of growth have an impact on the tree's mature
| height, i.e. will I end up with a shorter tree?

Probably. Not necessarily by much, though.


Regards,
Nick Maclaren.