I have a 4-5 metre tall mandarin tree (unsure of exact details) in
ground that I would like to clone. The intention is it will
be for a future bonsai.

After reading many websites the only specific issue that
remains (with regard to this tree) is where to start the
layering. I was thinking/hoping to work on an upward facing
branch where the leaves receive direct sunlight but the site
would be sheltered from the direct sun by the top of the tree.
The actual branch is about 1 inch in diameter at the site of
the potential layering. Is this a reasonable spot or will/should
I work on a newer branch that is not as wide (eg. pencil thick/1cm)?
Can I work on a wider branch, say 2 inch diameter?