Approach grafting for large trees
I am attempting to graft conifers with various methods in order to provide disease resistant rootstock. I would like to try approach grafting, using a semi established young tree (5 feet tall) as a rootstock and a smaller rooted cutting ( 1 foot tall) as the scion. My question is, will an approach graft be able to form a strong enough graft union to result in a mature stable trunk? I am uncertain of this because the approach graft methods only involve joining the partial width of the stock and scion stems.
What species of trees? Most grafted conifers are dwarf and the graft union isn't subject to wind stress or large snow loads. The graft union is typically the weakest part of a tree, so I don't know if I would recommend it for large trees.