So the rootstock from the previous tree is pre-programmed ONLY for the previous tree size? So even grafting a larger tree branch to the smaller root stock will result in a smaller tree. Excellent.
So this suggests that roots DO send out feeler roots to 'mark out their territory' which explains why the roots of my plants head to the outside of the pots. They mark it out and then settle down. no root bound (at least not in the sense we all presume), they just mark out how much space they have then settle down to collect what nutrients are present in the area. If there is a limited amount the plant above will not grow very big (referring to growing from seed).
Although grafting a 'larger' tree to a small tree root stock should not result in a 'smaller' tree so long as sufficient nutrients are being fed to it... unless the tree is only fed sufficient nutrients for the smaller tree. More likely, is that the tree is smaller when it starts producing apples, and not generally a smaller tree.
If this pisses you off because I haven't clicked the link, just ignore me... that'll force me to click the link.
i have a miniature lemon tree. it is the branch of a normal tree grafted to a dwarf tree stalk. i've had it for over 10 years. it is in the same 4(?) gallon pot it came in. it produces 100's of lemons each year. one year i grew a 2 ounce cola alongside it in the same pot. my marijuana plant grew up thru the center of the lemon tree. people would walk right by and not even notice. i have no pics of the bud though. it was before digital cameras were affordable.