In different orangeries the pots for fruit trees (in particular citrus fruit) seem rather small compared to what some gardeners suggest, and also compared to the following root ball table. What special treatment do the trees have to receive in order to healthly live in pots for their entire life? Are the roots cutted every few years? Is there some rule of thumb between root size and tree top size, or stem circumference, or any other parameter?
I am particularly interested for common fruit trees like apple, pear, plum, but also lemon, orange or mulberry trees.