There are situations when you find in your garden a tree that is too old to crop well and has rotten or severely diseased branches or trunk, then you should grub it out and burn it. When the tree is old but the trunk and the main branches are sound and the tree is merely overcrowded, then it can be rejuvenated by renovative pruning followed by a correct routine care.
The renovation work on a tree should be carried out in spring or summer fore stone fruiting trees and in winter on apples, pears and other pome fruiting trees. First of all you should cut out any branches that are dead, damaged or diseased or so low that they may trail on the ground when laden with fruits. The damaged or diseased branches should be removed completely or cut back to a healthy shoot.
After this first cut, search and remove crowded or crossing branches as they will shade the developing fruits and if they rub together they may become prone to diseases such as canker. Cut them back to their point of origin or to a vigorous sub-lateral facing the required direction. On a vigorous tree it is advisable to stagger this pruning over more than one year, because if the prunings are too severe on a single occasion it may only induce more vigorous, vegetative growth.
After this step you can continue with more precise pruning, such as spur thinning then maintain the tree with a routine pruning. Chemical inhibitors may be used to curb the regrowth of water shoots around the cuts. Wood paints are not recommended because they may seal in any infection.