Basic Components of a Fruit Tree

Let's break down the parts of a bare root deciduous fruit tree:
 

Most fruit trees that we grow are essentially two trees in one- the rootstock and the scion (a.k.a. the variety).  The scion is grafted or budded  onto the rootstock; this union is called the bud/graft union.  From then on, everything below the union is the rootstock, and everything above the union is the scion.  As part of general maintenance, be sure to watch out for any rootstock suckers- shoots coming from below the graft union, which if left to grow, will take energy away from the growth of the scion.

The rootstock will impart many characteristics on the tree; for the most part, however, we are concerned with size. With dwarfing and semi-dwarfing rootstocks we are able to grow what in the industry is called a 'pedestrian orchard,' one where we can perform most tasks from ground-level, maintaining trees in the 6-12 foot range. For more on rootstock descriptions, click here*.  In terms of rootstock/scion compatibility, grow apples on apple rootstock, and pears on pear or quince rootstock; most stone fruit (apricots, plums, cherries, peaches, nectarines, apriums, pluots) can all be grafted onto the same rootstock.
 

The scion of the tree will consist of the trunk, primary scaffold branches, and laterals.
Fruit will grow along the primary branches on some trees while most of the fruit will bear on short and weak lateral branches.  In other words, laterals are our friends

Learn where and on what aged-wood fruit develops on each of your trees.  

Apples fruit on 2-year and older wood.  Fruit buds last 8-10 years.
Pears fruit on 2-year and older wood. Fruit buds last 8-10 years.
Peaches/Nectarines fruit on 1-year wood only.  Fruit buds last 1 year.
Plums/Apricots fruit on 1, 2, and 3-year wood.  Fruit buds last 2-3 years.
Persimmons fruit on current season wood.  Fruit buds last 1 year.