In a lot of cases you have a lot of choice here---
particularly with apples. For a lot of the other fruits, your choices are
more limited. In any case, you need to determine how much level of
"hands on" management you want to invest in your orchards. A
general rule of thumb is that the more dwarfing the rootstock, then the more
"management" you will have to invest. This does not always mean
more time and labor, but it often means more attention to detail because you
really can't afford to screw up as much in high intensity, full dwarf orchards
as you can in semi-dwarf and standard root orchards.
For most stone fruits, you often have little choice in
rootstock, since most fruit trees are grown on "standard" roots.
The redeeming factor is that most stone fruits can be maintained at reasonable
tree heights and limb spreads through good growing practices, especially pruning and
fertilizing. One can even go to quite intense production in higher
densities than are often used if you are a good manager. Most stone fruits
can be planted in densities similar to semi-dwarf apples and pears.
Cherries are a new exception. With the advent of size
controlling and precocity enhancing rootstocks like Gisela® 5, then the
opportunity for "high density" and early production is
practical. Other Gisela® rootstocks are less dwarfing, may only be
slightly less precocious, and offer the opportunity to grow cherry orchards in
densities similar to semi-dwarf apples. Standard rootstocks for cherries
are probably on their way out for most varieties and systems, but will always
have their place in certain situations.
Apples and Pears have good choices for rootstocks ranging
from full dwarf (about 25-25% of the old standard, big apple tree of Grandpa's
time) to Semi-Dwarf, (ranging from 40-75%) which many growers still like, to
Semi-Standard (75-90%) which fewer growers continue to grow, although they
definitely have their place in certain sites.
For the new fruit grower, who feels they have a steeper
learning curve than most "newbies", I usually recommend
semi-dwarf rootstocks for apples and pears, the ordinary standard rootstocks for
most stone fruits, and the more "semi-dwarf" cherry rootstocks for
cherry. This is because their management is less demanding, you have more
opportunity to make "mistakes" without paying dearly for them and most
can be planted in very similar planting densities, making equipment needs much
less demanding and capital investment is moderate.
For the new grower, who feels they have more experience, or
they feel a real need for "pedestrian orchards", high production, or
who have committed themselves to being a real hands on manager, then rootstocks
in the full to a little less than full-dwarf range can be good choices.
For more information on particular rootstocks and their
individual characteristics, plusses and minuses, then click on "Rootstock
Basics".

Standard Size
Apples
Semi-Dwarf
Apples
Full Dwarf Apples