Seems like you have planted them at about the minimum spacing. There are
many variations of size of dwarf trees depending on the exact type of
rootstock
and the vigor of the scion. You may have to do some pruning, if they start to

bump into each other.

No need to do any pruning while they are still young, assuming they were
initially
trimmed by the supplier. They should have a distinct leader branch, so if
this is
not evident, I would select that branch and trim off any competing branches.
No need to trim off the smaller branches, unless they are too close to the
graft.

Most fruit sets on the new growth of branches, so excessive trimming of
them will effectively eliminate their giving fruit for the next season. It is

recommended to remove any fruit that appear the first season of production,
assuming they only number a handful. This will encourage the young tree to
put
it's energy into the roots to give a stronger tree. You can then harvest
fruit in
successive seasons. In general, it is better to do your pruning when the tree
is
dormant, although one can do some lighter pruning in the summer.

Sherwin D.
Zootal wrote:

I have about a dozen "semi-dwarf" fruit trees, each planted 12 feet apart.
Does anyone have experience with such trees? Did I plant them too close
together?

Also, when initially planting them as bare root trees, how severely should
they be pruned? And once they start to bud out, is it too late to prune
them?