About 10 years ago my neighbor planted two rows (staggered) of
evergreens to act as a privacy barrier.

Now the trees are getting pretty big and he is concerned that they
might choke each other out and die. He could remove one of the rows
but the "insides" of the trees don't have any healthy growth since not
much light gets in there.

Questions a

- Is it possible that the trees could choke each other out or can they
survive close to each other?

- If he does remove a row will the previously unexposed side of the
tree generate new growth or will the just look nasty forever.

Thanks for the help.