FWIW -- the one in trouble which may be a pine as ID'd above looks like it's growing between two fir trees.
It's already pushing into the larger fir tree on the left and will deform its symmetry if left unattended.
If what you want are conical trees, you may want to just go ahead and cut this one down to give the others more room.
...note that Christmas trees -- if thats is the look you are going for -- are in those perfect conical shapes because they are pruned into shape as they grow while at the tree farm...
Learning never ends because we can share what we've learned. And in sharing our collective experiences, we gain deeper understanding of what we learned.