trimming a Hemlock

[fireball33]

Hi y"all

the road to get to my driveway is a private road and there are 2 very tall
Hemlock trees that are growing to wide.. the road seems to be getting narrower.. my question is how much can i trim before the limb dies?
is now a good time to trim the tree ,its been cold out for a few weeks

i've taken a bunch down before but wanted to save these to for privacy

thanks to all in advance

 

[masterarbor]

I would go as conservatively as possible. It also depends on the amount of light it will receive post trimming. Aggressive trimming combined with low light may cause decline. Also, conservative yearly trimming is better that a five year crew cut. a pic would help with advise.

Good luck,
Kevin