Looks like a Douglas fir to me, which is psedotsuga = a fake hemlock, not a fir and not really a hemlock.
I've got a ton of them and they continue to confound me, but I'll tell you what I think I know. When they are going strong, they will pop buds on 'bare wood' and sometimes even on the trunk! So, my primary 'advice' is to focus first on getting it growing vigorously. They tolerate a lot of water, compared to pines. You should expect two flushes per growing season, unless you are not keeping it adequately watered.
Regarding pruning/trimming, cut no further back than to a bud or to a node because any branch(let) without a bud on the tip will inevitably die. In some circumstances you may want to keep a 'good as dead' chunk of foliage just for photosynthetic purposes (e.g. thicken a branch, canopy balance).
One or three buds 'always' appear at the tip of new growth and often a bud will also appear at the base of one or more leaves. If you look closely, you can see sort of an eye-shaped lesion on the branch-tip (distal) side of a leaf. A new bud will sometimes also appear from one or more of these and when it does, the spot will acquire a reddish color. This seems to be a good time to cut back to a bud as you need/desire as it seems to do the most to stimulate back budding. Trimming the second flush, on the other hand seems to be mostly affecting a shoot length adjustment, but, as I said, they continue to confound me.
I suppose it might turn out that you don't have a Douglas fir. I live in the midst of a Douglas fir forest. There are also tsuga marginata and abies grandis in abundance as well as a few picea sitchenesis. So I have an easy time identifying what pops up in my yard or what I might be collecting from the local forest. It would easier to be sure about what you've got if I/we had some idea of where you are and/or where you got this tree. Updating your profile with location and zone info. would be helpful.
If I've got the ID wrong
, nevermind.
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