I have to disagree with Harvestman re suitable locations. Granted a hammock needs trees (no shortage of those to over 4000 feet here) but a tent needs a bit of flat ground. I just did a hike to 4300' and the only flat ground was the trailhead parking lot, and the tent platforms (wooden decks) at 4000' (USD 8 per night, which isn't bad) You could hang a hammock anywhere from the foot very nearly to the summit. Weight? my one man tent weighs 3 1/2 lbs, my hammock is a heavy one at 2 1/5 lbs. If no trees, the hammock and tarp can be "hung" from my trekking poles, giving a full coverage tarp and an enclosed bug net. All in all, I'm not sure why I still have three tents.t
Ah Rick has supplied the answer. One of these days I might get lucky and want (need) to share, but that's my 5 1/2 lb 2 person tent.
Obviously a lot depends on location and personal preference.
Over here there isn't much in the way of vegetation about 900m (3000ft) much higher than that and it becomes extremely barren.
With regards to having flat ground, it really depends on the size of your tent, if your in a bivvy then you really only need a 2m x 1m spot of flatish ground.
With a tent you'll need a larger footprint, but in 30 years of camping around the world i've never not managed to find a flat enough piece of real estate on which to pitch my tent.
If i'm back over in the UK then there are some areas like say Scotland where you could find a couple of trees to hammock to.
Visit somewhere like the peak district or the brecon beacons and there are places where there are no trees as far as the eye can see.
It's the same over here.
In Northern Greece the forests are that deep it's easy to get lost, go hiking around the coastal areas though and you'd struggle to find 2 decent trees to tie to.
Even if you find trees many will be olive trees pruned to be short and stout, the vast majority would simply be to short to hammock off.
Then there is the factor of thunder storms.
In the months thunder storms are likely i consciously camp well away from any trees.
Summer is not really much better as forest fires are sadly a regular occurrence here, in July, August and the beginning of September i wouldn't camp in a forest of you paid me.
Even outside those months a fire is illegal and they are very harsh on anyone that flaunts that law.
If i'm being totally honest i could probably use a hammock say 30% of the time, another 20% may be possible but it'd be risky to find 2 sturdy trees the right height and strength.
The other 50% i honestly believe there would be nowhere to tie it at all.
I'd try a hammock those 30% of the times, but as said i sleep either on my side or on my belly, after trying cheap summer type hammocks i'm unsure how comfortable i'd be sleeping like that in one.
Cheers
Mark