Having to "go" on the trail

[SRMLECMcD]

I plan on staying very hydrated on the trails but coming from the east coast almost all of the hiking and climbing I've done is below treeline so there is always somewhere to go. Once above treeline what is the suggested method and etiquette?

[Alpine Guy]

"Where there's a will, there's a way". Can be a little challenging on mega-popular routes like Grays or Bierstadt but otherwise just pick your time & place.

[timisimaginary]

make sure to aim downwind.

[Alrightmax]

Believe it or not, CFI has a video about this https://www.youtube.com/watch?v=yu4cZ3VvGBc

[JQDivide]

Save it for the goats!

[mtree]

With a little imagination, you shall prevail.

Just remember no-one is interested in seeing you pee or poop...I should hope anyway.

[highpilgrim]

You could build a little rock cairn throne, a little off the trail and go to town.

Maybe even get your black sharpie out and document the occasion on a nearby rock under which you leave big pile of used tp.

[myfeetrock]

For those steeper hikes, don't forget to point it with the wind. If not, that shot into the void will come back at your face if you get a nice updraft.

[nomad]

Not sure which gender you are, but for dealing with being well hydrated for a guy is pretty simple. Step off the trail, act like you are just taking in the views and have at it. A few weeks back I rolled up on a female in full blast motion while I was descending on my mountain bike. She apologized, I looked the other way until she finished and we went our separate ways. No biggie.
For solid waste, try to plan ahead, worst case scenario, you have to take care of business, just be mindful of others and don't leave a mess. Pardon the pun.

[pvnisher]

Find a proper location. Out of view from others in the trail if possible, but sometimes that's not an option. Do your best. Don't go too far off the trail and trample the tundra, though.
Face downwind if applicable. Downhill is also good or else you might find yourself dancing around rivulets.
Set up in a slightly wide legged stance.
Dealers choice on going for distance, accuracy, coverage, or spelling.
Shaking more than three times is just playing with it.
Hand sanitizer, especially if there's a shared bag of granola, is appreciated.

[jaymz]

Above treeline, I think there's a shared assumption among everyone that if nature calls, you gotta do what you gotta do. As long as you're at least trying to be discreet, I doubt anyone is going to be offended. I've been on highly populated ridges and had to go... just stepped off a bit, turned my back to the crowd and went. People understand. Modesty kind of takes a back seat to convenience in that environment.
To play off mtree's remark above, someone here once said that if someone's watching you pee, you're not the one with the problem.

[two lunches]

pro tip: pack out your @#$&*ng toilet paper i am so sick of finding wads in the woods.