Looking for a word to describe the nature at higher places

I am looking for a word to describe nature at higher places, say, 2000 meters and above.

e.g. "I love ____ (mountains)" does not include water bodies, waterfalls, lakes etc.

Solution 1:

How about alpine?

of, pertaining to, on, or part of any lofty mountain.

very high; elevated.

growing on mountains above the limit of tree growth:

alpine plants

[Dictionary.com]

Additionally, this word is reminiscent of The Alps which should suit OP's purpose even better.

Solution 2:

The adjective montane is used for such flora and fauna (and regions). Collins gives a very broad definition:

montane [adjective]

of or inhabiting mountainous regions

[Collins]

While Merriam-Webster is more stipulative:

montane

• 1: of, relating to, growing in, or being the biogeographic zone of relatively moist cool upland slopes below timberline dominated by large coniferous trees

• 2: of, relating to, or made up of montane plants or animals

Recent Examples on the Web

• This means that parts of the vast montane forest that once stretched across much of central Africa now has permanent protection and is open to visitors. — Judy Koutsky, Forbes, 4 Oct. 2021
• Spring is a lovely time to explore the foothill and montane landscapes of Salt Lake City, where sunflowers, gum weeds, and bluebells are having their moment in the sun. — Wendy Altschuler, Forbes, 1 June 2021

[Merriam-Webster]

The 'sub-alpine' and 'alpine' zones are contrasted with the stipulative definition.

Solution 3:

I love highland lakes.

I love highland waterfalls.

I love highland trees.

I love highland flora and fauna.

I love highland clouds.

highland, n. and adj.

A. n. 1. a. Land which is naturally elevated in comparison to the surrounding area; high ground; the mountainous or elevated part of a country. Also: an area of such land, esp. a high headland or cliff.

B. adj. 2. gen. Of, relating to, or characteristic of a highland or highlands.
_{[selected samples]
1853 E. K. KANE U.S. Grinnell Exped. (1856) xxiv. 199   Merely the highland clouds over the mountains.
1951 N.Y. Times 15 Apr. xx. 19/1   The Blue Ridge mountains, from whose heights the flatlander can..understand the lure of highland life.
2010 D. A. ROTHERY Planets: Very Short Introd. ii. 57   Some Mars scientists see evidence for glaciers, especially at the eroded edges of highland plateaus.}

_{Source: Oxford English Dictionary (login required)}

Solution 4:

I love high altitudes. I thrive in a thin atmosphere.

(In case it's not obvious -- "thin atmosphere" refers to a place where the air pressure is low and the air molecules are more spread out.)

There are examples of the latter in Collins, for example "It swiftly evaporated into the thin atmosphere."