Assertion: alpine tundra | /r/AtLocation | the tops of mountains
Facets:
value: above the tree line
type: LOCATION
Source sentences:
text: Alpine tundra is found at the tops of mountains above the timberline, the point above which trees cannot grow.
text: Alpine tundra is found on the tops of mountains.
text: Alpine tundra are located at the tops of mountains, above the tree line.