> I don't know at what elevation trees stop appearing This is known as the "tree line", and varies a lot based on particular location (due to sun exposure, cli

> I don't know at what elevation trees stop appearing This is known as the "tree line", and varies a lot based on particular location (due to sun exposure, climate, and plant species). Here's a wikipedia article which outlines where the tree line: https://en.wikipedia.org/wiki/Tree_line https://en.wikipedia.org/wiki/Tree_line . Summary is that the treeline is rarely above 12k feet (3500m), though in Bolivia it gets all the way up to 17k feet (5200m)!! You are probably correct w.r.t. the main flow of the jet stream being far in excess of the highest tree lines in the world. The jet stream's main flow is usually 30k feet (10k meters) or higher.