Re: Really good?
Actually, there are trees on Everest. They grow below the treeline, or under 12,500 feet (plus or minus) in much of the Himalaya range. Some Junipers[0] have been found above 15,000 feet. I wouldn't expect you Brits to know this, though ... you lot don't have any mountains, and expect everything on the planet to be exactly like it is in Blighty.
[0] The aptly named Juniperus tibetica.