can trees grow at 1800 feet above sea level?

Absolutely. When I was in Colorado I went across the Continental Divide and there were trees well above 10,000 feet. It depends on the temperature, the slope, amount of sun and shadow, and the latitude.

The tree line in Rocky Mountain National Park is about 11,500 on warmer southwestern slopes but drops to about 8,000 feet on the northern sides. The species of tree changes with the altitude. The toughest tree that I know of is the bristlecone pine, which often forms the upper boundary at elevations as high as 12,500 feet. These trees can live to be over 2,000 years old.

Yes, Trees can grow even much higher than 1800 ft Above see level. Denver is a mile 5200 Ft above sea level and there are trees there.

Yes, I live at 2000 ft. above sea level, and there are lots of trees here.The tree level can vary depending on the area, but the tree line can be quite high(10,000 and up).

Yes, i went to a holiday in india, in the himachal pradesh state, i saw marijuana plants growing at an altitude of 22,000 feet. There were also apple trees.

yes - most of the high country thru Penn. , W. Va, Kentucky and Tenn. Is in that range (Smokies and Alleghenys) and theres a lot of timber growth.

Yes, as long there is enough CO2 for the tree.

Yes !!!! But a lot depends on the temp altitude ....

Yes, and much higher than that...

absolutely.

what's the temperature up there?