Question

1. The “tree-line” or “timberline” is the elevation at which trees no longer grow. Look at any very tall mountain and you’ll see a clear demarcation point where trees essentially stop growing. This happens for a variety of reasons; temperature decreases with elevation, air pressure drops with elevation, as does the moisture content. The highest tree-line in the world is found near Navado Sajama in Bolivia, at an elevation of 5200 m. As for the Canadian Rockies, the tree-line in Banff is approximately 2400 m above sea level. The average day temperature in summer at Banff is 20°C, and at Navado Sajama it is 7°C. Calculate the average atmospheric pressure (as a ratio of that found at sea-level) at Navado Sajama and in Banff and comment on how important temperature and atmospheric pressure are to determining the tree-lines at these locations.

Answer 1