The timberline or tree line is the elevation at which tree growth stops. Its location depends on temperature, soil, drainage, and other factors. The mountain timberline always would be higher near the Equator than near the poles if it were not for the abundant rainfall in equatorial mountains, which lowers the air temperatures. Forests near the tree line on windward slopes are often stunted and twisted by strong winds into strange shapes known as elfinwood. In the Northern Hemisphere, tree lines are somewhat lower, and vegetation may be denser on the south slopes.
Mountainous terrain is often both an asset and a hindrance to humans.
Mountains have provided protection from war-minded neighbors. The Swiss have thrived in their mountain environment because it has given them a degree of political independence that is unusual in their part of the world. The high mountains that border Switzerland on the west and north made it possible for the country to avoid military involvement in both world wars. The Swiss have, however, developed a high standard of living only with prodigious effort, determination, and ingenuity. Mountains have furnished valuable resources of minerals, timber, water, and scenery.