stratification

If you look for it, you'll find stratification almost everywhere. On a tall rain-forest tree, there may be different air plants clinging to it, different insects crawling on it, and different mammals making their homes at different levels. The earth beneath you may be stratified into several distinctive layers within the first 20 feet. If the wind you're feeling is moving at 10 miles per hour, at 30 feet above your head it may be 20 mph, and in the jet stream above that it may be 150 mph. If you climb a high mountain in Himalayas, you may begin in a lush, wet forest and end up in a windswept environment where not even lichen will grow.