Mangroves are plants that grow in the tidal zone of tropical coastal areas and are constantly subjected to ascending and descending water levels of high and low tides. They have adapted to this environment by anchoring themselves in the soil with their stilted roots. This way, they also prevent the coast from being destroyed by storms or flood waves. After the devastating tsunami of 2004, many countries have started planting mangroves at the coasts to try and prevent similar catastrophes in future.
The term ‘tree-line’ describes the height above which trees can no longer grow in the mountains. The main reason for this is the very low temperature in these places. If we climb a mountain, we find a temperature drop of about 6°C for every kilometre. In addition, the temperature fluctuations between day and night as well as summer and winter are very high. The soil cover is thin so the roots of trees do not get a firm hold. Only small pine trees, cedars, grass, and moss grow above the tree-line before the start of the rocky and icy area. 
