Quechua people Quinine, which is found naturally in bark of cinchona tree, is known to be used by Quechuas people for malaria-like symptoms. When chewed, coca acts as a mild stimulant and suppresses hunger, thirst, pain, and fatigue; it is also used to alleviate altitude sickness. Coca leaves are the raw material from which cocaine, one of Peru's most historically important exports, is chemically extracted. Many indigenous women wear the colorful traditional costume, complete with bowler style hat. The hat has been worn by Quechua and Aymara women since the 1920s, when it was brought to the country by British railway workers.
Tree converted into bark and the cambium layer creates new phloem and xylem cells. The bark is inelastic. Eventually the growth of a tree slows down and stops and it gets no taller. If damage occurs the tree may in time become hollow. Leaves are structures specialised for photosynthesis and are arranged on the tree in such a way as to maximise their exposure to light without shading each other. They are an important investment by the tree and may be thorny or contain phytoliths, lignins, tannins or poisons to discourage herbivory. Trees have evolved leaves in a wide range of