This tree genus is well known for the unmistakable aroma given off by its leaves. There are around 800 species of eucalyptus, most of them native to Australia, although the genus has expanded into many habitats and in the most diverse forms. There genus includes both shrub and tree species. Eucalyptus trees are fast growers, and have been planted all around the world for industrial, landscaping and reforestation purposes. However, the genus has a negative effect on biodiversity because it impoverishes the soil and the water metabolism.