Some trees produce oil that have health benefits. For example, the oil in tea tree leaves has anti-bacterial and anti-fungal properties. According to the National Institutes for Health, the oil has been used topically to treat athlete's foot, nail fungus, dandruff and acne.
Eucalyptus trees produce large amounts of oil inside their trunks and branches. One side effect of this is that the trees tend to ignite very quickly when exposed to fire. The oil inside the tree begins to bubble and pop violently, spreading the fire. Such trees can become a serious fire risk and potential problem in hot, arid areas when they are located near structures and homes. For example, during the Berkley Hills fire in California in the early 1990s, eucalyptus trees dotting the landscape were blamed for accelerating the blaze.
Many countries, such as Malaysia and Indonesia, use palm tree oil for cooking as well as cosmetic purposes. Because of the widespread demand, production of palm trees is promoted in agricultural areas. However, some regions have clear-cut jungle and other natural areas to create more land for palm oil production, according to a report for The Center for Science in the Public Interest. Such destruction raises concerns about the cost of market-driven agricultural changes.
The Brazilian Copaifera langsdorfii tree produces a natural diesel that can be harvested by boring a hole in the trunk. One tree produces 8 to 10 gallons of the ready-to-use fuel annually. While the existence of the natural diesel has been known since 1625, commercial production has not been attempted.