Plant resins are sticky substances produced by various plants, particularly trees, as a defense mechanism against injury or infection. These natural compounds can be found in the bark and are often released when the plant is damaged. Resins serve to seal wounds and deter pests, helping the plant to heal and survive. In addition to their protective role, plant resins have been used by humans for thousands of years. They are commonly found in products like incense, varnishes, and adhesives. Some resins, such as amber, are valued for their beauty and are often used in jewelry and decorative items.