A native to China, this tree is commonly referred to as the Hardy Rubber Tree. The sap from the tree can in fact be used to make rubber. If you tear a leaf or break a twig, you will see a stringy latex-like sap from which rubber can be produced. The tree can grow to a height of 40 to 60 feet tall. Useful as a tonic herb in traditional Chinese medicine, this tree is widely cultivated in China and is recommended for vitality enhancement and longevity. The Eucommia bark is highly valued and is known to have been mentioned over 2,500 years ago in a piece of herbal literature called the Shennong Ben Cao Jing.2 Extract from the bark is now used as a popular herb by athletes to help improve flexibility and fortify bones, ligaments, and tendons, especially in the knees, ankles, and back.