When the root or bark is steamed, it produces a volatile, white, crystalline compound with a characteristic pungent odor, usually referred to as camphor. (The aromatic oils in such plants as tansy and feverfew may also be referred to as camphor). Trees that produce the real camphor are slow-growing. In fact, the Chinese believe that it cannot be extracted from trees under fifty years old. In the US, camphor is extracted from leaves and twigs of the oldest trees, which does less damage than the more invasive Chinese method. Despite this, most of the camphor now used in the US is produced synthetically.
