Plant stem stems are asparagus, bamboo shoots, cactus pads or nopalitos, kohlrabi, and water chestnut. The spice, cinnamon is bark from a tree trunk. Gum arabic is an important food additive obtained from the trunks of "Acacia senegal" trees. Chicle, the main ingredient in chewing gum, is obtained from trunks of the chicle tree. Medicines obtained from stems include quinine from the bark of cinchona trees, camphor distilled from wood of a tree in the same genus that provides cinnamon, and the muscle relaxant curare from the bark of tropical vines. Wood is used in thousands of ways, e.g. buildings, furniture, boats,
Cinchona pubescens new stalks. If the bark is removed and the xylem is exposed to the elements, the tree will grow the bark back. The tree can even grow back if roots that are left in the ground are larger than 2 cm in diameter. It reproduces rapidly and spreads its seeds via wind. It reaches maturity and begins seeding in 4 years. Growing at a rate of 1–2 m per year, it quickly reaches a tall height where it can shade out the rest of the native plants. Adult trees grow much slower than juveniles. It has become an invasive species