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,
Birch bark the phloem, kills the tree by preventing the flow of sap to the roots. To prevent it from rolling up during storage, the bark should be spread open and kept pressed flat. Birch bark can be cut with a sharp knife, and worked like cardboard. For sharp bending, the fold should be scored (scratched) first with a blunt stylus. Fresh bark can be worked as is; bark that has dried up (before or after collection) should be softened by steaming, by soaking in warm water, or over a fire. Birch bark was a valuable construction material in any part of