Sap is the lifeblood of a tree, carrying both hydration and nutrition to every part of the plant along a network of veins. While all sap performs similar tasks within the tree, not all sap is made from the same ingredients. Because of this, some trees feature sap that is red and has a color more similar to the lifeblood of a human than of a plant.
One of the most recognizable of red-sap-producing trees is the eucalyptus. Eucalyptus trees such as the Eucalyptus robustus and the ironbark eucalyptus tree produce red sap when injured. This specialized sap is designed to quickly cover and coagulate around the tree's wounds, preventing infestation from insects. The color of the sap comes from the substance kino, which is the active ingredient, thickening and coagulating the sap as it covers the wound.
Sangre de Grado
Sangre de grado means blood of the dragon in Spanish and, in fact, a taxonomic classification for the sangre de grado tree is Croton draco. Like the eucalyptus, the sap of this tree coagulates quickly with a blood-red color, but, unlike the eucalyptus, it is a type of latex. This sealant covers the wound, keeping it free from infection by insect or airborne illness. Sap from the sangre de grado tree is used as a wound sealant to stop bleeding and is also used as an antifungal agent and itch reliever. This plant is native to South American countries including Ecuador, Peru and Colombia.
Once known as the Swietenia febrifuga, this Asian plant now called Soymida febrifuga grows from India to Sri Lanka. Known commonly as the Indian redwood, or bastard cedar, this tree also has red sap, but the color comes from its infusion with the kino chemical found in eucalyptus species. This tree is cultivated for its wood as well as for the red sap, which is used as a resin.
The Indian padauk tree, or Pterocarpus marsupium, is another species of tree with red sap. The sap from this tree was used as a wood dye, commercially known as red saunders. The wood, also reddish-brown in color, was used in construction. Red tree sap from the padauk tree is colored with kino, and the tree is sometimes called the East Indian kino tree.