Eucalyptus deglupta is a fast-growing tall tree, commonly known as the Rainbow Eucalyptus, the Mindanao Gum, or the Rainbow Gum. It is the only Eucalyptus species found naturally in the Northern Hemisphere. Its natural distribution spans New Britain, New Guinea, Ceram, Sulawesi and Mindanao. This tree is cultivated widely around the world, mainly for pulpwood used in making paper. Nevertheless, it is also a popular ornamental tree, due to its uniqueness amongst eucalyptus.
The Rainbow Eucalyptus gets its common name from the dazzling multi-colored streaks of color on its trunks and limbs. Many people may think that they were painted on, but these ever-changing colors are in fact an entirely natural feature. The rainbow eucalyptus bark is smooth, and as it grows, it exfoliates thin layers of spent tissue. This process occurs annually at different times. Once the layers come off, they expose new and fresh green bark. As the newly exposed bark gradually matures, it transforms from bright green to a dark green, and after that bluish to purplish, then pink to orange, and finally, the color becomes almost maroon right before exfoliation occurs. Because this process is happening in different zones of the trunk and in different stages, at the same time, the colors are varied and almost continually altering. As a consequence, the tree will never have the same color pattern twice, making it similar to a work of living art.
Source from wikipedia and eucalyptusdeglupta