From the wiki: "Eucalyptus deglupta is a 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. Now, this tree is cultivated widely around the world, mainly for pulpwood used in making paper. It is the dominant species used for pulpwood plantations in the Philippines."
"This tree is also grown for ornamental purposes, due to the showy multi-coloured streaks that cover the trunk. Patches of outer bark are shed annually at different times, showing the bright-green inner bark. This then darkens and matures to give blue, purple, orange and then maroon tones"
Detailed (dense) info from the World Agroforestry Centre's database on Eucalyptus deglupta
less detailed info from learned enthusiasts