The Most Colourful Tree on Earth

 
Photo: Jeff Kubina
Rainbow Eucalyptus (Eucalyptus deglupta)
The Rainbow Eucalyptus (Eucalyptus deglupta) or Mindanao Gum is the only species of Eucalyptus tree found in the northern hemisphere. As if that weren’t extraordinary enough, the up to 70-m tall tree also shines in the colours of the rainbow: its bark can take on a yellow, green, orange and even purple shading!


Nope, no crazy abstract painter has put a paint brush to this tree:
 
Photo: Lisa Jacobs
The unusual phenomenon is caused by patches of bark shedding at different times. The different colours are therefore indicators of the age of the bark: Freshly shed outer bark will reveal the bright green inner bark. This darkens over time and changes from blue to purple and then reaches orange and maroon tones.


Like a natural camouflage pattern:
 
Photo: carvalho
One would think that a tree this pretty and unusual should, well, if not be worshipped, at least be put on public display in parks and forests. Sadly, that is not the case. Rainbow Eucalyptus trees are cultivated around the world mainly for pulpwood creation purposes. Wood pulp is the most common ingredient when making paper, white paper that is. The pulp can be chemically or mechanically separated from the wood. It is a dry, fibrous material whose fibres disperse and become more pliable when suspended in water.


Rainbow Eucalyptus trees at the side of Hana Highway in Maui, Hawaii:
 
Photo: Forest & Kim Starr
Pulpwood’s here to stay though as it is considered a source of green energy, and demand has increased over the last few years. Currently though, trees cultivated specifically for pulp production account for only 16% of world pulp production. About 9% comes from old growth forests and the remaining 75% from second-, third- and more generation forests. That’s a lot of tree years wasted for a bit of pulpwood! However, reforestation and specific cultivation for pulp wood purposes are on the rise, making the trees a renewable energy.


Colourful wonder:
 
Photo: Amelia
If you want to spot a Rainbow Eucalyptus tree live and in all its glory, you’ll have to travel to Indonesia, Papua New Guinea or the Philippines, the tree’s only native places. However, it has been introduced worldwide as an exotic wood in South America, Malaysia, Sri Lanka, China and other countries.