You don't need to go to Peru to see the beauty of rare colorful trees because in Bondowoso, there is a rainbow forest whose tree trunks look colorful. This area was proposed as a Global Geological Park to UNESCO in terms of biology. The rainbow forest area reaching about 23 hectares is included in the Special Purpose Forest Area of Sumberwringin. This area is also used for research activities with core research (research and development) in the field of tree breeding and genetic conservation. It is called rainbow forest because the tree which has the Latin name eucalyptus in the forest, looks colorful like a rainbow, namely green, yellow, red, orange, and bluish. A biologist from the University of Jember, Rendy Setiawan said that the colors of the eucalyptus tree trunks a caused by the oxidation process between cambium and oxygen. Therefore, when the sap or cambium of the plant peels off, there is a color gradation.
The tree trunks in the rainbow forest will be green, yellow, red orange, dark blue, and then, it is brown. The cycle will last and always be repeated throughout the year. The rainbow tree or Eucalyptus deglupta itself is a rare species. At Sumberwringin, you can only find around 10 to 15 of these rainbow trees. The location is not far from Bondowoso City, about 24.6 km. This forest is located in the Karanganyar Hamlet of Daerungan Hamlet, Sumber Wringin Village, Sumber Wringin District, Bondowoso Regency, East Java. Local residents call it "Bogor Forest".
At first glance, it looks like the trees which are painted in colors. Even, in image, it looks like a Photoshop editing result. In fact, it is the natural beauty which is presented by the trees. The colorful-like rainbow on tree trunks is from the barks which are often peeled off. The layers of the tree bark peel off alternately. Not only being colorful, the trees are also looking high like a tower about 25 meters high. The characters of these trees are also different from other trees. There are no branches and twigs. The trunk of the tree is straight and towering. If any branches and twigs, they are usually at the top. That is just a little. The eucalyptus forest area in Bondowoso has existed since the Dutch era, precisely around 1939. The place is not officially opened as a tourism destination. But at certain times, a number of students from several universities come to carry out research. Meanwhile, the residents of Bondowoso and surroundings often use this area for selfies.