The tallest tree in Africa, and one of the tallest trees in the world, has been found growing on Tanzania's Kilimanjaro, Africa's highest mountain.

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The crown of E. excelsum towers more than 30 meters above its neighbours at Kilimanjaro. Image: Andreas Hemp

Standing 81.5 metres (approximately 267 feet) tall, the giant – Entandrophragma excelsum – belongs to the mahogany family and replaces the previous reigning height champion on the continent, an 81.5-metre-tall Sydney blue gum (Eucalyptus saligna) from Limpopo, South Africa that died in 2006. The tree is also ancient, estimated to be between 500 and 600 years old.

The E. excelsum specimen is also the first member of an indigenous tree species to hold the title. Though far from the loftiest tree in the world (that particular honour belongs to "Hyperion", a California redwood that measures in at 115.7 metres, or around 380 feet, tall), the Mount Kilimanjaro record-setter easily ranks among the tallest.

A line-up of some of the world's tallest tree species. Image: Hemp et al. 2016

The discovery comes after four years of research conducted by a team of scientists from Germany and Switzerland, who used laser instruments to accurately gauge the height of 32 specimens growing on Mount Kilimanjaro. The study's leader, Dr Andreas Hemp of the University of Bayreuth, first encountered the exceptionally tall tree while exploring the forests of the mountain decades ago, though he was unable to measure it accurately at the time.

The tree isn't just remarkable for its size, however. Along with its also-gargantuan E. excelsum neighbours, it's a crucial part of the mountain's ecosystem, playing host to a variety of local epiphytic plants, especially ferns that colonise its branches and bark.

"[The trees] are like a city in the forest," Hemp told New Scientist.

E. excelsum trees can be found in hard-to-reach gorges on the southern slopes of Kilimanjaro. Image: Andreas Hemp

There may be even larger trees in Africa, too. Although the continent is not known for producing arboreal giants, findings like this one suggest that other massive specimens – overlooked due to a shortage of research efforts – could be out there. In the case of Mount Kilimanjaro, for example, high temperatures, heavy precipitation and nutrient-dense volcanic soil offer the perfect conditions for primeval trees.

Unfortunately, these same conditions make the tree and its neighbours high-value targets for illegal logging operations, and the handful of square kilometres that make up this habitat are not part of a protected area. Hemp's team strongly recommends that the mountainous valley that shelters the trees be added to the nearby legally protected Kilimanjaro National Park.

"These valleys, in which the East African tree giants evidently have very good living conditions, should be integrated as soon as possible into the neighboring Kilimanjaro National Park," notes Hemp in a press release. "This would be an outstanding and at the same time particularly urgent protective measure. Otherwise, Kilimanjaro risks losing not only a unique biogeographical archive with highly diverse vegetation, but also its tallest trees."



Top header image: mar is sea Y, Flickr