The Aberdares

The Aberdares (Kikuyu name Nyandarua) is a 100-mile-long mountain range which forms the Eastern rim of the Great Rift valley. It is home to some ancient, enormous and very important trees. From the entrance, at 2000 metres above sea level, the park rises up to 4000 m at the top of the highest peak, Mount Satima. As you get higher, the landscape changes. And so do the trees.  

Life at high altitude is very tough.The trees that grow here have to find ways to protect themselves from getting burnt or dried out by the hot sun, but they also have to cope with freezing conditions at night and to strong winds. Trees have adapted to living in high places in a number of ways. They tend to be small in size (less chance of being blown over). Their leaves are adapted to prevent losing too much water when the sun is hot. Some, like the Hagenia, have downy hairs on their leaves and branchlets to screen them from the sun (and maybe to stop them freezing at night). Others, like the Juniper tree have tiny needle-like leaves (to reduce water loss and exposure to the sun). Some trees send a pinkish pigment to their leaves, or bark which acts like a sunscreen (you can see this in the young leaves of many trees, even at a lower altitude).  Growing together also helps the trees to keep warmer at night. 

This special part of Kenya is not only an important tree habitat, it’s also enormously important to people. The Aberdares is one of Kenya’s main ‘Water Towers’. The forests on the mountain slopes slow down the rainwater, helping it percolate into the ground. Without the trees the heavy rain would run off the mountain causing floods and landslides.  Instead, the water remains in the mountains where it feeds the important rivers, like the Tana, Athi and Ewaso Ngiro, that start their lives there. Millions of people (including the whole population of Nairobi and six other major cities) depend on the Aberdares for their water supply. The Aberdares was declared a protected area in 1932. In 1950 it became a National Park.

The Aberdares is a great example of how protecting our forests is the best way to protect ourselves.  

Come with us for a tree safari to the Aberdares...

The Farmlands

There are many farms on the foothills around the Aberdares National Park.  Over the years, people have cleared most of the forest for agriculture. The International Union for the Conservation of Nature IUCN tells us that Agriculture is the number one  threat to survival of the world's trees.

The Fence

The Aberdares national park has been protected since 1932.  This important fence, built by the Rhino Ark project, protects the trees and wildlife from poachers. It also protects the communities around the park, stopping wild animals coming and eating their crops.  Thanks to the fence, humans and nature can live side by side in harmony. (Learn more about this project here)

The Forest

The forests of the Aberdares are truly awe-inspiring.  Look out for gigantic Junipers (pencil ceders), Brittle-wood, African Olives and Podocarpus trees.  These trees provide food shelter for many animals and birds including elephants, buffalo, colobus monkeys and the rare mountain bongo.

The High Forest

As you climb higher, you will notice that there are less trees.  At 3000m the Juniper trees and Olive trees begin to disappear.  The Podocarpus tree (P. latifolius) can grow a little higher (3350 m). Eventually only the Hagenia trees are left. These trees can grow higher than any other tree in Kenya.  The Hagenia’s relative, Polylepis tomentella, also in the Rosaceae family, holds the record as the highest growing tree in the world! Click here to read more  https://www.guinnessworldrecords.com/world-records/86953-highest-tree

The East African Rosewood is the preferred habitat of the rare African long-eared owl. It hasn’t been spotted in the Aberdares for many years.  As we drove through the woodlands at dusk we saw an owl flit past.  We hope it was the long-eared owl! Click here to read more about this bird.

The moorlands

There are no trees at the top of the Aberdares.  Even the Hagenia can’t grow above 3600 metres.  Instead, you will see some unique and beautiful plants like giant lobelias and groundsel.  Some of these grow only in the highlands of East Africa.  Look out for the beautiful scarlet-tufted malachite sunbird which feeds on the lobelia flowers.

Explore some more!

Do you know where Kenya’s other water towers are? What can you find out about them? Do we have enough water in Kenya? How could we use our water better?

Have a look at the trees that grow near you. How are they adapted to the environment they are growing in?

Sources of information

Legesse Negash (2010). A Selection of Ethiopia's Indigenous Trees: Biology, Uses and Propagation Techniques. Addis Ababa University Press, Addis Ababa, Ethiopia. ISBN 

Quentin Luke and Henk Beentje - 100 trees to see on Safari

Aberdare National Park, KWS, The Official guide (2003)

Many thanks to Rupi Mangat and the Aberdares adventurers who came with us on this Tree safari.