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The Nairobi Arboretum, Kenya - Reflecting the Needs of the Community for Almost a Hundred Years

Volume 2 Number 9 - December 2002

Anne Birnie

The Nairobi Arboretum, set in the centre of the capital of Kenya consists of 30 ha containing a large collection of trees and shrubs from the tropics both native and from throughout the world. It has developed from a trial arboretum at the beginning of the twentieth century to a green refuge from the bustle of the city and a place for learning about biodiversity.

Nairobi was developed to support the construction of the railway from Mombasa on the coast to the shores of Lake Victoria, the source of the Nile which the British colonists wanted to control. The area was known as Enkare Neerobi meaning a 'place of cool waters'. It was used by the Maasai people as a watering place for their cattle herds.

Railway engines ran on steam generated from burning logs. A large supply of fuel was needed daily for the railway until 1952 when diesel oil replaced woodfuel. Around 1902 the colonial government gazetted an area of 3 km either side of the railway line so that fuelwood could be cut from the forests within the belt. Olive trees (Olea europaea subsp.africana) give out the highest heat when burnt, so Olive and Cedar trees (Juniperus procera), among others, were cut down. Foresters noted early that indigenous trees grew but slowly and suggested the planting of quick growing exotic softwoods to meet the demand. Nobody knew if such exotics could thrive in Kenya.

In 1907, provenance trials on the present arboretum site were set up with seed brought from Australia, Mexico, India, New Zealand and the U.K. Under Mr H.M. Gardner, (Chief Conservators of Forests (CCF) from 1928-47, the policy of “making as complete a collection as possible of indigenous shrubs and trees’’ was pursued and he extended greatly the collection of ornamental exotics. He designed the site well and plants were introduced each year for a long time despite drought and disease. Forest Stations had been set up all over the country and many large forest areas gazetted as protected Forest Reserves, including the Nairobi Arboretum in 1932. A plant inventory of the arboretum was typed in 1945, now in the herbarium library at the National Museum (NMK), providing valuable records of planting. The 1958 Guidebook to Nairobi Arboretum records “it is a daily sight to see schoolchildren.” The amenity and educational value of Nairobi arboretum had been accepted. Much botanical information about trees became known from the extensive collections of early foresters (now in the herbarium) and in 1962 Mr Greenway and Mr Dale wrote the first book on Kenya trees for the public.

Nairobi, now has a population of about three million and the arboretum is an important resource for the people of Nairobi. The arboretum’s space and strategic location means it has tremendous potential for raising public awareness about the importance of biodiversity. A survey showed that already 140,000 people had visited the arboretum in 1995.

The management of the Arboretum is under the Forest Department of the Ministry of Environment and Natural Resources, through the Nairobi Arboretum Management Board (NAMB) formally established in 1997 with a chairman appointed by the CCF.

An Arboretum Masterplan was proposed by the Board to provide a broad view of the future role of the arboretum in the context of Kenya national policies and international conventions. It was developed in consultation with stakeholders in 1996 by consultants, financed by British Government. One output of the plan was the commissioning of a full tree inventory. The Masterplan was approved and launched in January 2000. It includes plans for better management, an education centre, wedding garden, children’s area , and a variety of improvements. The Masterplan provides the basis for action.

The Arboretum has an active friends group, the Friends of Nairobi Arboretum (FONA), established in 1993 An MOU was signed by the CCF and the Chairman of FONA where the partnership agreed to develop the arboretum’s role “in environmental conservation and education, culture and recreation, science and research, urban amenity and civic pride.”

The Friends of Nairobi Arboretum (FONA)

FONA became a special project of the East Africa Natural History Society now Nature Kenya, (founded 1909), and was legally constituted. It has been extremely successful in raising public awareness and fund raising for improvements to the arboretum and staff development.

Public awareness
Throughout 1994 there were small monthly events for the public and Friends’ membership grew. TreeNews, a newsletter for members, was introduced. The public were involved in renaming the paths.

In February 1995 FONA held a much bigger event for the public, a concert on the grassy lawns of the arboretum, publicised as “Wind in the Trees. Sponsorship (from General Motors Kenya Ltd) has enabled this popular concert to continue as an annual event. Even deaf children were able to participate. Another regular event is Solar Energy Day, sponsored by solar energy companies.

FONA has organised one-day gardening courses including compost preparation for people employed in gardening and specially devised training courses for tour guides and for teachers. Tree and bird lists and trails have been made for children and for the public. Monthly Tree Walks have been introduced. There are regular visits by NatureKenya Birdwalks. In addition University students, schools, overseas visitors and tour agents have been hosted. Environmental NGOs held an open day to which Government Officers were invited to a lunch on site. Every weekend is now busy with people: singing, playing games, having a picnic or just relaxing in the pleasant environment away from the bustle of the city.

Fund raising and improvements
Armed with a well-designed brochure, the FONA committee sought funding from both local and international donors. Donors’ names were recorded on a Donors’ Board. The Netherlands Government, amongst others, gave a substantial donation in 1993. Initially, small improvements for visitors were introduced like toilet facilities, waste bins, seats and picnic tables. The trees on the ground were surveyed and a new programme to upgrade labels began. A donation of aluminium pieces helped considerably.

In 2001 FONA published a new guide book for the arboretum (Nairobi Arboretum - the place of trees for nature … for people FONA, November, 2001 Price: US$8.00 obtainable from the address above). It was launched by Mr Charles Njonjo, current Chairman of the Kenya Wildlife Service.

FONA has become a catalyst for companies and other organisations to support the revival of the arboretum. Significant contributions include the FONA office (Erica Mann), the shelter banda in the Central Lawn (BP Kenya), and the new paved Walk (The Ford Foundation), as well as the improved car park (General Motors, Kenya).

FONA funds the employment of two staff an Arboretum Development Officer and one gardener. FONA raised funds for the arboretum forester to attend the Diploma Course in Botanic Garden Management at the Royal Botanic Gardens, Kew, U.K in 1995 and funded the employment of the first

Indigenous trees in the arboretum

Kenya contains a great range of environments with over 800 indigenous tree species. Not surprisingly, trees natural to the highland forests of the Aberdare Range are well represented. The four commonest trees have over 100 specimens and of these, the two commonest are dominant members of the Nairobi dry evergreen-deciduous forests. They are, in descending order: Croton megalocarpus, Brachylaena huillensis, Podocarpus falcatus and Markhamia lutea. Croton megalocarpus (Mukinduri in the Kikuyu language) was chosen by FONA for its logo and over 300 mature trees have been counted, and recorded.

Suitable trees were introduced to the arboretum from all over Kenya but this policy has not been completed. Trees may be numerous because they regenerate naturally. There may be few in the arboretum because few were planted or because they died out. A few species may be classified as rare or endangered. Others grow only in a restricted location. Trees from the coast or lowlands rarely grow well in Nairobi but the arboretum has some.

There are 265 plants (4%) endemic to Kenya. For instance, Canthium keniensis is quite common in the arboretum and is endemic to Nairobi and Machakos forests. Two species described as Rare to Vulnerable in the arboretum. are Premna maxima (Muchichiu),once used for furniture, is endemic to north east Mount Kenya and Marsabit forests and Croton alienus are found, endemic to central Kenya, few remain in that area due to intense cultivation. There are old plantings of four tall Mvuli (Milicia excelsa), widely traded as Iroko. This tree has the most attractive timber for quality furniture and was extensively used by early settlers and also harvested for export. It is now totally overexploited in Kenya with only a few trees remaining in moist forests such as Kakamega and Shimba Hills.

A few examples of native species with medicinal, poisonous, stimulant properties are Zanthoxylum spp. which have a characteristic, thorny bark with medicinal properties. A single tree of Z. gillettii has been repeatedly hacked for its bark despite protective wire around the trunk. A large number of Miraa trees (Catha edulis) grow well in the arboretum; young shoots contain an effective drug. This has been a profitable export product for Kenya until recent control measures

Some timber trees of Kenya in the arboretum include the Silver oak (Brachylaena huillensis) which thrives and regenerates in the arboretum, Red stinkwood (Prunus africana), was a quality timber tree exported from Kenya but today it is better known for the medicinal properties of its bark, treating prostate problems, the East African yellow-wood (Podocarpus spp.) provided much high quality timber in Kenya but again too many have been removed, Mukui (Newtonia buchananii) its durable timber has been used for canoes and Meru oak (Vitex keniensis) endemic to the Meru slopes of Mount Kenya. Meru oak is now protected in the wild but is being planted in plantations and elsewhere; its quality timber like “oak” is harvested after 100 or more years, and makes beautiful furniture.

Exotic timber trees have been planted as demonstrations of economic trees around the world such as the African mahogany (Khaya anthotheca), growing in wet forests from Sierra Leone across to Uganda and south to Mozambique (its hardwood timber is imported to Kenya) and mahogany trees (Sweitenia mahogoni) from Central America. Other exotic trees include 35 species from Australia and over 40 from the Americas. Most exotic trees were planted because of their colourful blossom such as the Flame kurrajong (Brachychiton acerifolium) and Cigar cassia (Senna brewsteri). From the old Forest Annual Reports it is clear that a large number of introduced plants did not survive. An exception was the Mexican weeping pine (Pinus patula), now used extensively for paper and as a plantation softwood. Exotic bamboos thrive and the arboretum has palm trees from several countries as well as the indigenous Wild date palm (Phoenix reclinata).

Anne Birnie
Former Chairman of Friends of Nairobi Arboretum (FONA)
Friends of Nairobi Arboretum
c/o PO Box 44486, Nairobi
Tel: +254 2 746090/749957
Fax: +254 2 741049