Under Mr. H.M Gardner (Chief Conservator of Forests from 1928 – 1947) 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 made a complete design of the Arboretum and new plants were introduced each year for a long time. Mr Gardner and all subsequent CCF have continued to live in the stone house next to the Arboretum entrance, until 1997. This house is now the Tree Centre, hosting an education and information centre and FONA office.
After the independence of Kenya the Arboretum had little priority of Forest Department. From the 1970’s on the place was quite neglected when management levels declined due to inadequate government funding. This led to a situation that in 1993 the Arboretum was run down and much in need of renovations. A group of concerned citizens recognized the potential and importance of the Arboretum and established the Friends of Nairobi Arboretum - FONA. FONA became a project of Nature Kenya and started looking for local and international donors to save the Arboretum. An overall master plan to renovate and upgrade the Arboretum was launched in the year 2000 by the PS of the Ministry of Environment and Natural Resources.
Meanwhile the public has found its way to the unique place that the now 100 year old Arboretum is. In the middle of Nairobi city it provides a green space, for recreation and for education on nature and environment. It is visited by thousands of Nairobi’s citizens, as well as by tourists. They do sports, come for singing, praying or just to relax.