PART 11 
In view of the fact that Grevillea robusta has not the. 
characteristics of a shade tree with spreading branches, one can 
realise why this tree has not been successful in areas where a spreading 
tree would be desirable, and where a small number of shade trees to 
the acre would be an advantage, owing to lack of rainfall. On the 
other hand, it will be understood why this tree has given better results 
at the higher altitudes; in the first place, the rainfall is greater, and 
in the second place, a much lighter shade is required, not so much 
as to make a shade in the true sense of the word, as to act as an 
equalizer in extreme temperatures. In the Kericho District, where 
the rainfall is very great and strong winds are prevalent, Grevillea 
robusta was found very brittle and therefore unsatisfactory. Black 
wood Acacia melanoxylon was substituted and found satisfactory. 
It is considered, however, that this tree would be detrimental to the 
growth of coffee in a district where the rainfall is not as heavy as in 
Kericho, namely 70 inches. 
It has always been recommended that a mixed shade programme 
should be adopted, owing to the embryonic conditions of the coffee 
industry in the Colony. This has not been generally carried out, with 
the result that the subject of shade is still tentative. A number of 
trees are being tried, but it would be premature to give a definite 
decision as to which might be regarded as the most suitable, as a tree 
which may be found suitable in one district may prove unsuitable in 
another. At altitudes of 5,500 feet and under ** Mukuyu ’ Ficus 
Mallatocarpa is promising good results; as also has another tree, not 
yet identified. Albizzia moluccana would have been suitable had it 
not been found susceptible to attacks of root disease, and it has a 
further drawback of being brittle. In certain districts, where it has 
made extremely good growth, it has died out at from five to six years 
old, but this cause has not yet been ascertained. 
With regard to temporary shade, a certain measure of success 
has been achieved in the use of fast growing trees, yet on the other 
hand, there are a number of cases where its use has been detrimental 
to the growth of coffee. In the first place, temporary shade is only 
advocated under certain conditions, i.e., where hail is prevalent and 
where the growth of coffee is affected by cold. Secondly, when used, 
it is essential that permanent shade trees should be planted to take the 
place of the temporary shade, which should be thinned out from time 
to time, and after about three years it should have served its purpose. 
When it has been detrimental to coffee, the trees have been planted 
too closely and not thinned regularly, and no permanent trees have 
been established. Trees which are usually selected for temporary 
shade are very fast growing and are therefore in their nature, surface 
feeders. Care, however, should be taken to select such as are not too: 
voracious. 
A most successful and interesting experiment was carried out by 
Mr. S. O. Hemsted of the Trans-Nzoia with *“ artificial ’’ shade, by 
erecting posts and strands of plain wire over about 50 acres of coffee. 
The canopy was formed of maize stalks, grass, branches of macracarpa, 
etc. Ordinarily, the effect of shade diminishes the yield, but in this 
case, 1t increased the yield from a few cwts. per acre to about three- 
quarters of a ton per acre. The conditions under which this coffee was 
grown were not ideally suitable; the growth was affected by cold and 
clustered very badly. The effect of the ‘* artificial ’ shade was to. 
~4