Light intensities reaching the plantation floor in all sites were about half
of those in the open (Table 1). Although the spectral composition of the light
reaching the floors of the plantations were not measured due to lack of
appropriate equipment, it is known that in the temperate and tropical
regions, broad leaved canopies are selective filters that transmit sunlight in
the red and far-red bands [Carters, 1934; Evans, 1939]. The crowns of trees at Samaru were observed to start about 3-6 m from the tree bases, while
those at Kabama and Guga start about 6-8 m as stated earlier. This would
be expected to affect the amounts of light reaching the individual plantations
(Table 1). The reason for this variation in the height at which crowns start
forming is unknown.