In most cases, however, the confidence limits of the means of species'
relative densities per plantation were very high, being even higher than the
means in some cases (Table 2). This depicts a wide variation in the
distribution of the species within each site. However, natural forage yields
are known to vary enormously between years, depending on climatic or
animal and human factors such as drought, grazing intensity and bush fires
[deLeeuw, 1977]. As previously mentioned, these reserves and plantations
are fire-traced at their edges annually and also, grazing frequency and
intensity are controlled by forest guards. Also, the confidence limits of the
means of the relative light intensities within the plantations were very high
(Table 1). Again, this suggests large differences in the amounts of insolation
reaching different spots on the plantation floors. Such differences are expected
to arise from differences in intensities between sunflecked and shaded
areas, and also, due to occasional variation in light intensities arising from
wind sway of tree crowns during the time measurements were being made.
These variations are expected to affect the distribution of understorey plant
species due to reasons already given.