4.2.2. Growing in height
The height growth was used to estimate the number of years
needed by each species to be
outside fire events. Table 2 presents the total
height of different investigated trees and the
figure 13 informs about the
number of years needed by each species to reach the height of 1.3
m.
Number of individuals
4
2
5
3
0
1
a
Number of individuals
4
2
5
3
0
1
b
3 5 6 7
e of I
Age
2 3 8
Age
by t
Number of individuals
3
2
0
1
c
3 6 7 9 15
Number of individuals
2
3
0
1
d
3 4 5
Age
Age
Figure 13: Initial height growth for some of
investigated species. For all figures, the variable Age of abscise means
the number of years. (a) A. leiocarpa - (b): D. Microcarpum -
(c): I. doka - (d): P. erinaceus.
In these figures, axes X and Y describe respectively the
absolute frequency and the number of years. They show that the height growth
varies among species. Some savanna species such as A. leiocarpa, D.
microcarpum and I. doka need between 2 to 8 years to reach the
height of 1.3
m. However, D. abyssinica needs more time to reach the
same height of 1.3 m. In fact, this species grows slowly in wide and also in
height. It needs long time to be outside fire events.
4.2.3 Conclusion on tree species growth
A. leiocarpa, D. microcarpum and I. doka can
be categorized as fast-growing savanna species while D. abyssinica is
a slow-growing species. These observations are in accordance with those of
Worbes (1989). If we refer to anatomical characteriza tion described in our
results combined with the findings of Worbes (1989), we c ould assume a
relationship between wood colour and the growth performances. But, before
confirming this hypothesis, further studies on several savanna wood species are
necessary.
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