Flora Biodiversity Assessment in Bonga, Boginda and Mankira Forest

e undertaken in the area, so that appropriate (i.e. socially accepted and
environmentally sound) measures may be taken. The existing PFM program
needs to be strengthened.
C. Five frequency classes are recognized and shown in the following Table.
Lamprecht, 1989 has indicated as it is customary practice to assign the various
species to five classes based on their absolute 8 frequencies and depicted as follows
(Table 8):
Table 8. Frequency class of tree/shrub/lianas species in the study area
Class Absolute Frequency Presence 9
A=I 1-20 Rare
B=II 21-40 Seldom Present
C=III 41-60 Often present
D=IV 61-80 Mostly present
E=V 81-100 Constantly Present
Accordingly, all the species registered in the three forests are grouped in this
category to see whether each forest is heterogeneous or homogeneous. Lamprecht,
1989 indicated that diagrams with high values in D/E and low values in A/B indicate
constant or similar tree species composition (homogeneous). A high degree of
floristic heterogeneity is found when the situation is reversed i.e. when the values of
D/E are low and the values of A/B are high.
The following Table and figure are the result of the current survey. High values in the
three forests are in A/B. Hence it can be concluded that the forests’ floristic
composition with regard to trees/shrubs and lianas greater than 10 cm are
heterogeneous. Getachew Berhane and Yoseph Assefa in IBC, 2002 got similar result
for Boginda forest.
8 Expressed as percentage
9 Based on Lecture note on “General Ecology”, Wondogenet College of Forestry.
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