serikali ya mapinduzi zanzibar care tanzania and department

Number of stems
180
160
140
120
100
80
60
40
20
0
T1 T2 T3 T4 T5 T6
Transect
0.10 - 0.20
0.21 - 0.30
0.31 - 0.40
0.41 - 0.50
> 0.51
Figure 4.2: dbh versus number of trees (stems) in each of the six sampled
transects in Ngezi forest reserve, Pemba.
Number of tree
spp.
160
140
120
100
80
60
40
20
0
Transect number
5 – 10m
11 – 20m
21 – 30m
31 – 40m
Figure 4.3: Height range (in metres) versus number of trees in six sampled transects in
Ngezi forest reserve, Pemba
c) Tree height
Tree heights were estimated 5-10m class, the rest in 10m classes. The maximum
height in 5-10m class contained the largest number of trees followed by coastal forest
on coral rag. There were no trees in the 31-40 class tree heights. Figure 4.3 above
supports the observation made with a characteristic inverted J shape of the graph.
d) Forest Layers
Young and old secondary forests have a single or double layer, while late successional
stages have a more multi-layered structure (Budowski 1965, Jacobs 1988). In Ngezi
Forest Reserve Quassia indica, Barringtonia racemosa and the Raphia swamp forests
have single layers. Exotic tree forest plantations are successional stages with amore
multi-layered structure.
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