Abstract:
This work reported in this dissertation was conducted in Kiwengwa-Pongwe Forest
Reserve (KPFR) in Zanzibar. Specifically, the study assessed the forest structure, carbon
stock and forest degradation. Eleven transects were laid out in the North - South direction
and plots located along each transect. The distance between transects was 600 meters and
plots were laid down systematically at intervals of 300 meters along each transect.
Clusters of concentric circular plots of 5, 10 to 15 metres radius were established for
measurement of diameter at breast height (dbh). The measured trees were grouped into
the following classes: <4, 5-10, 11-20 and >20 em, The forest had composition of 60
species in 52 families, Stand density of 281 stems ha-1
, Basal area of 5.75 m2ha-1 and
Volume of 33.97 nr'ha". Biomass was 22.9 tha" with a Carbon stock of 11.7 tCha-1.
These results were slightly lower than earlier reported (1997) for the same forest, where
volume and biomass then stood at 35.37 rrr'ha" and 26.39 tha", respectively. The mean
Shannon & Wienner species diversity Index ranged from 0.83 at the forest edge to 1.74 at
the forest centre, with a mean of 1.34, which is considered to be low to medium.
Assessment of forest degradation showed removals of 159 stems ha-1 corresponding to a
basal area of 2.6 m2ha-1, volume of 18 rrr'ha', carbon of 6.1tCha-1 and C02 emission of
12tC02-e. These results indicated that KPFR is subject to degradation and hence a high
potential for enhance carbon sequestration and storage through sustainable forest
management. The study recommends that there is a need to upgrade the status of the
surveyed forest reserve to improve its forest structure and carbon sequestration and
storage potential.
