Impact of charcoal extraction on the miombo woodlands: The case of Kitulangalo area, Tanzania
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Date
2001
Authors
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Journal ISSN
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Publisher
Sokoine University of Agriculture
Abstract
1‘liis study was carried out to determine the impact of charcoal extraction to the
miombo woodlands of Kitulangalo area, near Morogoro. Tanzania. Both socio
economic and ecological aspects of charcoal production were studied. While the
socio-economic study involved interviewing 50% of charcoal makers in two villages
of Gwata-Ujembc and Mascyu. ecological survey was done in Kitulangalo SUA
Training Forest Reserve and the adjacent public lands. Systematic sampling design
used in an inventory in 1996 was repeated in 1999 in order to determine current stand
parameters and the forest change in general, including mean annual volume
increment. A total of 46 sample plots were laid out in the forest reserve. In public
lands stratified random sampling was applied where a total of 30 plots were laid at an
interval of 500 m apart on three and two transects laid perpendicular to the access
road and highway respectively at 0 km. 5 km. 10 km and 15 km interval. An average
charcoal making household was found to produce 43 bags of charcoal per month.
sold at Tshs. 1.000/= (USD 1.25 . 1 USD = Tshs. 800/- in 1999) per bag. The
household realizes an income of Tshs. 43.000/= per month which is above the
minimum salary rates paid currently to government workers and hence attracts more
people to join the business. The kiln efficiencies were observed to range from 17.5%
to about 30%. There is therefore a need to explore desirable ways of kiln preparation
and carbonization that can improve kiln efficiencies right at the field and not from
modern technologies which in most cases are expensive. The mean charcoal kiln
efficiency was found to be 23%. Preferred tree species for charcoal making include: Jidhernadia globiflora. Hrachyxteyia boehmii. Tamarindux indica. Acacia nigrexcex.
.■I. yerrardii. .1. ndolica. .1. yoetzei xubxp yoelzei. Combretum adenoyonium. C.
moHe. C. zeyheri. ('. codinum. IJoxcia xaPtcifolia. Diplorhynchux condylocarpon.
Pxeudolachnoxtylix
maproiineifolia.
Terminalia
Dioxpyrox kirkii. Xeroderrix xtuhlmannii.
mollix.
Pteleopxix
myrtifolia.
Mimuxopx kummeL Albizia harvey.
Lonchocarpux capaxxa and Lannen xchimperi. These species were having standing
wood volume of 24.5 nr’ha’1 and 56.5 m’ha'1 in public lands and reserved forest
respectively with corresponding basal area of 3.7 irrha’1 and 7.2 irrha’1 suggesting
low biomass in public lands compared to reserved forest. Stem numbers were 909
stems ha’1 in public lands and 354 stems ha’1 in forest reserve showing a reversed
trend compared to basal area and volume. This indicates more regeneration in public
land following disturbance than in the forest reserve. The public lands at roadside are
dominated by large trees of Acacia polyacantha. a pioneer tree species which is not
preferred for charcoal making due to its hooked thorns and lighter charcoal which
breaks easily during transportation. Other un-preferred tree species for charcoal
making were Sterculia africana and Adanxonia digitata due to their low density
charcoal. The Important Value Index (IVI). indicated that J. globijlora is the most
important tree species in both public lands and reserved forest. The species is among
the suitable tree species for charcoal making. The Index of Dominance (ID) was
0.092 and 0.065 in public lands and reserved forest respectively, indicating high
species richness in forest reserve compared to the public lands. The Shannon-Wiener
Index of Divers ity (H) calculated using natural logarithms were 2.9 and 3.13 in public land and reserved forest respectively, also suggesting high species diversity in
forest reserve compared to the public lands. Considering a conversion factor of fresh
wood volume to wood biomass of 0.85 and kiln efficiency of 23%. the weight of
charcoal that can be extracted from the woodland at the roadside is 56 kgs of
charcoal, equivalent to only one bag of charcoal per hectare. Similarly 54 bags may
be expected al 5 km distance while 125 bags may be extracted from beyond 10 km
from the highway. With the established stand growth rate of 2.3 in ’ha‘lyear’1 for the
re-growth miombo woodland al Kilulangalo. charcoal production could be sustained
al the levels observed at beyond 10 km away from the highway within felling cycles
range of 8 to 15 years for degraded forest at 5 km away from the highway and at
roadside.
Description
Dissertation
Keywords
Charcoal extraction, Ecological aspects, Woodlands, Ecological survey, Morogoro, Tanzania