Impact of charcoal extraction on the miombo woodlands: The case of Kitulangalo area, Tanzania

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Sokoine University of Agriculture


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.




Charcoal extraction, Ecological aspects, Woodlands, Ecological survey, Morogoro, Tanzania