Journal of Environmental Protection, 2011, 2, 1364-1369
doi:10.4236/jep.2011.210158 Published Online December 2011 (http://www.SciRP.org/journal/jep)
Environmental Burden of Charcoal Production
and Use in Dar es Salaam, Tanzania
Neema Msuya, Enock Masanja, Abrahamu Kimang ano Temu
Department of Chemical and Mining, University of Dar es Salaam, Dar es Salaam, Tanzania.
Received August 15th, 2011; revised October 19th, 2011; accepted November 22nd, 2011.
ABSTRACT
Tanzanian forests are excessively threatened by increased charcoal production fuelled by increased demand crucially
in Dar es Salaam city which consumes nearly 70% of all the charcoal produced in the country. Through use of eco-
logical modeling software STELLA® the environmental burden of charcoal production and use in Tanzania has been
established. The study has revealed that the country losses 150,433 ha of forest per year. Due to increase in popula tion
by year 2030 almost 2.8 million ha of forests will ha ve been lost. This is eq uivalent to 8.5% of the total forest cover th e
country had in 2009. The environmental burden includes air pollution characterized by a total emission of 49, 1.0, and
9.0, 12 million tonnes of CO2, SO2, NOx, and CH4, respectively by 2030. Other adverse impacts include loss of forest
cover which ultimately causes degradation of soil quality by increased soil erosion, degradation of water sources and
disruption of rainfall pattern including inducing draught. Taking into account that the agriculture in Tanzania is pri-
marily rain fed, this has an adverse impact in agricultural production. In the current exploitation of this important
natural resource, its sustainability is severely challenged and the whole concept of the forest being renewable is put
into que stion. From these finding s, it is recommended that concrete and deliberate efforts are made to reduce and even-
tually prohibit the use of charcoal in cities and towns.
Keywords: Charcoal Production, Environmental Burden, Forest Loss, Ecological Model
1. Introduction
Households in Tanzania generally use a combination of
energy sources for cooking that can be categorized as tra-
ditional (agricultural residues and fuel wood), interme-
diate (charcoal and kerosene) or modern (Liquefied Pe-
troleum Gas (LPG), biogas and electricity). Electricity is
mainly used for lighting and small appliances like radio,
Televisions and phone charging rather than cooking, and
represents a small share of total household consumption
in energy terms [1]. Over one million tonnes of charcoal
is used for cooking annually in Tanzania’s urban areas
which is equivalent to 109,500 ha of forest loss [2]. In-
creasing tendency to use charcoal instead of electricity or
LPG is driven by availability of charcoal and its pre-
sumed low price. The increased consumption of char-
coal results in increased forest cover loss. Among the
impacts of the forest loss is degradation of water sources,
reduction in soil quality and hence decreases in agricul-
tural productivity, damaged habitat, diminishing biodi-
versity, and reduced sequestration of carbon dioxide by
trees. The government tried to institute a ban of charcoal
production in 2006 but was largely unsuccessful [3] be-
cause no alternative source of fuel was provided.
Different designs of fuel-efficient charcoal stoves that
reduce charcoal consumption have been introduced and
promoted. These stoves while last longer, are not neces-
sarily user friendly, and are more expensive than the con-
ventional ones. Consequently, their introduction has not
changed the rate of consumption of charcoal. Tanzania
experienced a loss of forest cover of more than 10.5 mi-
llion ha between 1961 and 1998; this represents an an-
nual loss of 0.73% of forest cover [4]. Charcoal and fire-
wood use alone results in more than 70% of the forest
loss [5], while more than 40% of the forest loss can be
attributed to charcoal use alone [6]. There has been de-
liberate intervention to redress deforestation by planting
trees. Annual tree plantation in the average has been
25,000 ha with a survival of less than 10% i.e. 2500 ha,
which is approximately 2.3% of the annual forest cover
lost. At this rate of loss the concept of forest being a re-
newable energy resource is threatened.
Charcoal consumption results into about 9 million ton-

Environmental Burden of Charcoal Production and Use in Dar es Salaam, Tanzania1365
nes of CO2 per year [2]. Dar es Salaam alone use about
70% of the charcoal produced in the country. The Pugu
and Kazimzumbwi forest Reserves within the coastal
forests are receiving the brunt of the city’s charcoal in-
dustry. The only viable mitigation measure is therefore to
drastically reduce consumption of charcoal.
2. Charcoal Production and the
Environmental Burden in Tanzania
Most charcoal is produced from wood, but other sources
are possible such as coconut shells and crop residues.
Principal charcoal producing areas serving the Dar es
Salaam market include five districts in the Coast Region
(Kibaha, Kisarawe, Bagamoyo, Mkuranga and Rufiji),
two districts in Tanga Region (Kilindi and Handeni), and
Morogoro rural district. Main producers in the charcoal
market can be classified as: occasional, seasonal and full
time.
Full time producers live within the forest areas and
produce throughout the year. They only shift when the
wood is depleted. Seasonal producers produce only in
off-farming period since agriculture is their main occu-
pation. Occasional producers, on the other hand, make
charcoal to meet specific cash needs during the year [7].
Charcoal can be produced by either incomplete com-
bustion process or pyrolysis as described by Gomaa and
Fathi [8].
Pyrolysis refers the process by heating wood under
absence of oxygen in kilns having closed chambers. The
incomplete combustion is the basis of this carbonization
process through which charcoal is obtained from wood
within four consecutive phases. In the firstphase wood
loses only water and its external form does not signify-
cantly change. This occurs at temperatures below 170˚C.
Decomposition of wood is the second phase which oc-
curs between 170˚C and 270˚C. Organic acids and tars
are evolved together with water vapour. Also gases like
CO and CO2 are gradually evolved. The third phase takes
place between 270˚C and 350˚C, where wood decompo-
sition proceeds with Evolution of gases and organic liq-
uids at higher rate accompanied with heat. The final
phase occurs above 350˚C, where wood decomposition
takes place in a smoother manner. During this phase rela-
tive amount of CO and CO2 to H2 and light hydrocarbons
goes down as the temperature increases. The process
ceases at temperatures between 450˚C and 550˚C. Above
these temperatures the charcoal formed starts to be con-
sumed thus decreasing the yield. In Tanzania most of the
charcoal producers use the incomplete combustion me-
thod.
2.1. Charcoal Kilns Types and Efficiencies
There are mostly two types of kilns used in Tanzania.
These are improved and non improved kilns. Two types
of improved kilns are in use, the earth pit and the earth
mound. An earth pit kiln is constructed by first digging a
small pit in the ground. Then the wood is placed in the
pit and lit from the bottom, after which the pit is first
covered with green leaves or metal sheets and then with
earth to prevent complete burning of the wood. The earth
mound kiln is built by covering a mound or pile of wood
on the ground with earth, igniting the kiln and allowing
carbonization under limited air supply. When Pyrolysis is
complete the kiln gradually cools down and the charcoal
can be removed from the kiln. The mound is preferred
over the pit where the soil is rocky, hard or shallow, or
the water table is close to the surface. Mounds can also
be built over a long period, by stacking gathered wood in
position and allowing it to dry before covering and burn-
ing. Mound type is most preferred in Tanzania. Effi-
ciency of kiln and the quality of charcoal varies depend-
ing on the construction of the kiln (e.g. walls can be lined
with rocks or bricks and external chimneys can be used).
Figure 1 shows an example of traditional kilns used in
Tanzania. Evidence has shown that with the traditional,
unimproved earth kilns, much wood is converted into ash
instead of charcoal, the implication of which large amount
of logs have to be felled to produce charcoal.
Most kilns in Tanzania have efficiencies ranging from
11% - 19% for unimproved kilns while it ranges between
27% - 30% for improved type of kilns [7]. During char-
coal production nearly a third of the energy is lost due to
kiln inefficiencies. Most of charcoal producers in Tanza-
nia however, do not prefer the improved type of kiln due
to its high initial investment cost. The traditional earth
kilns are preferred as they need very little skill and low
capital investment.
2.2. Impacts of Charcoal Production and Use
The following are some of the impacts cause due to char-
Figure 1. Traditional kiln used in Tanzania.

Environmental Burden of Charcoal Production and Use in Dar es Salaam, Tanzania 1366
coal production and use.
2.2.1. Deforestation
Deforestation has been expressed as a gradual loss, main-
ly by indiscriminate tree felling, of forest and woodland
vegetation from a forested and woodlands locality over a
period of time. The major causes for deforestation in Tan-
zania are agricultural expansion, grazing, forest fire, char-
coal making and harvesting for timber. Production of
charcoal has remarkably become a factor of defores-
tation in most parts of the Coast region; it contributes
about 75% of the deforestation [9]. Profuse evidence of
the charcoal trade is visible throughout Tanzania: a visit
to any forest reveals the presence of charcoal makers. High-
ways are lined with charcoal bags for sale in the production
area and on the outskirts of towns.
Thousands of markets throughout the country offer
charcoal for sale. Direct environment impact of charcoal
production is caused by the felling of trees to produce
charcoal. Deforestation disturbs forest ecology by de-
stroying plant and animal habitats. It also destroys spe-
cies biodiversity and destroys water catchments [10].
Removal of forest vegetation disposes top soil materials
and makes them vulnerable to soil erosion by rainfall. As
a result soil fertility is decreased and consequently re-
duced agricultural productivity hence increased poverty.
The problems associated with felling trees that are not
replaced by regeneration or afforestation activities are
well known. These include depletion of water sources
and water catchments areas, reduction of carbon sinks;
and loss of habitat and biodiversity.
2.2.2. Environmental Pollution
Charcoal combustion emits carbon monoxide and nitro-
gen oxides. In extreme cases, carbon monoxide poison-
ing leads to brain damage and even death. Nitrogen ox-
ides emissions react with sunlight to produce dangerous
air pollution. Fumes from charcoal burning augment those
from diesel engines and industrial chimneys [11]. Char-
coal consumption makes a small but not negligible con-
tribution to climate change. According to Norconsult [11]
the relative contribution of fuel wood and charcoal com-
bustion in emissions is important for CH4 (46%), CO
(42%), and non-methane hydrocarbons (NMHC) (44%),
but less so for CO2 (32%). Health impacts of using char-
coal and firewood includes particulates, CO, NO2, for-
maldehyde and carcinogens.
2.2.3. Impact to Rainfall
Increased charcoal production and use leads to increased
cut of trees. This lead into clean land with less tree den-
sity, hence reduction on rainy season. Forests play a big
role in causing rainfall season therefore destruction of
forest is directly proportional to destruction of rain.
3. Methodology
An ecological modeling software STELLA® was used in
this study to assess the environmental burden of charcoal
production and use in Tanzania. The modeling procedure
as per Jǿrgensen [12] was as follows:
 Brainstorming: this involved characterization of all
factors influencing charcoal production at the site
and use;
 Priotization of factors relatively important to char-
coal production and use;
 Categorization of factors in state variables, forcing
functions and processes as presented in the concept-
tual diagram, Figure 2; and
 Development of conceptual diagram: the main dia-
gram showing the relationship between the state va-
riables, mass transport from one state variable to the
other, which are indicated by arrows, outputs and
inputs and the way they are controlled by forcing
functions. The process, which is taking place within
the system, is also indicated in the conceptual dia-
gram.
The model developed relied on mass balances only.
However, one could also do energy balances during char-
coal production and use but this study did not. For the
purpose of this study: one sack of charcoal weighs 56 kg
while kiln efficiency was taken to be 19%.
3.1. Mathematical Description
The Mass flows in and out of each state variable as ma-
thematical descriptions are.
3.1.1. Kiln Zone State Variable
The kiln zone state variable has one inflow and four out-
flows. The change of the amount in this zone can be ob-
tained by the following equation:


aqeous
aqueous nonsolids gases
dkiln wood P1P2P3P4
dt 
(1)
where wood is wood to be loaded, Pi is Pyrolysis prod-
ucts and i = 1, 2, 3
Figure 2. Conceptual diagram for charcoal production and
use (P stands for Pyrolysis while C is for combustion).

Environmental Burden of Charcoal Production and Use in Dar es Salaam, Tanzania1367
woodk1 Ccons (2)
where: C cons is the amount of charcoal consumed in
tonnes/year; k1 is conversion factor for wood to charcoal.
Typical pyrolysis products as percentage of the wood
burned are: Gases (56%), Liquids (25%) and solids (19%).
In this part the pyrolysis process was separated into four
parts, namely: P1 to P4 regarding the outcome/ product
of each part and are calculated using the percentages as
obtained from the literature as follows:
Liquid Produced0.25wood (3)
P1 aqueous0.56liquid produced (4)
P2 nonaqueous0.44liquid produced (5)
P3 solid0.19wood (6)
P4 gases0.56wood (7)
3.1.2. Stove Zone State Variable
The stove zone state variable has one inflow and two
outflows. The change of the amount in this zone can be
obtained by the following equation:

dstove P3 solidsC1 gasesC2 solid
dt  (8)
where;
C1 gases0.6P3 solids (9)
C2 solid0.05P3 solids (10)
The total pollution was the sum of the gases from py-
rolysis and those from combustion in the stove during
charcoal use.
3.1.3. Translating the Consumption into Hectares of
Forest
The amount of forest needed to produce one sack of char-
coal is given by [6]:
1
FsMs EkS  (11)
where: Ms is the mass of a single sack of charcoal [ton-
nes], Ek is the kiln efficiency [tonnes of wood per tonnes
of charcoal], S is the stock density [tonnes of wood/ha of
forest].
3.2. Data Analysis
Data on charcoal production and use were obtained from
various sources including the Ministry of Natural Re-
sources and Tourism (MNRT-Forest & Beekeeping De-
partment), Ministry of Energy and Minerals (MEM),
Tanzania Traditional Energy Development Organization
(TaTEDO), Tanzania Petroleum Development Corpora-
tion (TPDC) and ORYX. The data obtained were coupled
with the population projections to predict the future de-
mand for charcoal in Dar es Salaam. The analysis was
done using Excel software. These projections were used
as input into the ecological model (STELLA software) to
project the wood demand, forest cover loss and the pollu-
tion burden to be caused by charcoal consumption and
use. The main assumptions made were that household
consumption will remain the same throughout from 2010
to 2030 and the population projection of Dar es Salaam
will be the same up to 2030 [13].
4. Results and Discussions
4.1. Charcoal Consumption in Dar es Salaam
The results in Table 1 show that is no consistency in the
data on charcoal consumption in Tanzania and Dar es
Salaam in particular. The Table shows that for 2009 alone,
different sources have quoted different figures ranging
from 1600 to 2200 tonnes per day. This could be attri-
buted to the method used during data collection (sample
size, season, sampling points, etc.), population data used
and the average weight per sack as the sacks are of diffe-
rent sizes. For this study the average of them was used.
4.2. Forest Loss Due to Charcoal Production and
Use
There are many published estimates of the scale of Tan-
zanian deforestation. Table 2 gives some of the estimates.
The forest loss in Tanzania has been reported to be 0.73%
between 1961 and 1998 [4]. Table 2 indicates that there
is significant forest cover loss due to charcoal produc-
tion and use; a situation if not arrested could be disas-
trous.
4.3. Modeling Results
The results from the model have been characterized in
three categories; these are projected charcoal demand, pro-
jected forest loss and pollution burden.
Table 1. Dar charcoal consumption/day as obtained from
different sources.
YearDar population [13] Number of bags Charcoal i n tonnesSource
20092,961,000 28,857 1616 [14]
20092,961,000 33,125 1855 [15]
20092,961,000 40,000 2240 [16]
Table 2. Forest cov ers loss in Tan zania.
Year Forest Loss (ha) Source
2004 91,000 [17]
2005 130,000 - 500,000 [1]
2007 130,000 - 500,000 [3]
2008 92,000 [18]
2008 109,500 [2]

Environmental Burden of Charcoal Production and Use in Dar es Salaam, Tanzania 1368
4.3.1. Projected Charcoal Demand
The projected charcoal demand was used as the basis for
the projections for wood needed the forest cover to be
lost, and the pollution to be caused during charcoal pro-
duction and use. The average charcoal consumption in
Dar es Salaam (based on 2009 data) was 1904 tonnes/day,
equals to 694,960 tonnes per year. Using this charcoal
consumption as the basis, the projection for the charcoal
demand for the next 20 years was modelled by STELLA
with respect to population growth and the result is shown
in Figure 3.
Data in Figure 3 shows the graph of population pro-
jection trend by NBS [13]. Only twenty years to come (in
2030) the projection shows that more than 18 million
tonnes of charcoal will be consumed in Dar es Salaam.
This is when the population will be 4,469,297 people.
4.3.2. Projected Forest Loss
The results from the model show that 105,303 hectares of
forest were lost due to charcoal consumption in Dar es
Salaam in 2009. This is equivalent to 150,433 hectares of
forest loss due to charcoal use nationwide, which is wi-
thin the range provided by WWF [3] and Kilahama [1] in
Table 2. Figure 4 shows the projection of forest cover
which will be needed (or lost) to fulfill the demand for
charcoal in Dar es Salaam. The assumptions made were:
Household consumption will remain the same throughout
till 2030 and the population projection of Dar es Salaam
will be the same as per NBS [13].
In total more than 2.8 million hectares of forest should
be destroyed from 2010 to 2030 to fulfill the demanded
charcoal for Dar es Salaam alone, resulting into more
than 4.0 million hectares nationally. If this is amortized
in those 20 years; Tanzania has to lose 140,000 ha annu-
ally only for Dar charcoal market which is equal to 200,000
ha nationwide. Based on the value of USD 1500/ha of
forest [11] charcoal consumption in Dar es Salaam will
be causing a loss of about USD 210 m per year which is
equal to USD 300 m nationally, and this is about 1.5% of
Figure 3 . Projected charcoal demand for Dar es Salaam.
Figure 4. Forest cover required to fulfill charcoal demand in
Dar es Salaa m.
the current GDP.
4.3.3. Pollution Burden
Among the major effects of charcoal production and use
is the pollution burden to the environment as shown in
Figure 5. The results show that charcoal production and
use will result into a total of 49.7 million tonnes of CO2
up to 2030. This is a disaster not only to human health,
but also to environment and other creatures. The higher
the production rate for charcoal the higher the removal of
trees and at last no carbon sink. As shown in Figure 5;
the CO which will be emitted by 2030 and be absorbed in
atmosphere is more than 20 million tonnes. This is with
the assumption that half of the CO produced is not stable
and is converted to carbon dioxide immediately; other-
wise the amount could be more than this. CO poisoning
leads to brain damage if inhaled. Most of the trees used
for charcoal production contain some percentage of sul-
phur and this is the source of SO2. Poor design and con-
struction of the kilns and charcoal stoves result into im-
possibilities to control air during charcoal production and
Figure 5. Projecti ons for gas emissions due to charc oal pro-
duct ion and use.

Environmental Burden of Charcoal Production and Use in Dar es Salaam, Tanzania
1369
use and this is the source of NO2 in the produced gases.
The higher the production and use, the higher these gases
are produced. A total of 9,830,561, 1,109,762 and 12,478,
260 tonnes of NO2, SO2 and CH4, respectively will be
produced by 2030 only by continuing producing and using
charcoal in Dar es Salaam as shown in Figure 5.
5. Conclusions
From the analysis, more than 2.8 million ha of forest will
be cut to fulfill the demanded charcoal for Dar es Salaam
alone. Not only that but also the process of producing
and using this amount of charcoal has huge impact to the
environment as measured by the amount of gases which
will result and emitted to the atmosphere. Charcoal pro-
duction and use will result into about 2.5 tonnes of CO2
annually, making a total of 49.7 million tonnes of CO2 up
to 2030. This is a disaster not only to human health, but
also to environment 9 and other creatures. The higher the
production rate for charcoal the higher the removal of
trees and at last no carbon sink. Because of inefficiency
of the kilns and charcoal stoves a total of 20 million ton-
nes of CO will be released to the atmosphere up to 2030.
This is unhealthy given its poisoning potential. Other
gases resulting from production and use of charcoal in
Dar es Salaam are 9,830,000, 1,109,000 and 12,478,000
tonnes of NO2, SO2 and CH4 respectively.
The observed high level of methane produced calls for
appropriate technology to capture and re-use it as a natu-
ral gas. Some of these gases might lead into acid rain.
There is therefore, an urgent need to reduce pressure on
forests through advocacy of affordable and more envi-
ronmental friendly alternative sources of energy for cook-
ing in Tanzania.
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