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4. FUELWOOD CONSUMPTION AND SUPPLY

 

4.1. Fuelwood consumption

There are very few studies conducted on to the availability and consumption of fuelwood and/or charcoal both at national or regional level.

4.1.1. Studies Conducted at National level

 

Study Conducted by the Department of Energy

Where fuelwood consumption is concerned, the Department of Energy in co-operation with Lahmeyer International (a company from Germany) has carried out a project "Strengthening the Department of Energy (DOE)" during February 1996-March 1997. The main objectives of the project were: -

Strengthening the management capacity and development of the personnel in the DoE in areas of energy policies, planning, analysis, system modelling for energy and the environment, this includes in particular the initiation and establishment of a data base.

Formulation of recommendations aiming at improvement of energy efficiency and

Implementation of energy saving measures in the various economic sectors.

Development of energy standards and regulations in the electric utility, oil refining and distribution system and in the field of renewable energies.

16 different studies have been done, among which the household energy survey and the national energy balance have more relevance in regard to fuelwood consumption.

Household Energy Survey

The objective of the household energy survey is to conduct or guide an undertaking of a household energy survey of demand and supply and compile in a usable form. Beside this, recommendations concerning the following aspects should be provided:

the environmental impact of the harvesting of forest resources, animal dung and

agricultural residues,

the foreign currency impact of fuel-switching,

organisational issues in the manufacturing and marketing of improved cooking stoves and

renewable energy projects including village electrification.

In addition to this, the study team goes somewhat beyond the ToR in two aspects:

Some preliminary findings are set out based upon an initial analysis of the results, and

it recommends directions given for further in-depth analysis.

In the absence of reliable national population figures, a range of levels of household energy consumption are presented, and an illustrative example is presented giving estimated area and national energy consumption levels for a specimen set of population figures.

The field survey was carried out with national coverage according to a stratified design which sampled rural, small urban, medium urban and large urban (where applicable) in 11 Household Energy Areas (HEA, see Table 3) which defined for the purpose of the study in order to stratify the samples in homogeneous household energy-consuming zones. 2,065 households were interviewed in all the region of Eritrea.

 

 

Table 3: Samples Taken, by Strata and Cluster

HEA

Stratum

Actual Clusters Sampled

Actual Sample Size

Coastal Zone

Rural

Gahtalay (1)

Unga

20

45

" "

Returnees from Sudan

Gahtalay (2)

32

" "

Large Urban A

Massawa

91

" "

Large Urban B

Assab

100

N. Read Sea Zone

Rural

Dongolo-Tahtay

49

" "

Medium Urban

Ghindae

79

Northern Highlands

Rural

Halhal Rural

65

Southern Anseba

Rural

Halib Mentel

62

" "

Small Urban

Hagaz

50

" "

Large Urban

Keren

100

NW Lowlands (Barka)

Rural

Aderde

65

" "

Returnees from Sudan

Tekreret

66

" "

Small Urban

-

0

" "

Medium Urban

Agordet

61

S-W Lowlands (Gash)

Rural

Gogne Rural

66

" "

Small Urban

Tokombia

55

" "

Medium Urban

Barentu

66

SW Debub

Rural

Adineamin

Dirko

Adelgse

65

50

50

" "

Small Urban

Areza

71

SE Debub

Rural

Forto

Maereba

Kelay Bealtet

54

65

65

" "

Small Urban

Dekemhare

103

N.Debub

Rural

Tera-Emni

50

" "

Small Urban

-

0

Maekel

Rural

Tseazega

50

"

Small Urban

Embaderho

67

"

Largel Urban

Asmara City

303

Total

21 Strata

 

2,065

Data collected covered the following:

Type and source of all fuels

Distance and time taken for fuel collection (present and past)

Price of fuels consumed

Frequency of fuel collection

Amount of fuelwood, charcoal, agri-residue, animal dung and kerosene normally consumed, and extent of use of each for cooking, beverages, etc

Amount of each fuel actually consumed last month, and extent of use of each for cooking, water heating, lighting and other activities

Level of consumption and uses of electricity

Consumption of liquid propane gas (LPG)

Religion, ethnic group, household size and composition

Annual harvest volume, farm and non-farm income, livestock owned

Problems and possible solutions concerning household energy

According to this study, 78% of the total national energy consumption is consumed at household level and 59% of the total final national energy consumption is from woodfuel.

According to the household energy survey, 69.4% of the total household energy consumption is from fuelwood and 10.7% from charcoal (table 4).

 

Table 4: Total Household Energy Consumption: Using a Specimen 1996 Population Estimate of 2.9 million

Fuel

Quantity

Conver-sion

Factor

Units

Million

GJ

Million

TOE

%

Fuelwood

1.29Mil.MT

16.6

MJ/kg

21.41

511.1

69.4

Charcoal

0.114Mil.MT

29.0

MJ/kg

3.31

78.9

10.7

Animal Dung

0.37Mil.MT

12.0

MJ/kg

4.44

106.0

14.4

Agri-Residue

0.047Mil.MT

15.0

MJ/kg

0.71

16.8

2.3

Kerosene

0.0229Mil.MT

35.4

MJ/lt

0.81

19.3

2.6

LPG

0.00125Mil.MT

45.7

MJ/kg

0.06

1.4

0.2

Electricity

36.1Mil.kwhr

3.6

MJ/kwhr

0.13

3.1

0.4

Total

     

30.86

736.6

100.0

 

Key Findings

Household size varies geographically, from a mean of 4.23 in Maereba (SE Debub) to 7.34 in Barentu (SW Lowlands). The average household size for the total (unweighted) national sample is 5.52, with 95% confidence limits of ± 0.125.

Fuelwood is consumed by 88% of the households sampled, mainly for cooking. Per capita consumption of fuelwood varies from an average of 116 kg/y in Zoba Maekel Rural to 965 kg/y in Coastal Rural. When fuelwood is not readily available in the rural areas, the substitute is generally animal dung or agricultural residues.

The price of fuelwood ranges from 140 to 800 Nakfa/T, the higher end of the price range applying to Asmara. The (round-trip) distance travelled by household members to obtain fuelwood has risen significantly in many areas over the last 30 years to between 10 and 20 km, although the emergence since independence of traders selling fuelwood door-to-door has effectively eliminated this journey in several areas, particularly in small urban centres.

The pattern of charcoal consumption in Eritrea is a complex one. In the lowlands, some households re port buying it locally. In other areas, most of the charcoal consumed is taken in the form of partially burned fuelwood from the injera cooker. The unweighted mean consumption per capita of charcoal by the households interviewed is 42 kg/cap/y. Of this, between 10 and 14.5 kg/cap/y is obtained commercially. Charcoal ranges in price from 390 to 2,800 Nakfa/T, with an unweighted mean price of 1,400 Nakfa/T.

Animal dung is used principally not as a preferred fuel but as a substitute for fuelwood in areas where fuelwood is not easily available. Most of it is obtained locally and individually. It is not yet common for animal dung to be marketed commercially. The unweighted mean consumption rate of the household interviewed is 111 kg/cap/y.

The consumption of agricultural residues as a household fuel is not as widespread in Eritrea as other biomass fuels. As in the case of animal dung, the majority of the consumption takes place in the fuelwood-scarce parts of Debub. The unweighted mean consumption rate of the households interviewed is 13 kg/cap/y.

National Energy Consumption Levels

In order to illustrate the type of aggregation that will be possible to carry out for the estimate of national household energy consumption when the forthcoming population census has been conducted, energy intensities for each fuel consumed, and for each HEA, have been combined with an estimated population estimate of 2.9 million to provide illustrative figures for regional and national household energy consumption and possible scale of consumption of forest resources.

The following Table sets out estimated consumption of biomass fuels by households given a hypothetical 1996 population of around 2.9 million

 

Table 5: Estimated Consumption of Biomass Fuels by Households given a Hypothetical (1996 Population of around 2.9 Million)

Biomass Fuel

Consumption

Rate (weighted)

Annual Consumption

(Million MT)

Fuelwood

440 kg/cap/ann

1.29

Charcoal

39 kg/cap/ann

0.114

Animal Dung

126 kg/cap/ann

0.37

Agri-Residue

16 kg/cap/ann

0.047

These volumes refer to energy consumption. The supply of these fuels is more complicated, as much of the fuelwood reported above is re-used in the form of charcoal taken from injera cookers and from the brewing of drinks such as suwa (some of which is sold to informal sector and small-scale enterprises, which are not included in the survey). Thus, despite the figure of 114,000 T/y of charcoal consumed, the ban on charcoal has been quite successful. According to the household energy survey, it is estimated that only between 15,000 and 21,000 T/y of the total of 114,000 T/y are bought from markets or shops, and a substantial amount of this originates from "recycled" fuelwood. Much of the balance of between 93,000 and 99,000 T/y is also derived from recycling fuelwood already shown in the above table. However, the actual proportion of charcoal that originates in this way is unknown.

Nonetheless an estimate may be made that if between 30 and 60% of households cooking injera adopt the practice of "recycling" fuelwood for their own or other use, then the total quantity of charcoal so produced (including from suwa brewing) would be between 42,500 and 82,500 T/y. This would mean that the fuelwood used for kiln-produced charcoal could be between 195,300 and 443,300 T/y. This possible estimate charcoal tonnage range from partially burned domestic fuelwood is based on tentative estimates of the prevalence of this "recycling" practice and a charcoal conversion ratio in injera cooker of 8:1.

 

Table 6: Annual National Energy Demand, Fuel by Sector

Fuel type

Household

(in tonnes)

Social Institutions

Commercial Enterprises

All other sectors

Total

Fuelwood

1,293,631

462

39,977

0

1,334,070

Charcoal

114,159

13

3,247

0

117,419

Animal Dung

366,170

0

5,162

0

371,332

Agri-Residues

47,146

0

1,627

0

48,773

Note:

Social institution includes such as hospitals, boarding schools, hostels, and the like.

Commercial enterprise sector includes such as hotels, guest houses, traditional drinks

(brewery), tea shops, snack bars, restaurants, bakeries, injera baking, biscuits and pastries, grain mill, laundry, puncture repair, garage, pottery, lime kiln, brick making, wood workshop, metal workshop, jeweller, and blacksmith.

 

Based on the above study, the national woodfuel (both fuelwood and charcoal) consumption level is estimated at 1.48 million tonnes per annum, most of which comprised firewood (90.5%). This figure (1.48 million tonnes) is obtained from the table figure of 1.45 million tonnes on the assumption that all the charcoal consumed on national scale as not carbonised charcoal (i.e., kiln charcoal), rather a substantial amount of this quantity comes from the recycling process of fuelwood at the hearth. Thus, out of the total charcoal consumption, estimated at 117,419 tonnes, only 20% is considered to be kiln produced, i.e., 23,484 tonnes, and a kiln conversion efficiency of 30% is assumed (i.e., 6:1 ratio).

Study Conducted by FAO/ MOA

There was a Socio-economic study conducted by the FAO-TCP with the Ministry of Agriculture (MOA) in 1997. The general objective of the study is to improve the level of available data regarding socio-economic interactions with forest and wildlife in specific selected interventions. These include:

Inventory of surrounding villages of existing permanent closures and assessment of encroachment on these closures

Inventory of surrounding villages of proposed potential closures and existing actual use and claims on these areas.

Inventory of surrounding villages of the proposed potential forest plantation and existing use and claims on the area.

Inventory of village(s) to which temporary closure belong and assessment of fodder availability and existing pressure on the closure.

Inventory of village(s) in and near to the proposed potential game reserves and assessment of actual encroachment by concessions and logging;

Assessment of actual use of the area and threat or damage by wildlife.

Data is collected from twenty-six sample villages located in different Zobas and Sub-Zobas. Means of collecting data, was mainly from a group discussion in a sub-structured interview and from officials for some technical questions.

Parameters used to collect the required data include:

geographical and demographic parameters

Socio-economic parameters

Parameters which would help assessing forestry and wildlife aspects out of the twenty-six sample villages:

twenty six discussions on village inventories

thirteen on existing permanent closures

five on potential forest plantations

five on temporary closures

fourteen on potential game reserve

and three on existence of wildlife in some study sites

The output of this study in regard to fuelwood consumption is stated shortly as follows:

Fuelwood consumption for cooking purposes is very high in the Eritrean cities, towns and countrysides. In big towns, where electric power is available, few households use electric power and liquid propane gas (LPG) as an alternative for fuelwood, specially for baking Ingera (traditional leafy bread), which requires the highest energy consumption rate in a household. Kerosene is slowly being introduced in the countryside for cooking. Dung and agricultural residue, though they can not replace fuelwood (because of their poor energy output), could be mentioned as an energy alternative in households with livestock and cultivation areas, especially with maize field-aftermath. The following table indicates the estimated consumption rate of fuelwood / five headed household and other alternatives of energy sources used for cooking.

Table 7: Estimated Fuel Wood Consumption and other Alternatives of Energy Sources

Sample Villages

Selected in Relation to

Consumption Month/ Kg.

Purpose

Source

Distance(km)

Availability

Other Alternative of Energy Used

Adi sherbot

EPC

750

Cook/light

Surrounding area

3.0

Fair

-

Dekemhare

EPC,PC PGR

100

Cooking

Bahri

12.0

Scarce

Agri. Residue,

Dung, kerosene 20 lt/mon.

Dongolo Tahatai

EPC ,PGR

150

"

Surrounding area

5.0

"

Kerosine 25 lt/mon

Embatkala

EPC,PGR

200

"

" "

4.0

"

Agri. Residue,

kerosene 20 lt/mon

Laiten

EPC,PGR

150

Cook/light

Ghobo Barud

1.0

"

Dung

Ghaden

EPC,PGR

150

Cooking

Ghelata

30.0

Fair

Agri. Residue,

Dung, kerosine 15 lt/month

Mirara

EPC, PGR

100

"

Tekel Abamaitan

3.0

"

Agri. Residue, Dung,kerosine

Fishe

EPC, PGR

120

"

Surrounding area

0.5

"

Agri. Residue,

Dung, kerosine

Woki

EPC ,PGR

200

"

Kelkel, Bahri

10,18

Fair/scarce

Agri. Residue

Dung, kerosine 20 lt/mon

Zagir

EPC ,PGR

150

"

Midri Zagir

5-6

Fair

Kerosene, dung

Geza Medebai

EPC

150

"

Emba-Aila

7

"

-

Shiketi

EPC

22.5

"

Western side of Menguda

3-4

"

Agri. Residue, kerosine 20 lt/mon Dung 75 Kg/month

Lalai saro

EPC, PFP PC

300

"

Mai Lela

1.5

Scarce

-

 

Table 7 Continued

Sample Villages

Selected in Relation to

Consumption Month/ Kg.

Purpose

Source

Distance(km)

Availability

Other Alternative of Energy Used

Adi ľNefas

PFP, PC

50

Cooking

Asmara market

5.0

Good /Exp.

-Dung kerosene(20lt/ month)

Zigib

PFP,TC, PC

Can not afford

--

--

-

-

Dung, ( 80kg/month)

Kerosene

Tselot

PFP

200

Cooking

Asmara market

9.0

Good/ Exp.

Dung 45 kg/month

Kerosene(20lt/month)

Ad- Selahait

TC

300

Light/Cooking

Surrounding area

1.0

Good

--

Aderde

TC

200

"

" "

2-10

Fair

-

Ad- Berbere

TC

350

"

" "

1-3

Fair

-

Berak

TC

10

Cooking

Fallen branches & bushes, surrounding area

4

Fair

Dung 75 kg/month

Kerosene 20 lt/month

Shariki

PC

150

Light/ cooking

(aye hadro) surrounding area

1.0

Fair

Agr. Residue,

Dung

Menkalile

PGR

450

"

Barzole

24

Scarce

Dung

Engel

PGR

could not be estimated

"

Surrounding area

0.5

Good

-

Duluh

PGR

300

"

" "

3-10

Fair

Dung

Elit

PGR

700

"

" "

1.0

Good

-

Ad-Abraha

PGR

100

"

" "

2.0

Fair

Agricultural residue,

100 Kg / Month

The fuelwood consumption differs greatly from place to place, depending on the availability and price. Remote villages which have a better access to forests with adequate deadwood of trees and bushes use to consume more than villages located near big towns where they have no or little access to forests and they are forced to buy with higher prices. In addition for cooking, there are also villages where fuelwood is also used for light purposes. Such villages let fuelwood burning for the whole night to avoid darkness.

Having this in mind, one could imagine how far the wood consumption would differ from place to place and from household to household. The highest monthly fuelwood consumption in a household with five heads was given to be 700 kg, with no other additional source of energy. On the other hand, the lowest is 10 kg, with adequate other alternatives of energy (75 kg. dung /month and 20 litres of kerosene/month).

To collect fuelwood, people of some villages use to go as far as 30 km. and there are villages which do not need to go more than half a kilometre. All in all, the average distance, from study villages to the areas where fuelwood could be collected, would be estimated to be 6.5 km. The opinion of the village elders towards the availability of fuelwood in areas, mentioned to be, the centre of fuelwood collection, is summarised to be scarce 26%, fair 61% and good 13%, excluding the survey villages which buy fuelwood from Asmara.

 

The major uses of wood within Eritrea are for fuel and construction poles, while minor uses include sawn timber for utility and furniture, transmission poles and many splints.

In general, the rural communities and most urban households including some commercial enterprises depend on biomass fuel for energy, but the supply has dwindled. Hence, the rural people who used to enrich farmlands with animal manure and agricultural residues have minimised their traditional practice, not out of choice, but need. Instead, they are using such by-products for fuel due to the scarcity of fuel-wood. This is causing environmental deterioration and the reduction of soil fertility.

 

4.1.2. Studies Conducted at Regional Level (Western Lowland)

The FAO-TCP Project (1997) commissioned a study to assess fuelwood consumption and potential availability from the natural forests/ woodlands of the western lowland region, and to make an evaluation of the existing forest products regulation and licensing systems. The main objectives were as follows:

To assess the potential fuelwood availability from the natural forests/ woodlands of the Western Lowlands;

To gather information on the current levels of fuelwood and charcoal consumption derived from those forests/ woodlands;

to assess the sustainability of current production from those forests/ woodlands; and

To evaluate various options for better forest management, improved forest regulation and monitoring and for more efficient fuelwood utilisation.

The study is based on information and data gathered from a literature survey, concerned institutions and organisations, and from field studies to assess the woody biomass stock of the existing natural forests/woodlands in the region.

Literature survey relied upon for the study of fuelwood consumption and forest products regulations or monitoring and licensing systems. For the assessment of fuelwood consumption, this study has heavy drawn from the information and data obtained from the Ministry of Energy and Mines (MEM), and from other fuelwood and related studies carried out in Eritrea. For the forest product regulation and licensing, much of the information was obtained from the Ministry of Agriculture (MOA), Forestry and Wildlife Division.

Field survey was used mainly to collect information and data concerning the potential fuelwood availability from the natural forests of the Western Lowlands. The survey was mainly focused on the assessment of the biological production in order to determine the existing stock of the natural forests in the area, with details of species. In addition, the survey has also included the assessment of the existing deadwood stock in the region.

Woodfuel Consumption from Woodlands in the Western Lowlands

Compared to the national situation, the western lowlands are comparatively more dependent on woodfuel consumption for energy. Woodfuel contributes around 96.5% of the total energy used in the area, while the remaining 3.5% is met by other energy sources, mainly oil products. This heavy dependence on woodfuel is likely to continue for the near future as long as suitable alternative fuels are not able to substitute in terms of price, availability and customary preferences.

In the Western Lowlands, the household sector was found to be the dominant consumer of energy (94.7% of the total energy consumed), followed by the commercial enterprise sector (4.8%). Based on a study for a comparable area of Eritrea (Mendefera) Zoba Debub, household cooking consumes more than 95% of the total energy delivered into the household sector which means that the availability of fuelwood is intractably linked to the issue of food security.

The Western Lowlands of Eritrea encompasses 3.69 million hectares, mostly of Bush/Scrubland, Grassland/ Wooded Grassland, Closed to Medium Closed Woodland, Open Woodland, Reverine Forest, Agricultural Land and other unclassified land.

 

Table 8: Annual Energy Consumption of the Western Lowlands, in TJ

Fuel type

Household

Commercial Enterprises

Social Institutions

Total

Percent

Fuelwood

6925

331

1

7257

93.7

Charcoal

201

17

 

218

2.8

Oil, gas & electric

210

20

40

270

3.5

Total

7336

368

41

7745

100.0

Percent

94.7

4.8

0.5

100.0

 

Source: Modified (MEM, 1996).

According to the study of the Department of Energy, total annual woodfuel consumption for the Western Lowlands was estimated at around 0.48 million tonnes; that is around 33% of the annual national woodfuel consumption. The current per capita woodfuel consumption level in the Western Lowlands was found to be higher (0.75 t/cap/annum) compared to the national average (0.5 t/cap/annum). This can be explained by:

(i) Comparative abundance of woodfuel in the western lowlands;

(ii) The poor availability of alternative fuels; and

(iii) The consequential price advantage of woodfuel consumption.

 

Table 9: Annual Consumption by Energy Inputs for the Western Lowland Areas of Eritrea in tonnes

Fuel type

Household

Commercial Enterprises

Social Institutions

Total

Fuelwood

417,180

19,950

68

437,198

Charcoal

11,579

995

0

12,574

Woodfuel

458,864

23,532

68

482,465

Source: Modified (MEM, 1996).

Note:

The figures for woodfuel are based on the assumption that in the Western Lowlands carbonised charcoal accounts for 60% of the total charcoal consumed in the area, with the kiln conversion efficiency estimated at 30%. About 7338 t/yr. of charcoal are marketed annually in the areas, and this accounts for approximately 63% of the total charcoal consumed in the area. The Western Lowland is the main area where marketed charcoal is produced, and the figure 7338 t/yr. is around 50% of the total marketed charcoal supplies at national level.

A high proportion (83-87%) of the annual off-take is consumed locally, and the remainder is used elsewhere, mainly by the major urban centres in the highlands. More than 95% of the total quantity of woodfuel is consumed in the form of pure fuelwood, as opposed to charcoal (in fact, charcoal production in Eritrea is permitted only as a by-product of firewood combustion).

Biomass Assessment and Fuelwood Potential from Woodlands in the Western Lowlands

The study under the FAO-TCP project assessed from field studies the woody biomass stock of the existing natural forests/woodland in the Western Lowland region.

To collect the information on woody biomass (including deadwood), stratified systematic sampling was used. Using physiognomy as the key, the natural forests in the study area were stratified as follows:

Shrubland / Bushland: composed of woody vegetation of less than 4 meters height (average) with or without scattered trees; and crown cover over 10%.

Closed to medium closed woodland: woody vegetation composed of one layer of trees of touching or non-touching crowns but with more than 40% crown cover. Average height around 5 meters.

Open woodland to scattered trees: composed of woody vegetation of a single layer of trees with crown cover of 10 to 40%. Average height around 5 metres.

Riverine forests / Riparian woodland formation: composed of stands of trees, with or without understory shrubs or bushes, occurring on the major riverbanks and their major tributaries.

Wooded grassland or Grassland: bare soil with very sparse shrubs and/ or trees but low crown cover (1 to 10%) and some seasonal grass during the rainy period.

Agricultural land.The last category is included because agricultural lands can be a good source of woody biomass especially in areas where the practices of cultivation are not so intense and/or where traditional agroforestry is a common practice, just like the case of the Western Lowlands

Further sub-stratification by canopy cover percent was carried out for shrubland (stratum I) and riverine forest (stratum IV), and agricultural land was sub-divided into two categories.

A total of 68 samples were taken among the strata as shown in Table 10 below. The overall sampling intensity was 1.11%, although this ranged from 0.20% in shrubland to 14.7% in agricultural land.

 

Table 10: The MainLand Cover/Use Surveyed in the Field and the Number of Samples Taken

Land cover/use

Plot size (m2)

No. of samples

% of the sample area to the total cover area

Shrubland

Cover > 70%

Cover 70-40%

Cover 40-10%

100

24

8

8

8

0.20

Closed to medium closed woodland

400

5

0.70

Open woodland to scattered trees

400

5

0.30

Riparian woodland formation

Cover > 70%

Cover 70-40%

- Cover 40-10%

400

17

7

5

5

4.50

Wooded grassland

400

7

0.30

Agricultural land use

Moderately cultivated

Intensively cultivated

2500

10

5

5

14.71

Total

 

68

1.11

A road through each stratum was used as a base line, along which transepts were positioned at systematic intervals. Along each transept, the sample plots were positioned at random intervals.

The methods used to gather the data on the quantity of woody biomass at the plot level were of two types:

Shrubs and Bushes. For shrubby and bushy structures less than 4 meters height, the "cut and weight" method was used. Measurements for woody and foliar biomass were recorded separately. Where appropriate, diameter measurements of the main stems were also recorded with the aim to construct regression relationships between woody biomass and total biomass with diameter.

Trees exceeding 4 metres. For such trees, volumes were estimated on a standing basis using the "log rule method". Measurements were made of diameter at breast height (dbh), height, form factor and type of the species. In calculating the volume, the form factor was inflated so that volume estimates might include an allowance for branch wood as well as the main bole volume.

Data Analysis for Biomass Assessment

Based on field measurements, predictive equations were developed for green wood biomass (GWB) and green total biomass (GTB) in terms of the square of stem diameter (DIAM), measured at 1.3 metres above ground for trees and 0.3 metres for bushes and shrubs.

GWB (kg) = 7.88 + 0.168 * DIAM2 (R2 = 0.73)

GTB (kg) = 14.0 + 0.298 * DIAM2 (R2 = 0.75)

Green mass measurements were converted to airdry basis on the assumption that green moisture content was 20%, and air dry moisture content was 12%.

Volumes were converted to a mass basis using the airdry wood density for each species recorded. The weighted average woody biomass per unit area for each stratum was then applied to the area of the stratum, in order to derive the total woody biomass stock in the Western Lowlands.

Overall, the field study under the FAO-TCP project found that the average standing wood biomass (air-dry basis) was 22.5 t/ha. Minor branches (less than 3-cm diameter) and foliage brings this figure up to about 31.5 t/ha. Deadwood, which was measured separately, had an average mass of 1.5 t/ha.

Table 11: Assessment of the Live and Deadwood Biomass Stocking (in tonnes per ha) in the Natural Forest/Woodland of the Western Lowlands

Vegetation class

Live wood biomass

(air dray)

Total live biomass

(air dray)

Dead wood

Bush/ scrubland

Grassland/ wooded grassland

Woodland: Closed to Medium closed

Woodland: Open

Riverine Forest

Agricultural land

Weighted Average (all strata)

Weighted Average (excl.riverine forest)

13.6

3.2

51.3

39.0

133.0

5.4

23.0

17.0

22.0

4.5

72.5

56.0

164.5

6.5

31.5

25.0

1.9

0.5

1.4

1.7

6.0

0.1

1.5

Note:

Deadwood refers here to both the naturally fallen deadwood and as well as that found cut

and dried in the field

The figure for air-dry weight were calculated in ranges assuming a 25-35% MC of the

Total biomass weight.

It is clear from the above biomass stocking rates that the reverine forests exert a powerful influence on the average biomass stocking of 23 t/ha for live wood. A figure of 17 t/ha, disregarding the riverine forests, provides an average more typical of the prevailing vegetation types.

Applications of the estimates of biomass stocking to the areas of each stratum, enables an estimate of living and dead biomass for the western lowlands, as shown in Tables 11 and 12.

Table 12: Assessment of the Total Live and Deadwood Biomass from the Natural Forest/Woodland of the Western Lowlands (in million tonnes)

 

Vegetation class

Area in million ha

Total wood biomass

(air dray)

Total

Dead wood

Bush/ scrubland

Grassland/ wooded grassland

Woodland: Closed to Medium closed

Woodland: Open

Riverine Forest

Agricultural land

Total

Grand total

1.23

1.07

0.28

0.61

0.15

0.17

3.50

3.69

16.7

3.4

14.4

23.6

19.3

0.9

78.3

83.0

2.3

0.5

0.4

1.1

0.9

0.01

5.2

5.5

Note:

The figures for Grand total were calculated taking into account the non-classified 5.5% of the total Western Lowland areas.

The biomass energy consumed within the country is estimated to constitute about 82% of the whole, and of that of this, wood energy is estimated to be about 70%. The share of energy supplies for Asmara is estimated to be:

Fuelwood and charcoal

80%

Cowdung and crop residue

5%

Electricity

10%

Gas stoves and kerosene

5%

 

4.2. Fuelwood Supply for Asmara

Asmara the Capital City of Eritrea is found in the Central Highlands of the Country with total inhabitants of about 400,000 individuals. Fuelwood which is consumed in this city (total annual fuelwood consumption is about 60,000 tonnes) is obtained mainly from the Western Lowlands and some from Eastern Lowlands of Eritrea.

Fuelwood supply for this city, according to the Ministry of Agriculture reports is tabulated in table 13.

Table 13: Annual Fuelwood Supply to Asmara City

No

Year

Wood Supply

(in tonnes)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

33,392.5

22,900

10,471

-

6,000

6,840.3

10,000

15,402.9

19,647

38,312.3

18,988.1

11,695.4

13,056.3

29,859.7

24,535

18,224.8

19,833

13,058.2

42,603.8

25,835.2

12,485.6

10,466.5

19,707.4

20,927

7,752.9

Even the 1992 record of 42,603.8 tonnes (or 85,207 m3) supplied under license into the city Asmara begs some questions. Based on the total annual fuelwood consumption at national level, the city should be importing more than the recorded supply figures. Therefore, the possible explanation for the huge difference is:

More wood comes into the city than is licensed, through loose guarding of roadblocks, or through unguarded routes.

 

 

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