Recommendations concerning inventory of timber, fuelwood, and nontimber products and charcoal species regeneration



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Appendix D. Charcoal variables and conversions used in Senegal and the Sahel


CONVERSION FACTORS

Weights and volumes

Source

Dry stems conversion to m3 on basis of 0.67Mg/m3 or 670kg/m3 (DRY MASS TO FRESH VOLUME RATIO)

Trunk dry mass to fresh volume ratio = species weighted basic density = 0.68 Mg/m3.

Trunk + branch + stemlets = each 1/3 total Dry Mass

Trunk + its bark = 32-44% of Dry mass

Basic density of Anogeissus, Combretum glutinosum, and C. nigricans = 0.72-0.80 Mg/m3


1 Burkina Faso 620 to 785 mm rainfall

1 stère = 215 to 600 kg (twisted branches versus straight wood from thinning)

3

1 stère = 0.5 m3 = 130 kg green wood

1 m3 = 2 stères = 260 kg green

1 quintaux = 100 kg DRY = 2 big sacks of charcoal

1 tonne dry wood:

= 4 m3


= 8 stères

= 10 quintaux

= 20 sacks

1 truckload = 150-170 quintaux = 300-350 sacks = 40-50 stères

1 stère = 0.65 m3 = 2.5 sacks

1 m3 = 2.5 quintaux

9 tas = 300 sacks = 1 meule


Visites de terrain Kaolack 2005

Missirah 2006

Tamba 2007


Coefficient d’empilage south of 900mm rainfall (natural forest):

stère/m3 = 3.5 (bois 3-6cm)

stère/m3 = 2.2 (bois 7-12cm)

stère/m3 = 1.7 (bois 13cm+)

Tonnes/stère = 0.27

Density of wood T/m3 = 0.8

Density of charcoal =

Density of kerosene = 0.79



Sack of charcoal = “45kg”

Sack of charcoal = .045T

Quintaux = “100kg” = “2 sacks”

Quintaux/Tonne = 11

7

Coefficient of empilage: 0.45 to 0.8 m3 per stère

(if all wood is round and of same diameter: = pi/4 = 0.785)



9

Yield of charcoal per kg of wood




16% (Outchoun 1983) to 30% of weight of raw material (drier wood yield = higher); low avg = 20% (See other examples in doc)

3

Productivity per meule




20m diameter kiln pile = 400 sacks (Casamance)

6m radius kiln = 100 quintaux

13m diameter kiln pile = 200 sacks

1 stère = 80 to 130 kg of charcoal

1 four (meule) of 300 stères green

= 290 000 kg

= 29 tonnes green, or 2.7 tonnes dry (divide by 11)

1 truckload = 150 quintaux = 300 sacks = 40-50 stères

1 meule = 1 camion = 300 sacks loaded in front of Service Forestier = 9 “tas”


Visites de terrain Kaolack 2005

Missirah 2006

Tamba 2007


Energy yields:

Traditional meule = “18%”

Casamance kiln = “30%”

3-stone cooker = “20%”



7 (these references are all sourced)

UTILISATION AND ECOLOGY

Dakar market




100 000 tonnes/yr (1980)

3

300 000 tonnes of charcoal per year = 3 million quintaux

Visites terrain Kaolack 2005

(approx 10 quintaux per tonne)

Thies at 70km from Dakar was a main exploitation zone from 1950 to 1966, producing up to 2/3 of the total for Senegal. Closed for charcoal making from 1983.

St-Louis, 200+ km from Dakar, was prominent from 1970 to 1982 because of natural populations of Acacia nilotica killed off by drought.

Kaolack (200+km from Dakar) was prominent from 1959 to 1987, with stands on each side of the railroad. (Senegal population 1976 = 5 million)

Tambacounda, at 400-500 km from Dakar, took over in 1985, with a harvest on the order of one million quintaux per year. (Senegal population 1988 = 6.9 million)

Kolda at 700km from Dakar from 1990 to 1999 has gone from 4% to 67% of the total charcoal production. (Senegal Population 1990 = 7.3 million, 2000 = 9.5 million)

Quota proposed for 2000 was 60 000 tonnes plus 20,000 tonnes of reserves.

1994: Dakar ville charcoal consumption = 114,300 T, gaz = 40,300 T



7

Heat value




(An estimation of 70% of standing stock as being acceptable for fuelwood other species for fruit and other uses, or not dense enough) -- “Results of this study indicate that the share of commercial fuelwood in young successional forest could be much lower when taking into consideration the multiple uses of these forests.” “Nevertheless, the concept of commercial fuelwood depends on supply and demand and, with increased scarcity, less suitable fuelwood species will be used.”

Barkless wood preferred in Niger.

On an area-based volume, excluding branches, stemlets, bark, and non-optimal species results in a use-able 25% of volume.


1

Burkina Faso (620-785 mm rainfall)



Dry wood: 4500 to 4770 Kcal/kg;

Green wood: 3500 Kcal/kg X 0.08 = 280 Kcal/kg wood

(thermal E yield=8% or 5% on 3-stone stove)

Charcoal: 7500 Kcal/kg X 0.2 char yield X 0.28 = 420 Kcal/kg wood

(Thermal E=28%)

Petrol product: 10 000 Kcal/litre



3

tep = 42 Gjoules

kWh = 3.6 Mjoules

Pci of kerosene = 43.5 Mjoules/kg

Pci of butane = 45.7 Mjoules/kg

Pci of charcoal = 29 Mjoules/kg

Pci of wood = 17 Mjoules



7

Productivity per area




“If protected for 5 yrs after clearcutting, 0.6 to 3 m3/ha/yr”

Devineau (1997) used repeated meas. to estimate increment at 0.7 m3/ha/yr (mature savanna) and 0.3 m3/ha/yr (12-yr fallow)

Cameroun Regrowth @ 800mm rainfall = 0.5 m3/ha/yr, 3 yrs after clearcut.

Botswana regrowth @ <1000mm rainfall on sandy soil = 0.9 Mg/ha/yr

Burkina regrowth @ 1000mm rainfall = 0.7 m3/ha/yr in mature savanna

Guinea regrowth @ 1300mm rainfall = 1.3 m3/ha/yr in savane arbust; 2.3 m3 in savane boisée



1

“Exploitable” =15 stères/ha green + 3st/ha dead (Dosso)

(Combretum micranthum, C. nigricans, Guiera senegalensis)- Maradi and Dosso

2 Niger


11.3 m3/ha/year all species mixed

= 2640 kg/ha/yr

= 290 kg charcoal/ha/yr

= 3 quintaux/ha/yr



Visites terrain Kaolack 2005

Missirah 2006

Tamba 2007


6 years of cultivation leads to 50% density loss and 14 years leads up to 80% loss.

6

Total production of 1 million quintaux in 1994, and of 1500000 in 1988 and 1993.

7

Productivity in Mg/ha/yr = .051 + 1.082(pluviom)2 thus

600-800mm yields 0.4-0.7 m3/ha/yr.

Protection: increase by 25%; Degradation: decrease by 25%


8, cited in 9

Regen info; rotation age




“Short” (<20-yrs) coppice cut rotation recommended in Abbot and Lowore, 1999; Bellefontaine/Gaston/Petrucci 1997; Jensen 1995; Catinot 1994. Short rotation means a different proportion of bark and branchwood than older trees. This affects density although volume is the variable that is taxed and that is predicted in equations. Thus dry mass=more appropriate for evaluation of growth and fuelwood value.

“If Burkina Faso Forest Service applied the same cutting criteria for firewood trees as was used in 1982, a rotation period of more than 30 years would be required for regrowth to the same volume.” (Based on 29 to 70 m3/ha that were removed during clearcutting in 1982) -- i.e. woody Dry Mass in mature stand would be less than reported in other studies in same rainfall conditions.

CVs compared between current study 2004 and the CV for harvested wood in 1982 are comparable (11 to 29% range for both).

“Longer rotation periods may produce a larger proportion of commercial fuelwood and this option should therefore be investigated.” (pg 84)



1 Burkina Faso (620-785 mm rainfall)

Annual cut allows 69% to 80% of the annual growth

Allowable = >6m diam at 20cm ht, “taillis fureté” or selective removal of sprouts



(Combretum micranthum, C. nigricans, Guiera senegalensis)- Maradi and Dosso

2 Niger

Wound the roots at moment of high nutrient reserves for Combretums and many other sahelian spp= drageonnage

4

Combretum/ Anogeissus forests as “pseudo-climax” remain in spite of decreasing rainfall and degradation because of ability of stumps to regenerate since 1950s (pg. 25)

5

Note: Cutting permits do not have an expiration date, so once they are granted, the wood can be cut any time.

The quota system directs woodcutters to specific Regions by limiting quotas from each.



7

PRODUCTIVITY PER WORKER:

150 QUINTAUX PER SOURGA PER YEAR (Tamba 2007)
SOURCES

1. Nygard, R., L. Sawadogo, and B. Elfving. 2004. Wood-fuel yields in short-rotation coppice growth in the north Sudan savanna in Burkina Faso. Forest Ecology and Management 189 77-85. Elsevier B.V.

2. (c. 2003?) n.a. Résumé du Plan d’Aménagement forestier du massif de Baban Rafi Sud (Département de Madarounfa) 3 pages -- internet site

3. Keita, J.D. Undated. Article presenting a comparison of energy balance for fuelwood and for charcoal. 6 pages. See very interesting sections on economics of transport: it is shown that charcoal with a 28% thermal energy equals the price of its transport by old truck at a distance of 1000 km.

4. Bellefontaine, R, E. Nicolini, S. Petit. 1999. Réduction de l’érosion par l’exploitation de l’aptitude à drageonner de certains ligneux des zones tropicales sèches. Bulletin Réseau Erosion (IRD-Montpellier et CTA-Wageningen), no. 19, p. 342-352

5. Ba, M., A. Toure, and A. Reenberg. Mapping land use dynamics in Senegal. Case studies from Kaffrine Departments. Working paper 45.2004 for Sahel-Sudan Environmental Research Initiative, Institute of Geography, Copenhagen. 33 pages

6. Faye, E., D. Masse, and M. Diatta. 2002. Dynamique de la régénération ligneuse durant la phase de culture dans un système de culture semi-permanente du Sud du Sénégal. In Savanes africaines: des espaces en mutation, des acteurs face à de nouveaux défis. Actes du colloque, mai 2002. Marouna, Cameroun. 30 pages.

7. FAO Documents 1 and 5 on Consommation en Charbon de Bois au Senegal: Dept des Forêts Rapport d’étude sur les Données du Bois-Energie au Sénégal”, and “Etude sur les Ressources Forestières et les plantations Forestières au Sénégal”.

8. Clément, J. 1982. Estimation des volumes et de la productivité des formations mixtes forestières et graminéennes tropicales. B.F.T., No. 198, in CTFT Mémento Forestier page 507.

9. C.T.F.T. 1989. Mémento Forestier. Ministère de la Coopération et du Développement, Paris. Out of print.



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