Area closure and reforestation with Acacia [Tunisia]

technologies_1568 - Tunisia

Completeness: 78%

1. General information

1.2 Contact details of resource persons and institutions involved in the assessment and documentation of the Technology

Key resource person(s)

SLM specialist:

Hamdi Lazar

Direction générale des fôrets


SLM specialist:
SLM specialist:
Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)
Direction générale des fôrets - Tunisia
Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)
Institut des Régions Arides de Médenine (Institut des Régions Arides de Médenine) - Tunisia
Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)
Ghent University (UGent) - Belgium

1.3 Conditions regarding the use of data documented through WOCAT

The compiler and key resource person(s) accept the conditions regarding the use of data documented through WOCAT:


2. Description of the SLM Technology

2.1 Short description of the Technology

Definition of the Technology:

Protection and reforestation of degraded arid lands in pre-Saharan Tunisia.

2.2 Detailed description of the Technology


Protection and reforestation of degraded arid lands in central and southern Tunisia (Bled Talah region) with tree species Acacia tortilis subsp. raddiana. A. raddiana is a native trees species which is able to tolerate extreme droughts and to persist on the edge of the Sahara desert. Acacia plantations are set up following a 3m x 3m grid using seedlings of A. raddiana. Seedlings are planted in the bottom of infiltration pits which are constructed for rainwater harvesting. Protection of the plantation area is established by means of a fence.

Purpose of the Technology: The purpose of afforestation is the rehabilitation of degraded drylands and restoration of the original forest-steppe ecosystem in the Bled Talah region, which suffered for over a century from overexploitation of natural resources and intensification of agricultural activities. Focus is put on the synergy between the protection of the natural resources with the involvement of local people and the improvement of their livelihoods.

Establishment / maintenance activities and inputs: The protection of the Bled Talah region was initiated in 1936 and from then on several actions were undertaken such as the construction of a tree nursery and the creation of Integral Protection Zones through complete fencing. The Bled Talah area was designated as a UNESCO Biosphere Reserve in 1977. Bou Hedma National Park was officially created by the Ministry of Forests in 1980 covering an area of approximately 16.000 ha. The park consists of three Integral Protection Zones or core areas which are completely fenced, two agricultural zones and two buffer zones. Since the 1970s, several reforestation campaigns with A. raddiana are conducted in the Integral Protection Zones.

Natural / human environment: Arid Tunisia, i.e. the central and southern part of Tunisia, is characterized by an extremely irregular spatiotemporal rainfall pattern, a limited amount of rain (350 mm maximum per year), a limited number of days of rain (15 to 40 days a year) and a high average annual temperature (18 to 21 °C).

2.3 Photos of the Technology

2.5 Country/ region/ locations where the Technology has been applied and which are covered by this assessment



Region/ State/ Province:

Sidi Bouzid/Gafsa


Total area covered by the SLM Technology is 165 km2.

2.6 Date of implementation

If precise year is not known, indicate approximate date:
  • 10-50 years ago

2.7 Introduction of the Technology

Specify how the Technology was introduced:
  • through projects/ external interventions

3. Classification of the SLM Technology

3.2 Current land use type(s) where the Technology is applied

Grazing land

Grazing land

Extensive grazing:
  • Semi-nomadic pastoralism
Forest/ woodlands

Forest/ woodlands

  • (Semi-)natural forests/ woodlands
(Semi-)natural forests/ woodlands: Specify management type:
  • Selective felling
  • Acacia tortilis subsp. raddiana
Products and services:
  • Timber
  • Fuelwood
  • Grazing/ browsing

Major land use problems (compiler’s opinion): Overexploitation of natural resources such as tree cutting for fuelwood and intensification of agriculture such as intensive grazing of cattle lead to increased pressure on the environment causing severe degradation of the orginal ecosystem.

Major land use problems (land users’ perception): Less arable land and reduced fodder availability in the region.

Semi-nomadism / pastoralism: Yes

Selective felling of (semi-) natural forests: Yes

Forest products and services: timber, fuelwood, grazing / browsing

Future (final) land use (after implementation of SLM Technology): Forests / woodlands: Fp: Plantations, afforestations

3.3 Has land use changed due to the implementation of the Technology?

Grazing land

Grazing land

Forest/ woodlands

Forest/ woodlands

  • Tree plantation, afforestation

Grazing land: Ge: Extensive grazing land

Future (final) land use (after implementation of SLM Technology): Forests / woodlands: Fp: Plantations, afforestations

3.4 Water supply

Water supply for the land on which the Technology is applied:
  • rainfed

3.5 SLM group to which the Technology belongs

  • area closure (stop use, support restoration)

3.6 SLM measures comprising the Technology

vegetative measures

vegetative measures

  • V1: Tree and shrub cover
  • V2: Grasses and perennial herbaceous plants
structural measures

structural measures

  • S6: Walls, barriers, palisades, fences

Main measures: vegetative measures, structural measures

Type of vegetative measures: aligned: -linear

3.7 Main types of land degradation addressed by the Technology

soil erosion by water

soil erosion by water

  • Wt: loss of topsoil/ surface erosion
soil erosion by wind

soil erosion by wind

  • Et: loss of topsoil
chemical soil deterioration

chemical soil deterioration

  • Cn: fertility decline and reduced organic matter content (not caused by erosion)
physical soil deterioration

physical soil deterioration

  • Pk: slaking and crusting
biological degradation

biological degradation

  • Bc: reduction of vegetation cover
  • Bs: quality and species composition/ diversity decline
  • Bl: loss of soil life
water degradation

water degradation

  • Hg: change in groundwater/aquifer level

Main type of degradation addressed: Et: loss of topsoil, Cn: fertility decline and reduced organic matter content, Bc: reduction of vegetation cover, Bs: quality and species composition /diversity decline, Bl: loss of soil life

Secondary types of degradation addressed: Wt: loss of topsoil / surface erosion, Pk: sealing and crusting, Hg: change in groundwater / aquifer level

Main causes of degradation: deforestation / removal of natural vegetation (incl. forest fires) (tree cutting for fuel), over-exploitation of vegetation for domestic use (fodder), overgrazing (intensive grazing), population pressure

Secondary causes of degradation: land tenure, poverty / wealth

3.8 Prevention, reduction, or restoration of land degradation


Main goals: rehabilitation / reclamation of denuded land

Secondary goals: mitigation / reduction of land degradation

Third goals: prevention of land degradation

4. Technical specifications, implementation activities, inputs, and costs

4.1 Technical drawing of the Technology

Technical specifications (related to technical drawing):

Fenced plantation with Acacia trees on a 3m x 3m grid with cross section of infiltration pit (length given in cm)

Location: National Park Bou Hedma. Sidi Bouzid

Date: 2014-02-04

Technical knowledge required for field staff / advisors: high

Technical knowledge required for land users: moderate

Main technical functions: control of dispersed runoff: retain / trap, improvement of ground cover, improvement of surface structure (crusting, sealing), improvement of topsoil structure (compaction), stabilisation of soil (eg by tree roots against land slides), increase in organic matter, increase in nutrient availability (supply, recycling,…), increase of infiltration, increase / maintain water stored in soil, increase of biomass (quantity), promotion of vegetation species and varieties (quality, eg palatable fodder)

Secondary technical functions: control of raindrop splash, control of dispersed runoff: impede / retard, increase of surface roughness, improvement of water quality, buffering / filtering water, sediment retention / trapping, sediment harvesting, reduction in wind speed

Aligned: -linear
Vegetative material: T : trees / shrubs
Number of plants per (ha): 1000
Vertical interval between rows / strips / blocks (m): 3
Vertical interval within rows / strips / blocks (m): 3

Trees/ shrubs species: Acacia raddiana

Slope (which determines the spacing indicated above): 0%

Gradient along the rows / strips: 0%

Construction material (other): wire fence


Maarten De Boever

4.2 General information regarding the calculation of inputs and costs

other/ national currency (specify):

Tunisian Dinar

If relevant, indicate exchange rate from USD to local currency (e.g. 1 USD = 79.9 Brazilian Real): 1 USD =:


Indicate average wage cost of hired labour per day:


4.3 Establishment activities

Activity Timing (season)
1. seed collection June/July/August
2. tree nursery July/August
3. plantation rainy season (sept-->dec)
4. installation fence 1 day

4.4 Costs and inputs needed for establishment

Specify input Unit Quantity Costs per Unit Total costs per input % of costs borne by land users
Labour Labour ha 1.0 330.0 330.0
Construction material Iron wire fence ha 1.0 1600.0 1600.0
Construction material iron poles ha 1.0 800.0 800.0
Total costs for establishment of the Technology 2730.0
Total costs for establishment of the Technology in USD 1654.55

Duration of establishment phase: 8 month(s)

4.5 Maintenance/ recurrent activities

Activity Timing/ frequency
1. follow up plantation (irrigation) weekly 1 day by 2 workers for 1 year

4.6 Costs and inputs needed for maintenance/ recurrent activities (per year)

Specify input Unit Quantity Costs per Unit Total costs per input % of costs borne by land users
Labour Labour ha 1.0 30.0 30.0
Total costs for maintenance of the Technology 30.0
Total costs for maintenance of the Technology in USD 18.18

The above costs were calculated for the establishment of a 1 ha fenced plantation with 1000 seedlings on a 3m x 3m grid. From collecting seeds to planting of the seedlings and fencing the plantation it takes about 8 months. Irrigation through the first year after planting is done to ensure survival of the seedlings.

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

The most determinate factor affecting the costs is tree nursing. This factor is not only labour intersive but also high in water demand.

5. Natural and human environment

5.1 Climate

Annual rainfall
  • < 250 mm
  • 251-500 mm
  • 501-750 mm
  • 751-1,000 mm
  • 1,001-1,500 mm
  • 1,501-2,000 mm
  • 2,001-3,000 mm
  • 3,001-4,000 mm
  • > 4,000 mm
Specifications/ comments on rainfall:

Rainy season September-December

Agro-climatic zone
  • arid

Thermal climate class: subtropics

5.2 Topography

Slopes on average:
  • flat (0-2%)
  • gentle (3-5%)
  • moderate (6-10%)
  • rolling (11-15%)
  • hilly (16-30%)
  • steep (31-60%)
  • very steep (>60%)
  • plateau/plains
  • ridges
  • mountain slopes
  • hill slopes
  • footslopes
  • valley floors
Altitudinal zone:
  • 0-100 m a.s.l.
  • 101-500 m a.s.l.
  • 501-1,000 m a.s.l.
  • 1,001-1,500 m a.s.l.
  • 1,501-2,000 m a.s.l.
  • 2,001-2,500 m a.s.l.
  • 2,501-3,000 m a.s.l.
  • 3,001-4,000 m a.s.l.
  • > 4,000 m a.s.l.

5.3 Soils

Soil depth on average:
  • very shallow (0-20 cm)
  • shallow (21-50 cm)
  • moderately deep (51-80 cm)
  • deep (81-120 cm)
  • very deep (> 120 cm)
Soil texture (topsoil):
  • coarse/ light (sandy)
  • medium (loamy, silty)
Topsoil organic matter:
  • medium (1-3%)
  • low (<1%)
If available, attach full soil description or specify the available information, e.g. soil type, soil PH/ acidity, Cation Exchange Capacity, nitrogen, salinity etc.

Soil texture: coarse/medium (loamy sand/sandy loam)
Soil fertility is low
Soil drainage/infiltration is medium - poor
Soil water storage is low - medium

5.4 Water availability and quality

Ground water table:

5-50 m

Availability of surface water:

poor/ none

Water quality (untreated):

for agricultural use only (irrigation)

5.5 Biodiversity

Species diversity:
  • medium

5.6 Characteristics of land users applying the Technology

Market orientation of production system:
  • subsistence (self-supply)
  • mixed (subsistence/ commercial)
Off-farm income:
  • 10-50% of all income
Relative level of wealth:
  • poor
Individuals or groups:
  • employee (company, government)
  • men
Indicate other relevant characteristics of the land users:

Land users applying the Technology are mainly Leaders / privileged

Difference in the involvement of women and men: Mainly men are involved because the establishment of a plantation is labour intensive.

Population density: < 10 persons/km2

Annual population growth: 2% - 3%

5.7 Average area of land used by land users applying the Technology

  • < 0.5 ha
  • 0.5-1 ha
  • 1-2 ha
  • 2-5 ha
  • 5-15 ha
  • 15-50 ha
  • 50-100 ha
  • 100-500 ha
  • 500-1,000 ha
  • 1,000-10,000 ha
  • > 10,000 ha
Is this considered small-, medium- or large-scale (referring to local context)?
  • large-scale

Average area of land owned or leased by land users applying the Technology: < 0.5 ha, < 0.5 ha, 0.5-1 ha, 1-2 ha

5.8 Land ownership, land use rights, and water use rights

Land ownership:
  • group
  • individual, titled
Land use rights:
  • individual
Water use rights:
  • communal (organized)

5.9 Access to services and infrastructure

  • poor
  • moderate
  • good
  • poor
  • moderate
  • good
technical assistance:
  • poor
  • moderate
  • good
employment (e.g. off-farm):
  • poor
  • moderate
  • good
  • poor
  • moderate
  • good
  • poor
  • moderate
  • good
roads and transport:
  • poor
  • moderate
  • good
drinking water and sanitation:
  • poor
  • moderate
  • good
financial services:
  • poor
  • moderate
  • good

6. Impacts and concluding statements

6.1 On-site impacts the Technology has shown

Socio-economic impacts


fodder production


fodder quality


wood production


production area

Income and costs

farm income


Socio-cultural impacts

food security/ self-sufficiency


SLM/ land degradation knowledge


conflict mitigation


Improved livelihoods and human well-being

Comments/ specify:

The technology improves the livelihoods of local people directly through income generation from employment in the park and indirectly by the improvement of climatological conditions in the neighbourhood of the park.

Ecological impacts

Water cycle/ runoff

harvesting/ collection of water


surface runoff


excess water drainage


groundwater table/ aquifer




soil moisture


soil cover


soil loss


soil crusting/ sealing


soil compaction


soil organic matter/ below ground C

Biodiversity: vegetation, animals

biomass/ above ground C


plant diversity


habitat diversity

Climate and disaster risk reduction

emission of carbon and greenhouse gases


6.2 Off-site impacts the Technology has shown

buffering/ filtering capacity


wind transported sediments


6.3 Exposure and sensitivity of the Technology to gradual climate change and climate-related extremes/ disasters (as perceived by land users)

Gradual climate change

Gradual climate change
Season increase or decrease How does the Technology cope with it?
annual temperature increase well

Climate-related extremes (disasters)

Meteorological disasters
How does the Technology cope with it?
local windstorm well
Climatological disasters
How does the Technology cope with it?
drought not well

Other climate-related consequences

Other climate-related consequences
How does the Technology cope with it?
reduced growing period not well

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?
Short-term returns:

neutral/ balanced

Long-term returns:

slightly positive

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?
Short-term returns:

neutral/ balanced

Long-term returns:

neutral/ balanced

6.5 Adoption of the Technology

Of all those who have adopted the Technology, how many did so spontaneously, i.e. without receiving any material incentives/ payments?
  • 0-10%

Comments on acceptance with external material support: Until now no land users have implemented the technology because the government does not provide any incentives/subsidies.

There is no trend towards spontaneous adoption of the Technology

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
protection (less soil degradation) and rehabilitation of the natural ecosystem

How can they be sustained / enhanced? involvement of local people
direct and indirect improvement of the livelihoods of local people

How can they be sustained / enhanced? awareness raising
improved soil carbon stocks

How can they be sustained / enhanced? maintenance of existing and establishment of new plantations
increased biodiversity (trees act as fertility islands facilitating the growth of ground cover plants)

How can they be sustained / enhanced? maintenance of existing and establishment of new plantations

6.8 Weaknesses/ disadvantages/ risks of the Technology and ways of overcoming them

Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view How can they be overcome?
no tree planting initiatives undertaken by local people incentives/subsidies from government
no public awareness of importance to conserve natural resources set up of a large educational program with regular activities in the park and further elaboration of the small ecological museum

7. References and links

7.1 Methods/ sources of information

Links and modules

Expand all Collapse all