Reafforestation

Background Trees have an important role to play in natural as well as in agricultural ecosystems, including: shade and windbreaks, mobilization and cycling of nutrients, particularly from deep levels of soil, nitrogen fixation for tree legumes, carbon sequestration, habitat for many species of birds, insects, small mammals, epiphytic plants. Livestock raising can affect tree populations, either directly by damage on branches, trunk, sprouts, regrowing, or indirectly by deforestation during the establishment and protection of grasslands. | Background Objectives Techniques Targeted Livestock System Impact Context of Application Monitoring: EIA, Indicators References See Also

Objectives

- Reafforestation is implemented where tree cover has been reduced by climatic change or human activities.
- Regeneration of tree cover induces improved structure and fertility in soils, soil protection,forage availability during dry season.

Techniques

- Reafforestation can be implemented through different techniques with native or exotic species. Plantation and direct sowing are the most common.
- Plantation of local or exotic species is necessarily based on tree nurseries where different techniques may be used to improve the results of plantation. Costs are quite high.
- Direct sowing is a low cost technique but success rate is much lower. It needs seeds of high quality, seed pretreatment, low human and livestock pressure.
- The vegetative propagation (by stump sprouting or cork suckering) is a low cost technique which needs a minimum of control in the field to be oriented and stimulated.
- Other techniques can be used, the assisted regeneration, protection of islands of trees for seed prodution and dissemination, temporal land protection of land from herbivores (see Tree regeneration protection).
- Introduction of trees can be applied following different formats:

- Reafforestation plots (or parcels) : these plots have various shape and areas.
- Live fences (see Live fences and ligneous windbreaks): plantation of trees contiguous in limit of fields or pastures.
- Windbreaks (see Live fences and ligneous windbreaks) and shade trees.

Targeted Livestock System

Grazing and mixed systems in all agroecological zones.

Grazing System

LGA | LGS1 | LGS2 | LGS3 | LGH1 | LGH2 | LGH3 | LGT1 | LGT2 | LGT3
N | Y | Y | Y | Y | Y | Y | Y | Y | Y

Mixed System

MCG | MCR | MCC | MFF | MEF
Y | Y | Y | Y | Y

Industrial System

IFP | IPL | IPG | IRM | IDU | ISL | ITN | IMP
N | N | N | N | N | N | N | N

Impacts

- Positive environmental impact

- Improve biodiversity.
- Improve soil structure and fertility.
- Improve human being through firewood, fruits and by-products availability.
- Improve livestock feed availability and animal welfare.

- Negative environmental impact

- Some exotic species may be invasive or high water consumers.
- Tree plantation may increase bird pressure on crops.
- Tree plantation can decrease grass cover in case of high cover rate.

- Livestock productivity impact

- Tree foliage can be a good quality feed in tropics during the dry season (average nitrogen content 12% of dry matter, 20% for high quality feeds as Morus alba leaves).

Context of Application

- Favourable factors:

- Land tenure control.
- Availability of seeds.
- Availability of technical services.

- Unfavourable factors:

- High human and livestock pressure.
- Bird concentration.
- Bush encroachement or heavy spontaneous forest regeneration in pasture in humid zone.

Monitoring: EIA, Indicators

- Tree density or tree cover.
- Number of tree species concerned.
- Areas planted.
- Animal biodiversity.

References

Bellefontaine R., Gaston, A. and Pettrucci, Y. 1997. Aménagement des forêts naturelles des zones tropicales sèches. Cahier FAO Conservation N° 32. FAO, Rome, Italy, pp. 316.

Baumer M. 1997. L’agroforesterie pour les productions animales CTA-ICRAF - Bruxelles

See Also

Carbon Sequestration

Carbon Sequestration Schemes on Pasture Land

Creating and Strengthening Carbon Sinks: Pressure State Response Indicators.

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