1.2 Coordonnées des personnes-ressources et des institutions impliquées dans l'évaluation et la documentation de la Technologie

Nom du ou des institutions qui ont facilité la documentation/ l'évaluation de la Technologie (si pertinent)

Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) - Allemagne

1.3 Conditions relatives à l'utilisation par WOCAT des données documentées

Quand les données ont-elles été compilées (sur le terrain)?

01/08/2014

Le compilateur et la(les) personne(s) ressource(s) acceptent les conditions relatives à l'utilisation par WOCAT des données documentées:

Oui

1.4 Déclaration sur la durabilité de la Technologie décrite

Est-ce que la Technologie décrite ici pose problème par rapport à la dégradation des terres, de telle sorte qu'elle ne peut pas être déclarée comme étant une technologie de gestion durable des terres?

Non

Commentaires:

The technology described is a means to rehabilitate degraded rangeland. Through targeted harvesting of bushes, the bush density is reduced, allowing for better growth of grass.

1.5 Référence au(x) questionnaire(s) sur les Approches de GDT

2.1 Courte description de la Technologie

Définition de la Technologie:

On Namibian farmland bushes are harvested in order to reduce the excessive bush densities, that stiffle the growth of other plant species, especially grasses. Bush can be harvested manually (e.g. with axes), semi-mechanised (e.g. chainsaws) or fully mechanised (e.g. customised excavators). After cutting, the bush is typically left to dry and in a second step processed into a transportable format (e.g. wood chips).

2.2 Description détaillée de la Technologie

Description:

Bush thinning in the form of selective bush harvesting is applied on Namibian agricultural land. The main aim of the technology is the restoration of degraded rangeland, reducing bush densities, fostering the re-growth of grasses. According to the best available estimates about 45 million hectares of Namibian farmland are affected by bush encroachment. Bush encroachment negatively affects biodiversity, groundwater recharge and importantly the carrying capacity of rangeland. Bush encroachment equally hinders crop production, but this phenomenon is of less significance in Namibia due to the limited scope of crop production in the country. There is a multitude of causes for bush encroachment, among which overgrazing (i.e. overstocking with cattle or lack of rotational grazing), reduced frequency of wildfires and higher CO2 concentrations in the atmosphere feature strongly. Bush encroachment is not to be equated with the invations of alien species, since most encroacher species are indigeneous to Namibia

While it is believed that natural transitions in the ecosystems can on the long-run, under favourable climatic conditions, also lead to reductions of bush encroachment, active rehablitation measures are required in order to achieve improvements on the short-run. This is an aboslute necessity for many Namibian farmers, who experience severe economic difficulties due to the reduced productivity of their land.

Bush control comprises of responsive measures (bush thinning), follow-up measures (aftercare) as well as preventative measures (good rangeland management practices). Since vast areas of Namibian rangeland are heavily encroached by indigenous bush species, the focus is currently on responsive measures, i.e. bush thinning.

Bush thinning entails the practice of selectively harvesting a specified number of bushes, effectively reducing the number of bushes per given area. To determine the density of bush remaining after thinning, a formula based on tree equivalent (TE) and average annual rainfall is used. A tree equivalent is defined as a woody tree or bush of 1,5 metres in height. Thus, a 3 metre shrub would represent 2 TE, a 4.5 metre shrub 3 TE. As rule of thumb for estimating optimal bush density, about 30-35% of encroacher biomass should be removed. This rule is based on research that has been carried out mainly in South Africa over the past decades, measuring and comparing the re-growth experienced at various sites where bush had been harvested. Areas, in which too much bush was removed, experienced strong re-growth of bush, often resulting in even heavier bush encroachment.

Bush thinning follows strict environmental guidelines set by the Ministry of Environment and Tourism through the Environmental Management Act with regard to the equipment's used (avoiding negative side-effects such as disturbance of the soil) and the amount of bushes to be harvested (aiming at the right balance between reducing the encroachment and maintaining a healthy number of the desired bush species). The amount of bushes to be harvested must be determined by expert for each specific area and depends on various factors, e.g. soil type, topgraphy, severity of bush encroachment and intended land use type.

It is important to note, that as with most direct interventions in natural ecosystems, there is a lack of precise knowledge on the long-term effect of bush thinning and the appropriate intensity thereof. There is however no doubt that active bush control has an overall positive effect on the savanna ecosystem in Namibia.

In order to render bush thinning economically feasible, value chains have been developed. Through the processing and utilisation of the woody bush biomass, income can be generated and the cost of bush conrol balanced. Existing value chains include the production of charcoal, firewood, poles, bush based animal feed as well as heat and electricity. Value chains currently under development include composition materials, such as wood-plastic, wood-cement and bio-plastic.

Scientific observations have shown, that bush thinning cannot be implemented as a once-off activity, but requires regular follow-up to prevent the re-thickening of the bush. Follow-up measures (so-called aftercare) include the prevention of coppicing and re-growth. This can be achieved by applying aboricides selectively to the cut stems, stem fires or the introduction of browsers (e.g. goats). Research on the effectiveness and possible side effects of each of these methods is limited.

The need for bush control, and therewith bush thinning, is widely recognised among land owners and also acknowledged on the national political agenda.

A major challenge for the implementation of the technology is the limited suitability of available machines. The hardness and high mineral content of the woody biomass leads to high wear and tear on the equipment (both harvesting equipment and processing equipment, like chippers and pelletisers), often rendering operations unprofitable. Research into more suitable machinery is ongoing.

Further, the implementation of sustainable bush control must be improved through skills training and continuous monitoring of the long-term effects on rangeland.

2.3 Photos de la Technologie

2.4 Vidéos de la Technologie

2.5 Pays/ région/ lieux où la Technologie a été appliquée et qui sont couverts par cette évaluation

2.6 Date de mise en œuvre de la Technologie

Indiquez l'année de mise en œuvre:

2015

2.7 Introduction de la Technologie

Spécifiez comment la Technologie a été introduite: :

• grâce à l'innovation d'exploitants des terres
• au cours d'expérimentations / de recherches
• par le biais de projets/ d'interventions extérieures

Commentaires (type de projet, etc.) :

Since the 1950s the phenomenon of bush encroachment has been recognised by farmers in Namibia and counter measures have been implemented over the decades. The technologies applied largely relied on the means and innovative capabilities of the respective land owner. Only as of 2014, through the introduciton of a national Support to De-bushing Project, are technologies systematically researched and tested in the field.

3.1 Principal(aux) objectif(s) de la Technologie

• améliorer la production
• réduire, prévenir, restaurer les terres dégradées
• préserver l'écosystème
• conserver/ améliorer la biodiversité
• créer un impact économique positif

3.2 Type(s) actuel(s) d'utilisation des terres, là où la Technologie est appliquée

Commentaires:

Namibia is characterised by large commercial cattle farms. Du to its aridity the land is largely unsuitable for crop farming, with exceptions in high-rainfall areas such as the Grootfontein, Tsumeb, Otavi triangle.

The Northern parts of Namibia are managed as communal land, where farmers have lease holds for their land. In these areas a combination of millet production and cattle herding is common.

Si l'utilisation des terres a changé en raison de la mise en œuvre de la Technologie, indiquez l'utilisation des terres avant la mise en œuvre de la Technologie:

The implementation of bush thinning allows to maintain the land use (e.g. cattle ranching) and is typically applied to increase productivity in the long-term.

3.3 Informations complémentaires sur l'utilisation des terres

Approvisionnement en eau des terres sur lesquelles est appliquée la Technologie:

• pluvial

Nombre de période de croissance par an: :

• 1

Densité d'élevage/ chargement (si pertinent):

284 000 in targeted area of bush thinning (Otjozondjupa region)

3.4 Groupe de GDT auquel appartient la Technologie

• pastoralisme et gestion des pâturages
• Amélioration de la couverture végétale/ du sol

3.5 Diffusion de la Technologie

Spécifiez la diffusion de la Technologie:

• répartie uniformément sur une zone

Si la Technologie est uniformément répartie sur une zone, indiquez la superficie couverte approximative:

• 1 000-10 000 km2

Commentaires:

Currently bush thinning is implemented on a total of approximately 120.000 hectares (1.200 km2) of farmland per annum. These activities are not confied to certain areas, but spread across all of Namibia, typically concentrating in the most encroached areas (e.g. Otjozondjupa, Khomas, Oshikoto and Omaheke regions).

3.6 Mesures de GDT constituant la Technologie

3.7 Principaux types de dégradation des terres traités par la Technologie

3.8 Prévention, réduction de la dégradation ou réhabilitation des terres dégradées

Spécifiez l'objectif de la Technologie au regard de la dégradation des terres:

• prévenir la dégradation des terres
• restaurer/ réhabiliter des terres sévèrement dégradées

4.1 Dessin technique de la Technologie

4.2 Spécification/ explications techniques du dessin technique

Drawing of a bush harvesting site layout. The drawing depicts fully mechanised bush harvesting and immediate processing into wood chips. This set-up is most suitable for large-scale bush thinning, e.g. for the purpose of supplying biomass in larger quantities. Such off-take includes the potential export of bush in processed form (pellets) or energetic utilisation (e.g. local biomass power plants or biomass boilers in the industry). Currently two such energy solutions exist in Namibia, one at a local brewery and one at a local cement factory.

Note that a range of bush harvesting methods exist, ranging from fully mechanised (as depicted) to manual bush harvesting (e.g. with axes). The site layout and principles are the same in all scenarios, but harvesting speed and costs differ.

The bush harvesting process:
Bushes are harvested selectively with and excavator, to which a hydraulic sheer cutter is attached. The biomass is stacked in rows and left for drying some six to eight weeks (depending on weather conditions). The biomass is then further processed with a chipper and collected with a trailer for further transport off the farm (e.g. to a biomass power plant or industrial off-taker). As a rule of thumb, one third of the standing biomass is removed, leaving two thirds standing. Harvesting starts with smaller plants and then moves to larger ones, cutting only plants with 15 centimetres of diameter or less (as per Namibian forestry regulations).

Cost of bush harvesting can be calculated per hectare (e.g. land owner's perspective) or per tonne (in fuel supply agreements with off-takers). All below stated costs are approximations, as costs vary widely depending on the local framework conditions on a given piece of land. Typically the costs to harvest bush on one hectare range from 2,000 NAD to 4,000 NAD.

4.3 Informations générales sur le calcul des intrants et des coûts

Spécifiez la manière dont les coûts et les intrants ont été calculés:

• par superficie de la Technologie

autre/ monnaie nationale (précisez):

Namibia Dollar (NAD)

Indiquer le taux de change du dollars en monnaie locale (si pertinent): 1 USD= :

0,078

4.4 Activités de mise en place/ d'établissement

	Activité	Type de mesures	Calendrier
1.	Bush harvesting/felling	Végétale	Year around
2.	Stacking (and drying)	Autres mesures	Year around
3.	Feeding the chipping operation	Autres mesures	Year around
4.	Transport	Autres mesures	Year around

Commentaires:

The restorative measure includes bush harvesting/felling as well as aftercare measures. Additional activities include the processing (e.g. into chips) and transport of the woody material off the farm/land.

4.5 Coûts et intrants nécessaires à la mise en place

	Spécifiez les intrants	Unité	Quantité	Coûts par unité	Coût total par intrant	% du coût supporté par les exploitants des terres
Main d'œuvre	1 x Mechanic	person days	0,2	2000,0	400,0
Main d'œuvre	4 x Operators	person days	0,8	300,0	240,0
Main d'œuvre	1 x Operation manager chipping	person days	0,2	1000,0	200,0
Main d'œuvre	1 x Chipping operator	person days	2,0	150,0	300,0
Equipements	1 x 12t Excavator	pieces	1,0	120,0	120,0
Equipements	2 x Hydraulic grab and shearing attachments	pieces	2,0	60,0	120,0
Equipements	2 x Three wheel loggers	pieces	2,0	180,0	360,0
Equipements	1 x Chipper	pieces	1,0	840,0	840,0
Autre	Management and administration overhead	lump sum	1,0	200,0	200,0
Autre						12,0
Coût total de mise en place de la Technologie					2780,0

4.6 Activités d'entretien/ récurrentes

	Activité	Type de mesures	Calendrier/ fréquence
1.	Aftercare	Végétale	Annually

Commentaires:

When land is thinned it creates a vacuum in which weeds and woody plants (sometimes more aggressive colonisers than the original encroacher species) will quickly establish themselves. Regular aftercare needs to be applied in order to prevent the excessive re-growth of bush (and therewith new degradation of the land). Various methods are in use to manage the re-growth of bush following harvesting. These include selective application of arboricides, stem burning, and intensive browsing by goats or antelopes.

The more sustainable the bush harvesting itself has taken place, importantly not completely clearing larger areas of vegetation, the less likely is agressive re-growth of bush. In all bush thinning exercises it is important to leave larger bushes and trees untouched and to start by removing the smaller, less established bushes. In addition, not only individual larger bushes must be left standing, but also islands/patches of bushes, which fulfill important ecosystem services, e.g. habitat for animals.

4.7 Coûts et intrants nécessaires aux activités d'entretien/ récurrentes (par an)

Si possible, ventilez le coût de l'entretien selon le tableau suivant: spécifiez les intrants et le coût par intrant. Si vous n'êtes pas en mesure de ventiler le coût, donnez une estimation du coût total de l'entretien de la Technologie:

500,0

Commentaires:

Commonly aftercare is applied in form of manual application of herbicides to the cut stems, in order to prevent re-growth of the bushes.

4.8 Facteurs les plus importants affectant les coûts

Décrivez les facteurs les plus importants affectant les coûts :

(1) Investment in machinery (if not applied manually)
(2) Maintenance of machinery (high wear and tear due to hardness of wood and high mineral content)
(3) Remoteness of farms/land from buyers/markets

5.1 Climat

5.2 Topographie

Indiquez si la Technologie est spécifiquement appliquée dans des:

• non pertinent

5.3 Sols

5.4 Disponibilité et qualité de l'eau

La salinité de l'eau est-elle un problème? :

Non

La zone est-elle inondée?

Non

5.5 Biodiversité

5.6 Caractéristiques des exploitants des terres appliquant la Technologie

5.7 Superficie moyenne des terres détenues ou louées par les exploitants appliquant la Technologie

5.8 Propriété foncière, droits d’utilisation des terres et de l'eau

Propriété foncière:

• individu, avec titre de propriété

Droits d’utilisation des terres:

• individuel

Droits d’utilisation de l’eau:

• individuel

5.9 Accès aux services et aux infrastructures

6.1 Impacts sur site que la Technologie a montrés

Impacts socio-économiques

Production

Disponibilité et qualité de l'eau

Revenus et coûts

Impacts écologiques

Biodiversité: végétale, animale

6.3 Exposition et sensibilité de la Technologie aux changements progressifs et aux évènements extrêmes/catastrophes liés au climat (telles que perçues par les exploitants des terres)

Changements climatiques progressifs

Changements climatiques progressifs

	Saison	Type de changements/ extrêmes climatiques	Comment la Technologie fait-elle face à cela?
précipitations annuelles		décroît	pas bien

Extrêmes climatiques (catastrophes)

Catastrophes climatiques

	Comment la Technologie fait-elle face à cela?
sécheresse	pas bien du tout

Commentaires:

Despite only limited research exists, long periods of drought that the country has recently faced, are credited to climate change. Drought intensifies the challenge for farmers, as already degraded rangeland has limited capacity to recover in the absence of rain. The technology of bush thinning itself has limited effect if no rain follows the removal of bushes.

6.4 Analyse coûts-bénéfices

Quels sont les bénéfices comparativement aux coûts de mise en place (du point de vue des exploitants des terres)?

Quels sont les bénéfices comparativement aux coûts d'entretien récurrents (du point de vue des exploitants des terres)?

Commentaires:

Bush thinned land takes 3-5 years to fully recover its productive grass layer, thus direct economic benefits are only experienced with a delay.

6.5 Adoption de la Technologie

• cas isolés/ expérimentaux

Si disponible, quantifiez (nombre de ménages et/ou superficie couverte):

120'000 hectares are bush thinned per year in Namibia; figures on the increase

Parmi tous ceux qui ont adopté la Technologie, combien d'entre eux l'ont fait spontanément, à savoir sans recevoir aucune incitation matérielle ou aucun paiement?

• 50-90%

Commentaires:

Farmers largely implement bush control on their own initiative; increasingly value chains are being developed and dedicated service providers offer bush control.

6.6 Adaptation

La Technologie a-t-elle été récemment modifiée pour s'adapter à l'évolution des conditions?

Oui

Si oui, indiquez à quel changement la Technologie s'est adaptée:

• évolution des marchés

Spécifiez l'adaptation de la Technologie (conception, matériaux/ espèces, etc.):

Increasingly bush harvesting is carried out with mechanised means, aiming at large scale production for large biomass off-takers, both in the country and internationally.

6.7 Points forts/ avantages/ possibilités de la Technologie

Points forts/ avantages/ possibilités du point de vue de l'exploitant des terres
Effective measure against bush encroachment
Costs can be balanced with additional income through the sale of the biomass/biomass based products

Points forts/ avantages/ possibilités du point de vue du compilateur ou d'une autre personne ressource clé
Apart from the main purpose of rehabilitating rangeland, bush control has various side benefits, such as employment creation and industrialisation.
Bush control and biomass utilisation can contribute to energy security in the country.
The available range of technologies (from manual to fully mechanised) allows to develop viable concept for all types of land/land ownership scenarios.

6.8 Faiblesses/ inconvénients/ risques de la Technologie et moyens de les surmonter

Faiblesses/ inconvénients/ risques du point de vue de l’exploitant des terres	Comment peuvent-ils être surmontés?
High initial costs involved	Development of dedicated financial products
Possible negative consequences, such as more aggressive re-growth of species	Increased knowledge dissemination, skills development and mentorship programmes

Faiblesses/ inconvénients/ risques du point de vue du compilateur ou d'une autre personne ressource clé	Comment peuvent-ils être surmontés?
Necessity of cross-sector collaboration, e.g. agriculture, forestry, environment, industry, energy and resulting complexity	Introduction of effective steering body on national level
Challenges to sustain operations in communal areas/on land that is not owned by individuals	Development of concepts for community based projects and cooperation with relevant regional authorities and decision making bodies (e.g. Regional Councils, Conservancies)

7.1 Méthodes/ sources d'information

7.2 Références des publications disponibles

Titre, auteur, année, ISBN:

Baseline Assessment for De-bushing Programme in Namibia (2014)

Disponible à partir d'où? Coût?

GIZ Support to De-bushing Project, www.dasnamibia.org/downloads

Titre, auteur, année, ISBN:

Demand Survey for the implementation of a De-bushing Advisory Service (2015)

Disponible à partir d'où? Coût?

GIZ Support to De-bushing Project, www.dasnamibia.org/downloads

Titre, auteur, année, ISBN:

Value Added user-opportunities for encroacher bush (2015)

Disponible à partir d'où? Coût?

GIZ Support to De-bushing Project, www.dasnamibia.org/downloads

Titre, auteur, année, ISBN:

Compendium of harvesting technologies for encroacher bush (2015)

Disponible à partir d'où? Coût?

GIZ Support to De-bushing Project, www.dasnamibia.org/downloads

Titre, auteur, année, ISBN:

Assessment of biomass resource and potential yield in Namibia (2015)

Disponible à partir d'où? Coût?

GIZ Support to De-bushing Project, www.dasnamibia.org/downloads

Titre, auteur, année, ISBN:

Strategic Environmental Assessment (SEA) on bush thinning and biomass utilisation (2015)

Disponible à partir d'où? Coût?

GIZ Support to De-bushing Project, www.dasnamibia.org/downloads

Titre, auteur, année, ISBN:

Assesment of financial products and incentive schemes for bush harvesting and value addition (2015)

Disponible à partir d'où? Coût?

GIZ Support to De-bushing Project, www.dasnamibia.org/downloads

Titre, auteur, année, ISBN:

Environmental and forestry bush harvesting guidelines and generic Environmental Management Plan (2016)

Disponible à partir d'où? Coût?

GIZ Support to De-bushing Project, www.dasnamibia.org/downloads

Titre, auteur, année, ISBN:

Regional assessment of the economics of land degradation related to bush encroachment in Otjozondjupa, Namibia

Disponible à partir d'où? Coût?

GIZ Support to De-bushing Project, www.dasnamibia.org/downloads

7.3 Liens vers les informations pertinentes disponibles en ligne

Titre/ description:

De-bushing Advisory Service (DAS) Namibia, Resource Section

URL:

www.dasnamibia.org/downloads

Titre/ description:

Namibia Biomass Industry Group (N-BiG)

URL:

www.n-big.org

Titre/ description:

Videos

URL:

https://www.youtube.com/channel/UCwCICCfwf0SdVBqg2ZcAcKA