land use change and local forest dynamics in the forest-savannah boundary in central cameroon
DESCRIPTION
Edmond DouniasPresentation for the conference on Taking stock of smallholders and community forestryMontpellier FranceMarch 24-26, 2010TRANSCRIPT
![Page 1: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/1.jpg)
Land-use change and
local forest dynamics in the forest-savannah boundary
in Central Cameroon
Taking stock of smallholders and community forestry Session 13
Impact of local forestry practices on landscapes
![Page 2: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/2.jpg)
Let’s go to Central Cameroon
![Page 3: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/3.jpg)
Fairly recent introgression of forest onto savannah
Ongoing afforestation on African forest margins
Attested throughout Western and Central Africa
Bioclimatic origin of this phenomenon that started 1,000 years BP
Local perceptions and attitudes vis-à-vis spontaneous afforestation are poorly documented
Humans are hardly responsible for past bioclimatic events…
… But they have co-influenced the impact of such events on the environment…
… Humans are becoming a major driving force in the dynamics of ecosystems
![Page 4: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/4.jpg)
Multidisciplinary evidence of this extensive phenomenon
• Phytogeography • Botany • Phytosociology • Remote sensing • Pedology • Dendrochronology • Isotopic biochemistry • Sedimentology • Phytolites • Palynology • Ecology • Archeology • Anthropology
![Page 5: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/5.jpg)
Forest-savannah ecotone
• Rich ecosystem - Diversified mosaic
- Forest plants and animals meet with savannah plants and animals
- Life forms specific to the ecotone
• Dynamic ecosystem - Afforestation: 1 to 3 meters per year
- Changes perceptible in just a few years
- Ideal conditions to question adaptation to change
![Page 6: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/6.jpg)
Ecological heterogeneity of the ecotone
forest/savannah ecotone in the southern area
forest/savannah ecotone in the northern area
![Page 7: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/7.jpg)
Tikar…
• Warlike and conquering stratified
society
• Originally cereal cultivators
• Brought their ecology with them
• Sorghum progressively replaced
by maize
• “Absorption” of populations met
along migration
• Initiated into forest by Bedzan
Pygmies
and Bedzan
![Page 8: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/8.jpg)
Forest swiddeners and savannah cultivators
Intercropped swidden under forest
Monocultural (cassava) field in the savannah
![Page 9: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/9.jpg)
Non agricultural activities
hunting fishing
gathering
![Page 10: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/10.jpg)
Afforestation between 1950 and 1989
Sectors of faster afforestation: former village settlements
![Page 11: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/11.jpg)
Accelerated afforestation near residential sites Villages were built right up against the forest edge
![Page 12: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/12.jpg)
Accelerated afforestation near residential sites
Temporary swidden camps
![Page 13: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/13.jpg)
Accelerated afforestation near residential sites
Seasonal fishing camps
![Page 14: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/14.jpg)
Accelerated afforestation near residential sites
In 35 years
![Page 15: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/15.jpg)
Fragmented swidden area ⇒ fast afforestation
Single swidden area ⇒ slowed afforestation
Local strategies to control afforestation
![Page 16: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/16.jpg)
Selective tree cutting by forest swiddeners
Local strategies to control afforestation
![Page 17: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/17.jpg)
Seed rain and nucleation
Local strategies to control afforestation
![Page 18: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/18.jpg)
Coffee agroforest
1970s: Permanent agroforest belt as a fence against afforestation
Local strategies to control afforestation
![Page 19: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/19.jpg)
Agroforest trees as safety net Ictyotoxic bark of Albizia coriaria
Medicinal bark of Enantia chloranta
Storage of cola nuts in termites’ nests
Local strategies to control afforestation
![Page 20: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/20.jpg)
Pan-tropical invasive shrub
Good for agronomy • Voluntarily introduced as a cover crop
• Improves soil structure (stops the leaching of mineral elements, increases the depth of
the humus stratum, reduces soil acidity)
• Green manure
• Nematicide properties
Bad for ecology • Compromises forest regeneration
• The African variegated grasshopper (Zonocerus variegatus, Orthoptera,
Pyrgomorphidae)
1980s: invasion by Chromolaena odorata (Asteraceae)
Local strategies to control afforestation
![Page 21: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/21.jpg)
Suffrutescent plant: architecture smothers fire and protects tree seedlings of the forest edge
Abundant faunal circulation underneath (rodents) Early burned savannahs
Chromolaena facilitates afforestation Early burning of savannahs
Local strategies to control afforestation
![Page 22: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/22.jpg)
Exhausting clearing of young fallows invaded by Chromolaena
Delayed burning of fallows
Local strategies to control afforestation
![Page 23: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/23.jpg)
High caloric return of Chromolaena burning
Chromolaena compromises afforestation Delayed burning of fallows
Local strategies to control afforestation
![Page 24: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/24.jpg)
Effect of Chromolaena on the fallowing rotation
• No more forest regrowth • Fallowing period reduced to 5 years
Local strategies to control afforestation
![Page 25: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/25.jpg)
Socio-political system of savannah farmers more adapted to Chromolaena
Community farming activities and mutual aid
Increased man-days per hectare
Local strategies to control afforestation
![Page 26: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/26.jpg)
In brief
1980s Invasion by
Chromolaena odorata
![Page 27: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/27.jpg)
• Coupled human-nature shaping of ecosystems
• Analysis of biocultural interactions needed to catch local understanding
and influence of ecosystem dynamics (socioecological systems)
• Local rationality differs from the scientific and conservationist views
• Indigenous peoples are not de facto “conservationists”, but may
elaborate adaptive responses that are environmental-friendly
• “Conservationist” does not mean “conservative”. Adaptive responses
may be stimulated by external factors (cash crop plantations ; invasive
shrub)
• Innovative adoptions depend on socio-political features of the
considered community
Where do we go from here… … well, let’s go back to there!
![Page 28: Land use change and local forest dynamics in the forest-savannah boundary in central cameroon](https://reader033.vdocuments.mx/reader033/viewer/2022051209/5496de09ac7959132e8b5249/html5/thumbnails/28.jpg)
Thank you for your attention!