Edmond Dounias Presentation for the conference on Taking stock of smallholders and community forestry Montpellier France March 24-26, 2010

1. Taking stock of smallholders and community forestry
Session 13
Impact of local forestry practices on landscapes
Land-use change
and
local forest dynamics
in the forest-savannah boundary
in Central Cameroon

2. Let’s go to Central Cameroon

3. Fairly recent introgression
of forest onto savannah
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
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

4. Multidisciplinary evidence of
this extensive phenomenon
• Phytogeography
• Botany
• Phytosociology
• Remote sensing
• Pedology
• Dendrochronology
• Isotopic biochemistry
• Sedimentology
• Phytolites
• Palynology
• Ecology
• Archeology
• Anthropology

5. 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

6. Ecological heterogeneity
of the ecotone
forest/savannah ecotone in the forest/savannah ecotone in the
southern area northern area

7. Tikar… and Bedzan
• 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

8. Forest swiddeners
and savannah cultivators
Intercropped swidden under forest
Monocultural (cassava) field in the savannah

9. Non agricultural activities
hunting fishing
gathering

10. Afforestation between
1950 and 1989
Sectors of faster
afforestation: former
village settlements

11. Accelerated afforestation
near residential sites
Villages were built right up against the forest edge

12. Accelerated afforestation
near residential sites
Temporary swidden camps

13. Accelerated afforestation
near residential sites
Seasonal fishing camps

14. Accelerated afforestation
near residential sites
In 35 years

15. Local strategies to
control afforestation
Fragmented swidden area Single swidden area
fast afforestation slowed afforestation

16. Local strategies to
control afforestation
Selective tree cutting by forest swiddeners

17. Local strategies to
control afforestation
Seed rain and nucleation

18. Local strategies to
control afforestation
1970s: Permanent agroforest belt as a fence against afforestation
Coffee agroforest

19. Local strategies to
control afforestation
Agroforest trees as safety net
Ictyotoxic bark of Albizia coriaria Medicinal bark of Enantia chloranta
Storage of cola nuts in termites’ nests

20. Local strategies to
control afforestation
1980s: invasion by Chromolaena odorata (Asteraceae)
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)

21. Local strategies to
control afforestation
Early burning of savannahs
Chromolaena facilitates afforestation
Suffrutescent plant:
architecture smothers fire and protects tree seedlings of the forest edge
Abundant faunal circulation underneath (rodents)
Early burned savannahs

22. Local strategies to
control afforestation
Delayed burning of fallows
Exhausting clearing of young fallows invaded by Chromolaena

23. Local strategies to
control afforestation
Delayed burning of fallows
Chromolaena compromises afforestation
High caloric return of Chromolaena burning

24. Local strategies to
control afforestation
Effect of Chromolaena on
the fallowing rotation
• No more forest regrowth
• Fallowing period reduced to
5 years

25. Local strategies to
control afforestation
Community farming activities and mutual aid
Increased man-days per hectare
Socio-political system of
savannah farmers more
adapted to Chromolaena

26. In brief
1980s
Invasion by
Chromolaena
odorata

27. Where do we go from here…
… well, let’s go back to there!
• 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

28. Thank you for your attention!