The document summarizes a study on the long-term monitoring of rangelands in West Africa to understand the impacts of fire, tree cutting, and livestock grazing on carbon sequestration. Key points:
- The study established monitoring plots in six sites across Burkina Faso, Niger, and Senegal to assess impacts of these disturbances on tree growth and biomass over time.
- Allometric equations were developed to estimate above and below-ground biomass for common tree and shrub species based on measurements of diameter, height, and crown area.
- Preliminary results found total root biomass varied from 11-17 tons/hectare depending on treatment, with grazing, fire
Long-term monitoring of rangelands: Impacts of fire, tree cutting and livestock grazing on carbon sequestration in West Africa
1. October 29, 2014 1
Long-term monitoring of rangelands
Impacts of fire, tree cutting and livestock grazing on
carbon sequestration in West Africa
Jonas Koala1,2, Mohammed Said2, Louis Sawadogo1, Patrice
Savadogo1, Didier Zida1, Ermias Aynekulu3 and de Leeuw, Jan3
1Institut de l'Environnement et de Recherches Agricoles (INEREA)
2International Livestock Research Institute (ILRI), 3World
Agroforestry (ICRAF)
6TH All Africa Conference of Animal Agriculture (AACAA), KICC,
Nairobi, 27th – 30th October, 2014
3. Background
A critical pre-requisite to managing savanna woodland
for carbon storage and sequestration is a good
knowledge about tree and shrub biomass.
Providing accurate measurements of carbon stock is
difficult without precise measurements of biomass.
3
8. Experimental design
Each experimental site
18ha
Split into 8 blocks
4 blocks fenced to
exclude (non-grazed)
and the other four
were open for grazing
Each block further
divided 8 plots of 0.25
ha (50 x 50m)
separated from each
other by 20–30m fire-
breaks
9. Long-term monitoring of tree
growth at plot level
• Every five year:
complete
inventory of the
trees on each plot
(measurement of
dbh, height, crown
area)
• Once a year
monitoring of the
regeneration
DbH
Dbase
Height
11. Above ground biomass
Species specific equations were
developed for
Acacia dudgeoni
Acacia macrostachya,
A. leiocarpa,
C.ghasalense,
C. glutinosum,
C. micranthum,
C. nigricans,
C.febrifuga,
D. microcarpum,
E.africana,
P. thonningii
V. paradoxa
11
14. Direct roots biomass
assessment
Monolith
extraction to
assess
disturbances
effects on root
biomass at plot
level
Excavation to
assess in species
Anogeissus
leiocarpa, Detarium
microcarpum;
Piliostigma
thonningii and
Vitellaria paradoxa
14
15. 15
Allometric equations for Belowground biomass of
Four key species of savanna woodland
Source: Koala et al. in prep
16. 16
Treatments Total roots biomass weight (t/ha)
Mean±SE CI 95 %
LS US
CONTROL 16.79±1.55 13.745 19.837
Grazing 11.09±1.76 7.638 14.545
Early Fire 17.37±1.69 14.038 20.693
Cutting 12.09±1.85 8.471 15.719
Grazing x Fire 15.66±1.84 12.041 19.278
Grazing x Cutting 17.54±1.85 13.908 21.168
Fire x Cutting 16.53±1.58 13.429 19.636
Grazing x Fire x Cutting 11.69±2.16 7.453 15.937
Total roots biomass at layer 0-50 cm in savanna woodland
based on grazing, early fire and selective trees cutting and
their interactions
Source: Koala et al. in prep