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Carbon sequestration
Carbon sequestration rates were based only
on long-term permanent sample plot data
from Cameroon and were found to vary with
forest conditions (Table 10). Above ground
components had proportionately higher
sequestration rates (6.36 TonnesC/ha/yr)
compared to below ground carbon pools.
Undisturbed forests sequestered on average
16.52 TonnesC/ha/yr against 0.39 TonnesC/
ha/yr and 6.89 TonnesC/ha/yr by heavily and
moderately exploited systems respectively.
Mean sequestration rate for all forest conditions
was 7.93 Tonnes C/ha/yr. These figures on
carbon sequestration have implications for
REDD+ strategies. They show that to maintain
the highest carbon sequestration rates, then
the greatest value comes from above ground
biomass (trees) of undisturbed forests. These
data show that there is a carbon incentive to
conserve and sustainably manage undisturbed
mangroves under REDD+ strategies, rather than
to allow deforestation followed by replanting.
Exploitation regime
Biomass Carbon (MgC/ha/yr)
AGC
BGC
Total
Heavily exploited
0.19
0.20
0.39
Moderately exploited
5.21
1.68
6.89
Undisturbed
13.68
2.84
16.52
Average
6.36
1.57
7.93
Table 10: Carbon sequestration in mangrove forests in Cameroon under different disturbance regimes
Carbon dioxide (greenhouse gas)
emission potential
The most vulnerable carbon pools following
mangrove deforestation and degradation are
the above ground carbon, as well as soil carbon
from the top 30cm, where a large proportion
of mangrove carbon lies (Donato et al., 2011).
Estimating emissions from land-use change
was conducted using uncertainty-propagation
approach detailed in Donato et al., (2011). For
the mangrove of Central Africa, a conservative
low-end estimate of conversion impact, with
50% above ground biomass loss, 25% loss
of soil carbon from the top 30cm, and no loss
from deeper layers, in accordance with IPCC
default values for areas without high levels
of reclamation of mangrove habitat for other
land-uses. Use of low-end conversion impact
in the current study is justified by low-level
reclamation of mangroves for aquaculture and
agriculture in Central Africa.
Using these conservative estimates, we estimate
that 1,299 Tonnes of carbon dioxide would be
released per ha of cleared pristine mangrove in
Central Africa. This report estimates that 77,107
ha of mangrove were cleared in Central Africa
between 2000 and 2010, equating to estimated
emissions of 100,161,993 Tonnes of carbon
dioxide.
However, the net mangrove cover loss was only
of 6,800 ha so a more conservative estimate
would be of 8,833,200 Tonnes of carbon dioxide
emitted between 2000 and 2010.
Of course not all the carbon dioxide is released
immediately, and these emissions occur over
years or decades.