I am a MsC Student from Guinea-Bissau at Faculty of Sciences, Lisbon
I am using the Coastal Blue Carbon model to assess the carbon accumulation in
above and below-ground biomass at the mangrove forests in two Parks of my
I ran the Model but the results for carbon emissions seem to be inconsistent.
I am working in the Cacheu (PNTC) and Cantanhez (PNC) Parks, both with
significant mangrove areas.
Land Use Land Cover raster (GDAL-supported) of two parks were used for the
years 2002, 2007, 2010 and 2015, with 25m spatial resolution, made from
supervised classification of Landsat images .
For PNTC we have 35897, 35267, 38634 and 33949 hectares, respectively for
2002, 2007, 2010, and 2015.
For the period 2002-2007we have a decrease in mangrove area of -630ha, for
2007-2010 we have an increase of 3367ha, and for 2010-2015 we have a decrease
For PNC we have 21466, 20636, 23180 and 17909 hectares respectively for the
For the period 2002-2007we have a decrease in mangrove area of -830ha, for
2007-2010 we have an increase of 2544ha, and for 2010-2015 we have a decrease
We used the following input data for Processor:
LULC Lookup table - two classes Mangrove 1 (defined as a Coastal Blue Carbon
habitat ) / no mangrove 0 (defined as no Coastal Blue Carbon habitat)
Carbon pool initial template (MtCO2e/ha) - only Biomass pool was considered:
0.000143 MtCO2e/ha (value obtained from a former study in the country)
Transitions – we considered the following transitions
Mangrove to No mangrove (high impact);
No mangrove to No mangrove (no carbon change);
No mangrove to Mangrove (Accumulation); and
Mangrove to Mangrove (Accumulation)
Carbon pool transient template
Biomass half-life: 15 years (selected from Invest User Guide)
Biomass-high-imp-disturb: 100% biomass lost (selected from Invest User Guide,
but the value inserted was 1 for total biomass lost)
Biomass-yearly-accumulation (MtCO2e/ha/year): 0.0000049 (computed as a
proportion of 3.42% of total biomass, obtained from a published work).
With this input dataset we obtained:
- for C accumulation per hectare in the period, in MtCO2e:
2002-2007 – accumulation 0.0000245
2007-2010 - accumulation 0.0000147
2010-2015 - accumulation 0.0000245
(this is just the yearly increase multiplied by the number of years)
- for C emission per hectare in the period, in MtCO2e:
2002-2007 – emmision 0.000138531
2007-2010 - emmision 0.0000366
2010-2015 - emmision 0.000176
These results seem to be not correct, because the emission figures are too
high if compared with the obtained for accumulation. For instance, for
2002-2007 we have a little proportion of mangrove areas lost if compared to
the undisturbed area, which continued to accumulate, but the balance remained
negative. Also, for the period 2007-2010, in which the mangrove area
increased, the balance continues negative.
Can you help me in this subject?