Carbon stocks for six different land use classes in Niassa
province, Mozambique
MSc Arttu Pienimäki*, Prof. Markku Kanninen*,
Prof. Almeida Sitoe**, Dr Eshetu Yirdaw*
Source: Bing Maps (Nokia 2013; Earthstar Geographics SIO) and Google Earth (AfriGIS 2014)
Background:
This study covers Work Package 4 of the PAIMO project by
quantifying the changes in carbon stocks of the miombo
landscape of Northern Mozambique, including the recent
expansion of industrial forest plantations.
Study objective:
Compare the mean carbon stocks between the main types of
native vegetation and the forest plantations of introduced
species at the study site of Niassa province, MZ.
Methodology:
10 km
Study site. Red markers point the
measurement areas for native vegetation.
Blue markers point the measurement
areas for forest plantations.
1. Land use classification. Four classes of native vegetation:
Dense miombo, Open miombo, Other woody vegetation,
Fallow land. Two classes of forest plantations: Eucalypt
plantations, Pine plantations.
2. Field measurements. Stratified sampling, fixed grid of
sample plots on each measurement area. Measurements on
tree biomass, destructive sampling on shrubs & grasses, soil
sample collection from topsoil (30 cm) for soil organic carbon
determination. A total of 93 plots measured.
3. Calculations and analysis. Growth of the generally juvenile
plantations was modelled according to given management
schemes in order to enable comparison with stable-state
native vegetation classes. Carbon stock of trees was
calculated utilizing known allometrics. Soil organic carbon was
determined in laboratory with VarioMAX analyzer.
Soil organic carbon results
demonstrated a highly erratic behavior
with no statistically significant
differences between the land use
classes. Values are given as Mg*ha-1.
PiP
EuP
MDe
Results:
Aboveground carbon stocks of the plantations were found to
be of the same order of magnitude as those of the miombo
woodlands of native vegetation, whereas land use classes
with low tree cover (Fallow land, Other woody vegetation) had
notably lower figures. Unexpectedly, soil organic carbon
stocks demonstrated no statistically significant difference
between any of the six land use classes. This may be
explained by (i) limited time frame since the land use
conversions or (ii) soil mineralogical properties buffering
carbon stock changes.
OWV
Herbaceous
Shrubs & saplings
FaL
Trees
0
10
20
30
40
Aboveground carbon stock results.
Striped bars represent modelled
components. PiP = Pine plantations;
EuP = Eucalypt plantations; MDe =
Dense miombo; MOp = Open miombo;
OWV = Other woody vegetation, FaL =
Fallow land. Values are given as
Mg*ha-1.
100
Vegetation aboveground carbon
90
Vegetation belowground carbon
80
MOp
Soil organic carbon
70
60
50
40
Plantation growth modelling. Survey
data plotted against existing site index
(SI) curves. Eucalypt plantations (above)
demonstrate the poorest SI, whereas
pine plantations (below) mostly
demonstrate the medium SI.
Total carbon stock results (left).
Relatively high and even soil organic
carbon stocks partially mitigate the
differences between total carbon stocks
of the six land use classes. Striped
bars represent modelled components.
Values are given as Mg*ha-1.
30
20
10
0
FaL
OWV
MOp
MDe
EuP
PiP
*) VITRI, Viikki Tropical Resources Institute, Dept. of Forest Sciences, University of Helsinki, www.helsinki.fi/vitri
**) UEM, Universidade Eduardo Mondlane, Faculdade de Agronomia e Engenharia Florestal, www.uem.mz