10 Carbon Stocks from Peat Swamp Forest and Oil Palm Plantation …
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on an assumption that root: shoot ratio of oil palm plantation is equal to another
tree vegetation (Jourdan and Rey 1997). Vegetation C mass was calculated from
biomass by multiplying by a factor of 0.48 and 0.39 for vegetation and root biomass,
respectively (Kauffman and Donato 2012).
Symbols used in the equations area: AGB = Aboveground biomass, dbh = diameter at breast height (cm), H = height of the palm (m), sg = specific gravities (g/cm
3 )
to convert volume to downed wood biomass are from Chao et al. (2008). Sg for solid
and rotten woody debris are 0.5 and 0.23, respectively. N = number of pieces of
woody debris pieces, QMD = quadratic mean diameter of size class (cm), and L =
the transect length (m).
Litter and Understory
Litter and understory biomass were determined through destructive sampling. In
each circular plot, we harvested litter and understory vegetation from two 56 cm ×
56 cm microplots. Litter consisted of leaves, flowers, fruits, bark fragments, seeds,
and small twigs/woody stems. All plant samples were placed in a bag and transported
to the laboratory where they were oven-dried to a constant mass at 60 °C and then
weighed. The organic carbon content of the litter and understory were determined by
the induction furnace method with a Carbon Nitrogen Analyzer (LECO Corporation,
St. Joseph, Michigan, USA) in the Soil Biotechnology laboratory, Bogor Agricultural
University, Indonesia. The litter C content in the oil palm plantation was estimated
based on Khasanah et al. (2015) study.
Downed Wood
The mass of downed wood was measured using the planar intersect technique
(Kauffman et al. 2016; Kauffman and Donato 2012). At the center of each circular
plot, four 12 m transects were established diagonally at 45° off the main transect
(Figs. 2 and 3). Along each transect, coarse downed wood (diameter >7.5 cm) was
measured from 2 to 12 m and fine downed wood (diameter 2.5–7.5 cm) was measured
from 2 to 7 m. Coarse downed wood was separated into sound and rotten classes.
Fine downed wood was only counted. A quadratic mean diameter (QMD) was used
to estimate volume of the fine downed wood (Kauffman et al. 2016). We used data
of the specific gravity of downed wood reported by Chao et al. (2008). Volume and
specific gravity of downed wood were multiplied to estimate biomass. The biomass
was multiplied by a factor of 0.50 to estimate downed wood C mass (Kauffman and
Donato 2012).
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on an assumption that root: shoot ratio of oil palm plantation is equal to another
tree vegetation (Jourdan and Rey 1997). Vegetation C mass was calculated from
biomass by multiplying by a factor of 0.48 and 0.39 for vegetation and root biomass,
respectively (Kauffman and Donato 2012).
Symbols used in the equations area: AGB = Aboveground biomass, dbh = diameter at breast height (cm), H = height of the palm (m), sg = specific gravities (g/cm
3 )
to convert volume to downed wood biomass are from Chao et al. (2008). Sg for solid
and rotten woody debris are 0.5 and 0.23, respectively. N = number of pieces of
woody debris pieces, QMD = quadratic mean diameter of size class (cm), and L =
the transect length (m).
Litter and Understory
Litter and understory biomass were determined through destructive sampling. In
each circular plot, we harvested litter and understory vegetation from two 56 cm ×
56 cm microplots. Litter consisted of leaves, flowers, fruits, bark fragments, seeds,
and small twigs/woody stems. All plant samples were placed in a bag and transported
to the laboratory where they were oven-dried to a constant mass at 60 °C and then
weighed. The organic carbon content of the litter and understory were determined by
the induction furnace method with a Carbon Nitrogen Analyzer (LECO Corporation,
St. Joseph, Michigan, USA) in the Soil Biotechnology laboratory, Bogor Agricultural
University, Indonesia. The litter C content in the oil palm plantation was estimated
based on Khasanah et al. (2015) study.
Downed Wood
The mass of downed wood was measured using the planar intersect technique
(Kauffman et al. 2016; Kauffman and Donato 2012). At the center of each circular
plot, four 12 m transects were established diagonally at 45° off the main transect
(Figs. 2 and 3). Along each transect, coarse downed wood (diameter >7.5 cm) was
measured from 2 to 12 m and fine downed wood (diameter 2.5–7.5 cm) was measured
from 2 to 7 m. Coarse downed wood was separated into sound and rotten classes.
Fine downed wood was only counted. A quadratic mean diameter (QMD) was used
to estimate volume of the fine downed wood (Kauffman et al. 2016). We used data
of the specific gravity of downed wood reported by Chao et al. (2008). Volume and
specific gravity of downed wood were multiplied to estimate biomass. The biomass
was multiplied by a factor of 0.50 to estimate downed wood C mass (Kauffman and
Donato 2012).