208
N. Novita et al.
Forest Structure and Composition
Structure and species composition of trees were determined through tree identification and measurement of the diameter at breast height (dbh; 1.30 m height or
10 cm above the area of buttresses or other flared tree bases) of all trees in the
circular plots. The tree size class distribution in forest sites was separated into 10 cm
diameter classes. We also recorded tree status (dead or alive). Live trees with dbh
>2 cm were identified in all circular plots. Samples from plants not identified in
the field were determined at the Indonesian Institute of Science or the Lembaga
Ilmu Pengetahuan Indonesia (LIPI) in Bogor, Indonesia. Based on the field data, we
calculated the mean basal area, tree density, and Importance Values Index (IVI) to
describe relative abundance of each tree species. Species diversity indices were also
calculated, including Shannon’n (H’), Simpson’s reciprocal, and Shannon’s evenness
(H’E) (Sheehan 1984).
Overstory C Stocks: Trees and Oil Palm Vegetation
Allometric equations were used to calculate tree and oil palm biomass. The allometric
equation by Manuri et al. (2014) was selected to estimate tree biomass in forest sites
(Table 10.2). Dead tree biomass was estimated by applying to the allometric equation
used for living tree biomass a correction factor based on dead tree status (BSN 2011).
The allometric equation based on palm height presented by Khasanah et al. (2015)
was chosen to determine oil palm biomass. The palm height was defined as the
trunk height from ground level to the lowest frond in palm canopy (Khasanah et al.
2015). Root biomass in all types of ecosystems was estimated based upon a general
belowground allometric equation provided by Cairns et al. (1997). This was based
Table 10.2 Equations to estimate aboveground biomass in forest and oil palm plantation sites in
Tanjung Puting, Indonesia
C pool
Equation
Factor C conversion
Live tree biomass (kg/tree)
AGB tree = 0.136 * dbh 2.513
0.48
Oil palm biomass (Mg/palm) AGB OP = 0.0939 * H + 0.0951
0.48
Deadwood biomass (kg)
0.48
Status 2
AGB dw = 0.8 * (0.136 * dbh 2.513 )
Status 3
AGB dw = 0.7 * (0.136 * dbh 2.513 )
Root biomass
AGB root = exp (−1.085 + 0.9256 * ln
(AGB OP/tree )
0.39
Woody debris biomass (Mg)
0.50
>7.5 cm diameter
AGB wd = sg * [(µ 2 D 2 )/(8 * L)]
2.5–5.5 cm
AGB wd = sg * [µ 2 * (NQMD 2 )/(8 * L)]
N. Novita et al.
Forest Structure and Composition
Structure and species composition of trees were determined through tree identification and measurement of the diameter at breast height (dbh; 1.30 m height or
10 cm above the area of buttresses or other flared tree bases) of all trees in the
circular plots. The tree size class distribution in forest sites was separated into 10 cm
diameter classes. We also recorded tree status (dead or alive). Live trees with dbh
>2 cm were identified in all circular plots. Samples from plants not identified in
the field were determined at the Indonesian Institute of Science or the Lembaga
Ilmu Pengetahuan Indonesia (LIPI) in Bogor, Indonesia. Based on the field data, we
calculated the mean basal area, tree density, and Importance Values Index (IVI) to
describe relative abundance of each tree species. Species diversity indices were also
calculated, including Shannon’n (H’), Simpson’s reciprocal, and Shannon’s evenness
(H’E) (Sheehan 1984).
Overstory C Stocks: Trees and Oil Palm Vegetation
Allometric equations were used to calculate tree and oil palm biomass. The allometric
equation by Manuri et al. (2014) was selected to estimate tree biomass in forest sites
(Table 10.2). Dead tree biomass was estimated by applying to the allometric equation
used for living tree biomass a correction factor based on dead tree status (BSN 2011).
The allometric equation based on palm height presented by Khasanah et al. (2015)
was chosen to determine oil palm biomass. The palm height was defined as the
trunk height from ground level to the lowest frond in palm canopy (Khasanah et al.
2015). Root biomass in all types of ecosystems was estimated based upon a general
belowground allometric equation provided by Cairns et al. (1997). This was based
Table 10.2 Equations to estimate aboveground biomass in forest and oil palm plantation sites in
Tanjung Puting, Indonesia
C pool
Equation
Factor C conversion
Live tree biomass (kg/tree)
AGB tree = 0.136 * dbh 2.513
0.48
Oil palm biomass (Mg/palm) AGB OP = 0.0939 * H + 0.0951
0.48
Deadwood biomass (kg)
0.48
Status 2
AGB dw = 0.8 * (0.136 * dbh 2.513 )
Status 3
AGB dw = 0.7 * (0.136 * dbh 2.513 )
Root biomass
AGB root = exp (−1.085 + 0.9256 * ln
(AGB OP/tree )
0.39
Woody debris biomass (Mg)
0.50
>7.5 cm diameter
AGB wd = sg * [(µ 2 D 2 )/(8 * L)]
2.5–5.5 cm
AGB wd = sg * [µ 2 * (NQMD 2 )/(8 * L)]