Allometry of Biomass and Carbon Stock of Planted
Eucalyptus grandis Forest in Toba Highland
Onrizal
1
, Rudi Hartono
1
and Cecep Kusmana
2
1
Faculty of Forestry, Universitas Sumatera Utara, Jl. Tridharma Ujung No. 1 Kampus USU, Medan, Indonesia
2
Faculty of Forestry, Institut Pertanian Bogor, Bogor, Indonesia
Keywords: Allometry, Forest Biomass, Forest Carbon, Plantation Forest, Toba Highland.
Abstract: Forest plantations are not only for harvesting wood products; however they could play an important role in
climate change mitigation through carbon sequestration and fixation. This research aimed to create the
allometry equation for estimating aboveground biomass and carbon of planted Eucalyptus grandis forest in
Toba Plateau with harvesting method. The research showed that the biomass and carbon stock of planted E.
grandis increased following logarithmic model. The best allometry equations for aboveground biomass and
carbon stock of planted E. grandis were W
AG
= 0.0678D
2.5794
(R
2
98.8%) and C
AG
= 0.0266D
2.6470
(R
2
98.0%), respectively. Therefore, the above ground biomass and carbon storage of planted E. grandis could
be estimated only by measuring tree diameter (D) in the field that it is very beneficial both time and cost in
estimating the carbon storage in the plantation forests.
1 INTRODUCTION
In the global warming issues, carbon absorption by
forest ecosystem receives considerable attention
(Payn et al., 2015). Forests were recorded as main
element of the carbon sink in the global ecosystem
(Romijn, 2015) and they mostly influence the lives
of human societies as well as other organisms.
Forest plantation received significantly attention to
reducing carbon dioxide (CO
2
) from atmosphere
(Payn et al., 2015; Payn et al., 2014).
Forest biomass could provide estimation of
carbon storage in forest vegetation. Based on forest
biometrics, allometry equation can be used to
estimate forest biomass and carbon. In this case, the
validity of carbon estimation (Manuri et al., 2017) in
both natural and planted forest is one important key
in valuing the capacity of forests in mitigating
warming (Ellison et al., 2017). Therefore, it is
important to create the tools or model to estimate the
forest carbon.
Forest plantations in Toba plateau are dominated
with planting Eucalyptus, including E. grandis. The
planted E. grandis forests in Toba highland are
managed by PT Toba Pulp Lestari Tbk (PT TPL) as
raw material for pulping industry. The main
objective of this research was to develop allometric
equation of aboveground biomass and carbon stock
of planted E. grandis forests in Toba plateau, North
Sumatra.
2 MATERIALS AND METHODS
Field research was carried at Tele Sector as part of
PT TPL planted forest concession. The sites
distributed with varied elevation from 1,600 to 1,700
m above sea level. The mean of annual rainfall in the
area was 1,002.2 mm in period of 2005-2006
(PT TPL, 2006). The minimum of monthly rainfall
during this period was 23.2 mm in May, and the
maximum was 166.3 mm in July (Figure 1).
Six study sites were selected at different age-
stand of planted E. grandis forests. Then, 10 plots of
10 x 10 m in each study site were established based
on some guidelines and publications (Heriyanto et
al., 2002; Onrizal, 2004; Onrizal et al., 2005). For
each sub-plot, we measured the stem diameter at
1.3m height (D) and tree height of all trees. After
tree inventory, totally 18 trees were cut using
clipping techniques based on stratified random
sampling with diameter class as the basis of
stratification. The stem of the sample cut trees was
divided into horizons of 1 m long. From each
horizon, a fresh weight of each morphological tree
compartment, i.e. stem, branch, leaf, and flower and
Onrizal, ., Hartono, R. and Kusuma, C.
Allometry of Biomass and Carbon Stock of Planted Eucalyptus grandis Forest in Toba Highland.
DOI: 10.5220/0010102401290131
In Proceedings of the International Conference of Science, Technology, Engineering, Environmental and Ramification Researches (ICOSTEERR 2018) - Research in Industry 4.0, pages
129-131
ISBN: 978-989-758-449-7
Copyright
c
2020 by SCITEPRESS Science and Technology Publications, Lda. All rights reserved
129
fruit, were separately weighed. A small amount
sample of each tree compartment was taken and
dried in an oven at 80
o
C for 48 hours to obtain the
constant dry weight (Onrizal, 2004). Carbon content
of each tree compartment was analyzed by CN
analyzer.
0
20
40
60
80
100
120
140
160
180
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Rainfall (mm)
15.0
15.5
16.0
16.5
17.0
17.5
18.0
18.5
19.0
Temperature Average (oC)
Rainfall
Temp. Average
Figure 1: Distribution of monthly precipitation and
temperature in study site.
In terms of aboveground tree biomass and carbon
were estimated using simple allometry equation in
the form of Y = aX
b
, where Y is dry weight
(biomass) or carbon of tree components, X is
predictor variable (D), a is Y intercept, and b is
regression coefficient.
3 RESULTS AND DISCUSSIONS
Tree diameter (D) of planted E. grandis significantly
increased following the stand age (Figure 2). Based
on carbon content analyses by CN Analyzer showed
that the carbon content of E. grandis tree part was
44.92% of biomass with varying from 36.72 to
54.01% of biomass.
Allometry expressions of each above-ground
morphological tree compartment both biomass and
carbon follows logarithmic function with high
correlation for each part of trees. In this case, the
aboveground biomass and carbon stock of planted E.
grandis were significant correlation to the single
predictor, i.e. tree diameter (D) as shown at Table 1
and 2.
Table 3 shows the allometry coefficients which
were calculated from the allometry relations
between the biomass of various tree compartments
on tree diameter (D) for some tree species in tropical
region. Comparison of planted E. grandis forests
stand’s allometry coefficients obtained with those
reported for some trees shows that the allometry
coefficient “b” of total above-ground biomass for
planted E. grandis forests stand in study area was
comparable to that tropical tree species, such as
general tropical tree species, rubber tree (Hevea
brasiliensis), and non-rubber tree in the tropic.
Figure 2: Tree diameter of planted E. grandis plantation at
Toba plateau followed the stand age.
Table 1: Allometry biomass coefficient (W
n
= a*D
b
) of
every tree-parts of planted E. grandis plantations in Toba
plateau
No
.
Tree part
Coefficient R
2
(%)
R
a
2
(%)
a b
1. Stem 0.0436 2.6883 98.28 98.17
2.
Branch 0.0228 2.0779 82.03 80.90
3. Leaf 0.5775 0.6549 31.73 27.47
4.
Aboveground 0.0678 2.5794 98.80 98.73
Table 2: Allometry carbon stock coefficient (C
n
= a*D
b
)
of every tree-parts of planted E. grandis plantations in
Toba plateau
No. Tree part
Coefficient R
2
(%)
R
a
2
(%)
a b
1. Stem 0.0176 2.7511 97.40 97.24
2. Brach 0.0097 2.0848 83.66 82.64
3. Leaf 0.2167 0.7199 35.08 31.02
4. Abovegroun
d
0.0266 2.6470 98.04 97.92
Table 3: The allometry coefficient of aboveground
morphological compartment biomass on tree diameter (D)
for some tree species in tropical region
T
ree Species
Coefficient*
R
2
a b
1. Rubber tree (H. brasiliensis)
[#]
0.095 2.62 99.6
2
. Non-rubber tree
[#]
0.091 2.59 99.6
3
. E. grandis
[$]
0.068 2.58 98.8
*Allometry coefficients were calculated from the
allometry equation W
x
= a*D
b
,
[#]
= Pamoengkas et al.
(2000);
[$]
= this study
Based on Table 3, the aboveground biomass
(ABG) of planted E. grandis was similar than the
planted forest in tropical lowland region. It means
ICOSTEERR 2018 - International Conference of Science, Technology, Engineering, Environmental and Ramification Researches
130
that the planted E. grandis forest is potential activity
to carbon sequestration in the tropical highland.
4 CONCLUSIONS AND
RECOMMENDATIONS
Based on the results, we were able to provide
allometry equations that it was suitable for
estimating the biomass and carbon stock of E.
grandis plantation forests. Aboveground biomass
and carbon stock of E. grandis plantation forests
showed a very significant relation with tree diameter
at breast height (D) which forms a logarithmic
function. Therefore, the aboveground biomass and
carbon stock of E. grandis plantation forests could
estimate easily.
ACKNOWLEDGEMENTS
We express our gratitude to Director General Higher
Education, National Education Ministry which
funded under PEKERTI grant scheme in Fiscal Year
of 2006 and 2007. We would also like to
acknowledge the PT TPL Tbk officers for their
cooperation and assistance in fieldwork. Special
thanks to Ecology Laboratory, Research Center for
Biology, Indonesia Institute of Sciences for tree
carbon analyses by CN Analyzer.
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Allometry of Biomass and Carbon Stock of Planted Eucalyptus grandis Forest in Toba Highland
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