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The 3rd International Symposium for Sustainable Humanospphere (ISSH) A Forum of Humanospphere Science School (HSS) Bengkulu, 17 -18 September 2013

POTENTIAL OF

BIOMASS

AND

SPATIAL

DISTRIBUTION

OF

Correspponding author *

FOREST PLANTATION OF HYBRID EUCALYPTUS

Siti Latifah

Forestry Study Program, Faculty of Agriculture, University of North Sumatera, Jalan Tri Darma Ujung No. 1

USU, Medan 20155, Indonesia

Abstract

The purpose of this research was to estimate and determine the distribution ofbiomass in the forest of Hybrid Eucalyptus . The allometric equation was then developed based on growth dimension, i.e. the diameter. The research was conducted at the stands in year 0.3 up to 7 and 14 Hybrid Eucalyptus, in Industrial Plantation Forest of PT.Toba Pulp Lestari (PT.TPL) in Aek Nauli District, North Sumatera. The potency of biomass were estimated from direct measurement using destructive technique. Spatial distribution of biomass using geospatial technology. Results showed that hybrid Eucalyptus had an average above-ground biomass are 24,304 tons/ha. Criteria for low biomass ,

medium and high in each compartmen, resppectively

for 0 - 8 t / ha; 9 - 17 t / ha and 18 - 26 t / ha. Criteria for low biomass has the largest persentase is 84.5% and also has the largest area is 1,874, 3 ha. As for the medium and high biomass criteria each have a percentage 12.69% and 2.76% resppectively with an area of 281.3 ha and 61.2 ha

Introduction

Greenhouse gases may lead to an increased warming of the Earth or human-initiated global climate change. Vegetation acts as a sink—a natural storage area—for carbon dioxide by storing it over time through the process of photosynthesis. As burning occurs, it can release hundreds of years worth of stored carbon dioxide into the atmosphere in a matter of hours, This causes solar energy being trapped within earth atmosphere (Cruz et al. 2007). This change in global climate would affect forestry and agricultural sector (Anderson et al. 2011).

.

Key words

:

Hybrid Eucalyptus, biomass, forest, plantation, sppatial distribution

In relation with forest ability to absorb carbon, emission trade or carbon trade constitutes a new paradigm in forestry sector and could become opportunity for Indonesia which is a developing country, to obtain foreign exchange from this sector. Forests are carbon stores, and they are carbon dioxide sinks when they are increasing in density or area. Tropica warming until all available land has been reforested with mature forests.

One of the efforts to minimize impacts from climate change is stabilizing the CO concentration in atmosphere. This is related with forest ability to absorb CO from atmosphere, and then store it in forest stand in the form of organic matter or plant biomass. Therefore, potency of forest in carbon absorption could be estimated through calculation of plant biomass, because half of the biomass comprise carbon (IPCC 2001).

Eucalypt is one of the plant species which has potency in development of industrial plantation forest (Mindawati 2010), and has opportunity to produce carbon within rotation period (cutting cycle) which is considerably short(7-10 years) from growth process of the the planted trees .

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the future. Sustainable forest would have potential of environmental service to sequester carbon in increasing amount and duration in accordance with the determined rotation time

Materials and Methods / Experimental

The study was conducted in Aek Nauli sector of the Industrial Timber Estate (Hutan Tanaman

Industri - HTI) namely, PT. Toba Pulp Lestari(PT. TPL), and Laboratory of Forest Inventory,

Forestry Study Program, Faculty of Agriculture, University of North from May – August 2012. PT. TPL has an area 189,975 ha. Research activities were focused on obtaining reliable model to estimate above ground biomass in hybrid eucalypt stand at 0.3 up to 7 and 14 years of age.

Equipments being used in this research were measurement tape, hypsometer, and chainsaw. Materials being used in this research were stems, branches, leaves, and shoots of Eucalyptus. Measurement plot (sample plot) being used in this study had the size of 30 × 20 m ( 6 sample plot for each age class) and distance between sample plot were 10 × 10 m. Placement of sample plot was conducted by

systematic sampling with random start. The collected data comprise diameter at breast height (dbh),

branch free height, area size of crown section, and total tree height. Measurement of undergrowth vegetation was conducted at sub plots, measuring 2 × 2 m, within the sample plots.

Harvesting of biomass carbon stock is generally derived from the quantity of above ground biomass by assuming that 45% of the biomass value is composed of carbon (Onrizal 2004). Method which is most accurate is through destructive approach by cutting down trees and weighing all parts of the tree. Such destructive approach is frequently used to validate other method which tend to be less disturbing and requires low cost, such as carbon stock estimation by in situ non destructive and remote sensing measurement (Clark et al. 2001; Hua et al. 2007). Selected sample trees (3 trees for each age class) were cut down and their diameter measured at points of 0, 0.3, 1.3, 3.3, 5.3, 7.3, and 9,3 m above ground surface, and afterwards there was separation of tree parts into stems, branches, and leaves. Weighing was conducted for all tree parts. In stem part, there were data collection on length and fresh weight per section, whereas in branches, leaves, and shoots there were data collection on fresh weight. Litters and undergrowth vegetation were collected and classified into particular parts, and their fresh weight were measured

Characteristics of sample trees. All wood test samples were weighed for determining their fresh weight, and were subsequently dried in oven at temperature of 103 OC ± 2 OC for determining their dry weight. Percentage of water content (WC) was calculated with the following formula:

.

% WC =(( FW – ODW )/ ODW ) x 100% (1)

Note

% WC = percentage of water content

ODW = oven dry weight of test sample (g)

FW = fresh weight of test sample (g)

Density of wood test samples need to be known to calculate biomass of stem parts through approach of wood density with the following formula (Haygreen & Bowyer 1986):

D = M/V (2)

note:

D = density of wood test sample (kg m-3)

M = oven dry mass of wood test sample (kg)

V = air dry volume of wood test sample (m3)

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ODW = FW x [ 1 + (% 𝑊𝑊𝑊𝑊)

100 ] (3)

Note :

ODW = oven dry weight of test sample (g)

FW = fresh weight of segment of eucalypt tree (g) % WC = percentage of water content

Biomass of undergrowth vegetation and litter was calculated with the following formula:

DW tot = [ ( FW tot/DW ts)/ (FW ts/S area) ] (4)

note:

Dwtot = total dry weight (kg m-2) FWtot = total fresh weight (kg)

DWts= dry weight of test sample (g) FWts= fresh weight of test sample (g) Sarea= area size of sample (m2)

Forest biomass could be used to estimate carbon content within forest vegetation because 45% of the biomass is composed of carbon.So, the amount of carbon stock is equal 0.45 of the biomass (Onrizal 2004). Carbon sequestration (Co ) could be estimated with the fo llowing formula (Bismark et al. 2008):

Sequestration of CO2 =( Mr CO2/Ar C ) = 3.67 × carbon content [5]

Note :

Mr = molecule relative

Ar = atom relative

Reliability test of biomass model. Reliability test of a model is conducted by utilizing criteria to determine the best model in allometric model estimation. All equations were tested to determine which one is the best predictor of biomass for Hybrid Eucalyptus (Kuswadi,2004). The best model is the one which gives the largest coefficients of determination (R2) and coefficients of correlation (r), aggregative deviation percentage (AgD) < 1%, and average deviation percentage (AvD) > -1% and < 10%. Selection of model also considers the simplicity of model and their practicability to be used in the field (Catahan 2008).

Biomass Potential mapping

Live tree biomass estimates are essential for carbon accounting, bioenergy feasibility studies, and other analyses. Several models are currently used for estimating tree biomass on the basis of measurement of sample trees, there was construction of model which described the relationship between biomass and several variables. Several allometric models of biomass estimator were tried to

. Sppatial distribution of biomass and carbon storage potential is done by mapping potential stand biomass and carbon storage of Hybrid Eucalyptus. Prediction models based on carbon storage (Latifah, 2011). With allometric models of the Eucalyptus biomass will be obtained based on the data distribution of the potential biomass compartments. Then the value of the biomass can be calculated potential carbon storage in each of the Eucalyptus sppecies. Data values of biomass and carbon storage potential are then included in the map area of industrial forest plantations, so the final result is obtained in the form of a map of potential biomasaa stands of Hybrid Eucalyptus .

Results and Discussion

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obtain the best model for biomass estimation. Each tree sppecies is associated with a set of local volume and biomass equations. Although the particular form of the equations may differ, the biomass calculation of major aboveground biomass components is similar to that for Eucalyptus sppecies. Regional equations produce biomass estimates sppecific to each sppecies and separated into major aboveground components.

In terms of model application, alometric equation is specific for a particular species and location, so that allometric equations could not be compared across different sppecies and locations. However, in terms of composition of variables and forms of equation, various allometric equation could be compared to obtain the best model (Wenbo, 2007). Basically a good model is that which is simple enough, easy to be analyzed and easy to be applied. Apart from those, models should have considerably high accuracy of estimation (Latifah, 2000). In general, the selected model for each variable being tested, had good performance. On the basis of statistical analysis, it was obtained that allometric model Y = 1,351.09x 0.876. e (0.094x) had the best performance. This allometric model possessed R² value as large as 98,29%, r as large as 0.9849, AgD as large as 0,08%, and AvD as large as -0.28%. Therefore, this model fulfilled the requirement as a reliable model. Catahan (2008) stated that a model is categorized as reliable if the aggregative deviation percentage (AgD) < 1% and -1 % < AvD < 10%. Besides statistical consideration, according to Catahan (2008), the choice of best equation model should also consider the factor of practicability, efficiency, and ease in the collection of independent variable data in the equation.

Average deviation and aggregate deviation were used to measure the accuracy of a model. The smaller the values of AgD and AvD the more accurate would be the model. The value of AgD as large as 0.08% showed that the percentage of difference between value of estimation result and value of biomass measurement result of hybrid eucalypt was 0.08. On the other hand, value of AvD as large as -0.28% showed that average value of biomass estimation of hybrid eucalypt deviated as large as 0.28 from average value of their measurement result. Allometric model Y = Y = 1,351.09x 0.876. e (0.094x) had possessed good value, while its AgD and AvD were in conformity with the determined criteria.

Potential ofBiomass Hybrid Eucalyptus

Forests are a significant part of the global carbon cycle. Forests sequester carbon by conducting photosynthesis,which is the process of converting light energy to chemical energy and storing it in the chemical bonds of sugar. Carbon sequestration through forestry has the potential to play a significant role in ameliorating global environmental problems such as atmosppheric accumulation of GHG's and climate change. In relation with forest ability to absorb carbon, emission trade or carbon trade constitutes a new paradigm in forestry sector and could become opportunity for Indonesia which is a developing country, to obtain foreign exchange from this sector. Therefore, potency of forest in carbon absorption could be estimated through calculation of plant biomass, because half of the biomass comprise carbon (IPCC 2001).

Eucalyptus spp have been selected by PT. TPL as species at their forest plantations

because it is one of the species, which produces quality sample plotlpwood for paper and newspprint making. The biology of Eucalyptus is well known, seed of well-documented origin is available, nursery practices and silviculture are well defined and result is fairly predictable (Higman, et al. 2005). Even the mention of the results of analysis of wood sample plot material that best comes from the eucalyptus because of high levels of cellulose were conceived and pretty good tear resistance . Hybrid

Eucalyptus constitute the species which are developed as sample plotlp industry raw materials, in large

scale in PT. Toba Pulp Lestariwith cutting cycle (rotation) of 7-8 years. The results showed that. hybrids produced the highest increment of 289 m3/ha , while the lowest increment generated by E. pellita of 116 m3/ha ( Latifah , 2009) . Total Potential of biomass

Industrial Plantation Forest ( HTI ) PT . Toba Lestari Tbk . in Aek Nauli sector have four types of Eucalyptus spp and has a diversity of age classes are very diverse . In different types and age classes of stands of Eucalyptus spp are able to influence the content of the biomass on each stand

Eucalyptus spp . Table 1 indivatet that the variability in averagel above ground biomass, carbon

storage and

Hybrid Eucalyptus are shownin

Table 1 .

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explained that the total biomass is by summing biomass existing trees within compartment. The total potential of biomass Hybrid Eucalyptus is about 1102.7389 Ton with average of biomass is 24,3 t/ha. The difference in the biomass of forest stands was caused by differences in site quality and the types of clones eucalyptus. Site quality, in the context of timber management, can be defined as “ the timber production potential of a site for a particular species or forest type.” The words “ good” and “poor” are frequently used modifiers of site quality and simply imply a high productive potential as opposed to low potential. Genes are the basis for all biodiversity. A major reason for the differences between ecosystems is the differences in their species composition. Similarly, differences among species are due to differences in their genes. Among individuals of a species there is also variability in genes. Besides environment, heredity also affects tree growth. In a forest plantation, however, if the seeds used in forest planting are collected from stands considered significant in genetic variation, this factor is also considered as not constant (Nambiar and Alan, 1997). In addition, due to different total land area of compartment, and also differences in the number of trees in each compartment . This factor also affects the difference in carbon storage and carbon sequestration .

Types of Hybrid Eucalyptus has the most age classes ie 9 age classes include age 0.3 years , 1 year , 2 years , 3 years , 4 years , 5 years , 6 years old 7 years and 14 years . Hybrid eucalyptus with 1 year age class has the most extensive land area compared to other age classes is 877.3 ha of the total study area, and the lowest area is 14 year age class with area 0,6 ha

Table 1. Potential of biomass, carbon storage and carbon sequestration in various age

Age

Hybrid eucalyptus 3 year age class had the greatest total biomass is 349.7 tons . This suggests that hybrid eucalypytus 3 year age class have large biomass and carbon storage than other young age, namely 0.3, 1 and 2 years. However , at the age classes 1 and 2 years of Hybrid eucalyptus has a high value of total biomass is 249.9 tons and 1249.4 tons . This is due to eucalyptus is a kind of hybrid clones were cultivated into producing seeds in Industrial Plantation Forest. Hybrid eucalyptus has a high total biomass so much more in carbon sequestration .

Spatial Distribution of Biomass of Hybrid Eucalyptus

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urophylla. Besides eucalyptus species, pine species are also found in several compartments. However, in this study, we focused on eucalyptus.

In this study, Hybrid Eucalyptus has the highest total biomass due to the dominate species in the area. Eucalyptus dominate the sector compartments in Aek Nauli is about 270 compartments

Biomass (t/ ha)

. Biomass classification using the program ArcView are shown in table 2. Biomass criteria of low, medium and high , resppectively for 0 - 8 t / ha ; 9 up to 7 t / ha and 18 up to 26 t / ha. The majority of the areas in study site has biomass class 0 up to 8 t/ha with 1.874 ha or 84,55 % of total study site, followed by the biomass class 9 – 17 t/ha with 281,3 ha or 12,69 % of total study site, biomass clas 18- 26 t/ha with 61, 2 ha or 2,76 % of total study site. Biomass distribution of Hybrid eucalyptus in Aek Nauli sector is depicted in Table 2

Table 2 . Biomass distribution in each compartment of Hybrid Eucalyptus

Aera

(Ha) Percentage Criteria

0 s/d 8 1.874,30 84,55% Low 9 s/d 17 281,30 12,69% Medium 18 s/d 26 61,20 2,76% High

Total 2.216,80

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Figure 1. Map of biomass Hybrid Eucalyptus in Aek Nauli Sector, North Sumatera Indonesia

Conclusion

The allometric model Y = Y = 1,351.09x 0.876. e (0.094x) is selected as the best models for estimate biomass of hybrid eucalyptus. The total potential of biomass Hybrid Eucalyptus in study site is about 1102.7389 Ton with average of biomass is 24,3 t/ha. The difference in the biomass of forest stands was caused by differences in site quality, the types of clones eucalyptus, land area in ech compartmen, number of trees, and the average diameter of trees in each compartment.

Acknowledgment

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Bismark M, Heriyanto NM, Sofian I. 2008. Biomassa dan kandungan karbon pada hutan produksi di cagar biosfer Pulau Siberut, Sumatera Barat. Jurnal Penelitian Hutan dan Konservasi Alam. 5(5):397–407.

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Latifah S. 2009. Growth and yield models for eucalyptus species using geospatial technology in Aek Nauli, North Sumatra Province, Indonesia. [disertasi]. Philippines: University of the Philippines Los Baños.

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Wenbo C, Xiaofan Z. 2007. Estimation of forest parameters based on TM imagery and statistical analysis. Journal of Forest Research 18(3):241–244.

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Gambar

Table 1. Potential of biomass, carbon storage and carbon sequestration  in various age of hybrid eucalyptus
Table 2 . Biomass distribution in each compartment of Hybrid Eucalyptus
Figure 1. Map of biomass  Hybrid Eucalyptus in Aek Nauli Sector, North Sumatera Indonesia

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