Ecology and Development Series No. 28, 2005 

Editor-in-Chief: 

Paul L.G.Vlek 

Editors: 

Manfred Denich 

Christopher Martius 

Charles Rodgers 

Nick van de Giesen 

Syahrinudin 

The potential of oil palm and forest plantations for carbon 

sequestration on degraded land in Indonesia 

Cuvillier Verlag Göttingen 
ABSTRACT 

Terrestrial ecosystems play an important role in regulating the abundance of 

atmospheric carbon dioxide (CO2). Plantations of trees and perennial crops on degraded 

and marginal lands are an effective way of enhancing the build up of the terrestrial 

carbon (C) pool. The aim of this study is to quantify the potential of C sequestration 

through the conversion of Imperata cylindrica grasslands into oil palm and Acacia 

mangium plantations. Research was conducted in Sumatra and East Kalimantan 

(Indonesia). Total C stored in the systems (both below- and aboveground) was 

determined with destructive sampling techniques and the rate of C sequestration 

estimated with the false-time-series approach. Imperata cylindrica grasslands produce 

only a relatively small amount of biomass C (5.9-7.6 Mg ha-1) and have shallow roots 

(maximum depth 1.8 m) and, therefore, only a low level of soil carbon storage can be 

expected in this system. Biomass and biomass C of both oil palm and A. mangium

plantations increase with age to a level much higher than that of I. cylindrica grassland. 

In the oil palm plantations, rates are 84.4 and 76.8 Mg ha-1 5 m-1 in biomass and soil, 

respectively, while in A. mangium plantations 78.5 and 157.7 Mg C ha-1 5 m-1, 

respectively, can be achieved. Furthermore, the deep penetration of the roots (to a depth 

of 5 m) in these plantations promotes a substantial amount of C sequestration in the 

deeper soils. Soil C storage increases with plantation age to almost twice that of I. 

cylindrica grassland, suggesting that the establishment of plantations is beneficial not 

only in terms of C sequestration but also in terms of land rehabilitation. Although the 

magnitude of biomass C in the plantations is quite comparable, due to the longer period 

for the sequestration (plantation cycle of 9 and 30 years for the A. mangium and oil 

palm plantations, respectively), the rate of C sequestration in the biomass of the oil 

palm plantation is much lower (3.4 and 9.3 Mg ha-1 yr-1 for the oil palm and A. 

mangium plantations, respectively). However, there is a significant difference in the 

soil-C sequestration in these plantations (17.5 and 2.6 Mg ha-1 5 m-1 yr-1 for the A. 

mangium and oil palm plantations, respectively). Of the C stored in the systems, 81.2 

and 76.9% of the total C of the A. mangium and oil palm plantations, respectively, is 

assigned to the belowground C pool (soil and belowground biomass C) to a depth of 5 m. 

In I. cylindrica grassland, this value is 98.0%. Regardless of the difference in magnitude 

and distribution of the C sink, it is evident that oil palm and A. mangium plantations can 

play an important role in sequestering atmospheric CO2. The conversion of marginal 

land (mainly I. cylindrica grasslands) into such plantations should thus be encouraged. 

 
Das Potential von Ölpalmen- und Waldplantagen zur Kohlenstoffspeicherung auf degradierten Böden in Indonesien 

KURZFASSUNG 

Terrestrische Ökosysteme spielen eine wichtige Rolle bei der Regulierung der Menge 

von atmosphärischem CO2. Baumplantagen und der Anbau von Dauerkulturen auf 

degradierten Böden oder Marginalland sind wirksame Möglichkeiten, den terrestrischen 

C-Pool zu erhöhen. Die Studie in Sumatra und Ost-Kalimantan quantifziert das 

Potential der C-Speicherung durch die Umwandlung von Imperata cylindrica-Grasland 

in Ölpalmen- und Acacia mangium-Plantagen. Der Gesamtkohlenstoff im System 

(unter- und oberirdisch) wurde mit destruktiven Beprobungsmethoden und die CSpeicherungsrate in einer ‚falschen Zeitreihe’ bestimmt. Imperata cylindrica-Grasland 

produziert nur eine geringe Menge Biomasse-C (5.9-7.6 Mg ha-1). Aufgrund der relativ 

flachen Durchwurzelung (maximale Tiefe 1.8 m) ist in diesem System nur eine geringe 

Boden-C-Speicherung zu erwarten. Biomasse und Biomasse-C von Ölpalmen- bzw. A. 

mangium-Plantagen nehmen mit deren Alter auf ein Vielfaches der Menge in I.-

cylindrica-Grasland zu. In Ölpalmenplantagen erreichen die Werte 84.4 bzw. 76.8 Mg 

ha-1 5 m-1 in Biomasse bzw. Boden und in A. mangium-Plantagen 78.5 bzw. 157.7 Mg C 

ha-1 5 m-1. Außerdem führt das tiefe Wurzelwerk dieser Plantagen zu einer deutlichen 

Erhöhung der C-Speicherung in den tieferen Bodenschichten. Der Boden-C-Gehalt 

erreicht mit zunehmendem Alter der Plantage fast das Doppelte der Menge im I.-

cylindrica-Grasland, was darauf hindeutet, dass Plantagen nicht nur hinsichtlich der CSpeicherung sondern auch im Hinblick auf Landrehabilitation vorteilhaft sind. Obwohl 

der in der Biomasse gespeicherte Kohlenstoff in beiden Plantagensytemen vergleichbar 

ist, ergibt die längere Rotationszeit (30 Jahre bei der Ölpalmenplantage gegenüber 9 

Jahre für die A. mangium-Plantage) eine erheblich niedrigere C-Speicherungsrate in der

Ölpalmenplantage (3.4 bzw. 9.3 Mg ha-1 Jahr-1 für Ölpalmen- bzw. Acacia mangiumPlantage). Der Unterschied in der C-Speicherung im Boden ist beträchtlich: 17.5 und 

2.6 Mg ha-1 5 m-1 Jahr-1 für die A. mangium- bzw. Ölpalmenplantagen). Von dem 

Gesamtkohlentsoff der Plantagensysteme werden 81.2 (A. mangium) bzw. 76.9% 

(Ölpalmen) im unterirdischen C-Pool (Boden und unterirdische Biomasse) bis zu einer 

Bodentiefe von 5 m gespeichert. In I. cylindrica-Grasland sind es 98.0%. Unabhängig 

vom Unterschied in der Menge und Verteilung der C-Speicherung wird deutlich, dass 

Ölpalmen- und. Acacia mangium-Plantagen einen Beitrag zur Festlegung von 

atmosphärischem CO2 leisten könnten. Die Umwandlung von Marginalland 

(hauptsächlich I. cylindrica-Grasland) in derartige Plantagen sollte daher gefördert 

werden. 
TABLE OF CONTENTS 

1 INTRODUCTION................................................................................................ 1 

2 SITE DESCRIPTION........................................................................................... 5 

2.1 Sumatra .................................................................................................... 5 

2.2 East Kalimantan........................................................................................ 6 

3 IMPERATA CYLINDRICA GRASSLANDS: BIOMASS AND CARBON 

DISTRIBUTION.................................................................................................. 9 

3.1 Introduction .............................................................................................. 9 

3.2 Methodology .......................................................................................... 11 

3.3 Results and discussion ............................................................................ 12 

3.4 Conclusions ............................................................................................ 17 

4 ACACIA MANGIUM PLANTATIONS............................................................... 18 

4.1 Introduction ............................................................................................ 18 

4.2 Methodology .......................................................................................... 19 

4.3 Results and discussion ............................................................................ 21 

4.3.1 Biomass distribution............................................................................. 21 

4.3.2 Root distribution .................................................................................. 26 

4.3.3 Biomass carbon distribution ................................................................. 32 

4.3.4 Soil carbon distribution ........................................................................ 40 

4.3.5 Carbon distribution in Acacia mangium plantation system.................... 44 

4.4 Conclusions ............................................................................................ 46 

5 OIL PALM PLANTATIONS ............................................................................. 47 

5.1 Introduction ............................................................................................ 47 

5.2 Methodology .......................................................................................... 48 

5.3 Results and discussions........................................................................... 50 

5.3.1 Biomass distribution............................................................................. 50 

5.3.2 Root distribution .................................................................................. 55 

5.3.3 Biomass carbon distribution ................................................................. 62 

5.3.4 Soil carbon distribution ........................................................................ 69 

5.3.5 Carbon distribution in oil palm plantation systems ............................... 75 

5.4 Conclusions ............................................................................................ 77 

6 SUMMARY AND GENERAL DISCUSSION................................................... 79 

6.1 Biomass distribution ............................................................................... 79

6.2 Root distribution..................................................................................... 80

6.3 Carbon distribution ................................................................................. 85 

7 CONCLUSIONS AND RECOMMENDATIONS .............................................. 93 

7.1 Conclusions ............................................................................................ 93 

7.2 Recommendations................................................................................... 94 

8 REFERENCES .................................................................................................. 96 

ACKNOWLEDGEMENTS 
Introduction 

1

1 INTRODUCTION 

Climate change and global warming are among the most challenging environmental, 

economic and social issues worldwide. Global temperatures have increased by 0.3-

0.6 °C over the past 100 years and are expected to increase by a further 1-3.5 °C by 

2100, accompanied by changes in precipitation, storm patterns, and drought frequency 

and intensity (Santer et al. 1996; Kattenberg et al. 1996). Global warming, which has 

been associated with an unprecedented increase in atmospheric greenhouse gas 

concentrations, is expected to lead to negative impacts on valuable ecosystems, 

increased intensity and frequency of heat waves, and other climatic-related disasters as 

well as crop failures and freshwater scarcity. 

One of the most prominent anthropogenic-induced greenhouse gases is carbon 

dioxide (CO2), contributing to more than 51% of the global warming. The level of 

atmospheric CO2 has increased from 280 ppm in 1800 to a present more than 360 ppm. 

The atmosphere now contains about 760 Pg of carbon (C) as CO2. The annual global 

CO2 emission in the 1990s was 6.3 ±0.4 Pg C yr-1 (1 Pg = 1015 g). While most was 

derived from the burning of fossil fuel (IPCC 2001), land-use change, mainly tropical 

deforestation, also contributed an estimated 1.6 Pg C yr-1 (Houghton 1999). However, 

atmospheric C represents less than 30% of the C in terrestrial ecosystems. Vegetation 

contains nearly 500 Pg C, while soils contain another 2000 Pg C in form of organic 

matter and detritus (Schimel 1995; WBGU 1998; IPCC 2000). 

Terrestrial ecosystems play an important role in regulating the abundance of 

atmospheric CO2. Of the 406 Pg of C emitted during the period 1850 to 1998, 270 Pg C 

were derived from fossil fuel combustion and cement production, and 136 Pg C were 

emitted through land-use activities (IPCC 2000). Of these emissions, roughly 110 Pg C 

were absorbed back into terrestrial ecosystem sinks and about 120 Pg C were absorbed 

by oceans. The rest (176 Pg C) accumulated in the atmosphere. Thus, it is evident that 

there is a need to reduce atmospheric CO2, and other greenhouse gases (GHGs) and that 

policy measures must take into account the role of terrestrial ecosystems (IPCC 2000). 

There are great opportunities in forestry, agriculture, and other sectors for 

mitigating further increases in the atmospheric C pool. The options vary by social and 

economic conditions. Slowing or halting deforestation, improved natural forest 
Introduction 

2

management practices, afforestation, and reforestation of degraded forests and 

wastelands are the most attractive opportunities in the forestry sector (IPCC 2001). All 

activities leading to the preservation or enhancement of the existing terrestrial C pools, 

or to the prevention of an increase in atmospheric C pools such as the use of biomass to 

offset fossil fuel use should be the main focus of GHG mitigation projects. Some 

practical examples of mitigation strategies include fire or insect control, forest 

conservation, establishing fast-growing stands, changing silvicultural practices, planting 

trees in urban areas, ameliorating waste management practices, managing agricultural 

lands to store more C in soils, improving management of grazing lands, and replanting 

grasses or trees on cultivated lands (IPCC 2001). 

In the case of terrestrial C sinks, a forest ecosystem transforms atmospheric 

CO2 into C stock components (trees, roots, other vegetation, litter, and soil organic 

matter). Even though C stored in forests may ultimately be released through natural or 

anthropogenic disturbances, forest-C sequestration has been identified as one of the 

most promising options to reduce the build-up of atmospheric CO2 (Dixon et al. 1993; 

Sampson and Sedjo 1997; Marland and Schlamadinger 1999). IPCC (1996) estimated 

that 700 Mha of forestland might be globally available for C conservation. Of that, 138 

Mha might be available for slowed tropical deforestation, 217 Mha for regeneration of 

tropical forests, and 345 Mha for plantations and agroforestry. By 2050, a cumulative 

mitigation impact of 60 to 87 Pg C due to improved forest management could be 

expected, 45 to 72 Pg C of this is likely to occur in the tropics. Towards the end of this 

time interval, the mitigation impact could approach a maximum rate of 2.2 Pg C/yr 

(IPCC 2001). 

Notwithstanding the debate as to whether global forests are sources or sinks of 

greenhouse gases (Pelley 2003; Harmon 2001; Metting et al. 2001; Schimel et al. 2001; 

Lal and Singh, 2000; Ravindranath et al. 1997), managed fast-growing forests may 

enhance C sequestration (Lee et al. 2002; Ney et al. 2002; Metting et al. 2001; 

Papadopol 2000). Silvicultural strategies aiming at accelerating the stand growth are 

likely to increase the rate of C sequestration of the respective forests (Lee et al. 2002; 

Chen et al. 2000; Montagnin and Porras 1998). 

Plantation of trees and perennial crops on degraded and marginal lands is 

likely to be an effective way to enhance the build-up of terrestrial C pools. These 
Introduction 

3

plantations promote C sequestration not only in the biomass but also in deep soils. 

However, there is little information on the potential C sink that could be attained by 

conversion of degraded lands (such as Imperata cylindrica grasslands) into specific tree 

plantations such as Acacia mangium and oil palm. 

About 7.5-8.5 million ha of I. cylindrica grasslands are distributed on various 

islands in Indonesia (Garrity et al. 1997; Soekardi et al. 1993), an area that has been 

identified to have low economic and ecological values. In line with the extensive 

expansion of oil palm and forestry plantations (mainly in Sumatra and Kalimantan) 

planned by the government, conversion of these lands into plantations would be a 

promising option. 

The oil palm as a perennial crop has become important in Indonesia, firstly, as 

a major source of oils and fats for human food, secondly, as animal feeds, and thirdly, 

for the manufacture of many domestic products such as cosmetics, soap and detergents. 

The establishment of large-scale monoculture oil palm plantations in Indonesia began in 

1985 over an area of about 600.000 ha. In 1999, the area had expanded to about 3 

million ha (Glastra et al. 2002; Wakker 2000). 

Plantations of fast-growing species have been rapidly increasing in Asia in 

recent years (Cossalter and Pye-Smith, 2003). Acacia mangium is one of the most 

common fast-growing species in the humid tropics. Acacia mangium used to be planted 

primarily for site rehabilitation; however, due to its rapid growth and tolerance of very 

poor soils, this species is playing an increasingly important role in efforts to sustain 

commercial supplies of tree products while reducing pressure on natural forest 

ecosystems. Its quick growth and dense shade make the tree an effective tool in 

reforesting Imperata grass swards and reducing fire risk (Nitrogen Fixing Tree 

Association, 1987). It has been reported that this species has a great potential with 

regard to unproductive and degraded lands such as those infested by I. cylindrica

(Otsamo 2002; Hardiyanto et al. 1999; Otsamo et al. 1997). 

The main goal of this study is to evaluate the potential C sink that could be 

achieved by conversion of I. cylindrica grasslands into plantations (Acacia mangium

and oil palm). Furthermore, this study aims at quantifying the C pool and distribution of 

the plantation systems (Acacia mangium and oil palm) and I. cylindrica grasslands. The 
Introduction 

4

rate of biomass and C accumulation of the plantations was estimated from a false time 

series sampling. 

Field experiments were conducted on two islands in Indonesia (Sumatra and 

Kalimantan) between 2002 and 2004. In Sumatra, observation was conducted in the 

provinces North Sumatra and Jambi and in the province East Kalimantan in Kalimantan. 

The thesis consists of seven chapters. Following the introduction in Chapter 1, 

Chapter 2 provides the site description, and chapters 3, 4 and 5 present the analyses of 

biomass and C distribution of I. cylindrica grassland, Acacia mangium and oil palm 

plantations, respectively. A general discussion on the biomass and C stored in the two 

plantation systems and I. cylindrica grasslands is presented in Chapter 6, and the overall 

conclusions and recommendations are given in Chapter 7. 
Site description 

5

2 SITE DESCRIPTION 

The study was conducted on the two Indonesian islands of Sumatra and Kalimantan. 

The sites were selected based on the abundance of the I. cylindrica grasslands and the 

plan for the establishment of plantations in these regions. 

2.1 Sumatra 

The study was carried out in two provinces of Sumatra, i.e., North Sumatra for the 20- 

and 30-year-old oil palm plantations and Jambi in south Sumatra for the 3- and 10-yearold oil palm plantations. North Sumatra is located between 0° 04’ and 4° 11’ north 

latitude and 97° 53’ and 100° 13’ east longitude, and Jambi 0° 45’ and 2° 25’ south 

latitude and 101° 10’ and 104° 55’ east longitude (Anonymous 1997). 

Altitudes in North Sumatra and Jambi range from 0-250 m asl near the coast to 

more than 1500 m asl inland. The geomorphology of these regions is flat to undulating 

near the coast and rolling to mountainous in the upland of the Bukit Barisan mountains. 

The geomorphology of these regions affects the rainfall pattern, leading to high local 

variation in rainfall distribution. Based on the Schmidt and Ferguson classification, 

climate types A to E are found, with annual rainfall ranging from less than 1500 mm to 

more than 4500 mm. The plots in the study area were all located in climate type A. 

The climate of the island of Sumatra is humid tropical, being classified as Af 

according to the Köppen classification (Köppen 1931) or as humid forest according to 

the FAO (2001). In the lowlands, the annual average temperatures are 26-27° C. Daily 

maxima range from 30° C to 36° C and daily minima are around 22° C. However, the 

more specific climate of the study region is classified according to Köppen as Aafw – a 

tropical rainy isothermal climate with hot summers (hottest month more than 22°C), 

without a dry season (mean precipitation in driest month more than 60 mm) and two 

rainfall maxima (February-April and October-December). Monthly rainfall and 

temperature distribution of this site are presented in Figure 2.1. 

The soils of Sumatra have developed under year-round high temperatures and 

precipitation and are highly weathered and leached. These soils have low cationexchange-capacities, high acidity and shallow top-soils. However, in areas with 

volcanic ash or alluvial deposits, soils of higher fertility are found. Most of the soils in 
Site description 

6

the lowland areas are fine textured and are well drained and highly weathered (BPN 

1993). In some cases, these soils are derived from acid volcanic tuff sediments and have 

high Al saturation. Kaolinitic clay minerals dominate the clay fraction of the soils. 

The soils of the study site are Typic Hapludults, characterized by low fertility, 

clay loam and silty clay texture for the upper and lower soils, respectively. The drainage 

of the soils is moderately good (slightly slow) to good, the effective soil depth of 50-

100 cm and solum depth more than 1 m (PMP-SMART 2001). 

2.2 East Kalimantan 

East Kalimantan lies between 115o26'28" - 117o36'43" east longitude and 1o28'21" north 

latitude - 1o08'06" south latitude. Similar to the Sumatra sites, the climate in East 

Kalimantan is classified as Aafw (Bremen et al., 1990; Ohta et al. 1992), i.e., a tropical 

rainy isothermal climate with hot summers (hottest month more than 22°C), without a 

dry season (mean precipitation in driest month more than 60 mm) and two rainfall 

maxima (April-May and December-January). The mean annual rainfall ranges between 

approximately 2000 mm in the north and 2500 mm in the south (Voss 1982). Mean 

monthly temperature is 27°C (RePPProT 1987). Highest daytime temperatures of 35°C 

0

20

40

60

80

100

120

J F M A M J J A S O N D

Month

Monthly Rainfall (mm)

0

10

20

30

40

50

60

Monthly Temperature (°C)

320

Jambi, Sumatra 1990-2000 

50 m a.s.l. 2087 mm 

Figure 2.1: Monthly rainfall and temperature curves of study sites in Jambi, south 

Sumatra 

Temperature 

Rainfall
Site description 

7

and lowest nighttime temperatures of 19°C have been recorded (Voss 1979). Mean 

monthly temperature and rainfall are depicted in Figure 2.2. 

The eastern part of the province belongs mainly to the physiographic region of 

the Kutai Valley and Ridge Fold Belt. This region is dominated by systems of high, 

rugged, strongly folded and faulted mountains, hogbacks and cuestas, piedmont areas, 

low mountains and rugged hills, and undulating plains (Voss 1982; and Ohta 1992). 

However, the physiography of the western part of this province is rather smooth with 

altitude ranging between 50 and 1500 m as1. 

The soils in this region have developed from the middle-late Miocene and 

early Miocene rocks dominate the geology of the province. These rocks have a 

thickness of approximately 2100 m to 8000 m. The middle-late Miocene rock consists 

mainly of muddy sandstone and mudstone. Coal layers are also abundant. Early 

Miocene rocks are largely calcareous mudstones with interbedded limestone, coaly 

sandstones and occasional tuff beds (Voss 1983; and Ohta et al. 1992). 

Typic Paleudults and Typic Hapludults are the major soils in the region 

(Bremen et al. 1990 and Ohta et al. 1990). However, besides Entisols, Inceptisols and 

0

20

40

60

80

100

120

J F M A M J J A S O N D

0

10

20

30

40

50

60

Kenangan, Balikpapan 

60 m asl 

1960-1980

2281 mm

 Month 

Monthly rainfall (mm) 

Monthly temperature (°C) 

300 

Figure 2.2: Temperature and rainfall curves of East Kalimantan 

Temperature 

Rainfall 
Site description 

8

Spodosols, Aquic Paleudults and Aquic Hapludults can also be found (Bremen et al. 

1990 and IHM 1989) 

The Ultisols have a mixed clay mineralogy consisting of kaolinite, 

chlorite/vermiculite and oxides of aluminum and iron. Small amounts of mica are 

reported by Kawana (1976). Sand and silt fractions are dominated by quartz Ruhiyat 

(1989). Soil properties of the Sumatra and East Kalimantan are presented in Table 2.1. 

Table 2.1: Soil properties of top- and subsoil in study sites in Sumatra and East 

Kalimantan, Indonesia 

Sumatra East Kalimantan Parameter Topsoil Subsoil Topsoil Subsoil 

Soil type (USDA) Typic Paleudults Typic Paleudults 

Soil texture (pipette) SL-SiCL SC-C SL-SiCL CL-C 

pH (H2O) 4.3 4.4 4.3 4.4 

Organic C (mg g-1, dry combustion) 15.4 3.9 16.0 6.0 

Total N (mg g-1, dry combustion) 1.4 0.4 1.6 0.9 

Available P (mg kg-1, Bray II) 5.8 3.4 7.6 2.6 

CEC (cmolc kg-1, NH4OAc) - - 26.7 31.8 
Imperata cylindrica grasslands: biomass and carbon distribution 

9

3 IMPERATA CYLINDRICA GRASSLANDS: BIOMASS AND CARBON 

DISTRIBUTION 

3.1 Introduction 

Low income, inappropriate technology, low input and poor understanding regarding 

land management have led to huge areas of deforested land in the tropics. In many 

cases, farmers with land adjacent to forest zones cleared the forests and converted the 

land into agricultural land to meet their subsistence needs. Due inappropriate land 

management systems, much of this area has been abandoned and invaded by I. 

cylindrica, the most common weed in the tropics. Today, I. cylindrica covers an area of 

more than 8.5 million ha in Indonesia alone (Garrity et al. 1997; Soekardi et al. 1993). 

Imperata cylindrica is a perennial, rhizomatous grass and reproduces from 

seed and rhizomes; however, flowering is rare and generally occurs only after human 

disturbance or stress (Sajise 1972). The plant is stemless, growing in loose to compact 

tufts with slender, flat, linear-lanceolate leaves from the rhizomes (Hubbard et al. 1944). 

It is a serious pest throughout the tropical and subtropical regions and ranked as the 

seventh most troublesome weed worldwide (Holm et al. 1977). Imperata cylindrica has 

been reported to compete for nutrients, light, and water, and cause physical injury to 

neighboring plants through rhizomes penetrating the roots of these plants (Boonitee and 

Ritdhit 1984; Eussen and Soerjani 1975; Jagoe 1938). Furthermore, I. cylindrica has 

low nutritional values due to the high C/N ratio, and high lignin and polyphenol 

contents (Hartemink and O’Sullivan 2001). 

The persistent and aggressive rhizomes of I. cylindrica are the main 

mechanism for survival and local spread, which makes the weed difficult to control. I. 

cylindrica is able to invade areas that will not support other vegetation, as it can tolerate 

a wide range of soil and climatic conditions (Hubbard et al. 1944; Eussen and 

Wirjahardja 1973). 

Shade, repeated herbicide application, and mechanical control have all been 

used to control I. cylindrica (Macdicken et al. 1997 Terry et al. 1997). Mechanical 

control is, however, very labor intensive and the use of herbicide (Glyphosate) is costly 

and open to environmental risks. There is the potential of using Mucuna in the fallow 
Imperata cylindrica grasslands: biomass and carbon distribution 

10

period to control this grass (Carsky 2001; Akobundu 2000). Nevertheless, because of no 

direct additional product, acceptance by the farmers in south east Asia is low. 

Imperata cylindrica grass is usually found on soils with low pH, fertility, and 

organic matter content and soils that are highly leached (Sajise 1980; Wilcut et al. 

1988). However, recent studies report that this grass grows fast in a wide range of soils 

and climatic zones (Snelder 2001; Garrity et al. 1997; Santoso et al. 1997) creating a 

vast area of unproductive grassland. This is unfavorable from both ecological and 

economical points of view: low biomass (Otsamo 2002), C accumulation, and 

biodiversity, enhanced soil degradation and compaction (Ohta 1990); the grass also has 

a very limited use. Moreover, this grassland is susceptible to fire that may extend to the 

forests in the vicinity of this grassland, resulting in an increased coverage. Thus, I. 

cylindrica grasslands emerge as fire-climax vegetation in areas where periodic fires 

hold back the natural secondary succession of forest (Eussen and Wirjahardja 1973). As 

a consequence of the unfavorable environmental conditions created by grass 

competition, allelopathy, fire susceptibility, soil degradation and compaction (Ohta 

1990; Dela Cruz 1986; Soerianegara 1980), such grasslands are difficult to reforest or 

use for agricultural purposes, unless intensive land preparation and management are 

employed (Otsamo 2002; Otsamo et al. 1997). Land preparation for tree or crop 

plantations is very labor intensive and may require 200 man days ha-1 (Van Noordwijk 

et al. 1997) or 800-1000 hours ha-1 (Ruthenberg 1976). 

However, this grass is susceptible to shade (Otsamo 2002; Brook 1989; Eussen 

1981) resulting in reduced carbohydrate storage, rhizome and tuber-bulb production, 

shoot dry weight, increased susceptibility to competition and herbicides, and decreased 

vigor and regeneration (Macdicken et al. 1997). Plantations of fast growing trees are, 

therefore, effective in suppressing and elimination of this grass (Otsamo et al. 1997; 

Turvey 1996). Fast growing tree plantations may ameliorate the strongly fluctuating 

microclimate conditions and reverse soil degradation by enhancing soil microbiological 

activities through increased litter production and nitrogen fixation (Fisher 1995; Ohta 

1990; Dela Cruz 1986), thus facilitating the reinvasion of native species (Otsamo 2000; 

Lugo 1997; Parrotta et al. 1997). 

The potential use of agroforestry for the reclamation of I. cylindrica grassland 

has also been reported (de Foresta and Michon 1997; Santoso et al. 1997). 
Imperata cylindrica grasslands: biomass and carbon distribution 

11

While the distribution of I. cylindrica grassland, its effect on soil properties 

and its reclamation potential have been intensively studied, data on the above- and 

belowground biomass and C distribution of this grassland system are still scarce. Such 

data are important for determining the base line of C storage of the system, which can 

be used in greenhouse-gas mitigation projects such as planting trees in marginal lands. 

The focus of this study is, therefore, to quantify the biomass and C stock of the system, 

both above- and belowground, as well as soil-C distribution. 

3.2 Methodology 

Observation and sampling for the determination of biomass and C storage of I. 

cylindrica grassland were conducted at both the Sumatra and East Kalimantan sites. 

Three 3 m x 3 m plots were established on each site. Each plot consisted of three 1 m x 

1 m sub-plots. All above ground biomass of I. cylindrica inside the sub-plots was 

harvested and weighed. Sub-samples were dried to a constant weight at 60°C and dry 

weight was determined. Thereafter, the samples were ground to pass a 0.2 mm sieve and 

stored for further chemical analyses. 

Root biomass was sampled and collected at 16 drilling points in each plot to a 

depth of 3 m (using an 8-cm-diameter root auger in 15-cm increments) distributed on a 

systematical sampling basis (Figure 3.1). In some cases a less-weathered parent material 

layer was found at 3 m depth, presenting a physical barrier and preventing sampling for 

deeper soil layers. Roots were separated from the soil core by water saturation and 

flushing: soil cores were watered in small flasks overnight for soil suspension. In the 

case of heavy clayey soils (common for soil layers deeper than 50 cm), calgon (sodium 

polyphosphate) was added to the suspension to enhance the dispersion capacity of the 

soils. Hereafter, the suspension was rinsed under a medium pressure water tap and the 

roots were collected with 2-mm and 65-μm sieves. The samples were processed 

following the same procedure as for aboveground biomass samples. 

Soil samples for chemical analysis were drawn in line with the procedure of 

root biomass sampling. A small portion of the soil mass sample was drawn from each 

soil core of the root sampling. Samples were then mixed to six depth classes, 0-15, 15-

30, 30-50, 50-100, 100-200 and 200-300 cm, air dried and ground to pass a 2-mm sieve. 

A soil profile was established nearby one of the three plots on each site for 

observation of soil morphological characteristics and sampling of soil bulk density. Soil 
Imperata cylindrica grasslands: biomass and carbon distribution 

12

bulk density was sampled at depths of 0-15, 15-50, 50-100, 100-200 and 200-300 cm. 

Three to six soil core samples were drawn at each depth depending on the range of the 

soil depth and its presumed variation (3, 4, 5, 6 and 6 core samples for the depths 0-15, 

15-50, 50-100, 100-200 and 200-300 cm, respectively). 

Carbon and nitrogen (N) content of the samples was determined on the basis 

of dry combustion with a CNS (C, N, Sulfur) analyzer. Total C of the system was 

calculated based on C content and mass of each compartment of the system. 

The data were analyzed with analysis of variance (ANOVA) and means were 

compared with the Least Significant Different (LSD) test procedure. 

3.3 Results and discussion 

Above- and belowground biomass of I. cylindrica grasslands varied within and among 

sites (Table 3.1). However, the difference was not significant at α = 0.05. The 

aboveground biomass ranged from 6.0 to 10.1 Mg ha-1, which is close to the 11.4 Mg 

ha-1 in I. cylindrica grasslands in South Kalimantan reported by Otsamo (2002). 

Although not significant, both above- and belowground biomass of the systems in East 

Kalimantan site were higher than in Sumatra. This difference may be the result of 

genetics, environment or seasonal variations of the systems. Nevertheless, since the data 

Root augering points 

1 m

Figure 3.1: Layout of root sampling of Imperata cylindrica grassland at the study sites 

in Sumatra and East Kalimantan, Indonesia 
Imperata cylindrica grasslands: biomass and carbon distribution 

13

were consistent with the organic C of the soils, the results reflect the difference in soil 

resources. Belowground biomass was higher than aboveground biomass by a factor of 

1.5 for the systems in East Kalimantan and by a factor of 1.3 for those in Sumatra. 

Table 3.1: Above- and belowground biomass of Imperata cylindrica grassland at the 

study sites in Sumatra and East Kalimantan, Indonesia 

Biomass (Mg ha-1) Site Aboveground Belowground1

Total 

Below-/ 

aboveground ratio 

East Kalimantan 8.8±1.2 13.1±1.2 21.9±2.4 1.5±0.1

Sumatra 7.4±2.3 9.5±1.9 16.9±4.2 1.3±0.1

ns ns ns ns 

1 Down to 3 m soil depth; ns not significantly different at α = 0.05; three replications 

Root biomass of I. cylindrica grasslands was distributed to a maximum depth 

of 180 cm. However, most of the roots were confined to the top soil layer (Table 3.2), 

i.e., 79.5% of the root biomass was found in the top 15 cm and 90% in the upper 41 cm. 

This implies that the conventional and mechanical elimination of this grass will never 

succeed, because of the difficulty of removing of the deep rhizomes. Measures could be 

combined with a sound and environmentally friendly chemical application before shadebased (Macdicken et al. 1997) and soil fertility improvement measures (Santoso et al. 

1997) could effectively control this grass. The magnitude of root biomass of 12.4 Mg 

ha-1 was in the range of that of cool-season grass and switch grass of riparian buffers of 

10.9-16.8 Mg ha-1 (Tufekcioglu et al. 2003; 1999). Although the biomass of I. 

cylindrica grassland systems is comparable to that the above systems, the distribution in 

I. cylindrica grassland was more concentrated in the upper soil layers: 88.4% of the 

roots was found in the top 35 cm, while this was 83.0 and 81.0% for the cool-season 

grass and switch grass systems, respectively (Tufekcioglu et al. 2003; 1999). 

Bulk density of soils developed under I. cylindrica grasslands ranged from 1.1 

to 1.5 depending on site and soil depth (Table 2). The soil bulk density of the East 

Kalimantan site was slightly lower than that of the Sumatra site. This difference may 

relate to past land-use history, parent material and the development of respective soils. 

Bulk density of the soils in East Kalimantan increased with depth, which can be 

attributed the decreasing biological activities. At the Sumatra site, bulk density peaked 

at the depth of 50-100 cm (maximum illuviation horizon) and declined to a depth of 

300 cm. However, at both sites, bulk density of the top soils characterized by the dense 
Imperata cylindrica grasslands: biomass and carbon distribution 

14

root biomass (Soepardi 1980; Soerjatna and McIntosh 1980) was significantly lower (α

= 0.05) than that of deeper soils. 

Table 3.2: Root biomass and bulk density of soils in Imperata cylindrica grasslands at 

the study sites in Sumatra and East Kalimantan, Indonesia, by depth 

Root biomass (Mg ha-1 Depth ) Bulk density 

(cm) East Kalimantan Sumatra East Kalimantan Sumatra 

0-15 9.9a 7.3a 1.08a 1.11a

15-50 1.5b 1.1b 1.29b 1.36b

50-100 0.9c 0.5c 1.34b 1.50b

100-200 0.2d 0.2d 1.35b 1.43b

200-300 0.0e 0.0e 1.39b 1.37b

Values followed with the same letters are not significantly different at α = 0.05. 

Even though the bulk density of soils developed under I. cylindrica grassland 

was higher than that of primary forests of 1.0 (top soil) and 1.3 (sub-soil) (Ruhiyat 

1989), the bulk density of topsoil of plantations of 1.1 to 1.2 and subsoil of 1.3 to 1.4 

(Bremen et al. 1990; Ruhiyat 1989) is comparable to that of under I. cylindrica

grassland. However, compared to the values reported by Bremen et al. (1990) and 

Ruhiyat (1989), the increase in soil bulk density from the top- to subsoils of I. 

cylindrica was much more distinct. 

Carbon and N content of the aboveground biomass of I. cylindrica (40.7% ± 

0.7% and 0.62% ± 0.06%, respectively) was higher than that of belowground biomass 

(30.7% ± 2.2% and 0.56% ± 0.05%, respectively) but only the C content was significant 

(p of < 0.001 and 0.13, respectively). These values are based on six replications for the 

aboveground biomass and three replications for the belowground biomass. The C 

content of I. cylindrica leaves of 42.6% reported by Hartemink and O’Sullivan (2001) 

was quite comparable to that of the aboveground biomass of the present study. This 

concentration did not much differ compared to that of Piper aduncum and Gliricidia 

sepium (40.4 and 43.8%, respectively) reported by Hartemink and O’Sullivan (2001). 

The average C:N ratio of the belowground biomass (55) was lower than that of 

aboveground biomass (66). However, the values were considerably lower than the 110 

reported by Hartemink and O’Sullivan (2001). Compared to that of Piper aduncum and 

Gliricidia sepium of 26 and 18, respectively (Hartemink and O’Sullivan 2001), the C:N 

ratios of I. cylindrica were much higher. The rate of decomposition of I. cylindrica
Imperata cylindrica grasslands: biomass and carbon distribution 

15

leaves was much slower than that of Piper aduncum and Gliricidia sepium, which could 

not be explained by the C:N ratio alone; the process is also influenced by the lignin plus 

polyphenol over N ratio (Hartemink and O’Sullivan 2001). 

On average, the biomass C of the I. cylindrica grassland systems in the East 

Kalimantan and Sumatra sites was 3.6 and 3.0 Mg ha-1 (aboveground), 4.0 and 2.9 Mg 

ha-1 (belowground) and 7.6 and 5.9 Mg ha-1 (total), respectively (Table 3.3). This 

magnitude is in the range of the biomass C of cool-season grass and switch grass of 

riparian buffers reported by Tufekcioglu et al. (2003). Compared to aboveground 

biomass C of I. cylindrica grassland of 1.7-1.9 Mg ha-1 reported by Ginting (2000) and 

Lachica-Lustica (1997), the results are somewhat higher, but lower than the 8.5 Mg ha-1

reported by Lasco et al. (1999). Although belowground biomass was significantly 

higher than aboveground biomass (p = 0.027), due to the lower C content of the 

belowground biomass (30.7% and 40.7% for the below- and aboveground biomass, 

respectively), the belowground and aboveground biomass C did not differ much. The 

ratio of below- to aboveground biomass C was 1.0 and 1.1 in Sumatra and East 

Kalimantan, respectively. A similar ratio was reported by Tufekcioglu et al. (2003) for 

the cool-season and switch grasslands of riparian buffers in Iowa. 

Table 3.3: Above- and belowground biomass C of Imperata cylindrica grassland at the 

study sites in Sumatra and East Kalimantan, Indonesia 

Biomass C (Mg ha-1) Site Aboveground Belowground Total 

East Kalimantan 3.6±0.5 4.0±0.4 7.6±0.9 

Sumatra 3.0±0.9 2.9±0.6 5.9±1.5 

ns * ns 

ns = not significantly different at α = 0.05; * significantly different at α = 0.05; three replications 

Soil organic C and nitrogen are the main limiting factors in grassland 

productivity and are affected by biomass removal (periodic burning), low input of 

organic matter and loss of organic matter by surface erosion (Snelder 2001). Soil C 

content of soils at both sites decreased persistently with depth (Table 3.4). Values were 

1.27 and 1.08% in the top 15-cm depth dropping to 0.15 and 0.10% at the 200-300-cm 

depth for East Kalimantan and Sumatra, respectively. There was a sharp decrease in the 

first 15-cm depth to the second 15 cm, after which the C content declined gradually to a 

depth of 300 cm. 
Imperata cylindrica grasslands: biomass and carbon distribution 

16

Table 3.4: Carbon content and storage of soils in Imperata cylindrica grasslands at the 

study sites in Sumatra and East Kalimantan, Indonesia 

Site 

East Kalimantan Sumatra 

Soil 

Depth 

(cm) C content (%) C storage 

(Mg ha-1) C content (%) C storage (Mg ha-1) 

0-15 1.27a 20.6 1.08a 18.1 

15-30 0.88a 17.1 0.70b 14.3 

30-50 0.75a 19.3 0.57b 15.5 

50-100 0.53a 35.7 0.44b 32.7 

100-200 0.27a 36.6 0.18b 25.7 

200-300 0.15a 21.4 0.10b 14.0 

0-300 - 150.6 - 120.3 

Values followed by the same letters are not significantly different at α = 0.05. 

Imperata cylindrica grassland systems have a dense mat of rhizomes near the 

surface, which is a positive factor with respect to erosion control and a source of organic 

material (Soepardi 1980; Soerjatna and McIntosh 1980). It plays a positive role on 

sloping lands in reducing soil movement and as a vegetative filter for run-off carrying 

sediments. The relatively high C content of the top 15-cm soil could be due to the 

abundance of root mass. However, compared to the C content of the topsoil of 

plantation systems of 1.6 to 2.3% (Mackensen 1998; Syahrinudin 1997; Bremen et al. 

1990), the C content of the soils under I. cylindrica grasslands is even lower. This is in 

agreement with the previous finding that the C content of the soils in regularly burnt I. 

cylindrica grasslands tends to decline (Van Noordwijk et al. 1997; Ohta 1990). 

Furthermore, even though without fire a reasonable soil organic matter level might be 

maintained, litter quality and subsequent N mineralization are low (Hartemink and 

O’Sullivan 2001; Van Noordwijk et al. 1997). 

With the exception of the 0-15-cm layer, the C content of the soils at the East 

Kalimantan site was significantly higher than that of at the Sumatra site (p < 0.001). 

Since there was no evidence of differences in fire events at these sites, the difference 

suggests that there was already a difference in the level of soil C content prior to the 

invasion of I. cylindrica. 

Distribution of the C storage of soils developed under I. cylindrica grassland is 

presented in Table 3.4. The results show that the top 50-cm soil depth contributed less 

than 40% of the total soil C storage to a depth of 3 m, and the contribution of the top 

100-cm soil was 61.5-67.0%. This suggests that contribution of the C storage in the 
Imperata cylindrica grasslands: biomass and carbon distribution 

17

deep soils is significant and, due to its high variability, must be assessed. The C storage 

to a depth of 3 m in this study is quite comparable to that in oxisols of secondary and 

primary Brazilian forests and traditional crops (130.0-145.0 Mg ha-1), but higher than 

that of oil palm and passion fruit plantations (108.0 and 125.0 Mg ha-1, respectively) 

(Sommer et al., 2000). Little information exists on the C storage in deep soils in the 

study region; however, the 47.9-56.9 Mg ha-1 in the top 50-cm soil are still in the range 

of values for forest plantations (42.1-67.5 Mg ha-1) (Mackensen 1998; Syahrinudin 

1997; Bremen et al. 1990; Ruhiyat 1989). Nevertheless, compared to secondary and 

primary forests (57.7-69.9 Mg ha-1) (Ruhiyat 1989), the soil C storage of I. cylindrica

grassland systems is lower. 

Of the total 126.2-158.2 Mg ha-1 C, only 2.3-2.4% were stored in aboveground 

biomass. Compared to forest ecosystems, contribution of aboveground biomass C to the 

total C storage of grassland systems is generally much lower (Sharrrow and Ismail 

2004).

3.4 Conclusions 

Imperata cylindrica grassland stored only a relatively small amount of biomass C (5.9-

7.6 Mg ha-1) implying that conversion into a more C-rich tree-based system would be 

promising tool to enhance C sequestration. Moreover, the roots of I. cylindrica extended 

to a maximum depth of only 180 cm. With most of these roots being confined to the 

topsoil, little organic material is deposited in deeper layers. Despite the dense mat of 

rhizomes, the extent of C stored in the top soils was modest. As sequestration is of 

global concern, the conversion of this grassland into systems with higher biomass 

accumulation and deeper root penetration is required. 

Soil C content at both study sites decreased significantly with depth from the 

top 15 cm to the 3-m depth and was considerably higher in East Kalimantan than in 

Sumatra. With similar land-use history, the differences in soil C are likely to be related 

to the level prior to the invasion. 
Acacia mangium plantations

18

4 ACACIA MANGIUM PLANTATIONS 

4.1 Introduction 

Tropical forests play an important role in the global C budget, and some evidence 

suggests that tropical forests may sequester atmospheric CO2 (Sataye et al. 2001; Grace 

et al. 1995). However, Cox et al. (2000) and White et al. (2000) estimated that a 

substantial amount of C could be released from tropical forests if temperatures increase 

due to global climate change. 

Studies on the sequestration and dynamics of C in tropical soils have recently 

gained importance. These are mainly driven by the fact that the changes in the 

magnitude of C held in soil organic matter may significantly change the levels of 

atmospheric CO2 (Schlesinger 1991). Estimates for the quantity of organic C in the 

upper meters of soil world-wide range from 1220 Gt to 1550 Gt (Eswaran 1995; Post et 

al. 1982; Schlesinger 1977; Schlesinger 1984), which is nearly twice the aboveground 

biomass of 560-835 Gt (Sombroek et al. 1993). Soils, in particular those in the tropics, 

could be large sinks of atmospheric C if well managed (Lugo and Brown 1993). The 

transformation of forestland into agricultural land leads to substantial losses of 

aboveground biomass, but the effect on soil C stocks remains poorly understood. It is 

commonly assumed that after conversion to agricultural use the soil becomes 

impoverished in C, which is reversed during the fallow period (Cerri et al. 1991; 

Greenland and Nye 1959; Lugo and Brown 1993; Raich 1983). 

The sequestration of C into vegetation and soil sinks is one of the mechanisms 

for reducing net greenhouse gas emissions. Conservation strategies, which sequester C, 

include converting marginal lands to compatible land-use systems, restoring degraded 

soils, and adopting best management practices. Notwithstanding the debate as to 

whether global forests are sources or sinks of greenhouse gases (Pelley 2003; Harmon 

2001; Metting et al. 2001; Schimel et al. 2001; Lal and Singh, 2000; Ravindranath et al. 

1997), managed fast growing forests may enhance C sequestration (Lee et al. 2002; Ney 

et al. 2002; Metting et al. 2001; Papadopol 2000). Silvicultural strategies aiming at 

accelerating stand growth are likely to increase the rate of C sequestration of the 

respective forests (Lee et al. 2002; Chen et al. 2000; Montagnin and Porras 1998). 
Acacia mangium plantations

19

Plantations of fast-growing species have been rapidly increasing in Asia in 

recent years (Cossalter and Pye-Smith, 2003). Acacia mangium is one of the most 

common fast growing species planted in the humid tropics. Plantations of A. mangium 

have been established at many secondary forest and grassland sites across the region, 

covering about 20×106 ha (ca. 9.4% of the total forested area) in ASEAN countries in 

the year 2000 (FAO 2003). A. mangium used to be planted primarily for site 

rehabilitation; however, due to its rapid growth and tolerance of very poor soils, this 

species is playing an increasingly important role in efforts to sustain commercial 

supplies of tree products while reducing pressure on natural forest ecosystems. Its quick 

growth and dense shade make the tree an effective tool in reforesting Imperata grass 

swards and reducing fire risk (Nitrogen Fixing Tree Association 1987). It has been 

reported that this species has a great potential with regard to unproductive and degraded 

lands such as those infested by I. cylindrica (Otsamo 2002; Hardiyanto et al. 1999; 

Otsamo et al. 1997). The establishment of plantations with this species in areas for 

forestry-based C offset projects is, therefore, promising. 

There are about 7.5-8.5 million ha of I. cylindrica grasslands distributed in 

various islands in Indonesia, an area that would be large enough to support the extensive 

expansion of oil palm and forestry plantations planned by the government. These 

plantations have high potential to be promoted in the world-C trade and they may, 

therefore, increase the foreign exchange earnings of the country. However, the question 

as to how much CO2equivalent can be sunk by converting I. cylindrica grassland into 

plantation is still open. To answer this question, studies on the biomass and C storage of 

both I. cylindrica grasslands and man-made forests are of utmost importance. 

In this study, efforts are devoted to quantifying the biomass and C 

accumulated in A. mangium plantations of different ages and biomass and C 

distribution. 

4.2 Methodology 

Plots for the determination of biomass and C storage of an A. mangium plantation were 

established at the East Kalimantan site. Three 0.05-ha circular plots (r = 12.6 m, 

consisting of 55 trees of a full standing stock plantation with a planting space of 3 m x 

3 m) were established in a 1-, 4-, and 9-year-old A. mangium plantation. Extreme 
Acacia mangium plantations

20

variation in stand density, undergrowth coverage and land slope was avoided. Thus, 9 

plots were established (3 stand ages, 3 replications). To minimize errors induced by the 

variation of soil type, all observation plots were established in loamy to clayey Ultisols, 

considering that this is the most common soil in the region. 

The diameters of the trees in each plot were measured and the data used to 

estimate the total biomass of the respective stand. For this, the data was combined with 

the results of the tree biomass sampling to build an allometric equation. Twenty trees 

were harvested and uprooted. Total biomass of the harvested trees was weighed, and 

samples were drawn from the different components (root, stem, branch, twig and leaf) 

and weighed. Samples were dried to constant weight at 60°C. Thereafter, samples were 

ground to pass a 0.2-mm sieve for chemical analysis. 

Three 5 m x 5 m subplots were established to assess the biomass of woody 

undergrowth occupying the respective plot. All woody undergrowth in these sub-plots 

was harvested and uprooted. Total biomass was weighed and the samples were sorted 

into roots (medium and coarse), stems, branches and twigs, and leaves. Thereafter, the 

procedure as for the trees was carried out. To estimate the total biomass and C stored in 

the herbaceous undergrowth, three 1 m x 1 m sub-plots were established, and the 

herbaceous undergrowth in these sub-plots was harvested and weighed to calculate the 

total fresh weight. Samples were drawn representatively for total dry weight assessment. 

Thereafter, the same procedure as for the tree samples was followed. 

Only litter in the L and F layers of the soil was considered as litter standing 

stock in this work, because the H layer was incorporated into the soil sample. In each 

main plot, three 0.5 m x 0.5 m subplots were established to collect the litter. The litter in 

these subplots was collected, sorted into woody and non-woody components and 

weighed (fresh and air dry). A small sample of each component was drawn and 

processed following the same procedure as for the tree samples. 

To complete the biomass determination, three subplots 3 m x 3 m in 

accordance with the planting space of the A. mangium plantations were established in 

each main circular plot. Fine root and soil samples were drawn at 17 drilling points to a 

depth of 3 m (using an 8-cm-diameter soil core auger in 15 cm increments) distributed 

in a systematical sampling system on the basis of the distance to the closest trunk: 10 

cm (A), 50 cm (B), 100 cm (C), 150 cm (D) and 212 cm (E) (Figure 4.1). Roots were 
Acacia mangium plantations

21

separated from the soil core by water saturation and flushing as described in Section 

3.2. 

A soil profile was established near the center of one of the three plots of each 

plantation age for observation of the soil morphological characteristics and sampling of 

soil bulk density. Soil sampling and analysis were carried out following the procedure 

described in Section 3.2. 

Data were analyzed with analysis of variance (ANOVA) and means compared 

with the Least Significant Different (LSD) test procedure. 

4.3 Results and discussion 

4.3.1 Biomass distribution 

The biomass of the A. mangium plantations was assessed using an allometric equation 

based on the results of the destructive sampling of the trees. Six allometric equations 

were developed; all are at p < 0.001. 

A1

D3

D1

E 

C1

B1

C3

D2

D4

B4

C4

B2

C2

A3

B3

A4

A2

Distance to closest 

trunk: 

A = 10 cm 

B = 50 cm 

C = 100 cm 

D = 150 cm 

E = 212 cm 

Figure 4.1: Layout of root and soil sampling in Acacia mangium stand in East 

Kalimantan, Indonesia 

Root auger point 

Trunk base 
Acacia mangium plantations

22

Y = 0.0065X 2.7601, r

2

 = 0.9452 for root biomass (excluding fine root biomass) 

Y = 0.034X 2.7166, r

2

 = 0.9442 for stem biomass 

Y = 0.0608X 2.0034, r

2

 = 0.9470 for branch biomass 

Y = 0.0399X 1.9189, r

2

 = 0.8711 for leaf biomass 

Y = 0.2518X 2.1679, r2 = 0.9205 for aboveground biomass 

Y = 0.1027X 2.4942, r2 = 0.9628 for total biomass 

Y = expected biomass of the tree compartment 

X = tree diameter at breast height. 

Allometric equations developed to estimate biomass and volume of the stands 

in most of the previous studies are based on the diameter and height of trees (Yantasath 

et al. 1992; Halenda 1989; Ruhiyat 1989; Bustomi 1988). However, the results in this 

study show that estimations of tree biomass based on diameter alone can provide 

accurate and reliable results. Since tree height is to a large extent dependent on tree 

diameter and the relation of tree diameter, and since height is likely species specific, 

estimations of tree biomass and volume based on tree diameter can be quite reliable, 

especially when the stand consists of mono species. Furthermore, measurement of the 

height of the standing trees is difficult in the field and may, therefore, be subject to 

errors, thus estimation of the stand yield (biomass or volume) based on tree diameter 

alone is recommended. 

Most allometric equations in former studies are developed from a single stand 

age (Syahrinudin 1997; Halenda 1989; Ruhiyat 1989; Lim 1988, 1986), mainly 

supported by the assumption that tree form may change with stand age. In contrast to 

this assumption, the results in this study show that the established allometric equations 

are applicable for a very wide range of stand ages (1- to 9-year-old stands). This implies 

that the equations can be employed for similar plantations elsewhere, regardless of the 

age of the stand. Soemarna and Bustomi (1986) developed an allometric equation fitted 

for 3- to 7-year-old A. mangium stands. Hiratsuka et al. (2003) found that the allometric 

equations of aboveground biomass of 6-year-old stands of A. mangium in Benakat, 

Indonesia and Sonbe, Vietnam, 7-year-old stands in Madang, Papua New Guinea 

(PNG), and 8-year-old stands in Benakat and Bogor, Indonesia, were not site dependent. 

The equation developed in this study confirms their finding (r2 = 0.99, p < 0.001) that 

the allometric equation for A. mangium plantations is not site specific and that the 
Acacia mangium plantations

23

equation can be applied for any plantation of this species, regardless of stand age and 

site conditions. 

Biomass distribution of the plantations is presented in Table 4.1. The diameter 

distribution of the 4- and 9-year-old stands is comparable to that of the so-called site 

index 18.0 m of 15.3 and 20.5 cm, respectively, reported by Newaz and Millat-EMustafa (2004). Nevertheless, the results on the diameter distribution of the 1-year-old 

stands of 5.6 cm in this study are higher than their finding of 3.2 cm. The average 

diameter of 1-year-old A. mangium stands ranged widely from 1.8 to 8.8 cm 

(Yanthasath et al. 1986; Paudyal and Nik Muhamad 1990), depending on site 

conditions, planting space and material, and plantation management. 

Table 4.1: Stand density, diameter and biomass distribution in Acacia mangium 

plantation system in East Kalimantan, Indonesia

Stand age 

Stand 

density 

Diameter 

of trees 

(DBH) 

BGB AGB Litter Total 

biomass RBGB RWUG RHU

(year) (trees ha-1) (cm) (Mg ha-1) (%) 

Mean 1580 5.6 11.3 16.8 1.6 29.7 38.1 5.0 14.3

1 SD 121.7 1.2 2.7 1.9 0.3 4.6 2.7 4.4 7.9

n 3 237 3 3 3 3 3 3 3

Mean 626.7 15.0 18.7 64.8 9.3 92.8 20.1 13.4 1.0

4 SD 30.6 3.4 4.4 1.5 1.8 7.05 3.2 1.2 0.2

n 3 94 3 3 3 3 3 3 3

Mean 713.3 20.7 36.3 139.2 5.9 181.4 20.0 0.4 0.1

9 SD 83.3 5.7 4.9 18.5 0.8 23.3 1 0.1 0.03

n 3 107 3 3 3 3 3 3 3

SD = standard deviation, DBH = diameter at breast height, BGB = belowground biomass, AGB = 

aboveground biomass, RBGB = relative belowground biomass to total biomass, RWUG = relative woody 

undergrowth biomass to total biomass, RHU = relative herbaceous undergrowth to total biomass. 

There was an increase in stand diameter variation in line with age of the 

plantation. Since it is assumed that the stand is genetically homogeneous, this may 

reflect the increase in the effect of the environmental factors such as differences in 

micro relief, access to soil nutrients and water, as well as symbiosis with certain 

Rhyzobium strains (Martin-Laurent et al. 1999; Galiana et al. 1995; 1998). 

Total biomass accumulation increased from only 25.4 Mg ha-1 in the first year 

of the plantation to 181.2 Mg ha-1 in the ninth year. It is obvious that the biomass of the 

A. mangium stands already surpassed that of I. cylindrica of 21.9 Mg ha-1 in the very 

early stage of the plantation. This implies that establishment of A. mangium plantations 
Acacia mangium plantations

24

is a promising tool if the biomass is the concern, especially in marginal and degraded 

lands (Otsamo, 2002, Otsamo et al. 1997). 

Aboveground biomass of the 4-year-old stands (52.6 Mg ha-1) (Table 4.2) in 

this study was in the range of that of 5- to 7-year-old Eucalyptus deglupta stands (45.7-

81.2 Mg ha-1) (Syahrinudin 1997; Ruhiyat 1989). Compared to the biomass of 4-yearold Gmelina arborea stands (3.7 – 10.9 Mg ha-1) studied by Swamy et al. (2003), this 

value is higher. However, the contribution of belowground biomass of 17.5-40.2% 

(Swamy et al. 2003) is in agreement with the results of the present study of 20.0-38.1%. 

It is important to notice that the accumulation rate of belowground biomass was quite 

high in the first years (almost similar to that of aboveground biomass) and declined with 

plantation age. 

Table 4.2: Biomass distribution of Acacia mangium plantation system in East 

Kalimantan, Indonesia

Stand age Fine 

root 

Coarse 

root Stem Branch Leaf AGB BGB Total biomass

(year) (Mg ha-1) 

Mean 9.5 1.3 6.5 3.2 1.8 11.5 10.8 22.3 1 SD 2.7 0.3 1.4 0.6 0.3 2.3 3.0 5.3

Mean 9.5 8.0 37.2 10.7 4.7 52.6 17.5 70.1 4 SD 4.3 0.3 1.5 0.4 0.2 1.9 4.2 4.2

Mean 12.3 23.9 108.7 19.6 10.2 138.4 36.2 174.7 9 SD 2.2 3.5 15.5 1.9 1.2 18.5 4.9 23.1

SD = standard deviation, GB = belowground biomass, AGB = aboveground biomass; three replications 

of each stand age; fine roots were defined to depth of 3 m. 

Information on the biomass of young plantations (less than 3 years old) is 

scarce. Compared to the aboveground biomass of 1-year-old Eucalyptus deglupta

plantations of 3.1 Mg ha-1 (Syahrinudin 1997), the results in this study are much higher. 

Aboveground biomass of A. mangium plantations ranges widely depending on factors 

such as planting space (tree density), site quality, silvicultural practices and plant 

material characteristics. However, in general, the magnitude of aboveground biomass in 

this study is still in range of that reported in previous studies (Table 4.3). 

Biomass of all compartments of the stands increased with stand age. There is, 

however, no significant difference in fine root biomass across plantation age. 

Belowground biomass of the 4- and 9-year-old stands is in the range of that of 
Acacia mangium plantations

25

Amazonian primary forest and secondary vegetation (22.0 – 34.0 ton ha-1 6 m-1) 

(Sommer et al. 2000). 

Table 4.3: Stand density and aboveground biomass of Acacia mangium plantations of 

different ages and sites 

Stand 

age 

(year) 

Stand 

density 

(trees ha-1) 

Aboveground 

biomass 

(Mg ha-1) 

Site Reference 

1 1580 11.5 East Kalimantan, Indonesia This work 

3.5 1089 54.4 Sarawak, Malaysia Lim and Hamzah 1985 

3.5 625 64.1 Malaysia Lim 1985 

4 626.7 52.6 East Kalimantan, Indonesia This work 

4 2500 48.0 Thailand Yantasath 1992 

4 10000 128.0 Thailand Yantasath 1992 

4 1566 90.4 Malaysia Lim 1988 

4.5 1089 86.9 Sarawak, Malaysia Lim 1986 

5 600 58.9 East Kalimantan, Indonesia Ruhiyat 1989 

6 696 67.5 East Kalimantan, Indonesia Ruhiyat 1989 

6 1289 122.4 Sonbe, Vietnam Hiratsuka et al. 2003 

6 822 132.6 Benakat, Indonesia Hiratsuka et al. 2003 

6 1369 157.5 Benakat, Indonesia Hiratsuka et al. 2003 

6 787 133.2 Benakat, Indonesia Hiratsuka et al. 2003 

6 877 172.8 Benakat, Indonesia Hiratsuka et al. 2003 

6 903 143.5 Benakat, Indonesia Hiratsuka et al. 2003 

6.8 730 123.2 Malaysia Halenda 1989 

7 708 96.6 East Kalimantan, Indonesia Ruhiyat 1989 

7 506 99.7 Madang, PNG Hiratsuka, et al. 2003 

9 713.3 138.4 East Kalimantan, Indonesia This work 

9 1382 189.5 South Sumatra, Indonesia Hardiyanto, et al. 1999 

Information on the undergrowth biomass of forest plantations is very scarce, 

and reports on the importance and contribution of undergrowth in tropical forest 

plantations are even rarer. Biomass distribution of litter standing stock and undergrowth 

is presented in Table 4.4. Total biomass of woody undergrowth of the 4-year-old stands 

was notably higher than that of the 1- and 9-year-old stands. In the first year of the 

plantation, there was intensive undergrowth management controlling the development 

of the undergrowth. This management was less intensive in the second year and only 

occasional during the consecutive years, since the canopy closure became well 

developed (Syahrinudin 1997). Nevertheless, tree mortality in the 4-year-old stand was 

rather high (this is a common case for plantations established in degraded lands, e.g., I. 

cylindrica grassland, if there is no intensive management) (Soerianegara 1980; Otsamo 

et al. 1997). A stand density of 626 trees ha-1 allowed vigorous development of woody 

undergrowth. 
Acacia mangium plantations

26

Table 4.4: Biomass of undergrowth (above- and belowground) and litter standing stock 

in Acacia mangium stands of different ages in East Kalimantan, Indonesia

Aboveground biomass Stand age Belowground 

biomass WU HU Total 

Litter standing 

stock 

(year) (Mg ha-1) 

Mean 0.45 1.04 4.25 5.29 1.64 

1 SD 0.39 0.58 1.51 1.73 0.63 

n 6 6 9 6 9 

Mean 1.15 11.31 0.91 12.22 9.27 

4 SD 0.40 3.62 0.38 1.24 3.71 

n 6 6 9 6 9 

Mean 0.11 0.60 0.17 0.78 5.96 

9 SD 0.04 0.19 0.13 0.17 1.58 

n 3 3 9 3 8 

SD = standard deviation, WU= woody undergrowth, HU = herbaceous undergrowth. 

In line with the undergrowth biomass, the litter standing stock of the 4-yearold stands was highest. This may relate not only to the dense undergrowth, but also to 

the growth physiology of the stand, i.e., litter production is normally highest in the early 

fast growing period of the stand and then declines as the stand gets close to maturity 

(Lugo et al., 2004). A 9-year-old stand is possibly very close to the mature state for the 

A. mangium stands. The litter standing stock in this study is, however, in agreement 

with that of former studies (7.0-19.6 Mg ha-1) (Syahrinudin 1997; Ruhiyat 1989). 

4.3.2 Root distribution 

Roots are important for anchorage, water and nutrient uptake, storage of carbohydrates 

and synthesis of growth regulators. Fine roots represent a small portion of the total 

biomass of the ecosystem (De Agelis et al. 1981), typically less than 5 % (Jackson et al. 

1997; Vogt et al. 1996), but play a significant role in determining the functioning of the 

system. A significant part of the net primary production of both native and managed 

ecosystems is in some cases allocated to the fine root production (Harris et al. 1977; 

Buyanovsky et al. 1987). A magnitude of 30% to 50% of the C cycled annually in forest 

ecosystems is probably allocated to fine root production (Grier et al. 1981; Vogt et al. 

1996). Of the global primary production, roots consume about 30% (Jackson et al. 

1997). 

Fine root biomass of the A. mangium plantation system ranged from 9.5 Mg 

ha-1 3 m-1 (in the first and fourth year) to 12.3 Mg ha-1 3 m-1 (in the ninth year). This is 
Acacia mangium plantations

27

quite comparable to the root biomass of I. cylindrica of 12.4 Mg ha-1 3 m-1. However, 

the vertical distribution of the root biomass of I. cylindrica grassland was restricted to 

the topsoil (Figure 4.2). The results of this study are in agreement with those of previous 

works (Curt and Prévosto 2003; Makkonen and Helmisaari 1999; Hendricks and 

Bianchi 1995; Vogt et al. 1996). Curt et al. (2001) reported estimates of fine root 

biomass of Douglas fir in the upper 30 cm soil of 17.3-28.4 Mg ha-1. These values are 

clearly higher than those in this study, which are, however, quite comparable to those 

reported by Santantonio et al. (1977) studying fine root biomass (<5 mm) in the upper 

soil in Douglas-fir forests of Oregon ranging from 8.5 to 10.1 Mg ha-1. The values in 

this study are also in agreement with those for plantations in Michigan and Oregon 

reported by Fogel (1983) (about 8.0 to 24.1 Mg ha-1). 

Generally, fine root biomass contributes only a small portion of the total 

biomass of the system, typically less than 5% (Jackson et al. 1997; Vogt et al. 1996). 

The results in this study are, nevertheless considerably higher, especially for the 

younger stands (1- and 4-year-old stands) with averages of 37.35, 10.33 and 6.81% for 

the 1-, 4- and 9-year old stands, respectively. It seems that the fine root system of the 

plantation developed early from the beginning of the plantation to a required level, 

thereafter being maintained in a narrow dynamic range.

In line with the results of previous works (Swamy et al. 2003; Tufekcioglu et 

al. 2003; Curt et al. 2001; Dhyani and Tripathi 2000; Sommer et al. 2000), the fine 

roots of the A. mangium plantation systems were concentrated in the top centimeters of 

the soil profile. In the 3 m-deep soil profile, more than 50% of the fine root biomass was 

found in the top 30 cm. However, compared to I. cylindrica grassland, the fine roots of 

A. mangium penetrated much deeper to a depth of 3 m. This is much deeper than the 1.8 

m in I. cylindrica grassland. Moreover, 90% of the root biomass of I. cylindrica

grassland confined to a depth of 41 cm was clearly much shallower than for A. mangium

plantation systems, where values were of 157 cm, 167 cm and 170 cm for the 1-, 4- and 

9-year-old stands, respectively. 

Fine root biomass showed a continuous decrease with soil depth, thus being in 

accordance with many previous studies (Curt and Prévosto 2003; Curt et al. 2001; 

Tufekcioglu et al. 1999; Nie et al. 1997), which indicate that this root profile usually 

corresponds to a vertical decrease in nutrients, porosity, and water storage capacity in 
Acacia mangium plantations

28

the soil profiles (Sainju and Good 1993). Fine roots proliferate in the A-horizon of most 

soils due to the accumulation of organic matter, higher CEC and organic C, N, P and K 

concentration (Bowen 1984; Kalisz et al. 1987; Pritchett and Fisher 1987; Sainju and 

Good 1993). A rapid vertical decrease in fine root density was observed in a highly 

acidic soil under spruce stands (Jentschke et al. 2001). 

The vertical distribution of fine roots indicates the rooting strategy of trees and 

is species specific and genetically inherited (Curt and Prévosto 2003; Polomski and 

0

50

100

150

200

250

300

0.0 0.1 1.0 10.0

Fine root biomass (Mg ha-1 15 cm-1)

Soil depth (cm)

IC

AM1

AM4

AM9

Figure 4.2: Vertical distribution of fine root biomass of the Acacia mangium

plantation system (AM) and Imperata cylindrica grassland (IC) in East 

Kalimantan, Indonesia (1, 4 and 9 = 1-, 4- and 9-year-old stand) 
Acacia mangium plantations

29

Kuhn 1998; Brown 1992). There are very few reports on the root distribution in A. 

mangium plantation systems. However, the results of this study show that the 

distribution of the fine root biomass of the plantations was similar regardless of age. 

This high fine root biomass accumulation in the top few centimeters of the soil is typical 

for many pioneer trees (Polomski and Kuhn 1998; Perala and Alm 1990; Grime 1979). 

This shallow concentrated rooting strategy may allow an efficient use of the topsoil 

resources (Crabtree and Berntson 1994). 

The lateral extent of woody roots may exhibit a high degree of plasticity and 

depend on environmental conditions (Millikin and Bledsoe 1999; Belsky 1994). In line 

with previous findings (Purbopuspito and Van Rees 2002; Jose et al. 2001; Peter and 

Lehmann 2000; Jones et al. 1998), although not significant, there was a slight decrease 

in the horizontal distribution of the fine root biomass with distance to the tree base in 1- 

and 9-year-old stands (Figure 4.3). Such a decrease could not be observed in the 4-yearold stand. This may relate to the dense undergrowth occupying the sites of this stand. 

However, Millikin and Bledsoe (1999) reported that distance from tree did not 

significantly affect fine root biomass of blue oak. 

Root distribution is highly variable and is constrained by the microsite spatial 

variability created by the soil environment or by the different plant species existing on 

each site (Roy and Singh 1995; Vogt et al. 1995). The present results show that the 

Figure 4.3: Horizontal distribution of fine root biomass of Acacia mangium

plantation system in East Kalimantan, Indonesia; rectangles are means 

and stake bars are standard deviations 

4-year-old stand

0

2

4

6

8

10

12

14

16

0 50 100 150 200 250

Distance to closest trunk (cm)

Biomass (Mg ha-1 1 m-1

)

1-year-old stand

0

2

4

6

8

10

12

14

16

0 50 100 150 200 250

Distance to closest trunk (cm)

Biomass (Mg ha-1 1 m-1

)

9-year-old stand

0

2

4

6

8

10

12

14

16

0 50 100 150 200 250

Distance to closest trunk (cm)

Biomass (Mg ha-1 1 m-1

)
Acacia mangium plantations

30

distribution of the fine root biomass in the A. mangium plantations was highly 

heterogeneous, with coefficients of variation ranging from 41.3-216.2% and 5.6-153.7% 

for within and among sites, respectively. The variability within sites was much higher 

than that among sites, on average by a factor of 2 (coefficient of variation of 108.0 ± 

21.0% and 57.1 ± 22.3% for within and among sites, respectively). A considerable 

variability of Douglas-fir root biomass within microsite has also been observed (Curt et 

al. 2001). This high variability of fine root biomass within sites may reflect a high 

micro-spatial variability of the soil resources of the system. It could, therefore, be of 

interest to determine to what extent soil and microsite patches can modify fine root 

biomass, architecture, and seasonal turnover, thus conditioning the exploitation of soil 

resources (Drexhage and Gruber 1998; Fitter 1994; Pritchett and Fisher 1987). 

Details on the variability of the vertical fine root biomass distribution of the 

system are depicted in Figure 4.4. In general, the variability was considerably low in the 

first 15 cm of the soils, followed by an increase to a depth of 120-165 cm. Thereafter, 

variability decreased to the depth of 3 m. However, there were some exceptions to this 

general trend. The 1-year-old stands exhibited a persistent increase in the variability of 

vertical fine root biomass distribution to a depth of 3 m. It is the question whether this 

4-year-old stand

0

50

100

150

200

250

300

0 50 100 150 200 250

Coefficient of variation (%)

Soil depth (cm)

1-year-old stand

0

50

100

150

200

250

300

0 50 100 150 200 250

Coefficient of variation (%)

Soil depth (cm) 

9-year-old stand

0

50

100

150

200

250

300

0 50 100 150 200 250

Coefficient of variation (%)

Soil depth (cm)

Within Site

Among Site

Figure 4.4: Variability of vertical fine root biomass distribution within and among 

sites of Acacia mangium plantation systems in East Kalimantan, 

Indonesia 

Soil depth (cm)Soil depth (cm)
Acacia mangium plantations

31

increase is the result of the insufficient sample size or whether it illustrates the real 

variability of the distribution. 

In the first 1 m depth of the soil, the same sample size was applied in 

determining the fine root biomass distribution in all stand ages (153 root auger points). 

However, for the second and third 1-m depth, a more intensive sampling was 

undertaken for the 4-year-old stand, i.e., a sample size of 65 and 45 root auger points, 

respectively. The sample size for the respective depth of the 1- and 9-year-old stands 

was only 20 and 15. Based on the variability of the fine root biomass of the defined soil 

profile (to depth of 3 m) and the sample size, it was observed that the variability of the 

fine root biomass was not significantly affected by the sample size. Compared to the 

deeper part of the soil profile (second and third 1-m depth) where a 15-65 sample size 

was used, employing a 153 sample size in the first 1-m depth did not significantly 

reduce the variability. It is also evident that increasing the sample size from 15 to 45 

auger points and from 20 to 65 auger points for the third and second 1-m depth, 

respectively, did not result in a significant reduction in the variability. This implies that 

employing the core sampling method does not give a precise result in the assessment of 

the fine root parameters of a system, especially if a small sample size is applied. 

The variability of the fine root biomass was, to some extent, defined by the 

soil bulk density of the sites (Figure 4.5). Generally, there was a positive non-linear 

correlation between soil bulk density and coefficient of variation of fine root biomass. It 

was observed that the correlation between soil bulk density and coefficient of variation 

of fine root biomass followed the Modified Exponential model (y = aeb/x, r = 0.75, p < 

0.001, a = 1086.26, b = -3.45). This is in line with the finding of Curt et al. (2001) 

reporting that the soil physical characteristics may alter the root system of Douglas fir. 

Nevertheless, it is interesting that the coefficients of variation of fine root biomass of 

the 9-year-old A. mangium stand were distributed below the expectation line of the

equation. This may reflect that the older plantations have a somewhat better ability to 

manipulate the detrimental environment, thus allowing an optimal exploitation of the 

soil resources. 

Compared to that of I. cylindrica grassland (coefficient of variation ranged 

from 34.65 to 94.85%) in the vicinity of the plantation systems, the variability of the 

fine root biomass of A. mangium was higher. However, the vertical trend of the 
Acacia mangium plantations

32

variability of the root biomass distribution in the I. cylindrica grassland system was 

rather similar to that of 1-year-old A. mangium plantations. On the one hand, this high 

variability may be beneficial, if it reflects the ability of the system to adapt to the 

unfavorable environment so that the optimal utilization of resources may still be 

maintained. On the other hand, it may be disadvantageous, if this variability has resulted 

from the disability of the system to manipulate its environment. 

4.3.3 Biomass carbon distribution 

Carbon content of the stand biomass varied from 27.9% to 45.6% (Table 4.5) depending 

on the tree compartment. These figures are slightly lower than the assumption of 50% 

proposed by Brown and Lugo (1984) and Hamburg (2000). Compared to the root 

biomass of secondary and primary forests (43.9-46.6%) (Sommer et al. 2000), C 

content of the root biomass in this study (excluding those of fine root biomass) was 

quite comparable. Among those compartments, C content variability of fine root and 

Figure 4.5: Relationship between soil bulk density and variability of fine root biomass 

of Acacia mangium plantation system (A) and Imperata cylindrica

grassland (IC) in East Kalimantan, Indonesia; 1, 4 and 9 = 1-, 4- and 9-

year old stands; E(CV) = expected coefficient of variation of the systems 

0

20

40

60

80

100

120

140

160

1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7

Soil bulk density

Coefficient of variation of fine root biomass 

(%)

E(CV) IC A1 A4 A9

Coefficient of variation 

of root biomass (%) 
Acacia mangium plantations

33

leaf biomass was the highest, ranging from 27.9-34.2% and 39.1-43.9% (coefficient 

variation of 10.9 and 7.7%) for the fine root and leaf biomass, respectively. The 

variability of the C content in other compartments was considerably low (coefficient 

variation ranging from 0.7 to 2.8%). 

Excluding the C content of the fine root biomass, the C content among tree 

compartments was not significantly different. This implies that sampling of tree 

compartments is only important in determining the dry matter of each compartment of 

the stand, and sampling in different compartments to determine their C content is not 

necessary. 

Contrary to expectation, there was no significant difference in C content of the 

tree compartments across plantation age. This also implies that sampling for different 

stand ages to determine their C content is unnecessary. 

Table 4.5: Carbon content of tree compartments of different ages of Acacia 

mangium stands in East Kalimantan, Indonesia

Root Stand age Fine Coarse Stem Branch Leaf 

(year) (%) 

1 29.7 43.8 44.6 45.6 39.1 

4 34.2 43.6 45.1 44.3 43.9 

9 27.9 44.9 45.1 43.8 42.9 

Mean 30.6a 44.0b 44.9b 44.5b 42.4b

SD 3.3 0.9 0.3 1.3 3.3 

n 9 7 6 7 8 

SD = standard deviation, mean values followed by the same letters are not significantly different at α = 

0.05. 

The C content of undergrowth biomass in the studied stands ranged from 37.3 

to 41.6% (Table 4.6). Average C content of the woody undergrowth biomass was 40.9, 

40.7, 39.3, and 38.9 for the root, stem, branch, leaves compartment of the woody 

undergrowth, respectively and 38.8% for the herbaceous undergrowth. Nevertheless, 

there were no significant differences in C content among the compartments. The 

variability of C content within compartments was considerably low (coefficient of 

variation of 2.1, 2.9, 5.4, 3.3, and 4.6% for the root, stem, branch, leaves compartment 

of the woody undergrowth and herbaceous undergrowth, respectively). 
Acacia mangium plantations

34

Table 4.6: Carbon content of undergrowth and litter standing stock under different 

ages of Acacia mangium stands in East Kalimantan, Indonesia

Woody undergrowth 

Stand age Roots Stems Branches Leaves

Herbaceous 

undergrowth 

Litter 

standing 

stock 

(year) (%) 

1 38.0 41.6 nd 38.8 40.8 35.4 

4 41.5 41.2 39.3 38.4 37.3 34.4 

9 40.5 39.5 nd 39.5 38.3 37.8 

Mean 40.9a 40.7a 39.3a 38.9a 38.8a 35.8b

SD 0.9 1.2 - 1.3 1.8 4.9 

n 6 6 2 6 6 6 

SD = standard deviation, nd = not determined; mean values followed by the same letters are not 

significantly different at α = 0.05. 

Compared to that of trees and undergrowth, the C content of litter standing 

stock biomass was, however, slightly lower (average of 35.8%), but the variability was 

higher (coefficient variation of 13.6%). This implies that a larger number of samples is 

required for a better assessment of the C content of the litter standing stock. 

Table 4.7: Total C distribution of different ages of Acacia mangium plantation 

system in East Kalimantan, Indonesia

Stand age BGB AGB Litter Total RBGB RWUG RHU 

(year) (Mg ha-1) (%) 

Mean 3.6 7.2 0.6 11.4 31.5 5.3 15.2 1 SD 0.8 0.9 0.1 1.7 7.3 2.9 4.7 

Mean 7.2 28.5 3.2 38.9 18.6 13.1 0.9 4 SD 1.5 0.7 0.6 2.5 3.8 1.3 0.2 

Mean 14.2 62.1 2.2 78.6 18.1 0.4 0.1 9 SD 1.9 8.3 0.3 10.3 0.7 0.1 0.02 

SD = standard deviation, BGB = belowground biomass C, AGB = aboveground biomass C, RBGB = 

relative belowground biomass C to total, RWUG = relative woody undergrowth biomass C to total C of 

the system, RHU = relative herbaceous undergrowth to total biomass C to total C of the system. 

Total biomass C distribution of the A. mangium plantation system is presented 

in Table 4.7. Both below- and aboveground biomass C increased persistently in line 

with age of the plantation. It was 3.6 and 5.5 Mg ha-1 in the 1-year-old plantation and 

14.2 and 62.1 Mg ha-1 in the 9-year-old plantation, respectively. 

Total C stored in the plantation system increased from 9.6 Mg ha-1 in the 1-

year-old plantation to 78.6 Mg ha-1 in the 9-year-old plantation. Compared to I. 

cylindrica grassland, where values were 7.5, 4.0, 3.6 Mg ha-1 for the total, below- and 

aboveground biomass C, respectively, it is clear that the total biomass C accumulated in 
Acacia mangium plantations

35

the plantation system has surpassed that of I. cylindrica grassland early in the beginning 

of the plantation. However, the curve of the annual rate of C sequestered by the system 

is quite flat across plantation age (Figure 4.6). This implies that when C sequestration is 

the concern, plantation management for more than 9 years (harvesting expectation for 

pulp production) seems to be beneficial. Furthermore, if the C of the stems as the 

harvested component is the concern, harvesting of a 9-year-old A. mangium stand is 

considered too early, because it would not have reached the peak of its economic cycle. 

The average annual C sequestration in the biomass of the system of 9.3 Mg ha-1

yr-1 was remarkably higher than that of riparian planted poplars of 2.9 Mg ha-1 yr-1

(Tufekcioglu et al. 2003). 

With regard to the practical implication of the measurement of biomass C of A. 

mangium in forestry-based C offset projects, a simple and reliable method should be 

established. The results in this study show that estimation of the biomass of A. mangium

stands from tree diameters is sufficiently accurate and reliable. Both aboveground and 

belowground biomass C of the stand could be well estimated with this method (Table 

4.8). However, there is no parameter for simplifying the measurement of the biomass C 

Figure 4.6: Annual carbon storage in biomass of Acacia mangium plantation system 

in East Kalimantan, Indonesia; TC = total biomass carbon, SC = stem 

biomass carbon 

0

2

4

6

8

10

12

0 2 4 6 8 10

Plantation age (year)

Annual carbon stored (Mg ha-1) Annual carbon stored (Mg ha

TC SC

-1) 
Acacia mangium plantations

36

of undergrowth, litter standing stock and fine roots of the plantation. There is a wide 

range of biomass values of undergrowth and litter standing stock in A. mangium

plantations, and they should, therefore, be measured directly in each specific stand. 

Among of the biomass compartments, measurement of fine root biomass is the most 

time consuming and labor intensive. The results show that there was a small variation of 

fine root biomass and biomass C among plantation ages, but the variation within sites 

was considerably high (see Figure 4.5). This implies that estimation of fine root biomass 

and biomass C with a small sampling size is subject to high errors. Applying a sample 

size of 153 auger points resulted in coefficients of variation of 108.0 ± 21.0% and 57.1 

± 22.3% for within and among sites, respectively. However, fine root biomass C ranged 

from 2.8 to 3.4 Mg ha-1, producing less than 5% of the total biomass C of the mature 

plantation system. Therefore, estimations of fine root biomass C of A. mangium

plantation systems with a factor of 4% of the total biomass C of the system for the 

mature plantations or adopting a magnitude of 3.0 Mg ha-1 for the young plantations 

would be sufficient and is recommended. 

Table 4.8: Allometric equations for biomass C (Mg ha-1) estimation of Acacia 

mangium plantations in East Kalimantan, Indonesia, based on tree 

diameter (DBH, cm) 

Dependent Variable a b r2p 

Coarse and medium roots C 0.0051 2.6198 0.9669 < 0.001 

Stem C 0.0599 2.2971 0.9111 < 0.001 

Branch C 0.0752 1.6512 0.9428 < 0.001 

Leaf C 0.0265 1.8208 0.8941 < 0.001 

Aboveground biomass C 0.1188 2.1546 0.9258 < 0.001 

Total biomass C 0.1143 2.2219 0.9441 < 0.001 

Regression model: Y = a * DBHb 

There is little information on the total biomass and C storage of plantations in 

the tropics. Most publications deal with aboveground biomass of stands (excluding 

biomass of undergrowth and litter standing stock, an exception to studies of Syahrinudin 

1997 and Ruhiyat 1989) and information on belowground biomass and C stock is very 

scarce. Based on available data on aboveground biomass of A. mangium plantations 

presented in Table 4.3 and the assumption of a C content of 43.3% (overall average of C 
Acacia mangium plantations

37

content of A. mangium plantations in this study), a general rate of C accumulated in this 

plantation system was constructed (Figure 4.7). 

Figure 4.7 shows that general accumulation of C in aboveground biomass of A. 

mangium stands follows the Gompertz Relation (Y = a*exp(-exp(b-cx)), a = 75.18, b = 

1.38, c = 0.39, r2 = 0.58 and p < 0.001). Calculation of the general rate of C sink in the 

aboveground biomass of the stands gave an average of 8.0 Mg ha-1 yr

-1, which is 

slightly higher than the calculation based on the data in the present study of 6.5 Mg ha-1

yr-1. These figures are, however, lower than the estimation by ISME (1999) of 12.5 Mg 

ha-1 yr

-1. Compared to the total biomass C sink in this study of 9.3 Mg ha-1

 yr

-1

, 

aboveground biomass C of the stand produced 70% of the total C accumulated in the 

system. Applying this value, the general rate of total C sink of A. mangium plantation 

system of 11.4 Mg ha-1 yr

-1 was calculated. With regard to timber production, if there is 

no requirement for a minimum tree dimension and the price for the timber is flat across 

tree dimension and age, the best cutting cycle would be at the age of 6 years (Figure 

4.8), because at this point of time, the CAI (Current Annual Increment) crosses the MAI 

0

10

20

30

40

50

60

70

80

90

0 2 4 6 8 10

Plantation age (year)

0

2

4

6

8

10

12

CAI and MAI (Mg ha-1 yr-1

)

Aboveground biomass C (Mg ha

-1) 

Figure 4.7: General rate of carbon sink in Acacia mangium plantation system; 

references see Table 4.3 
Acacia mangium plantations

38

(Mean Annual Increment) indicating the highest stand growth rate and revenue for the 

plantation. 

In contrast to the persistent increase of the belowground biomass, the relative 

contribution of belowground biomass C to total biomass C decreased in the older stages 

of the plantation. However, the contribution of belowground biomass C of the 4-yearold stands was quite comparable to that of the 9-year-old stands. This suggests that the 

contribution of the belowground biomass C in the older stands is fairly stabile (average 

18.4% ± 2.7%). As sampling of the belowground biomass C is time and labor 

consuming, this figure could be adopted for estimation of the belowground biomass C 

of similar plantation systems elsewhere. 

The ratio of belowground to aboveground biomass (root/shoot ratio) of forest 

systems is strongly influenced by stand age and site characteristics (Cairns et al. 1997). 

However, the results show that the range of this ratio is relatively narrow for the older 

plantations (4- and 9-year-old stands) (0.23-0.27). These values are in the range of those 

of temperate forests of 0.15-0.40 reported by (Cairns et al. 1997). 

In general, relative contribution of both woody and herbaceous undergrowth 

biomass C decreased with plantation age. The contribution of woody and herbaceous 

undergrowth biomass C dropped from 6.7 and 18.9% in the first year to 0.36 and 0.08% 

in the ninth year, respectively. This drop relates to the canopy development of the stand, 

since well established A. mangium stands have a dense canopy, and there is little 

available light for the development of undergrowth. Nevertheless, due to the high 

mortality rate of the stands, contribution of woody undergrowth in the 4-year-old stands 

was remarkably high (13.2%). 

The distribution of total biomass C in A. mangium stands is presented in Table 

4.9. Excluding that of the fine root compartment, total biomass C of all compartments of 

the stand increased in line with the plantation age. Of those compartments, the stem 

compartment stored the largest amount of biomass C, followed by the branch, coarse 

root and leaf compartments. However, the biomass C in the coarse root compartment in 

the 9-year-old stand was higher than that in the branch compartment. It is interesting to 

note that the ratio between the biomass C of the coarse root and stem compartment 

seemed to be maintained in the specific narrow range. It was 20.5%, 20.9% and 21.9% 
Acacia mangium plantations

39

for the 1-, 4-, and 9-year-old stands, respectively. This strongly implies that estimates of 

coarse root biomass C from that of the stem compartment are quite credible. 

Table 4.9: Total C distribution in Acacia mangium stands of different ages in East 

Kalimantan, Indonesia 

Stand age Fine 

root 

Coarse 

root 

Stem Branch Leaf AGB BGB Total 

(year) (Mg ha-1) 

Mean 2.8 0.6 2.9 1.5 0.7 5.0 3.4 8.5 1 SD 0.8 0.1 0.6 0.3 0.1 1.0 0.9 1.9

Mean 3.2 3.5 16.8 4.7 2.1 23.6 6.7 30.3 4 SD 1.5 0.1 0.7 0.2 0.1 0.9 1.4 1.5

Mean 3.4 10.7 49.0 8.6 4.4 61.9 14.2 76.1 9 SD 0.6 1.6 7.0 0.8 0.5 8.3 1.9 10.1

SD = standard deviation, BGB = belowground biomass C, AGB = aboveground biomass C; three 

replications of each stand age; fine roots were defined to depth of 3 m. 

Total fine root biomass C of the A. mangium plantation system ranged from 

2.8 Mg ha-1 in the first year to 3.4 Mg ha-1 in the ninth year. However, there was no 

significant difference in fine root biomass C among the plantation ages. The overall 

average of total fine root biomass C was 3.2±0.9 Mg ha-1. 

Table 4.10: Total C distribution of litter standing stock and undergrowth in Acacia 

mangium stands in East Kalimantan, Indonesia

Aboveground biomass C Stand age Belowground 

biomass C WU HU Total 

Litter standing 

stock C 

(year) (Mg ha-1) 

Mean 0.17 0.43 1.73 2.16 0.58 

1 SD 0.13 0.20 0.53 0.73 0.12 

n 6 6 9 3 9 

Mean 0.47 4.61 0.34 4.95 3.19 

4 SD 0.10 0.57 0.05 0.61 0.62 

n 6 6 9 3 9 

Mean 0.04 0.24 0.07 0.30 2.21 

9 SD 0.01 0.08 0.03 0.10 0.30 

n 6 6 9 3 9 

WU= woody undergrowth, HU = herbaceous undergrowth 

Although undergrowth biomass C played only a minor contribution to the total 

biomass C of the system, it may have an important role in litter production of the 

system, which in turn may benefit the enrichment of the soil C of the system. Since 

undergrowth grows fast and has a short life cycle, a considerable amount of litter may 
Acacia mangium plantations

40

have been contributed. This hypothesis is supported by the data (Table 4.10) showing 

that a large amount of litter standing stock C was found in the 4-year-old stand, which 

had a considerably high amount of undergrowth biomass C. However, litter production 

of a plantation system does not solely rely on the presence of undergrowth but to some 

extent also depends on the physiological characteristics of the stands. 

4.3.4 Soil carbon distribution 

The patterns of soil C distribution vary highly with soil age, soil texture, rainfall and 

temperature patterns, and vegetation type. The vertical distribution in both I. cylindrica

grassland and A. mangium plantation systems was quite similar to that in previous 

studies reported by Syahrinudin (1997) and Ruhiyat (1989) in soils in the same region. 

Soil C content decreased in line with the soil depth (Figure 4.9) and was highly depth 

dependent (r2 ranged from 0.97 to 0.99). The slope of the decrease in the soil C content 

is steep in the upper 50 cm of the soils and more gentle in the deeper soils. 

Nevertheless, a distinct difference in the vertical soil C distribution can be observed 

between I. cylindrica grassland and A. mangium plantation systems. Compared to that 

of the A. mangium plantation system, the slope of the decrease in I. cylindrica grassland 

was less steep in the upper 50 cm but m steeper for the lower part of the soil profile (see 

Figure 4.8). This demonstrates the strong influence of fine root biomass on soil C 

content. Although the vertical distribution of soil C is determined by soil depth, spatial 

variation seems to be dictated by the fine root biomass distribution (r2 of 0.83-0.99). 

Soil C content is the result of litter (above- and belowground) production 

defined by vegetation type and development stage, and soil respiration controlled by 

root respiration and by decomposition of litter and soil organic matter. Soil physical 

properties such as texture and structure may control the respiration of the soils (De Jong 

and Schappert 1972). Soil temperature and moisture are the most important factors 

regulating soil respiration (Kicklighter et al. 1994; Lloyd and Taylor 1994; Howard and 

Howard 1993). However, the results in this study do not show a significant difference in 

soil C content in the upper part of the soil (top 50 cm), which is the layer affected most 

strongly in terms of soil temperature by the conversion of I. cylindrica grassland into A. 

mangium plantation. It seems that the influence of the plantation on soil temperature 

and moisture was offset by the effect of belowground litter production. In the upper 50 
Acacia mangium plantations

41

cm soil, the fine root biomass of I. cylindrica grassland (2.5 kg dm-3) was much higher 

than that of A. mangium (1.4-1.6 Mg dm-3). However, the roots of I. cylindrica

grassland, which were confined to a shallow top layer of the soil (1.8 m) may explain 

the lower soil C content in the deeper soils in contrast to the fine roots of A. mangium, 

which extend to a depth of 3 m. 

Soil C storage in this study is in the range of that reported in previous studies 

(Mackensen 1998; Syahrinudin 1997; Bremen et al. 1990; Ruhiyat 1989). Total C 

stored in the soils in A. mangium plantation systems ranged from 158.6 – 246.2 Mg ha-1

3 m-1 (Figure 4.9). These values are somewhat higher than the values of primary and 

secondary forests of 130.0 – 145.0 Mg ha-1 3 m-1 reported by Sommer et al. (2000). The 

C values in the soils in the I. cylindrica grassland ranged widely (from 120.3 Mg ha-1 3 

Figure 4.8: Vertical distribution of soil C content (%) in different ages of Acacia 

mangium stands in East Kalimantan, Indonesia 

0

50

100

150

200

250

300

0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60

Carbon content (%)

Soil depth (cm)

Imperata cylindrica

Acacia mangium 

1-year-old stand

Acacia mangium 

4-year-old stand

Acacia mangium 

9-year-old stand

Imperata cylindrica

Acacia mangium 

Acacia mangium 

Acacia mangium
Acacia mangium plantations

42

m

-1 in Sumatra to 150.6 Mg ha-1 3 m-1 in East Kalimantan). However, since the A. 

mangium plantations are located in East Kalimantan, the base line for all calculations of 

the soil C sink of the plantations is the soil C storage of I. cylindrica in East 

Kalimantan. 

Soil C storage is largely dependent on environmental, biogeochemical and 

land management factors. Different land use and management practices influence soil 

properties such as soil temperature, moisture, microbial biomass, organic matter and 

fine root biomass, which in turn affect the magnitude of soil respiration (Lee and Jose 

2003; Raich and Tufekcioglu 2000; Kelting et al. 1998) and soil C dynamics. Trees can 

substantially increase the organic matter input into the system through the turnover of 

leaves and roots (Jose et al. 2000). The results in this study show that the conversion of 

I. cylindrica grassland into A. mangium plantation considerably increased the soil C 

storage. The rate of soil C accumulation was 1.7 – 3.0, 3.4 – 4.6 and 3.5 – 4.9 Mg ha-1

yr

-1 for the first, second and third 1-m-depth, respectively. There was a slight decrease 

Figure 4.9: Soil C storage in Imperata cylindrica grassland and Acacia mangium

plantation systems in East Kalimantan, Indonesia 

0

50

100

150

200

250

300

350

0-50 50-100 100-200 200-300 0-300

Soil Depth (cm)

Total carbon (Mg ha-1

)

Imperata cylindrica

Acacia mangium, 1-year-old stand

Acacia mangium, 4-year-old stand

Acacia mangium, 9-year-old stand

Acacia mangium,

Acacia mangium,

Acacia mangium,

Total carbon (Mg ha

-1) 

Soil depth (cm) 
Acacia mangium plantations

43

at a depth of 0-50 and 50-100 cm during the early stages of plantation establishment, 

which may be related to the lower litter production. However, the deeper soils 

experienced an increase in C storage from the beginning of the plantations (Figure 4.9). 

An increase in soil C accumulation (0-100 cm) from 0.66 to 1.17 Mg ha-1 yr-1 by 

incorporating legume trees in a grass pasture was reported by Tarré et al. (2001). Sataye 

et al. (2001) estimated an increase in soil C of 0.5 to 3.0 Mg ha-1 yr-1 in forest 

plantations in the tropics. A magnitude of soil organic matter sink of 1.1 Mg ha-1 yr-1

was reported by Lugo et al. (2004) in restored neotropical forest systems in Puerto Rico. 

The most important finding of this study is that the conversion of I. cylindrica

grassland into A. mangium plantation led to a much higher C sequestration in deep soils 

than in the upper soil layers. This finding is in contrast to the proposed soil C change 

measurement in forestry offset projects to a depth of only 1 m (Hamburg 2000). While 

most previous soil C studies concentrate on the upper soil layers down to a maximum 

depth of 2 m (Tufekcioglu et al. 2003; Tarré et al. 2001; Brown and Lugo 1990; Fisher 

et al. 1994; Moraes et al. 1995), the results of this study confirm the finding of Sommer 

et al. (2000), Trumbore et al. (1995) and Nepstad et al. (1994) showing the importance 

of root penetration in deep soil layers for C sequestration. Moreover, the C sequestered 

in deep soils could be more beneficial than that sequestered in shallow soils, because 

soil organic matter of deep soils is more resistant to decomposition and thus has a 

longer resident time (Gaudinski et al. 2000; Van Dam et al. 1997). The overall rate of 

soil C sequestration by this conversion was 8.6 – 12.7 Mg ha-1 yr-1. These figures are 

indeed much higher than those reported in former studies. With a rate of biomass C 

accumulation of 9.3 Mg ha-1 yr-1, an aboveground litter production of 3.2 Mg ha-1 yr-1

, 

and a fine root biomass production ranging from 66 –70% of net primary production 

(Fogel 1985; Grier et al. 1981), a magnitude of 41.7 Mg C ha-1 yr-1 could be allocated 

for fine root production. This suggests that the above values of soil C sequestration are 

still reasonable. Furthermore, it should be taken into account that most of the 

sequestration (more than 75%) is assigned to the deeper part of the soils (1-3 m depth). 

If the plantations are harvested after 9 years (expected harvesting age for pulp 

production), a soil C sink of 77.4 – 113.9 Mg ha-1 could be expected. These values are 

higher than for C sequestered in the biomass of the plantation system amounting to only 

78.6 Mg ha-1.
Acacia mangium plantations

44

4.3.5 Carbon distribution in Acacia mangium plantation system 

Carbon content of the stand biomass of the A. mangium plantation varied from 27.9% to 

45.6% depending on the tree compartment. Variability was highest in fine root and leaf 

biomass, ranging from 27.9-34.2% and 39.1-43.8% (coefficient variation of 10.9 and 

7.7%), respectively. Variability in other compartments was considerably low, with 

coefficient variations ranging from 0.7 to 2.8%. The C content of undergrowth biomass 

of 37.3 to 41.6% was quite comparable to that of stand biomass. Compared to that of 

trees and undergrowth, the C content of litter standing stock biomass was, however, 

slightly lower (average of 35.8%), but variability was higher (coefficient variation of 

13.6%). 

Below- (to depth of 3 m) and aboveground C stocks increased substantially 

from 162.2 and 7.8 Mg ha-1 for the 1-year-old plantation to 260.4 and 64.4 Mg ha-1 for 

the 9-year-old plantation, respectively (Figure 4.10). Compared to I. cylindrica

grassland with 154.6 and 3.6 for the below- and aboveground C stocks, respectively, it 

is clear that the level of C stocks of the A. mangium plantation was higher than that of 

the I. cylindrica grassland since the early stages of the plantation. Of the C stored in the 

-100 -80 -60 -40 -20 0 20 40 60 80

Carbon stock (Mg ha-1)

Belowground biomass

Soil

Litter

Undergrowth

Crop

Figure 4.10: Carbon distribution of Imperata cylindrica grassland and Acacia 

mangium plantation systems in East Kalimantan, Indonesia; 

belowground C stock was defined to depth of 3 m; values for the aboveand belowground C of the Imperata cylindrica grassland were 

considered as the baseline for the plantations 

Belowground baseline Aboveground baseline 

300 240 180 120 60 

Belowground Aboveground

A. mangium, 9-yr-old 

A. mangium, 4-yr-old 

A. mangium, 1-yr-old 

Imperata cylindrica
Acacia mangium plantations

45

biomass of the plantation systems, 18% (4- and 9-year-old stands) to 32% (1-year-old 

stand) was allocated to the belowground biomass. The rate of C accumulation in the 

biomass of the A. mangium plantation systems averaged 9.3 Mg ha-1 yr-1

. 

Soil C content of the systems decreased in line with soil depth and was highly 

depth dependent (r2 ranged from 0.97 to 0.99 and p of < 0.001). However, spatial 

variation seems to be dictated by the fine root biomass distribution in the system (r2 = 

0.83-0.99 and p < 0.001). 

Conversion of I. cylindrica grassland into A. mangium plantation led to a much 

higher C sequestration in the deep soils. The rate was 1.7-3.0, 3.4-4.6 and 3.5-4.9 Mg 

ha-1 yr-1 for the depths 0-1, 1-2 and 2-3 m, respectively. A potential soil C sink of 77.4-

113.9 Mg ha-1 could be expected by this conversion. More than 75% of this amount was 

allocated to the deep soils (100-300 cm soil depth). Together with the C sequestered in 

the biomass of the plantations, C sequestration of 156.0-192.5 Mg ha-1 could be 

achieved. 

It is interesting that most of the C stored in the plantation system was allocated 

to the belowground stock (soil and belowground biomass C), a fact that has been 

ignored in most previous works, due probably to the difficulty in the assessment of this 

component. The results show that belowground C contributed to more than 95% in the 

early stages of the plantation (1-year-old) and then declined with age to only 80% in the 

9-year-old plantation (Table 4.11). However, the relative contribution of the 

belowground C stock of the A. mangium plantations was lower than that of the I. 

cylindrica grassland system (98%). 

Table 4.11: Below- and aboveground C stock distribution of Imperata cylindrica

grassland and Acacia mangium plantation systems in East Kalimantan, 

Indonesia 

 Belowground 

 Soil Biomass 

Aboveground 

biomass Belowground / total System 

(Mg ha-1) (%) 

Imperata cylindrica 150.6 4.0 3.6 97.7 

1-year-old 158.6 3.6 7.8 95.4 

4-year-old 196.9 7.2 31.7 86.6 Acacia 

mangium 

9-year-old 246.2 14.2 64.4 80.2 

Belowground C stock was defined to depth of 3 m 
Acacia mangium plantations

46

4.4 Conclusions 

Biomass and biomass C of the A. mangium plantation system increased with age to a 

level much higher than that of I. cylindrica grassland, implying that the conversion of 

marginal lands into plantations should be encouraged. In term of greenhouse gas 

mitigation, these plantations may lower the magnitude of atmospheric CO2 not only 

through sequestration, but also by preventing an increase in atmospheric CO2 through 

the use of the biomass produced in this plantation for bio-fuel replacing the use of fossil 

fuel. 

The deep penetration of the roots in A. mangium plantations likely has 

important implications for C sequestration in the deeper soils. Soil C storage increased 

with plantation age to almost twice that of I. cylindrica grassland, suggesting that the 

establishment of plantations is beneficial not only in terms of C sequestration but also in 

terms of land rehabilitation, as a considerable amount of nutrients may associate with C 

stored in the system. Furthermore, an increase in soil C storage may improve soil 

physical properties such as stability of soil structure and water holding capacity, and 

soil chemical properties such as nutrient availability. It could also increase CEC and 

thus decrease the risk of toxicity through certain elements, e.g., Al, which in turn would 

increase the fertility status of the respective soils. 

Conversion of I. cylindrica grassland into A. mangium plantations could 

sequester 78.4 Mg C ha-1 in the plantation biomass during a period of 9 years. The 

average rate of C accumulation in the biomass of the plantation was 9.3 Mg ha-1 yr-1

. 

Compared to total C stored in the biomass of I. cylindrica grassland of 7.6 Mg ha-1, an 

additional 70.8 Mg C ha-1 could be expected in the biomass alone. Together with that 

sequestered in the soil (to a depth of 3 m) of 95.7 Mg ha-1, a magnitude of C 

sequestration of 166.5 Mg ha-1 could be achieved. 
Oil palm plantations

47

5 OIL PALM PLANTATIONS 

5.1 Introduction 

There is an increasing interest in the importance of the role of terrestrial ecosystems in 

the global C budget. Tropical forests store a large amount of C (428 Pg in soil and 

vegetation, Watson et al. 2000) and serve as both a sink for and source of atmospheric 

C. Land-use change and forestry activities, primarily deforestation of the tropical 

forests, are a significant source of CO2 emissions, representing 1.6 Pg yr-1 of the total 

anthropogenic emission of 6.3 Pg yr-1 (Watson et al. 2000; Houghton et al. 1995). 

Plantations, either forests or woody perennial crops, have led to a decrease in 

the C pool to a magnitude of 50% lower than the original forest stock (Lasco 2002). Oil 

palm plantations are becoming the center of environmental controversies with regard to 

deforestation in the tropics. They have been made responsible for most of the 

deforestation in South East Asia. Nevertheless, this would not be the case if the 

plantations were established in degraded lands or in unproductive forests. It is obvious 

that whether such plantations facilitate the sink or emission of CO2 depends on the 

initial condition of the land on which the plantations are established. 

The oil palm as a perennial crop has become important, firstly, as a major 

source of oils and fats for human food, secondly, as animal feeds, and, thirdly, for 

manufacture of many domestic products such as cosmetics, soaps and detergents 

(Khalid et al. 1999). The establishment of large-scale monoculture oil palm plantations 

in Indonesia began in 1985, when they covered about 600.000 ha. In 1999, the area had 

expanded to about 3 million ha (Glastra et al. 2002; Wakker 2000). 

Production and trade in oil palm commodities has expanded rapidly in 

response to an increasing world population and improved living standards. The global 

production of palm oil has increased very rapidly, more than doubling between 1970 

and 1980. In 1980, palm oil became the world’s second most important vegetable oil 

after soybean. 

Oil palm is currently one of the major sources of vegetable oil in the world. 

The crop ranks second among the world oil production crops and first in the 

international market of vegetable oils and fats. This crop is grown in lowlands of the 

humid tropics (15° N - 15° S) with an evenly distributed rainfall of 1,800-5,000 
Oil palm plantations

48

mm/year and is well adaptable to a wide range of soils and to low pH, but sensitive to 

high pH (above 7.5) and to stagnant water (Wichmann 2001). 

These plantations show a very high productivity (Lamade and Setyo 2002) and 

there is evidence of the success of plantations in degraded land such as I. cylindrica

grasslands in Sumatra and Kalimantan. There are about 7.5-8.5 million ha of I. 

cylindrica grassland distributed over many islands in Indonesia, an area which would be 

sufficient for the extensive expansion of oil palm and forestry plantations planned by 

the government. These plantations have a high potential to be promoted in the world C 

trade and may, therefore, increase the foreign exchange earnings of the country. 

However, the question as to how much CO2can be sunk by converting I. cylindrica

grassland into plantations is still open. To answer this question, studies on the biomass 

and C storage of oil palm plantations compared to those of I. cylindrica grassland are of 

utmost importance. 

In this study, efforts are focused on quantifying the biomass and C 

accumulated in the oil palm plantations at different ages, as well as biomass and C 

distribution in the plantations. 

5.2 Methodology 

Sampling for the biomass and C storage inventory of oil palm plantations was carried 

out on sites in Sumatra and East Kalimantan. However, due to the time and labor 

constraints, sampling for aboveground biomass and C stock was conducted for 

plantations in Sumatra alone. Three 0.05 ha circular plots (r = 12.6 m, consisting of 7 oil 

palm trees; Figure 5.1) were established in 3-, 10-, 20- and 30-year-old oil palm 

plantations in Sumatra and 3- and 10-year-old plantations in East Kalimantan. Extreme 

variation in stand density, undergrowth coverage and land slope was avoided. Thus, 12 

plots were established in Sumatra (4 stand ages, 3 replications) and 6 plots in East 

Kalimantan (2 stand ages, 3 replications). To minimize errors induced by the variation 

of soil type, all observation plots were established in loamy to clayey Ultisols, as this 

soil type is the most common in these regions. 

For the biomass estimation, a palm tree from each crop age, with diameter and 

height approximately equivalent to the mean of the population, was harvested and 

uprooted. Total biomass of the harvested trees was weighed and samples were drawn 
Oil palm plantations

49

from the different components (trunk base, trunk, frond base, petiole, rachis, leaflet, 

spear, cabbage and inflorescence) and weighed. Samples were dried to a constant 

weight at 60°C to obtain the total dry weight of each component. Thereafter, samples 

were ground to pass a 0.2-mm sieve for chemical analysis. The trunk base was defined 

as the part of trunk developed belowground including roots developed underneath the 

trunk base to a depth of 1 m. 

Nine 0.5 m x 0.5 m sub-plots were randomly established to assess the biomass 

of the herbaceous undergrowth occupying the respective plot. All undergrowth in these 

sub-plots was harvested and weighed to calculate the total fresh weight. Samples were 

50 cm 

Sub-plot for undergrowth inventory 

and litter standing collection

Soil profile observation point 

Observation plot 

Root sampling zone 

Oil palm tree

C

Oil palm tree

C

B

Oil palm tree

B

Debris piling zone 

Root sampling 

A1

B1

C1

E1 D1

F

A2

C2

B2

D2

E2 A3

B3

C3

D3

E3

A1

B1

C1

E1 D1

F

A2

C2

B2

D2

E2 A3

B3

C3

D3

E3

A1

B1

C1

E1 D1

F

A2

C2

B2

D2

E2 A3

B3

C3

D3

E3

Root sampling 

Figure 5.1: Layout for the biomass and carbon storage sampling on oil palm 

plantation in Sumatra and East Kalimantan, Indonesia 

Root sampling 
Oil palm plantations

50

drawn representatively for the total dry weight assessment. Thereafter, the same 

procedure as for the tree samples was followed. 

Litter standing stock was defined as the litter in the L and F layers of the soils, 

because the H layer was incorporated into the soil sample. Sampling for litter standing 

stock was carried out as for undergrowth sampling. All litter in the sub-plots was 

collected, sorted into woody and non-woody components and weighed (fresh and air 

dry). A small sample from each component was drawn and processed following the 

same procedure as for tree samples. 

To estimate the total biomass of the system, root biomass was sampled and 

collected at 16 drilling points in each subplot (three subplots/plot) to a depth of 5 m 

(using an 8-cm-diameter root auger in 15 cm increments) distributed in a systematical 

sampling on the basis of the distance to the closest trunk – 10 cm (A), 100 cm (B), 200 

cm (C), 300 cm (D), 450 (E) and 520 cm (F). Roots were separated from the soil core 

by means of water saturation and flushing. 

A soil profile was established nearby the center of one of the three plots of 

each plantation age for observation of soil morphological characteristics and sampling 

of soil bulk density. Soil sampling and analyses were carried out following the 

procedure described in Section 3.2. 

Data were analyzed with analysis of variance (ANOVA) and means were 

compared with the LSD-test procedure.

5.3 Results and discussions 

5.3.1 Biomass distribution 

Both below- and aboveground biomass of the system increased persistently with 

plantation age. Total biomass of the system was 40.9, 117.9, 157.9 and 204.3 Mg ha-1

for the 3-, 10-, 20- and 30-year-old plantations (Table 5.1), respectively. Compared to 

the total biomass of I. cylindrica grassland near the plantations of 16.9 Mg ha-1, the total 

biomass of the oil palm plantations already surpassed that of I. cylindrica in the very 

early stage of the plantation. This suggests that conversion of I. cylindrica grassland 

into oil palm plantation is beneficial if biomass and land rehabilitation is the concern. Of 

the compartments of the system (crop, undergrowth and litter standing stock), the crop 

contributed the highest amount of biomass, accounting for 85.6-94.3%. Undergrowth 
Oil palm plantations

51

contributed 1.4-2.9% of the total biomass and litter standing stock 4.3-11.5%. Despite 

the minor contribution of these compartments to the total biomass, they could play an 

important role in the functioning of the system such as controlling soil erosion and 

surface run-off, and promoting soil C and nutrient cycles as well as soil biological 

activities. The undergrowth dry matter of a 5-year-old oil palm plantation can range 

from 2-3 Mg ha-1 to 7-8 Mg ha-1 depending on the extent of weeding (Chen et al. 1991) 

and this could decline to between 0.5 and 1 Mg ha-1 in the consecutive years. The values 

in this study ranging from 1.2 to 3.6 Mg ha-1 are still in this range. 

Table 5.1: Above- and belowground biomass distribution of different ages of oil 

palm plantation systems in Sumatra, Indonesia 

Aboveground biomass Age Belowground 

biomass Litter Undergrowth Crop 

Total 

biomass 

Relative 

belowground to total 

(year) (Mg ha-1) (%) 

3 13.3 4.7 1.2 21.7 40.9 32.5 

10 25.0 5.1 1.6 86.3 117.9 21.2 

20 40.1 15.7 3.6 98.4 157.9 25.4 

30 52.4 17.9 3.2 130.7 204.3 25.6 

Belowground biomass was defined to depth of 5 m. 

Aboveground crop biomass increased from 21.7 Mg ha-1 in third year of the 

plantation to 130.7 Mg ha-1 for the 30-year-old plantation. Aboveground biomass in 

previous studies varies widely from 68.9 to 86.0 Mg ha-1 for a 25-year-old oil palm 

(Nordin 2002) and a 23-year-old plantation (Khalid et al. 1999) to about 192.0 to 202.0 

Mg ha-1 for the 14- and 19-year-old oil palm (Sitompul and Hairiah 2000), respectively. 

Rees and Tinker (1963) reported a magnitude of aboveground biomass in 7- to 22-yearold oil palm plantations of 26.2-84.4 Mg ha-1. It is obvious that the aboveground 

biomass of the plantation systems is variable and may be influenced by the inherent 

characteristics, pedoagroclimatic conditions and management. 

Of the crop aboveground biomass, the trunk contributed 56.7 to 75.3%. These 

figures are considerably higher than those reported by (Khalid et al. 1999a) of 48% but 

are in agreement with those reported by Rees and Tinker (1963) of 7- to 22-year-old oil 

palm plantations of 42.8-73.0%. Trunk biomass in this study ranged between 13.1 and 

94.3 Mg ha-1 for the 3- and 30-year-old plantations, respectively (Table 5.2). Compared 

to the trunk biomass reported in previous studies of 36.7-46.8 Mg ha-1 for 22- to 27.5-
Oil palm plantations

52

year-old plantations (Khalid et al. 1999a; Corley et al. 1971; Tinker and Smilde 1963), 

the results are considerably higher. However, they are in agreement with the 88.5 Mg 

ha-1 of a 15-year-old plantation reported by Ng et al. (1968). 

Table 5.2: Biomass distribution of the oil palm trees of different ages in Sumatra, 

Indonesia 

Belowground Aboveground 

Age Root Trunk base Trunk Frond base Rachis Leaflet Others 

(year) (Mg ha-1) 

3 12.0 1.3 13.1 1.2 4.6 1.4 1.40 

10 16.1 8.9 49.0 20.5 9.9 4.8 2.16 

20 27.6 12.5 74.1 2.3 15.8 4.3 5.71 

30 35.7 16.7 94.3 3.3 24.2 6.4 6.54 

Trunk base, defined as part of trunk developed belowground including roots developed underneath the 

trunk base to depth of 1 m; rachis, including petiole; others, including spear, cabbage and 

inflorescences; root biomass was defined to depth of 5 m. 

The biomass of the frond base increased substantially from 1.2 Mg ha-1 in the 

3-year-old plantation to 20.5 Mg ha-1 in the 10-year-old plantation, then declined to only 

2.3 and 3.4 Mg ha-1 in the 20- and 30-year-old plantation, respectively. There was an 

increase in frond base biomass from 3- to 10-year-old plantations in line with the 

increase in the trunk dimension of the crops. However, due to the abscission of the 

frond base of the older plantations (in most cases, frond bases begin to be detached from 

the trunk at the plantation age of 13 to 18 years), the biomass of the frond base of the 

older plantations (20- and 30-year-old) was pronouncedly lower. Khalid et al. (1999a) 

reported a magnitude of frond base of a 23-year-old oil palm plantation of 129.1 kg 

palm-1 equivalent to 17.6 Mg ha-1. This is quite comparable to the results in this study 

for the 10-year-old plantation (23.7%), which is in agreement with the 18-22% reported 

in the previous studies (Khalid et al. 1999a; Henson 1993). 

Rachis biomass, including petioles, increased from 4.6 to 9.9, 15.8 and 24.2 

Mg ha-1 for the 3-, 10-, 20- and 30-year-old plantations, respectively. Compared to the 

values reported by Khalid et al. (1999a) for a 23-year-old oil palm plantation of 110.5 to 

127.9 kg palm-1 equivalent to 15.0-17.4 Mg ha-1 and Rees and Tinker (1963) for 7- to 

22-year-old oil palm plantations of 42.7-101.8 kg palm-1 equivalent to 5.8-13.8 Mg ha-1

, 
Oil palm plantations

53

the results in this study are still comparable. The relative contribution of the rachis was 

considerably high in the young plantation. It was 21.1% in the 3-year old plantation and 

dropped to only 11.4% in the 10-year-old plantation as the other compartments of the 

crop developed, especially trunk and frond base. Nevertheless, there was an increase in 

the contribution of rachis to the crop aboveground biomass of the older plantations. It 

was 16.1 and 18.5% for the 20- and 30-year-old plantations, respectively. Similar values 

(17.6-20.4%) in a 23-year-old oil palm plantation in Malaysia were reported by Khalid et 

al. (1999a) and (12.9-22.2%) in a 7- to 22-year-old plantation (Rees and Tinker 1963). 

Leaflet biomass of the plantation system increased from only 1.42 Mg ha-1 (3-

year-old plantation) to 4.82 Mg ha-1 (10-year-old plantation), then fluctuating between

4.34 Mg ha-1 (20-year-old plantation) and 6.44 Mg ha-1 (30-year-old plantation). These 

figures are still comparable to those of 7- to 22-year-old oil palm plantations (24.7-48.5 

kg palm-1 equivalent to 3.4-6.6 Mg ha-1) (Rees and Tinker 1963) and of a 23-year-old 

plantation (7.9 Mg ha-1) (Khalid et al. 1999a). However, the relative contribution of 

leaflet biomass was somewhat low, ranging from 4.4-6.5%. Compared to the values 

reported by Khalid et al. (1999a) of 9.3% of the crop aboveground biomass and by Rees 

and Tinker (1963) of 8.0-12.8%, these are somewhat lower. 

Biomass of other components (spear, cabbage and inflorescences) increased 

from only 1.4 to 2.2, 5.7 and 6.5 Mg ha-1 for the 3-, 10-, 20- and 30-year-old plantation 

systems, respectively. The relative contribution of these components was rather high in 

the early stage of the plantations. It was 6.4% for the 3-year-old plantation, decreased to 

2.5% for the 10-year-old plantation and to only 1.9% for the 20- and 30-year-old 

plantations. Khalid et al. (1999a) reported a slightly higher contribution of 3.2% in a 23-

year-old oil palm plantation in Malaysia. 

Root biomass of the system was 12.0, 16.1, 27.6 and 35.7 Mg ha-1 for the 3-, 

10-, 20- and 30-year-old plantations, respectively. Compared to the root biomass of a 

23-year-old plantation of 16.00 Mg ha-1 reported by Khalid et al. (1999b) and that of a 

27.5-year-old of 17.8 Mg ha-1 reported by Corley et al. (1971), the root biomass of 

mature oil palm in this study was considerably high. However, Khalid et al. (1999b) 

defined the root biomass to a depth of 60 cm and Corley et al. (1971) to a depth of 

90 cm, while in this study the total depth was 5 m. Biomass to a depth of 90 cm was 7.7, 

10.1, 18.2 and 24.2 Mg ha-1 for the 3-, 10-, 20- and 30-year-old plantations, 
Oil palm plantations

54

respectively. These figures are quite comparable to the findings of Khalid et al. (1999b) 

and Corley et al. (1971). Sommer et al. (2000) reported a similar root biomass in a 9-

year-old oil palm plantation in Eastern Amazon (14.0 Mg ha-1 6m-1). Roots contributed 

14.4-34.2%, and together with the trunk base produced 22.4-38.0% of the total crop 

biomass. These results are in agreement with those reported in previous studies (Khalid 

et al. 1999b; Corley et al. 1971). 

There was a persistent increase in both below- and aboveground biomass of 

the oil palm plantation with age. However, the aboveground biomass was 

logarithmically correlated with age, while belowground biomass was linearly correlated 

(Figure 5.2). A similar trend in relation of oil palm biomass with plantation age in 

Malaysia was found by Nordin (2002). 

Figure 5.2: Trend of relation of biomass of oil palm compartments with age of 

plantation in Sumatra, Indonesia 

y = 68.2Ln(x) - 36.7

R

2

 = 0.99**

y = 44.6Ln(x) - 25.0

R

2

 = 0.97*

y = 34.5Ln(x) - 27.0

R

2

 = 0.99*

y = 1.45x + 9.88

R

2

 = 0.99**

y = 0.56x + 2.04

R

2

 = 0.90ns

0

50

100

150

200

250

0 5 10 15 20 25 30

Plantation age (year)

Biomass (Mg ha-1

)

Total

Crop

Trunk

Root & trunk base

Litter standing stock
Oil palm plantations

55

The rate of biomass accumulation in the system was 13.6, 11.8, 7.9 and 6.8 

Mg ha-1 yr-1 for the 3-, 10-, 20- and 30-year-old plantations and the overall weighed 

average was 8.3 Mg ha-1 yr-1. Compared to the 10.0 Mg ha-1 yr-1 reported by ISME 

(2000), the annual rate of biomass accumulation in this study is somewhat lower. 

However, depending on how this rate is calculated, without weighing, the annual rate of 

the biomass of the oil palm in this study reaches 10.0 Mg ha-1 yr-1

. 

5.3.2 Root distribution 

There was a large difference in root biomass between the oil palm plantation in Sumatra 

and that in East Kalimantan (Table 5.3). The reasons will be elaborated in the following 

discussion. Root biomass in Sumatra ranged from 12.0 to 16.1, 27.6 and 35.7 Mg ha-1 5 

m

-1 for the 3-, 10, 20 and 30-year-old plantations, respectively. Compared to the values 

in East Kalimantan of 21.2 and 31.7 Mg ha-1 5 m-1 for the 3- and 10-year-old 

plantations, respectively, the root biomass in Sumatra was much lower. However, the 

root biomass in both sites was higher than that of I. cylindrica in the neighborhood of 

the respective sites, which was 8.7 Mg ha-1 5 m-1 in Sumatra and 12.4 Mg ha-1 5 m-1 in 

East Kalimantan. Moreover, the vertical distribution of the root biomass of I. cylindrica

grassland was restricted to the top soil layer (Figure 5.3). 

Table 5.3: Vertical root biomass distribution in oil palm plantation systems in East 

Kalimantan and Sumatra, Indonesia 

East Kalimantan Sumatra Depth 3-year-old 10-year-old 3-year-old 10-year-old 20-year-old 30-year-old

(m) (Mg ha-1) 

0-1 16.5 21.6 8.1 10.8 19.7 26.4 

1-2 2.5 5.9 2.2 2.7 4.8 5.9 

2-3 1.1 2.7 1.0 1.7 1.8 1.9 

3-4 0.9 1.1 0.5 0.6 0.9 1.1 

4-5 0.3 0.3 0.1 0.2 0.4 0.3 

0-5 21.2 31.7 12.0 16.1 27.6 35.7 

In the 5-m deep soil profile, more than 50% of the root biomass was found in 

the top 60 cm. However, compared to I. cylindrica grassland, the roots of the oil palm 

penetrated much deeper, i.e., to a depth of 5 m. This is much deeper than the I. 
Oil palm plantations

56

cylindrica grassland with a depth of only 1.8 m. Penetration of oil palm roots to a depth 

of 6 m was reported by Sommer et al. (2000). 

Distribution of the roots of the oil palm plantation seems to be site and age 

dependent. It is interesting that although distribution of 50% of the root biomass of the 

oil palm plantation in East Kalimantan (31 and 41 cm depth for the 3- and 10-year-old 

plantations, respectively) was shallower than in Sumatra (46, 58, 58, and 59 cm depth 

for the 3-, 10-, 20- and 30-year-old, respectively), distribution of 90% of the root 

biomass in both sites was not significantly different: 90% of the root biomass in East 

Kalimantan was found to a depth of 244 and 223 cm in the 3- and 10-year-old 

plantations, respectively, and in Sumatra to depths of 228, 239, 207 and 219 cm in the 

0

100

200

300

400

500

0.0 0.1 1.0 10.0 100.0

Root biomass (Mg ha-1 30cm-1)

Soil depth (cm)

I. cylindrica

Oil palm

Average

A

B

C

D

E

F

Figure 5.3: Vertical distribution of root biomass of a 10-year-old oil palm plantation 

and Imperata cylindrica grassland (IC) systems in East Kalimantan, 

Indonesia; A, B, C, D, E and F = 10, 100, 200, 300, 450 and 520 cm from 

the trunk base 

Soil depth (cm) 
Oil palm plantations

57

3-, 10-, 20- and 30-year-old plantations, respectively. The first 1-m depth produced 67-

78% of the total root biomass (to depth of 5 m). 

The root biomass consisted mainly of primary roots, which contributed 47, 70, 

84 and 80% to total root biomass of the 3-, 10-, 20- and 30-year-old plantations, 

respectively. Secondary and tertiary (including quaternary) root biomass contributed 11-

16% and 5-37%, respectively. Compared to the root biomass reported by Khalid et al. 

(1999b) of 50, 20 and 30% for the primary, secondary and tertiary roots, respectively, 

these results are still comparable. While the biomass of both primary and secondary 

roots increased continuously with age, the biomass of tertiary roots (including 

quaternary roots) fluctuated, which is probably the result of the physiological demands 

of the plant and environmental conditions (Figure 5.4). 

However, the contribution of tertiary and quaternary roots to the total root 

biomass was considerably high in the top 15 cm of soil, declining sharply in the deeper 

soils (77 to 22%, 41 to 11%, 27 to 4% and 44 to 8% for the 3-, 10-, 20- and 30-year-old 

plantations, respectively). A similar trend in a 23-year-old oil palm plantation in 

Malaysia was reported by Khalid et al. (1999b), who found that tertiary roots 

Figure 5.4: Biomass of primary, secondary and tertiary (including quaternary) roots 

of oil palm plantation systems in Sumatra, Indonesia 

y = 0.08x + 0.56

R

2

 = 0.96

y = 0.07x + 0.20

R

2

 = 0.95

y = 0.008x + 0.10

R

2

 = 0.96

0.1

1.0

10.0

0 5 10 15 20 25 30

Plantation age (year)

Biomass (kg m-3

)

All roots

Primary roots

Secondary roots

Tertiary & quaternary roots
Oil palm plantations

58

contributed 53% in the top 15 cm and declined to only 25% of the total root biomass at 

the 15-30 cm soil depth. Wright (1951) reported that most of the tertiary roots of oil 

palm on deep acid sandy soils in West Africa were confined to a depth of 10 cm. 

Vertical distribution of fine roots indicates the rooting strategy of trees and is species 

specific and genetically inherited (Curt and Prévosto 2003; Polomski and Kuhn 1998; 

Brown 1992); this shallow concentrated rooting strategy may allow an efficient use of 

the topsoil resources (Crabtree and Berntson 1994). Fine-roots proliferated in the Ahorizon of most soils, due to accumulation of organic matter, higher CEC and higher 

nutrient concentration in organic C, N, and K (Bowen 1984; Kalisz et al. 1987; Pritchett 

and Fisher 1987; Sainju and Good 1993). 

Although roots of oil palm can penetrate deeper than 4 m, the majority have 

been found in the top 45 cm (Lambourne 1935). The largest magnitude of root biomass 

is to be found between a soil depth of 20 and 60 cm (Tailez 1971), but the exact depth 

Sumatra

0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8

Root biomass (Mg ha-1 15cm-1)

Soil depth (cm) p

3-year-old

10-year-old

20-year-old

30-year-old

East Kalimantan

0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8

Root biomass (Mg ha-1 15cm-1)

Soil depth (cm) p Soil depth (cm) 

Soil depth (cm) 

Figure 5.5: Vertical distribution of root biomass of oil palm plantations in Sumatra 

and East Kalimantan, Indonesia 
Oil palm plantations

59

of the root concentration depends to large extent on the soil type (Chan 1977). Root 

biomass of the oil palm plantations at both sites showed a parallel trend of vertical root 

distribution. Most of the roots of the young plantations (3-year-old) were concentrated 

in the uppermost 15 cm and decreased with soil depth. However, the concentration of 

roots in the uppermost soils was more pronounced for the plantations at the East 

Kalimantan site (Figure 5.5). 

The vertical distribution of root biomass in the older plantations is in 

agreement with that reported by Khalid et al. (1999b) and Chan (1977). There was an 

Figure 5.6: Lateral distribution of root biomass of different ages of oil palm 

plantations in Sumatra (below) and East Kalimantan (above), Indonesia 

East Kalimantan

0

10

20

30

40

0 100 200 300 400 500

Distance to closest trunk Base (cm)

Root biomass (Mg ha-1 1m-1) 

rr

3-year-old

10-year-old

Sumatra

0

10

20

30

40

0 100 200 300 400 500

Distance to closest trunk Base (cm)

Root biomass (Mg ha-1 1m-1) 

rr

3-year-old

10-year-old

20-year-old

30-year-old

130

130

Distance to closest trunk base (cm) 

Root biomass (Mg ha

-1 1m

-1) Root biomass (Mg ha

-1 1m

-1) 
Oil palm plantations

60

increase in root biomass at a depth of 15-30 cm for the 10- and 20-year-old plantations, 

and at a depth of 15-45 cm for the 30-year-old plantation. Thereafter, biomass declined 

with depth, but again at a depth of 0-45 cm, the magnitude of root biomass of the 

plantations in East Kalimantan was much higher. 

The lateral extent of woody roots may exhibit a high degree of plasticity and 

depend on environmental conditions (Millikin and Bledsoe 1999; Belsky 1994). Roots 

of oil palm may grow laterally to a distance of more than 12 m (Wright 1951). 

However, Zaharah et al. (1989) reported that roots of mature oil palms can absorb 

nutrients as far as 36 m away from the base trunk. Feeding roots up to more than 6 m 

away from the trunk base and lateral roots of more than 20 m have also been observed 

(Lambourne 1935). Nevertheless, root density decreases with distance to the trunk base, 

and the majority of the absorbing roots of mature oil palms may extend to a radius of at 

least 3.5-4.5 m from the trunk base (Ruer 1967). A high root biomass was concentrated 

near the trunk base (10 cm from the trunk base), decreasing sharply at a distance of 1 m, 

then declining gradually to a distance of 3 m from the trunk base. Hereafter, it was more or 

less stabile or fluctuated slightly to a distance of 5.2 m from the trunk base (Figure 5.6). 

Khalid et al. (1999b) reported that the lateral distribution of the roots of a 23-

year-old oil palm plantation in Malaysia was the same as in this study, which is also in 

agreement with that of a 14-year-old oil palm plantation in West Africa (Purvis 1956). 

A similar distribution in other systems has also been reported (Purbopuspito and Van 

Rees 2002; Jose et al. 2001; Peter and Lehmann 2000; Jones et al. 1998). The lateral 

and vertical trend of root biomass density in the 10-year-old oil palm plantation in East 

Kalimantan is depicted in Figure 5.7. There was a high concentration of root biomass 

close to the trunk base to a depth of less than 50 cm. 

In general, root biomass density can be classified into 6 zones. The first zone 

constituted the highest concentration of root biomass, which reached more than 10 kg 

m

-3 in the 10-year-old oil palm plantation. This zone developed near the trunk base to a 

distance of less than 1 m and within a soil depth of 15 cm and 50 cm. However, this 

zone sometimes extended to a depth of more than 75 cm in the old plantation (30-yearold) without an increase in the lateral distance to the trunk base. The second zone 

developed directly in the outer of the first zone to a distance of rarely more than 2 m 

from the trunk base and to a depth of 50 cm, where the root biomass showed a density 
Oil palm plantations

61

of 5-10 kg m-3. The third zone emerged in the outer area of the second zone, extending 

to a distance of 4 m from the trunk base close to the soil surface but confined to a 

shallow soil depth below the second root zone of less than 60 cm. The root biomass 

density of this zone ranged from 3-5 kg m-3. The fourth root zone showed a biomass 

density of 1-3 kg m-3 and developed in the outer area of and below the third root zone to 

a distance of 5.2 m from the trunk base (planting space was a triangular 9 m x 9 m x 

9m) to a depth of 40 cm at a distance of 5 m from the trunk base and of 160 cm near the 

trunk base. Below this zone, a root zone with a root biomass density of 0.5-1 kg m-3 was 

sometimes observed. This zone developed at depths of 40-150 cm to a distance of 5 m 

from the trunk base and of 160-280 cm near the trunk base with some 

discontinuousness. The final root zone developed below the fifth root zone, with a 

biomass density of less than 0.5 kg m-3; due to the high spatial variation, further 

zonation of this root biomass is not possible. 

It is important to bear in mind that this is not a static zonation. The zones may 

shrink and swell depending on numerous genetically inherited factors and the 

environmental conditions of the plantation. In some cases, it was observed that the 

second and third zones had developed in a very narrow lateral range of between 50 and 

Trunk 

> 10 kg m-3

5-10 kg m-3

3-5 kg m-3

1-3 kg m-3

 0.5-1 kg m-3

< 0.5 kg m-3

Figure 5.7: Vertical and lateral root biomass density of a 10-year-oil oil palm 

plantation in East Kalimantan, Indonesia 

Distance to trunk base (cm)

Soil depth (cm)
Oil palm plantations

62

100 cm from the trunk base. An intensive sampling of roots near to the trunk base (0-

100 cm) is, therefore, of utmost importance, if an accurate estimate is required. 

5.3.3 Biomass carbon distribution 

The C content of the compartments of the oil palm plantation systems ranged widely 

from 32.3 to 44.2% (Table 5.4). However, only leaf litter and tertiary roots (including 

quaternary roots) compartments had low C contents of 32.3 and 36.6%, respectively, 

while for the other compartments these values ranged from 39.4 to 44.2%. The average 

C content of 41.7, 38.4 and 40.3% for the crop aboveground biomass, non-crop 

aboveground biomass, and root and trunk base biomass, respectively, resulting in an 

overall average of 40.4%, was much lower than the assumed values of 50% applied for 

most of the previous studies. However, the average values have to be corrected with the 

relative biomass of each compartment. The calculations resulted in a weighed average 

of 41.3%, and the use of this value in converting biomass to C stock instead of the 

above-mentioned 50% is recommended. 

Table 5.4: Carbon content of compartments of oil palm plantation systems in 

Sumatra and East Kalimantan, Indonesia 

Mean SD Compartment (%) n 

Spear 39.5 bcd 3.3 6 

Leaf 43.7 de 2.5 6 

Rachis 41.4 cd 1.1 10 

Frond base 41.4 cde 0.9 6 

Trunk 42.6 de 1.6 6 

Crop 

aboveground 

compartments 

Average 41.7 1.0 - 

Undergrowth 39.3 c 2.9 8 

Non-leaf litter 43.7 de 1.1 4 

Leaf litter 32.3 a 6.6 8 

Non crop 

compartments 

Average 38.4 2.8 - 

Trunk base 44.2 e 1.8 12 

Primary root 41.1 cd 2.9 20 

Secondary root 39.4 c 3.9 20 

Tertiary root 36.6 b 4.4 20 

Trunk base and 

roots 

Average 40.3 1.2 - 

Average 40.4 1.7 - 

SD = standard deviation; mean values followed by the same letter are not significantly different at 

α = 0.05 
Oil palm plantations

63

The C content of the both the aboveground compartments and the trunk base 

of the oil palm plantations was not affected by plantation age. Although intensive root 

and soil sampling was performed in East Kalimantan, there was no sampling for 

aboveground biomass, so that it is not possible to compare C content and accumulation 

of the aboveground biomass. However, there is no difference in the C content of the 

non-crop biomass (litter and undergrowth). 

Contrary to the aboveground biomass C content, site and plantation age had a 

significant effect on the C content of root biomass. In general, the values in East 

Kalimantan averaged 35.7%, which is significantly lower (α = 0.05) than the 40.7% in 

Sumatra. Plantation age may also have a significant effect on the C content of the root 

biomass (Table 2); younger plantations (3- and 10-year-old) showed a significantly 

lower C content than the older plantations (20- and 30-year-old). Root type was also a 

source of variation. Coarser roots (primary and secondary roots) show a higher C 

content than smaller roots (tertiary and quaternary roots). Nevertheless, in contrast to 

the younger plantations, the effect of root type on C content of the root biomass was less 

pronounced in the older plantations (Table 5.5). 

Table 5.5: Carbon content of different root types of different ages of oil palm 

plantations in Sumatra and East Kalimantan, Indonesia 

Plantation Root type 

age Primary Secondary Tertiary Mean SD 

(year) (%) 

n 

3 39.4 39.2 34.1 37.6a 3.4 18 

10 40.9 36.7 34.5 37.4a 5.0 18 

20 43.7 42.9 42.1 42.9b 1.0 9 

30 42.0 41.4 40.0 41.1b 2.7 15 

Mean 41.1b 39.4b 36.6a 39.8a - - 

SD 2.9 3.9 4.4 - 4.1 - 

n 20 20 20 - - 60 

SD = standard deviation; mean values followed by the same letter are not significantly different at α = 

0.05; tertiary roots including quaternary roots 

Biomass C of the system increased decisively with plantation age and was 

16.6, 49.4, 65.3 and 84.6 Mg ha-1 for the 3-, 10-, 20- and 30-year-old plantations, 

respectively (Table 5.6). These values are slightly lower than those reported by 

Noordwijk et al. (2000) and Hairiah and Sitompul (2000), which ranged from 62.4-91.0 
Oil palm plantations

64

Mg ha-1, given that they defined the belowground biomass C to depth of 30 cm only. 

Compared to the biomass C of the neighboring I. cylindrica grasslands of 3.0, 2.9 and 

5.9 Mg ha-1 for the aboveground, belowground and total biomass C, respectively, it is 

obvious that total biomass C of oil palm plantations has already surpassed that of I. 

cylindrica in a very early stage of the plantation. This suggests that conversion of I. 

cylindrica grasslands into oil palm plantations is beneficial if C sequestration and land 

rehabilitation are of interest. Of all compartments (crop, undergrowth and litter standing 

stock), the crop provided the major biomass C to the system, accounting for 87.8-

94.5%. Undergrowth contributed 1.3-2.8% and litter standing stock 3.9-9.4%. Despite 

the minor contribution of these compartments, they could play an important role in the 

functioning of the system, such as in controlling soil erosion and surface run-off, and 

promoting soil C and nutrient cycles as well as soil biological activities. 

Table 5.6: Above- and belowground biomass C distribution of four different ages of 

oil palm plantation systems in Sumatra, Indonesia 

Plantation Aboveground biomass C 

age 

Belowground 

biomass C Litter Undergrowth Crop 

Total 

Relative 

belowground to 

total 

(year) (Mg ha-1) (%) 

3 5.41 1.56 0.47 9.15 16.59 32.63 

10 10.40 1.94 0.63 36.37 49.35 21.08 

20 16.63 5.51 1.43 41.69 65.26 25.48 

30 21.75 6.25 1.26 55.33 84.60 25.71 

Belowground biomass C was defined to depth of 5 m 

Carbon stored in the aboveground crop biomass increased from 9.2 Mg ha-1 in 

the 3-year-old plantation to 36.4, 41.7 and 55.3 Mg ha-1 for the 10-, 20- and 30-year-old 

plantations. Aboveground biomass C of previous studies varied considerably from 31.0-

62.0 Mg ha-1 for a 10-year-old oil palm to as high as 96.0-101.0 Mg ha-1 for 14- and 19-

year-old oil palm plantations (Sitompul and Hairiah 2000). It is clear that the 

aboveground biomass of the plantation systems is highly variable; this may be the result 

of inherited characteristics, pedoagroclimatic conditions and management. However, to 

some extent, it also depends on the method of biomass quantification and conversion to 

the C pool. 
Oil palm plantations

65

There is only little information on the fractionation of biomass C of oil palm 

plantations in the literature. The following discussion is based on biomass fractionation 

data and an assumption of a biomass C content of 41.3%. Of the crop aboveground 

biomass C, the trunk contributed 57.3 to 75.7%. These figures are relatively higher than 

the 48% reported by Khalid et al. (1999a), but are in agreement with those reported by 

Rees and Tinker (1963) of 7- to 22-year-old oil palm plantations of 42.8-73.0%. 

Biomass C of the trunk in this study increased from 5.6 Mg ha-1 for the 3-year-old 

plantation to 20.9, 31.5 and 40.2 Mg ha-1 for the 10-, 20- and 30-year-old plantations, 

respectively (Table 5.7). Compared to the trunk biomass C of previous studies of 15.2-

19.3 Mg ha-1 (36.7-46.8 Mg ha-1 biomass) for 22- to 27.5-year-old plantations (Khalid et 

al. 1999a; Corley et al. 1971; Tinker and Smilde 1963), these results are considerably 

higher. However, they are in agreement with the value for a 15-year-old plantation of 

36.6 Mg ha-1 (88.5 Mg ha-1 biomass) reported by Ng et al. (1968). 

Table 5.7: Above- and belowground biomass C distribution of four different ages of 

oil palm trees in Sumatra, Indonesia 

Stand Belowground Aboveground 

age Root Trunk base Trunk Frond base Rachis Leaflet Others 

(year) (Mg ha-1) 

3 4.8 0.6 5.6 0.5 1.9 0.6 0.6 

10 6.5 3.9 20.9 8.5 4.1 2.1 0.9 

20 11.1 5.5 31.5 1.0 6.5 1.9 0.7 

30 14.4 7.4 40.2 1.4 10.0 2.8 1.0 

Trunk base, defined as part of trunk developed belowground including roots developed underneath the 

trunk base to depth of 1 m; rachis, including petiole; others, including spear, cabbage and 

inflorescences; root biomass was defined to depth of 5 m 

The C stored in the biomass of the frond base increased substantially from 0.5 

Mg ha-1 in the 3-year old plantation to 8.5 Mg ha-1 in the 10-year-old plantation, then 

declined to only 1.0 and 1.4 Mg ha-1 in the 20- and 30-year-old plantations, 

respectively. In line with the increase in the trunk dimension, there was an increase in 

the biomass C accumulated in the frond base in the early stage of the plantations (from 

3- to 10-year-old). However, due to the abscission of the frond base in the older 

plantations (generally plantation age of 13 to 18 years), the biomass C accumulated in 

the frond base of the older plantations (20- and 30-year-old) was pronouncedly lower. 

Khalid et al. (1999a) reported a magnitude of frond base biomass of a 23-year-old oil 
Oil palm plantations

66

palm plantation of 129.1 kg palm-1 equivalent to 7.3 Mg C ha-1. This is quite 

comparable to the 23.3% for the 10-year-old plantation in this study, which is in 

agreement with the 18-22% in previous studies (Khalid et al. 1999a; Henson 1993). 

Carbon stored in rachis biomass, including petioles, increased from 1.9 to 4.1, 

6.5 and 10.0 Mg ha-1 for the 3-, 10-, 20- and 30-year-old plantations, respectively. 

These values are comparable to those reported by Khalid et al. (1999a) for a 23-year-old 

oil palm plantation (110.5-127.9 kg palm-1 equivalent to 6.2-7.2 Mg C ha-1) and those 

reported by Rees and Tinker (1963) for 7- to 22-year-old oil palm plantations (42.7-

101.8 kg palm-1 equivalent to 2.4-5.7 Mg C ha-1). The relative contribution of the rachis 

biomass C to the crop aboveground C stock was considerably high in the early stage of 

the plantation. It was 20.7% in the 3-year-old plantation and dropped to only 11.2% in 

the 10-year-old plantation as the other compartments of the crop developed, especially 

trunk and frond base. Nevertheless, there was an increase in the contribution of rachis 

biomass C of the older plantations (15.7 and 18.1% for the 20- and 30-year-old 

plantations, respectively. A similar contribution through rachises (17.6-20.4%) of a 23-

year-old oil palm plantation in Malaysia was reported by Khalid et al. (1999a) and 12.9-

22.2% of 7- to 22-year-old plantations by Rees and Tinker (1963). 

Leaflet biomass C increased from only 0.6 Mg ha-1 (3-year-old plantation) to 

2.1 Mg ha-1 (10-year-old plantation), then fluctuating between 1.9 Mg ha-1 (20-year-old 

plantation) and 2.8 Mg ha-1 (30-year-old plantation). These figures are comparable to 

those of 7- to 22-year-old oil palm plantations of 24.7-48.5 kg palm-1 equivalent to 1.4-

2.7 Mg C ha-1 (Rees and Tinker 1963) and of a 23-year-old plantation of 7.9 Mg ha-1

equivalent to 3.3 Mg C ha-1 (Khalid et al. 1999a). However, the relative contribution of 

leaflet biomass C was somewhat low, ranging from 4.6-6.8%. Compared to the 9.3% 

reported by Khalid et al. (1999a) and the 8.0-12.8% reported by Rees and Tinker 

(1963), these values are somewhat lower. 

Biomass C of the other components (spear, cabbage and inflorescences) 

increased from only 0.6 to 0.9, 0.7 and 1.0 Mg ha-1 for the 3-, 10-, 20- and 30-year-old 

plantation systems, respectively. The relative contribution of these components was 

rather high in the early stage of the plantations. It was 6.0% for the 3-year-old 

plantation, decreasing to 2.4% for the 10-year-old plantation and only 1.8% for the 20- 
Oil palm plantations

67

and 30-year-old plantations. Khalid et al. (1999a) reported a slightly higher value for a 

23-year-old oil palm plantation in Malaysia (3.2%).

Root biomass C was 4.8, 6.5, 11.1 and 14.4 Mg ha-1 for the 3-, 10-, 20- and 

30-year-old plantations, respectively. Compared to the root biomass of a 23-year-old oil 

palm of 16.0 Mg ha-1 equivalent to 6.6 Mg C ha-1 reported by Khalid et al. (1999b) and 

that of a 27.5-year-old oil palm of 17.8 Mg ha-1 equivalent to 7.4 Mg C ha-1 reported by 

Corley et al. (1971), the values for the mature oil palm were considerably high. 

However, instead of to a depth of 5 m as in this study, Khalid et al. (1999b) defined the 

root biomass to a depth of 60 cm and Corley et al. (1971) to a depth of 90 cm. The 

biomass C of the oil palm roots to a depth of 90 cm in this study was 3.2, 4.2, 7.5 and 

10.0 Mg ha-1 for the 3-, 10-, 20- and 30-year-old plantations, respectively. These figures 

are quite comparable to the findings of Khalid et al. (1999b) and Corley et al. (1971). 

Sommer et al. (2000) reported quite similar values for a 9-year-old oil palm plantation 

in Eastern Amazon (6.0 Mg ha-1 6m-1). Biomass C of roots contributed 13.8-33.1% and, 

together with that of the trunk base, produced 22.2-37.2% of the total crop biomass C. 

Individual values were 29.1, 13.1, 17.0 and 17.0% for the 3-, 10-, 20- and 30-year-old 

plantations, respectively, which, together with trunk base, gave 32.6, 21.1, 25.5 and 

25.7% of the biomass C for the 3-, 10-, 20- and 30-year-old plantations, respectively. 

The low contribution of the belowground biomass C of the 10-year-old plantation was 

due to the accumulation of the frond base biomass; there was no abscission of the frond 

bases in the 10-year-old plantation in this study. Since belowground biomass C may 

contribute significantly to the total biomass C – in this study it was more than 20% of 

the total biomass C without abscission of the frond bases and more than 25% with 

regular abscission – incorporation of belowground biomass C in studies of C stock and 

budget is of utmost importance. 

There was a persistent increase with age in the C accumulated in both belowand aboveground biomass of the oil palm plantations. However, aboveground biomass 

C was logarithmically correlated with age, while belowground biomass C was linearly 

correlated (Figure 5.8). A similar trend was observed in Malaysia by Nordin (2002). 

As elaborated above, there was a strong dependency of C sequestration in the 

biomass of the oil palm plantations with plantation age. This suggests that, if biomass 

data are lacking, estimation of biomass C based on plantation age is quite credible. 
Oil palm plantations

68

Estimation of belowground biomass C with an allometric equation is strongly 

recommended, since data on belowground biomass are very limited, due mainly to the 

difficulty in its quantification, as quantifying belowground biomass is not only labor 

intensive and time consuming but also costly. If sufficient information on aboveground 

biomass C is available, estimating belowground biomass C with a factor of 0.2 of the 

total biomass C if there is no pronounced abscission of the frond bases or 0.25 if the 

frond bases are intensively detached is recommended. 

The rate of biomass C accumulation of the system was 5.5, 4.9, 3.3 and 2.8 

Mg ha-1 yr-1 for the 3-, 10-, 20- and 30-year-old plantations and the overall weighed 

average 3.4 Mg ha-1 yr-1. In comparison with the value reported by ISME (2000) of 5.0 

Mg ha-1 yr-1, the annual rate of biomass C accumulation in this study was somewhat 

lower. However, depending on how this rate is calculated, i.e., without weighing, the 

annual rate of biomass accumulation would come to 4.1 Mg ha-1 yr-1 and, employing the 

Figure 5.8: Trend of relation of biomass of oil palm compartments with the age of the 

plantations in Sumatra, Indonesia 

y = 28.3Ln(x) - 15.5

R

2

 = 0.99**

y = 18.9Ln(x) - 10.7

R

2

 = 0.97*

y = 14.7Ln(x) - 11.5

R

2

 = 0.99**

y = 0.60x + 4.03

R

2

 = 0.99**

y = 0.20x + 0.73

R

2

 = 0.91*

0

10

20

30

40

50

60

70

80

90

0 5 10 15 20 25 30

Plantation age (year)

Biomass carbon (Mg ha-1

)

Total

Crop

Trunk

Root & trunk base

Litter standing stock
Oil palm plantations

69

assumption of a C content of 50%, increase the estimation of the biomass C 

accumulation to 5.0 Mg ha-1 yr-1. 

5.3.4 Soil carbon distribution 

Soil C content of the systems varied highly depending on site, vegetation type, 

plantation age, spatial position and depth; all factors had a highly significant effect on 

soil C content (p < 0.001). Although the values for the plantations in Sumatra and East 

Kalimantan differed, the vertical trend was similar (Figure 5.9). The effect of vegetation 

type, plantation age and spatial position (distance to closest trunk) on soil C content was 

primarily associated with the effect of the fine root biomass of the system. This is 

demonstrated by the high correlation between fine root (tertiary and quaternary roots) 

biomass of the system and soil C content (r2

 = 0.69-0.87 and p < 0.001). However, the 

correlation between fine root (tertiary and quaternary roots) biomass and soil C content 

of the younger plantations (3-year-old) was rather weak for the plantations in East 

Kalimantan (r2 = 0.52 and p < 0.001), and there was no correlation for the 3-year-old 

plantation in Sumatra (r2

 = 0.04 and p = 0.32). 

This suggests that the effect of roots in the younger plantations on soil C 

content was significantly held back by other factors, such as changes in soil 

temperature, moisture and disturbances in soil structure during the establishment of the 

plantation. A slight increase in root biomass from 8.9-12.2 Mg ha-1 1 m-1 for the 

grassland system to 8.1-16.5 Mg ha-1 1m-1 for the young oil palm plantation was not 

enough to maintain the level of the soil C content of the plantations. 

One of the most important findings in this study is that the vertical distribution 

of soil C in the oil palm plantations was not the same as that in the I. cylindrica

grassland system. The oil palm plantation system was apparently able to achieve higher 

soil C accumulation in the deep soils, either by enhancement of organic C deposition or 

by inhibition of decomposition of the soil organic matter in the respective soil depth. 

However, the former seems to be more important. As a consequence of the deep 

penetration of the roots of oil palm plantations (to a depth of 5 m) compared to the I. 

cylindrica grassland systems (to a depth of only 1.8 m) a substantial amount of organic 
Oil palm plantations

70

C could be deposited in the deep soils, thus increasing the soil organic C of the 

respective soil depth. 

Although the C content in the soils in older oil palm plantations was higher 

than that in I. cylindrica grassland, it should, nevertheless, be noticed that there was a 

significant decrease in the upper soil layers in the younger plantations (3-year-old). This 

decrease indicates that there were losses in soil organic matter and thus nutrients, either 

by the more intensive decomposition of the soil organic matter due to changes in soil 

Figure 5.9: Vertical distribution of carbon content of soils in Imperata cylindrica

grassland and oil palm plantation systems in East Kalimantan (above) 

and Sumatra (below), Indonesia 

Sumatra

0

50

100

150

200

250

300

350

400

450

500

0.0 0.1 1.0 10.0

Soil C content (%)

Soil depth (cm)

 Imperata cylindrica

 Oil palm, 3-year-old

 Oil palm, 10-year-old

 Oil palm, 20-year-old

 Oil palm, 30-year-old

East K alimantan

0

50

100

150

200

250

300

350

400

450

500

0.0 0.1 1.0 10.0

S oil C content (% )

Soil depth (cm) Soil depth (cm) Soil depth (cm) 
Oil palm plantations

71

moisture and temperature or through surface soil erosion; elimination of the I. 

cylindrica grassland with its dense root mat increases the soil erosion risk, especially on 

slopes. 

The vertical distribution of soil C in both I. cylindrica grassland and oil palm 

plantation systems was quite similar to that reported by Syahrinudin (1997) and Ruhiyat 

(1989) in previous studies in the same region. Soil C content of the systems decreased 

in line with soil depth and was highly depth dependent (r2 = 0.99 and p < 0.001). There 

was a very marked decrease in soil C content with depth in the upper 50 cm of the soil, 

which slowed down below this depth. Nevertheless, there was a distinct difference in 

the vertical soil C distribution between the I. cylindrica grassland and oil palm 

plantation systems. Compared to that in soils in the oil palm plantation system, the 

decrease in the I. cylindrica grassland was less abrupt in the upper 50 cm of the soil, 

whereas it was more distinct deeper down (see Figure 5.9). This demonstrates the strong 

influence of fine root biomass on soil C content. On the one hand, the high root biomass 

and dense root mat in the uppermost soils in the I. cylindrica grassland led to a higher C 

content in the upper soils (on average, root biomass density of the top 15 cm soil in the 

oil palm plantations of 2.6 g cm-3 was much lower than that of the I. cylindrica

grassland of 6.6 g cm-3); on the other hand, the deeper root penetration of the oil palm 

plantations led to a higher C content in the deeper soils. 

Soil C content is the result of litter (above- and belowground) production 

defined by the vegetation type and development stage of the system, and of the soil 

respiration, which is controlled by root respiration and decomposition of litter and soil 

organic matter. Soil physical properties such as texture and structure may also control 

respiration (De Jong and Schappert 1972). Soil temperature and moisture are, however, 

the most important factors regulating soil respiration (Kicklighter et al. 1994; Lloyd and 

Taylor 1994; Howard and Howard 1993). Conversion of I. cylindrica grasslands into oil 

palm plantations could affect soil C content several ways, such as through changes in the 

rate of litter production, increase in temperature of the uppermost soils, increase in surface 

run-off facilitating surface erosion, altered soil horizonization, and modified soil structure 

and bulk density. Carbon content of the upper soils in the younger plantations (3-year-old 

at both sites and 10-year-old in East Kalimantan) was significantly lower than that in the 

I. cylindrica grasslands (p < 0.001). Biomass production of oil palm plantations is, indeed, 
Oil palm plantations

72

much higher than that of I. cylindrica grasslands; however, little of the produced biomass 

is returned to the soils, especially in the early stages of the establishment of the 

plantations. The impact of the plantations on the temperature of the uppermost soils could 

be significant for the younger plantations, as the canopy closure is not yet established and 

the development of undergrowth is suppressed. Elimination of I. cylindrica may reduce 

the rate of infiltration, causing an increase in surface run-off and surface erosion, which in 

turn may alter soil horizonisation, structurization and bulk density. The impacts on soil 

horizonisation and bulk density are summarized in tables 5.8 and 5.9. 

It is clear that the establishment of oil palm plantations on I. cylindrica

grasslands was, in most cases, detrimental to the pedogenesis processes, especially in 

the early stages of the plantations. This adverse impact was, nevertheless, reversed in 

later stages. In contrast to the impacts on soil horizonisation, the unfavorable impacts on 

the soil bulk density of the uppermost soils was retained till the end of the plantation 

cycle. Since soil fertility plays an important role in determining plant growth and 

productivity, proper attention should be focused on this subject, otherwise sustainability 

of the plantation will never be achieved. 

Table 5.8: Horizonisation of soils developed under Imperata cylindrica grasslands 

and oil palm plantations in East Kalimantan and Sumatra, Indonesia 

East Kalimantan Sumatra 

Oil palm Oil palm 

Soil 

depth Imperata 

cylindrica 3-yr-old 10-yr-old

Imperata 

cylindrica 3-yr-old 10-yr-old 20-yr-old 30-yr-old

1 AE E EB AE E E AE AE 

2 E BE BE E Bt EB E E 

3 EB Bt1 Bt1 EB Bt2 Bt Bt1 Bt1 

4 Bt1 Bt2 Bt2 Bt1 BC Bg/BC Bt2 Bt2 

5 Bt2 CB BC Bt2 BC BC 

6 BC BC 

Table 5.9: Bulk density of soils developed under Imperata cylindrica grasslands and 

oil palm plantation systems in East Kalimantan and Sumatra, Indonesia 

East Kalimantan Sumatra 

Oil palm Oil palm Soil 

depth Imperata 

cylindrica 3-yr-old 10-yr-old

Imperata 

cylindrica 3-yr-old 10-yr-old 20-yr-old 30-yr-old

(cm) (g cm-3) 

0-15 1.1 1.3 1.3 1.1 1.2 1.2 1.3 1.2 

15-50 1.3 1.4 1.4 1.4 1.3 1.3 1.3 1.3 

50-100 1.3 1.5 1.4 1.5 1.4 1.3 1.3 1.4 

100-200 1.4 1.4 1.4 1.4 1.3 1.3 1.4 1.4 

200-500 1.4 1.4 1.4 1.4 1.2 1.4 1.4 1.5 
Oil palm plantations

73

Soil C storage in this study is in the range of that reported in previous studies 

(Mackensen 1998; Syahrinudin 1997; Bremen et al. 1990; Ruhiyat 1989). Total C 

stored in the soils in oil palm plantation systems ranged from 139.2-260.6 Mg ha-1 5 m1

. These values are somewhat higher than those of primary and secondary forests of 

156.0-176.0 Mg ha-1 5 m-1 and the value for a 9-year-old oil palm plantation of 131.0 

Mg ha-1 5 m-1 reported by Sommer et al. (2000). However, there was an extremely high 

magnitude of soil C in the 10-year-old plantation in Sumatra (482.4 Mg ha-1 5 m-1). This 

reflects the high variation of C sequestration in tropical soils. Nevertheless, this figure 

does not represent the common magnitude of C stock in most Ultisols in the tropics; the 

soil C stock to a depth of 1 m of 250.2 Mg ha-1 in this plantation was very much higher 

than that reported in previous studies (83.3-95.2 Mg ha-1) (Mackensen 1998; 

Syahrinudin 1997; Bremen et al. 1990) and is, therefore, excluded in the estimate of the 

C sequestration rate of the oil palm plantation. The values for the C stored in the soils in 

I. cylindrica grassland varied strongly (from 137.6 Mg ha-1 5 m-1 in Sumatra to 188.1 

Mg ha-1 5 m-1 in East Kalimantan). 

Soil C storage is largely dependent on environmental, biogeochemical and 

land management factors. Different land use and management practices influence soil 

properties such as soil temperature, moisture, microbial biomass, organic matter and 

fine root biomass, which in turn affect the magnitude of soil respiration (Lee and Jose 

2003; Raich and Tufekcioglu 2000; Kelting et al. 1998) and soil C dynamics. Trees 

could substantially increase the organic matter input into the system through the 

turnover of leaves and roots (Jose et al. 2000). The results in this study show that the 

conversion of I. cylindrica grassland into oil palm plantation considerably increased the 

amount of soil C stored in the system. However, the C stock in soils in the younger 

plantation (3-year-old) in East Kalimantan was considerably lower than that of the I. 

cylindrica grassland. However, the C stock to a depth of 3 m in the 3-year-old oil palm 

plantation in East Kalimantan was lower than that of the I. cylindrica grasslands; only at 

a depth of 0-1 m, it was significantly different (Figure 5.10). The C stock at a depth of 

0-1 m in the 10-year-old plantation in East Kalimantan was also lower than that in the I. 

cylindrica grasslands but not significantly different. In contrast to the uppermost soils, 

the C stock in the deeper soils (1-5 m) in the 10-year-old oil palm plantation in East 

Kalimantan was significantly higher than that in both I. cylindrica grassland and 3-year-
Oil palm plantations

74

old plantation. The overall C stock to a depth of 5 m of the soils in the oil palm 

plantations was higher than that of I. cylindrica grassland, and the rate of soil C 

sequestration to a depth of 5 m was 1.8 Mg ha-1 yr-1

. 

In Sumatra, the C stock only in 0-1 m depth in the 3-year-old plantation was 

lower than that in the I. cylindrica grasslands (Figure 5.10). The C stock to the depth 5 

m in oil palm plantations of all ages was significantly higher (p < 0.001) than that in the 

Figure 5.10: Carbon stock of soils in Imperata cylindrica grassland and oil palm 

plantation systems in East Kalimantan (above) and Sumatra (below), 

Indonesia 

East Kalimantan

0

50

100

150

200

250

300

350

0-100 100-200 200-300 300-400 400-500 0-500

Soil depth (cm)

Soil carbon stock (Mg ha -1

)

Sumatra

0

50

100

150

200

250

300

350

0-100 100-200 200-300 300-400 400-500 0-500

Soil depth (cm)

Soil carbon stock (Mg ha-1

)

 Imperata cylindrica

 Oil palm, 3-year-old

 Oil palm, 10-year-old

 Oil palm, 20-year-old

 Oil palm, 30-year-old

500 
Oil palm plantations

75

I. cylindrica grasslands. On average, conversion of I. cylindrica grassland into oil palm 

plantations led to a soil-C sink of 2.6 Mg ha-1 5 m-1. Compared to East Kalimantan (1.8 

Mg ha-1 5 m-1), the value in Sumatra was much higher; this is primarily due to the 

difference in the soil-C stock at the establishment of the plantation. 

Oil palm plantations showed a higher C stock in the deeper soils (1-5 m), 

which was detected in the early stage of the plantations (3-year-old). In contrast to 

deeper soils, there was a decrease in the C stock in the upper 1-m soil in the oil palm 

plantations, especially in the early stage (3-year-old). However, the soil-C stock 

increased with age to a level that was higher than that of the I. cylindrica grasslands. 

5.3.5 Carbon distribution in oil palm plantation systems 

Biomass C of the system increased persistently with plantation age, and there was a 

strong correlation between biomass C and age of the plantations. Total and aboveground 

biomass C are highly logarithmically correlated with plantation age (r2

 = 0.99 and 0.97, 

p = 0.006 and 0.015, respectively), whereas belowground biomass C is highly linearly 

correlated (r2

 = 0.99 and p = 0.002). These high correlation and probability levels 

suggest that the models might be applicable to other oil palm plantations elsewhere 

having similar pedoagroclimatic conditions. However, in cases where there is sufficient 

information on aboveground biomass C of the system, estimates of belowground 

biomass C with a factor of 0.2 of the total biomass C (equivalent to 0.25 of the 

aboveground biomass C) if there is no pronounced abscission of the frond bases or 0.25 

of the total biomass C (equivalent to 0.33 of the aboveground biomass C) if the frond 

bases are regularly detached from the trunk of the crops are recommended. 

The rate of biomass C accumulation in the system was 5.5, 4.9, 3.3 and 2.8 Mg 

ha-1 yr-1 for the 3-, 10-, 20- and 30-year-old plantations, respectively, and the overall 

weighed average was 3.4 Mg ha-1 yr-1. Total biomass C of the system was 16.6, 49.4, 

65.3 and 84.6 Mg ha-1 for the 3-, 10, 30-, 20- and 30-year-old plantations, respectively 

(Figure 5.11). Compared to the biomass C of the I. cylindrica grasslands in the 

neighborhood of the plantations of 3.0, 2.9 and 5.9 Mg ha-1 for the aboveground, 

belowground and total biomass C, respectively, it is clear that total biomass C of oil 

palm plantations already surpasses that of I. cylindrica grasslands at a very early stage 

of the plantation. This suggests that conversion of I. cylindrica grassland into oil palm 
Oil palm plantations

76

plantations is beneficial if biomass C accumulation and land rehabilitation are the 

concerns. 

Of total biomass C, roots and trunk base produced 22.2-37.2%. The crop 

contributed the highest magnitude of aboveground biomass C (81.9-93.4%) followed by 

litter standing stock (5.0-13.9%) and undergrowth (1.6-4.2%). Of the crop aboveground 

biomass C, trunk contributed the highest portion (57.3 to 75.7%) followed by frond base 

(2.3-23.3%), rachis including petiole (11.2-20.7%) and leaflet (4.6-6.8%). Other 

compartments, including spear, cabbage and inflorescence, contributed 1.8-6.0% to the 

total crop aboveground biomass. 

The soil-C content was strongly affected by vegetation type, plantation age, 

spatial position (distance to closest trunk) and depth (p < 0.001). However, the effect of 

vegetation type, plantation age and spatial position on soil-C content was primarily 

associated with the effect of the fine root biomass; this is demonstrated by the high 

-100 -80 -60 -40 -20 0 20 40 60 80

Carbon stock (Mg ha-1)

Belowground biomass

Soil

Litter

Undergrowth

Crop

Figure 5.11: Carbon distribution of Imperata cylindrica grassland and oil palm 

plantation systems in Sumatra; belowground carbon stock was defined to 

depth of 5 m; values for above- and belowground carbon of Imperata 

cylindrica grassland were considered as baseline for the plantations 

540

Belowground

240 180 120 60

Aboveground

Belowground baseline Aboveground baseline

Oil palm, 30-yr-old

Oil palm, 20-yr-old

Oil palm, 10-yr-old

Oil palm, 3-yr-old

Imperata cylindrica
Oil palm plantations

77

correlation between fine root (tertiary and quaternary roots) biomass and soil-C content 

(r2 = 0.69-0.87 and p < 0.001). 

A sizeable amount of soil C could be gained by conversion of I. cylindrica

grassland into oil palm plantations. The average rate of soil C sequestration was 0.7, 

0.4, 0.5, 0.5 and 0.5 Mg ha-1 yr-1 for the depths 0-1, 1-2, 2-3, 3-4 and 4-5 m, 

respectively. A potential soil C sink to depth 5 m of 76.8 Mg ha-1 could be expected by 

this conversion. More than 70% of this amount was allocated to the deep soils (1-5 m 

depth). Together with that sequestered in the biomass of the plantations, a C sink of 

178.8 Mg ha-1 could be achieved. The average rate of soil-C sequestration to a depth of 

5 m (2.6 Mg ha-1 yr-1)was lower than the rate in the biomass (3.4 Mg ha-1 yr-1). This 

may reflect that oil palm assigns little biomass to the belowground compartment of the 

plantation system. 

It is interesting that most of the C stored in the oil palm plantation was 

allocated to the belowground stock (soil and belowground biomass C); this has been 

ignored in most previous works due probably to the difficulty in the assessment of this 

component. The results show that belowground C contributed to more than 93% at the 

beginning of the plantation (3-year-old) and then declined with age to only 75% in the 

30-year-old plantation (Table 5.10). However, the relative contribution of belowground 

C stock was lower than that of the I. cylindrica grassland system (98%). 

Table 5.10: Below- and aboveground C-stock distribution in Imperata cylindrica

grassland and oil palm plantations in Sumatra, Indonesia 

Belowground 

Soil Biomass 

Aboveground 

biomass 

Belowground / 

System total 

(Mg ha-1) (%) 

Imperata cylindrica 137.6 2.9 3.0 97.9 

3-year-old 161.2 5.4 11.2 93.3 

10-year-old 482.2 10.4 38.9 92.1 

20-year-old 155.0 16.6 48.6 71.7 Oil palm 

30-year-old 232.4 21.7 62.8 75.3 

Belowground C stock was defined to depth of 5 m 

5.4 Conclusions 

The persistent increase in biomass and biomass C of the oil palm plantation with age 

suggests that establishment of this plantation in degraded lands such as those infested by 

I. cylindrica weed is an effective tool to promote higher terrestrial C storage. 
Oil palm plantations

78

Although the rooting system of the oil palm plantation was deep, it could only 

moderately improve the soil C storage compared to I. cylindrica grassland. This implies 

that the plantation allocates only a small portion of the biomass to the belowground 

production, and thus oil palm plantations are less effective in soil C enrichment. 

With a rate of C sequestration in biomass of 3.4 Mg ha-1 yr-1 and in soil of 2.6 

Mg ha-1 yr-1, conversion of I. cylindrica grassland into oil palm plantations could 

increase the terrestrial C storage of 96.1 Mg ha-1 in biomass alone; together with that 

sequestered in the soil (to depth of 5 m), a C sink of 172.9 Mg ha-1 in 30 years could be 

expected. 
Summary and general discussion

79

6 SUMMARY AND GENERAL DISCUSSION 

6.1 Biomass distribution 

Biomass production of both A. mangium and oil palm plantations increased with 

plantation age. Although the rate of biomass production of A. mangium plantations 

(21.3 Mg ha-1 yr-1) was much higher than that of the oil palm plantations (8.3 Mg ha-1

yr-1), due to the short rotation of A. mangium plantations (9 years for pulp production 

but 25-30 years for oil palm), the amount of biomass accumulated at the end of the 

rotation was quite similar (Figure 6.1). 

In contrast to I. cylindrica grassland, the main part of the biomass of these 

plantations is allocated to the aboveground compartments. Furthermore, at the end of 

the rotation, the total biomass of the A. mangium and oil palm plantations (181.2 and 

204.3 Mg ha-1, respectively) was much higher than that of the I. cylindrica grassland 

systems near these plantations (21.9 and 16.9 Mg ha-1). This shows clearly that the 

Figure 6.1: Biomass distribution of Imperata cylindrica grassland, Acacia mangium

and oil palm plantations; belowground biomass defined to depth of 5 m 

for oil palm plantation, 3 m for Imperata cylindrica grassland and Acacia 

mangium plantation 

-60 -30 0 30 60 90 120 150

Biomass (Mg ha-1)

Litter Undergrowth Crop

Belowground 

60 30 

Aboveground 

30-year-old

9-year-old

Oil palm 

I. cylindrica 

A. mangium 

I. cylindrica 
Summary and general discussion

80

conversion of I. cylindrica grassland into A. mangium and oil palm plantations is highly 

beneficial if biomass enhancement is to be addressed. 

The biomass of the undergrowth in the 9-year-old A. mangium plantation (0.8 

Mg ha-1) was considerably lower than that of the oil palm plantation (3.2 Mg ha-1). This 

is probably related to the dense canopy closure of the A. mangium plantation. Although 

an allelophatic effect of leaf exudates of A. mangium has been reported, this low 

biomass accumulation was more likely the effect of light deficiency, as the undergrowth 

biomass was higher under the more open canopy of the 4-year-old plantation (12.2 Mg 

ha-1). A wide range of values of undergrowth biomass of fast growing tree plantations 

has been reported in previous studies with values ranging from 2.9 to 4.6 Mg ha-1 for A. 

mangium plantations, 2.8 to 5.9 Mg ha-1 for Paraserienthes falcataria plantations, and 

2.6 to 18.5 Mg ha-1 for Eucalyptus deglupta plantations (Syahrinudin 1997; Ruhiyat 

1989). 

The litter standing stock accumulated under the A. mangium plantations (6.0 

Mg ha-1) was significantly lower than that under the oil palm plantations (17.9 Mg ha-1). 

The values for fast growing tree plantations reported in previous studies ranged from 

10.1 to 13.8 Mg ha-1 for A. mangium plantations, 14.9 to 17.0 Mg ha-1 for 

Paraserienthes falcataria plantations and 7.0 to 19.5 Mg ha-1 for Eucalyptus deglupta

plantations (Syahrinudin 1997; Ruhiyat 1989). 

The belowground biomass of the A. mangium plantations (36.3 Mg ha-1) was 

significantly lower than that of the oil palm plantations (52.4 Mg ha-1) However, the 

relative contribution of belowground biomass to total biomass for the A. mangium

(20.1%) and oil palm plantations (25.6%) was not significantly different. 

6.2 Root distribution 

Tree root systems are involved in soil-C and nutrient enrichment through root turnover, 

acting as a safety net by interception of leached nutrients or the physical improvement 

of compact soil layers (Alongi et al. 2004; Suamy et al. 2003; Tufekcioglu et al. 1999). 

Root distribution in I. cylindrica grassland, A. mangium (fine root) and oil palm 

plantation systems is depicted in Figure 6.2. The fine root biomass of the A. mangium

plantations ranged from 9.5 Mg ha-1 3 m-1 (in the1- and 4-year-old plantations) to 12.3 

Mg ha-1 3 m-1 (in the 9-year-old plantation). This is quite comparable to the root 
Summary and general discussion

81

biomass of I. cylindrica of 12.4 Mg ha-1 3 m-1. However, the vertical distribution of the 

root biomass of I. cylindrica grassland was restricted to the top shallow soil layer, i.e., 

the roots were distributed to a depth of 1.8 m in the I. cylindrica grassland and up to 3 m 

in the A. mangium plantations. The root biomass of the oil palm plantations in East 

Kalimantan of 20.0 and 30.3 Mg ha-1 3 m-1 for the 3- and 10-year-old plantations, 

respectively, and that in Sumatra of 11.4, 15.3, 26.3 and 34.3 Mg ha-1 3 m-1 for the 3-, 

10-, 20 and 30-year-old plantations, respectively, was considerably higher than that of 

the A. mangium plantations. 

The fine root biomass showed a continuous decrease with soil depth. In the 5-

m deep soil profile, more than 50% of the fine root biomass of the A. mangium

plantations was concentrated in the top 30 cm of the profile, which was considerably 

shallower than that of oil palm plantations of 50 cm. However, 50% of the root biomass 

0

100

200

300

400

500

0.0 0.1 1.0 10.0 100.0

Root biomass (Mg ha-1 30cm-1)

Soil depth (cm) ,

Oil palm

Average

A

B

C

D

E

F

A. Mangium

1-yr-old

4-yr-old

9-yr-old

I. cylindrica

Figure 6.2: Vertical distribution of root biomass in 10-year-old oil palm plantation 

(to depth of 5 m; A, B, C, D, E and F = 10, 100, 200, 300, 450 and 520 

cm from the trunk base), Acacia mangium plantation (fine root biomass; 

to depth of 3 m) and Imperata cylindrica grassland (to depth of 3 m) Estimated root biomass below 3m

Soil depth (cm) 
Summary and general discussion

82

of both A. mangium and oil palm plantations was still deeper than that of I. cylindrica

grassland, which was concentrated in the top 10 cm of the soil profile. Furthermore, 

90% of the root biomass of I. cylindrica was confined to a depth of 41 cm; this was 

clearly much shallower than that in the A. mangium plantations with a depth of 237 cm 

and that in the oil palm plantations of 227 cm. 

Figure 6.3 shows the distribution of the root biomass with depth. Both absolute 

(in Mg ha-1) and relative (in % of 0-5 m depth) root biomass cumulatively increased 

with cumulative soil depth. However, the variation of the relative root biomass 

decreased with the increase of the cumulative sampling depth, while the variation of the 

absolute root biomass increased or was maintained at a certain level. 

The root biomass of I. cylindrica was distributed within a depth of less than 2 m (94, 98 

and 100% for depths 0-0.6, 0-1 and 0-2 m, respectively). Root biomass of A. mangium

was sampled to a depth of 3 m, but the established root distribution curve (Figure 6.2) 

Figure 6.3: Vertical distribution of root biomass of Imperata cylindrica grassland, 

Acacia mangium (fine root biomass) and oil palm plantations; columns 

are means, stake bars are standard deviations 

0

5

10

15

20

25

30

35

0-60 cm 0-1 m 0-2 m 0-3 m

Root biomass (Mg ha-1

) ,

Imperata cylindrica

Acacia mangium

Oil palm

40

50

60

70

80

90

100

0-60 cm 0-1 m 0-2 m 0-3 m

Soil depth

Root biomass (% of 0-5 m) ,
Summary and general discussion

83

does not indicate that there are no roots immediately below this depth. The distribution 

of the roots below 3 m is, therefore, estimated based on the distribution curve of A. 

mangium at a depth of 0-3 m combined with the distribution curve of oil palm at a depth 

of 0-5 m. Root biomass of the A. mangium plantation was 67, 76, 87 and 94% for the 

depths 0-0.6, 0-1, 0-2, and 0-3 m, respectively. Root biomass of the 30-year-old oil 

palm plantation was 55, 71, 88 and 95% for the depths 0-0.6, 0-1, 0-2, and 0-3 m, 

respectively. The established curve for the oil palm plantations indicates that very little 

root biomass is to be found at a depth of more than 5 m. 

Root sampling in the deep soils is time and labor consuming. It was found that 

when using a manual root sampler, sampling roots to a depth of 1 m took three times as 

long as sampling to a depth of 60 cm; sampling to a depth of 3 m required 16-20 times 

more time and labor than for the depth 1m. Sampling to a depth of 5 m took three times 

longer than for the depth 3 m. A flexible and reliable method for root studies should, 

therefore, be established. 

The results of this study show that there is no great constraint in the estimation 

of roots of grassland systems, because these roots are mainly (> 98%) concentrated in 

the topsoil to a depth of less than 1m. However, this is not the case for the oil palm and 

A. mangium plantation systems, where 90% of the root biomass is distributed to a depth 

of more than 2 m. Given the constraints in root sampling and the coefficient variation of 

the relative root biomass to a depth of 1 m of less than 10%, root sampling to a depth of 

1 m employing a factor of 1.3 and 1.4 to estimate the total root biomass of A. mangium

and oil palm plantations, respectively, is recommended. 

Although the lateral extent of woody roots may exhibit a high degree of 

plasticity and depend on environmental conditions (Millikin and Bledsoe 1999; Belsky 

1994), the results show that the lateral distribution of the root biomass in the plantations 

(A. mangium and oil palm) was species specific and is probably genetically inherited. In 

contrast to that of the oil palm plantations, lateral distribution of root biomass in the A. 

mangium plantations was not significantly affected by the distance to the closest trunk 

base. However, in line with previous findings (Purbopuspito and Van Rees 2002; Jose et 

al. 2001; Peter and Lehmann 2000; Jones et al. 1998), there was a slight decrease in the 

horizontal distribution of the fine root biomass in the A. mangium plantations with 

distance to tree base (Figure 6.4), i.e., 9.3 and 7.4 Mg ha-1 1m-1 at a distance of 10 cm 
Summary and general discussion

84

and 212 cm, respectively. Root biomass of the oil palm plantations, which was mostly 

concentrated at a distance of less than 1 m from the trunk base, is in agreement with 

former findings (Khalid et al. 1999b; Purvis 1956). Values were 30.2, 15.3, 10.0, 7.7, 

7.7 and 8.1 Mg ha-1 1m-1 at a distance of 10, 100, 200, 300, 450 and 500 cm from the 

trunk base, respectively. 

Acacia mangium

0

5

10

15

0 50 100 150 200

Oil palm

0

10

20

30

40

0 100 200 300 400 500

Distance to closest trunk base (cm)

Figure 6.4: Lateral distribution of root biomass of Acacia mangium (fine root 

biomass) and oil palm plantations; rectangles are means, stake bars are 

standard deviations. 

Root biomass (Mg ha

-1 1m

-1) 
Summary and general discussion

85

6.3 Carbon distribution 

The C content of the biomass in the oil palm plantation systems ranged widely from 

32.3 to 44.2% (Figure 6.5). However, while the C content of the leaf litter (32.3 %) and 

tertiary roots, including quaternary roots, (36.6%) was low, that of the other 

compartments ranged from 39.4 to 44.2%. The weighed average was 41.3%; this figure 

was used for converting biomass to C stock instead of the value of 50% (Hamburg 

2000). 

The C content of the stand biomass of the A. mangium plantations varied from 

27.9% to 45.6%, depending on the tree compartment. The C content of the fine root 

biomass was the lowest (mean of 30.6%) followed by litter standing stock (35.8%) and 

undergrowth (35.8%). The average C content of the other compartments (coarse root, 

stem, branch and leaf) ranged from 42.4 to 44.9%. The overall average of the C content 

of A. mangium (43.3%) was slightly higher than that of I. cylindrica (35.7%) and oil 

palm plantation (41.3%). These figures are slightly lower than the 50% proposed by 

Hamburg (2000). Compared to that of the root biomass of secondary and primary 

20

25

30

35

40

45

50

Fine root

Litter

Undergrowth

Coarse root

Stem

Branch

Leaf

Carbon content (%) 

I. cylindrica A. mangium Oil palm

Carbon content 

Figure 6.5: Carbon content of compartments of Imperata cylindrica grassland, 

Acacia mangium and oil palm plantations; branch = including twig for 

Acacia mangium, including frond base, petiole and rachis for oil palm 

plantations 

Carbon content (%) 
Summary and general discussion

86

forests (43.9-46.6%) (Sommer et al., 2000), the C content of root biomass in this study 

(excluding that of fine root biomass) is quite comparable. 

In the plantation systems, C content of fine roots, litter standing stock and leaf 

biomass of the oil palm plantations was higher than that of A. mangium plantations, 

while that of the remaining compartments (undergrowth, coarse roots, stem and branch) 

was lower. Excluding the C content of the leaf biomass, the order of magnitude of the A. 

mangium and oil palm plantations was identical, i.e., stem > branch and coarse root > 

leaf > undergrowth > litter > fine root. 

The variability of the C content of litter standing stock and fine root biomass 

of both A. mangium and oil palm plantation systems was considerably higher than that 

of the other compartments; coefficient of variation was 13.6 and 10.9% for A. mangium

plantations and 20.4 and 12.0% for the oil palm plantation systems, respectively, while 

the coefficients of the other compartments (undergrowth, coarse root, stem, branch and 

leaf) were less than 10%. 

Below- and aboveground biomass C of both A. mangium and oil palm 

plantation systems increased persistently in line with age of the plantations. Carbon 

stored in below- and aboveground biomass of A. mangium plantations increased from 

3.6 and 6.1 Mg ha-1 in the early stage of the plantation (1-year-old) to 14.2 and 64.3 Mg 

ha-1 at the end of the plantation cycle (9-year-old); this does not differ much from the 

values for the oil palm plantations, which increased from 5.4 and 11.2 Mg ha-1 in the 

early stage of the plantation (3-year-old) to 21.8 and 62.8 Mg ha-1 at end of the 

plantation cycle (30-year-old), respectively. At the end of the plantation cycle, the total 

C stored in the biomass of the A. mangium and oil palm plantation systems amounted to 

78.5 and 84.6 Mg ha-1, respectively. Compared to that stored in the biomass of the I. 

cylindrica grasslands of 7.5, 4.0, 3.6 Mg ha-1 for total, below- and aboveground biomass 

C, respectively, it is clear that the biomass C accumulated in both A. mangium and oil 

palm plantation systems already surpassed that of I. cylindrica grassland in the early 

stage of the plantation. 

The rate of C sequestration in the biomass of the A. mangium plantations (9.3 

Mg ha-1 yr-1) was remarkably higher than that of the oil palm plantation (3.4 Mg ha-1 yr-1). 

However, due to the length of the plantation cycle, i.e., 9 years for A. mangium

plantations for pulp production and 25-30 years for commercial oil palm plantations, at 
Summary and general discussion

87

the end of the plantation cycle, the magnitude of biomass C was similar (Figure 6.6). 

These rates are also higher than those of riparian poplars (2.9 Mg ha-1 yr-1) (Tufekcioglu 

et al. 2003). 

Of the total biomass C, belowground biomass C was 38.1, 20.1 and 20.0% for 

the 1-, 4-, and 9-year-old A. mangium plantations, respectively, equivalent to a rootshoot ratio (below-aboveground ratio) of 61.4, 25.2 and 25.0%, respectively. This high 

contribution of belowground biomass C in the early stage of the plantations was mainly 

due to the fast development of the fine roots in the beginning of the plantation cycle. It 

was maintained in a narrow dynamic range of magnitude until the end of the plantation 

cycle. 

Belowground biomass C of the oil palm plantations gave 32.6, 21.1, 25.5 and 

25.7% of the total biomass C equivalent to a root-shoot ratio (below-aboveground ratio) 

of 48.4, 26.7, 34.2 and 34.6% for the 3-, 10-, 20- and 30-year-old plantations, 

respectively. The low contribution of belowground biomass C of the 10-year-old 

plantation was due to the accumulation of frond base biomass; there was no abscission 

of the frond bases in the 10-year-old plantation in this study. 

-120 -100 -80 -60 -40 -20 0 20 40 60 80

Carbon stock (Mg ha-1)

Belowground biomass

Soil

Litter

Undergrowth

Crop

Figure 6.6: Carbon stock distribution of Imperata cylindrica grassland, Acacia 

mangium plantation and oil palm plantation systems 

300 240 180 120

Belowground Aboveground 

360 60

Oil palm, 30-yr-old 

I. cylindrica 

A. mangium, 9-yr-old 

I. cylindrica 
Summary and general discussion

88

Since belowground biomass C may contribute significantly to the total 

biomass C of the plantation systems (in this study it was more than 20% in both 

systems), incorporation of belowground biomass C in studies of C stock and budget is 

of utmost importance. However, due to the difficulty in determining belowground 

biomass, it is proposed to estimate the magnitude of belowground biomass C from that 

of aboveground of the system. Estimation of belowground biomass C with a factor of 

0.25 of the aboveground biomass for A. mangium plantations, of 0.25 for oil palm 

plantations if there is no pronounced abscission of the frond bases, or of 0.33 if the 

frond bases are regularly detached, is recommended.

Table 6.1: Aboveground biomass, C storage and C sequestration rate of plantation 

systems in different regions in the tropics 

Plantation Age Biomass Carbon C sink rate

(year) (Mg ha-1) (Mg ha-1 yr-1)

Site Reference 

4 69.5 31.3 7.8 Philippines Kawara et al. 1981 

5 87.4 37.8* 7.6 East Kalimantan Ruhiyat, 1989 

5 75.6 34.0 6.8 Philippines Kawara et al. 1981 

7 96.4 43.4 6.2 Philippines Kawara et al. 1981 

9 108.2 48.7 5.4 Philippines Kawara et al. 1981 

10 111.5 48.3* 4.8 East Kalimantan Ruhiyat, 1989 

Paraserienthes 

falcataria

9 90.1 39.0* 4.3 East Kalimantan Ruhiyat, 1989 

9 120.7 54.3 6.0 Philippines Kawara et al. 1981 

Gmelina arborea 7 85.7 38.6 5.5 Philippines Kawara et al. 1981 

9 87.4 39.3 4.4 Philippines Kawara et al. 1981 

Tectona grandis 5 49.6 21.5* 4.3 De Angelis et al. 1981

Eucalyptus 

grandis 4 63.7 15.9 North Sumatra, 

Indonesia Retnowati 1998 

9 114.9 49.8* 5.5 East Kalimantan Ruhiyat, 1989 

7 89.0 38.6* 5.5 East Kalimantan Ruhiyat, 1989 

4 49.3 21.4* 5.3 East Kalimantan Syahrinudin, 1997 

6 65.3 28.3* 4.7 East Kalimantan Syahrinudin, 1997 

9 94.1 40.7* 4.5 East Kalimantan Ruhiyat, 1989 

E. deglupta 

5 47.4 20.5* 4.1 East Kalimantan Ruhiyat, 1989 

E. nitens 5 72.6 31.4* 6.3 New Zealand Oliver et al., 1984 

E. saligna 4 38.5 16.7* 4.2 New Zealand Krapfenbauer and 

Andrea, 1989 

E. urograndis 4.5 40.4 17.5* 3.9 North Amazon, 

Brazil Spangenberg, 1994 

4 64.8 28.5 7.1 East Kalimantan This study Acacia mangium 9 139.2 62.1 6.9 East Kalimantan This study 

3 22.9 9.6 3.2 Sumatra This study 

10 87.9 37.0 3.7 Sumatra This study 

20 102.0 43.1 2.2 Sumatra This study Oil palm 

30 133.9 56.6 1.9 Sumatra This study 

*

 Values were computed from aboveground biomass with a factor of 0.43. 
Summary and general discussion

89

Aboveground biomass C of plantations in the tropics ranges widely depending 

primarily on the plantation species (Table 6.1). Acacia mangium and Paraserienthes 

falcataria plantations are among the most productive plantations with regard to 

aboveground biomass and C accumulation. However, the rate of biomass and C 

accumulation of Paraserienthes falcataria declines sharply in the older plantations. 

There was a very high rate of aboveground biomass C sequestration of a 4-year-old 

Eucalyptus grandis plantation in North Sumatra, Indonesia, of 15.9 Mg ha-1 yr-1

(Retnowati 1998). This is twice as much as the values for A. mangium of 6.9 – 7.1 Mg 

ha-1 yr-1. In contrast to the high annual net primary production of oil palm plantations, 

ranging from 11.9 Mg ha-1 yr-1 in Sumatra (Setyo et al. 1999; Lamade and Setyo 2002) 

to 20.1 Mg ha-1 yr-1 in Malaysia (Henson and Chai 1997; Henson 1998), the rate of the 

accumulation of the aboveground biomass C of oil palm, ranging from 1.9 to 3.7 Mg ha1

 yr-1 was the lowest among the plantations. This is primarily due to the removal of the 

harvested biomass, which can amount to 20-42% (Setyo et al. 1999; Lamade and Setyo 

2002; Henson and Chai 1997; Henson 1998). 

Compared to that of natural forests (Table 6.2), the aboveground biomass C 

density of plantations is much lower. This implies that if C sequestration is the concern, 

plantations should be established in non-forested areas or those with a low viability of 

natural succession. 

Table 6.2: Aboveground biomass and C density of natural forests in different 

regions in the tropics

Biomass C Density No (Mg ha-1) Site Reference 

1 406 175.8 Brazil Klinge 1976 

2 357 154.6 Caparo, Venezuela Hase 1981 

3 460 199.2 East Kalimantan, Indonesia Ruhiyat 1989 

4 390 168.9 Indonesia Hairiah and Sitompul 2000 

5 325 140.7 Indonesia Sitompul and Hairiah 2000 

6 254 110.0 Indonesia Noordwijk et al. 2000 

7 264 114.3 Khade, Ghana Greenland and Kowal 1960

8 316 136.8 Panama Golley et al. 1975 

9 378 163.7 Rio Lara, Panama Golley et al. 1975 

10 276 119.5 Rio Sabana, Panama Golley et al. 1975 

11 265 114.9 Philippines Kawara et al. 1981 

Values for C density were computed from aboveground biomass with a factor of 0.43. 
Summary and general discussion

90

The patterns of soil C distribution vary highly with soil age, soil texture, 

rainfall, temperature patterns, and vegetation type. The vertical distribution of the soil C 

of both I. cylindrica grassland and A. mangium and oil palm plantation systems in this 

study was quite similar to that of previous studies by Syahrinudin (1997) and Ruhiyat 

(1989) for the soils in the same region. The soil C content decreased in line with soil 

depth and was highly depth dependent (r2 = 0.97 to 0.99 and p < 0.001). However, 

spatial variation was driven by the distribution of the fine root biomass of the system: r2

= 0.83-0.99 and p < 0.001 for the A. mangium plantations and r2 = 0.69-0.87 and p < 

0.001 for the oil palm plantations. Soil C content decreased sharply in the upper 50 cm 

of the soils and more gradually deeper down. Nevertheless, a distinct difference in 

vertical soil C distribution between I. cylindrica grassland and A. mangium and oil palm 

plantations was observed. Compared to A. mangium and oil palm plantations, the 

decrease in the soil C content under I. cylindrica grassland was less abrupt in the upper 

50 cm of the soils and more distinct in the lower part of the soil profile. This difference 

seemed to be governed by the difference in fine root distribution. On one hand, a high 

root biomass and dense root mat in the top layer of the soils under I. cylindrica

grassland led to a higher C content (6.6 g dm-3) in the first 15-cm depth compared to the 

A. mangium plantations (2.6 dm-3) and the oil palm plantations (3.4 dm-3); on the other 

hand, deeper root penetration in the A. mangium and oil palm plantations led to a higher 

C content in the deeper soils. 

Soil C storage in this study is in the range of that reported in previous studies 

(Mackensen 1998; Syahrinudin 1997; Bremen et al. 1990; Ruhiyat 1989). Total C 

stored in the soils in the A. mangium plantations (210.4 – 325.5 Mg ha-1 5 m-1) was 

considerably higher than that in the oil palm plantations (139.2 – 260.6 Mg ha-1 5 m-1). 

These values are somewhat higher than those of primary and secondary forests (156.0 – 

176.0 Mg ha-1 5 m-1) and a 9-year-old oil palm plantation (131.0 Mg ha-1 5 m-1) reported 

by Sommer et al. (2000). However, there was an incredibly high magnitude of soil C in 

the 10-year-old plantation in Sumatra (482.4 Mg ha-1 5 m-1). This reflects the high 

variation of C stock in tropical soils. This figure, however, does not represent the 

common magnitude of C stock in most Ultisols in the tropics; the soil C stock to a depth 

of 1 m in the 10-year-old oil palm plantation (250.2 Mg ha-1) was very much higher 

than that reported in previous studies (83.3-95.2 Mg ha-1) (Mackensen 1998; 
Summary and general discussion

91

Syahrinudin 1997; Bremen et al. 1990) and is, therefore, excluded in the estimate of the 

C sequestration rate of the oil palm plantations. There was a wide range of C stored in 

the soils under the I. cylindrica grasslands (ranging from 137.6 Mg ha-1 5 m-1 in 

Sumatra to 188.1 Mg ha-1 5 m-1 in East Kalimantan). 

Soil C storage is largely dependent on environmental, biogeochemical and 

land management factors. Different land use and management practices influence soil 

properties such as soil temperature, moisture, microbial biomass, organic matter and 

fine root biomass, which in turn affect the magnitude of soil respiration (Lee and Jose 

2003; Raich and Tufekcioglu 2000; Kelting et al. 1998) and soil C dynamics. Trees can 

substantially increase the organic matter input into the system through the turnover of 

leaves and roots (Jose et al. 2000). The results in this study show that the conversion of 

I. cylindrica grassland into A. mangium and oil palm plantations considerably increased 

the amount of soil C. On average, the rate of soil C accumulation in the A. mangium

plantations (2.3, 4.0, 4.2 and 6.9 Mg ha-1 yr-1) was much higher than that of the oil palm 

plantation (0.7, 0.4, 0.5 and 1.0 Mg ha-1 yr-1) for depths 0-100, 100-200, 200-300 and 

300-500 cm, respectively. As oil palm plantations do not allocate a large part of the 

biomass production to the belowground compartment (Lamade and Setyo 2002), a 

lower soil C sequestration could be expected. An increase in soil-C accumulation (0-100 

cm) from 0.7 to 1.2 Mg ha-1 yr-1 by incorporating legume trees into a grass pasture was 

reported by Tarré et al. (2001). Sataye et al. (2001) estimated an increase in soil C of 

0.5 to 3.0 Mg ha-1 yr-1 in forest plantations in the tropics. A rate of soil organic matter 

sink of 1.1 Mg ha-1 yr-1 was reported by Lugo et al. (2004) for restored neotropical 

forest systems in Puerto Rico. The C sink in the first 1-m depth in this study is still in 

the range of the above-mentioned studies. To depth of 5 m, the rate of soil C 

sequestration in the A. mangium and oil palm plantations systems reached 17.5 and 2.6 

Mg ha-1 yr-1 contributing to 157.7 and 76.8 Mg ha-1 soil C for the entire plantation 

cycle, respectively (Figure 6.6). 

It was, however, observed that there was a slight decrease in soil C storage at a 

depth of 0-100 cm during the early stages of both A. mangium and oil palm plantations. 

This may relate to the lower litter production in this stage. Nevertheless, the deeper soils 

experienced enrichment of C storage from the very beginning of the plantations. 
Summary and general discussion

92

It is interesting that the conversion of I. cylindrica grassland into A. mangium

plantation led to a much higher amount of C sequestered in the deep soils than in the 

upper layers. In contrast, conversion of I. cylindrica grassland into oil palm plantation 

led to a higher amount of C sequestered in the upper soils (0-1 m). The results show that 

the soil C stock at a depth of 0-1 m represents only 36.1% and 46.7% of the total soil-C 

stock (0-5 m depth) of A. mangium and oil palm plantation systems, respectively. 

Compared to that of the I. cylindrica grassland system of 56.1%, there is no doubt that 

the conversion of I. cylindrica grassland into plantations improves the C sink in deep 

soils (1-5 m). This finding is in contrast to the proposed soil-C change measurement in 

forestry offset projects to a depth of only 1 m (Hamburg 2000). While most previous 

soil-C studies concentrate on the upper soil layers down to a maximum depth of 2 m 

(Tufekcioglu et al. 2003; Tarré et al. 2001; Brown and Lugo, 1990; Fisher et al., 1994; 

Moraes et al., 1995), the results confirm the findings of Sommer et al. (2000), Trumbore 

et al. (1995) and Nepstad et al. (1994), which show the importance of root penetration 

in deep soil layers for C sequestration. Moreover, the C sequestered in deep soils could 

be more beneficial than that sequestered in shallow soils, because soil organic matter in 

deep soils is more resistant to decomposition and thus has a longer resident time 

(Gaudinski et al. 2000; Van Dam et al. 1997). 

Together with the C sequestered in the biomass of the plantations, a magnitude 

of soil-C sequestration during the whole plantation cycle of A. mangium (9 years) and 

oil palm (30 years) of 236.3 and 161.4 Mg ha-1, or an average rate of 26.8 and 6.0 Mg 

ha-1 yr-1, respectively, could be achieved. Of these amounts, 72.7 and 61.1% were 

assigned to the belowground C pool (soil and belowground biomass C). Thus, 81.2 and 

76.9% of the total C of the A. mangium and oil palm plantations, respectively, were 

stored to depth 5 m. However, compared to the I. cylindrica grassland system (98.0%), 

the relative contribution of belowground C of A. mangium and oil palm plantations was 

much lower. 
Conclusions and recommendations

93

7 CONCLUSIONS AND RECOMMENDATIONS 

7.1 Conclusions 

Imperata cylindrica grassland stored only a small amount of biomass C (5.9 – 7.6 Mg 

ha-1) implying that conversion of this grassland into a biomass- and C-rich system is a 

promising tool for the building of the terrestrial C. Moreover, due to the root 

distribution pattern of this grassland, i.e., most of the roots were concentrated in the 

upper centimeters of the soil, only a small amount of C could be stored in the deep soils. 

Furthermore, although there was a dense mat of rhizomes in the top centimeters of the 

soil under the I. cylindrica grasslands, the magnitude of C stored in the uppermost soils 

was only moderate. Hence, if C sequestration is the concern, conversion of this 

grassland into a system promoting higher biomass accumulation and deep root 

penetration is of great interest. 

Both oil palm and A. mangium plantations could sequester much more C than 

I. cylindrica grassland. However, although the magnitude of biomass C in these 

plantations was quite comparable (at the end of the plantation cycle it was 78.5 Mg ha-1

in the A. mangium and 84.4 Mg ha-1 in the oil palm plantations), due to the longer 

sequestration period (plantation cycle of 9 years for the A. mangium and 30 years for the 

oil palm plantations), the rate of C sequestration in the biomass of the oil palm 

plantation was much lower (9.3 Mg ha-1 yr-1 for the A. mangium and 3.4 Mg ha-1 yr-1 for 

the oil palm plantations). 

The roots of both plantations penetrate to deep soils; however, due to the 

different nature of the roots and also probably the different allocation strategy of the 

produced organic constituents combined with the different management practices, 

significant differences in the soil-C sink of these plantations were determined. The C 

sink of the A. mangium plantation was much larger than that of the oil palm plantation: 

157.7 Mg ha-1 5 m-1 or 17.5 Mg ha-1 5 m-1 yr-1 for the A. mangium plantation and 76.8 

Mg ha-1 5 m-1 or 2.6 Mg ha-1 5 m-1 yr-1 for the oil palm plantations. 

These differences seemed to affect not only soil-C sink of the systems but also 

C accumulation pattern. Although the magnitude of biomass C stored in both systems 

was quite similar, the C accumulated in the biomass of the A. mangium plantations, 
Conclusions and recommendations

94

representing only 29% of the total C sequestered in the system, was much lower than 

that of the oil palm plantations of 45%. 

On average, the total C sink (soil and biomass C) during the whole plantation 

cycle of A. mangium (9 years) and oil palm (30 years) reached a magnitude of 236.3 and 

161.4 Mg ha-1, equivalent to the average rate of C sequestration of 26.8 and 6.0 Mg ha-1

yr-1, respectively. Of these amounts, 72.7 and 61.1% were assigned to the belowground 

C pool (soil and belowground biomass C) and, thus 81.2 and 76.9% of the C of the A. 

mangium and oil palm plantations, respectively, were stored to depth of 5 m. However, 

compared to the I. cylindrica grassland system (98.0%), the relative contribution of the 

belowground C stock of A. mangium and oil palm plantations was much lower. These 

figures demonstrate the importance of the aboveground biomass C in the plantations. 

7.2 Recommendations 

Neither the biomass of the plantations nor that of I. cylindrica grassland could reach the 

50% C content suggested by former authors (Brown and Lugo 1984; Hamburg 2000). 

The calculations in this study on the C content of the biomass of A. mangium and oil 

palm plantations came to averages of 43 and 41%, respectively. However, there was a 

large difference in C content between above- and belowground biomass of I. cylindrica

grassland (41 and 31%, respectively). Therefore, it is proposed to use these figures for 

the computation of the biomass C of these systems. 

Measurements of the biomass of plantations with destructive sampling 

methods are lengthy and costly. Therefore, there is a need to develop methods for 

estimating the biomass of plantations with non-destructive methods. There was a high 

dependency of the biomass and biomass C of the oil palm plantations on age (r2 > 0.9, p

< 0.05) (figures 5.2 and 5.8). Biomass and biomass C of the A. mangium plantations 

were highly dependent on the tree diameter of the stand (r2 > 0.9, p < 0.001) (Table 4.8). 

Allometric equations established in this study could be used to estimate both above- and 

belowground biomass and biomass C of the respective plantations, while belowground 

biomass could be estimated either with the allometric equation or with the 

belowground-aboveground ratio described in chapters 4 and 5. 

Among the compartments of the biomass of the plantation systems, 

measurement of the fine root biomass is the most time consuming and labor intensive. 
Conclusions and recommendations

95

In the oil palm plantations, total belowground biomass and biomass C could be 

estimated with allometric equations, but this was not the case for the A. mangium

plantations. Only those of coarse roots of A. mangium plantation can be estimated with 

allometric equations, but not for those of fine roots. The results show that there was a 

small variation of fine root biomass and biomass C among plantation ages, but the 

variation within sites was considerably high (see Figure 4.4). This implies that 

estimation of fine root biomass and biomass C with a small sampling size is subject to 

high errors. Applying a sample size of 153 auger points resulted in coefficients of 

variation of 108.0 ± 21.0% for within and 57.1 ± 22.3% among sites. However, fine root 

biomass C of A. mangium plantations ranging from 2.8 to 3.4 Mg ha-1 produced less 

than 5% of the total biomass C of the mature plantation system. Therefore, estimation of 

fine root biomass C of A. mangium plantations with a factor of 0.04 of the total biomass 

C of the system for the mature plantations or adopting a magnitude of 3.0 Mg ha-1 for 

the young plantations is recommended. 

The biomass of undergrowth and litter standing stock of A. mangium

plantations varied widely and there is no simple parameter which could be employed to 

estimate the magnitude of these compartments. They should, therefore, be measured 

directly in each specific stand. This also applies to soil C. 
References 

96

8 REFERENCES 

Alongi, D.M., Wattayakorn, G., Boyle, S., Tirendi, F., Payn, C. and Dixon, P. 2004. 

Influence of roots and climate on mineral and trace element storage and flux in 

tropical mangrove soils. Biogeochemistry 69: 105-123. 

Anonymous. 1997. Jambi Dalam Angka (Jambi in figures). Biro Pusat Statistik Propinsi 

Jambi. Indonesia. 

Belsky, A.J. 1994. Influences of trees on savanna productivity: tests of shade, nutrients 

and tree-grass competition. Ecology 75: 922-932. 

Bowen, G.D. 1985. Roots as a component of tree productivity. In: Cannel M.G.R. and 

Jackson J.E. (eds.), Trees as Crop Plants. Inst. Terrestrial Ecology 

Huntingdon, England, 303–315. 

Bowen, G.D. 1984. Tree roots and the use of soil nutrients. In: G.D. Bowen and E.K.S. 

Nambiar (eds.), Nutrition of Plantation Forests. Academic Press, New York, 

147-209. 

BPN (Badan Pertanahan Nasional), Kantor Wilayah Propinsi Jambi. 1993. Rencana 

Batas dan Tata Guna Tanah di Kawasan Taman Nasional Kerinci Seblat 

(Boundary Plan and Land Allocation in the Area of Kerinci Seblat National 

Park). Jambi, Indonesia. 

Bremen, H.V., Iriansyah, M. and Andriesse, W. 1990. Detailed soil survey and physical 

land evaluation in a tropical rain forest, Indonesia. A study of soil and site 

characteristics in twelve permanent plots in East Kalimantan. The Tropenbos 

Foundation-Ede, The Netherlands. 

Brook, R.M. 1989. Review of literature on Imperata cylindrica (L.) Raeuschel with 

particular reference to South East Asia. Tropical Pest Management 35 (1): 12-

25. 

Brown, S. and Lugo, A. 1990. Effects of forest clearing and succession on the carbon 

and nitrogen content of soils in Puerto Rico and US Virgin Islands. Plant Soil

124: 53–64. 

Brown, A.H.F. 1992. Functioning of mixed species stands at Gisburn NW England. In: 

Cannell, Malcolm and Robertson (eds.), The Ecology of Mixed-Species Stands 

of Trees. Oxford Blackwell Publ., London. 125-150. 

Brown, S. and Lugo, A.E. 1984. Biomass of tropical forests: a new estimate based on 

forest volumes. Science 223: 1290-1293. 

Bustomi, S. 1988. Tabel isi pohon lokal Acacia mangium untuk daerah Balikpapan, 

Kalimantan Timur (Local tree volume table of Acacia mangium Willd. For the 

Balikpapan Forest District, East Kalimantan). Bul. Pen. Hutan 495: 31-38. 

Buyanovsky, G.A., Kucera, C.L. and Wagner, G.A. 1987. Comparative analysis of 

carbon dynamics in native and cultivated ecosystems. Ecology 68 (6): 2023-

2031. 

Cairns, M.A., Brown, S., Helmer, E.H. and Baumgardner, G.A. 1997. Root biomass 

allocation in the World’s upland forests’. Oecologia 111: 1-11. 

Cerri, C. C., Volkoff, B., and Andreaux, F. 1991. Nature and Behavior of Organic 

Matter in Soils under Natural Forest, and after Deforestation, Burning and 

Cultivation, Near Manaus. Forest Ecology and Management 38: 247–257. 

Chan, K.W. 1977. A rapid method for studying the root distribution of oil palm and its 

application. In: Earp, D.A. and Newall, W. (eds.), International Develpments 

in Oil Palm, Incorporated Society of Planters, Kuala Lumpur. 131-151. 
References 

97

Chen, C.P.H.K., Wong and Dahlan, I. 1991. In: Y.W. Ho et al. (eds.), Recent Advances 

on the Nutrient of Herbivores. Malaysian Society and Animal Production. 233-

246. 

Chen, W.J., Chen, J.M., Price, D.T., Cihlar, J. and Liu, J. 2000. Carbon offset potentials 

of four alternative forest management strategies in Canada: a simulation study. 

Mitigation and Adaptation Strategies for Global Change 5: 143-169. 

Corley, R.H.V., Gray, B.S. and Ng, S.K. 1971. Productivity of the oil palm (Elaeis 

guineensis Jacq.) in Malaysia. Expl. Agric. 7: 129-136. 

Cossalter C., Pye-Smith, C. 2003. Fast-wood forestry: myths and realities. CIFOR, 

Indonesia. 

Cox, P.M., Betts, A.R. Jones, C.D., Spall, S.A. and Tottendell, I.J. 2000. Acceleration 

of global warming due to carbon-cycles feedbacks in a coupled climate model. 

Nature 408: 184-187. 

Crabtree, R.C. and Berntson, G.M. 1994. Root architectural responses of Betula lenta to 

spatially heterogeneous ammonium and nitrate. Plant Soil 158: 129-134. 

Curt, T. and Prévosto, B. 2003. Rooting strategy of naturally regenerated beech in 

Silver birch and Scots pine woodlands. Plant Soil 255: 265-279. 

Curt, T., Lucot, E. and Bouchaud, M. 2001. Douglas-fir root biomass and rooting 

profile in relation to soils in a mid-elevation area (Beaujolais Mounts, France). 

Plant and Soil 233: 109–125. 

De Agelis, D.I., Gardner, R.H. and Shugart, H.H. 1981. Productivity of forest 

ecosystems studied during the IBP: the woodland data set. In: D.E. Reichle 

(ed.), Dynamic Properties of Forest Ecosystems. Cambridge University Press, 

Cambridge, 567-659. 

De Foresta, H. and Michon, G. 1997. The agroforest alternative to Imperata grasslands: 

when smallholder agriculture and forestry reach sustainability. Agroforestry 

systems 36 (1/3): 105-120. 

De Jong, E. and Schappert, H.J.V. 1972. Calculation of soil respiration and activity 

from CO2 profiles in the soil. Soil Science 119: 328-333. 

Dela Cruz, R.E. 1986. Constraints and strategies for the regeneration of Imperata

grasslands. In: Proceedings of the symposium in Bogor, Indonesia, 9-11 May 

1984. Biotrop Special Publication No. 25. Bogor, Indonesia, 23-24.

Dhyani, S.K. and Tripathi, R.S. 2000. Biomass and production of fine and coarse roots 

of trees under agrisilvicultural practices in north-east India. Agroforestry 

Systems 50: 107–121. 

Dixon, R.K., Winjum, J.K. and Schroeder, P.E. 1993. Conservation and sequestration of 

carbon: the potential of forest and agroforest management practices. Global 

Environmental Change, 3 (2): 159-173. 

Drexhage, M. and Gruber, F. 1998. Architecture of skeletal root system of 40-year-old 

Picea abies on strongly acidified soils in the Harz Mountains (Germany). Can. 

J. For. Res. 28: 13–22. 

Eswaran, H. E., Van der Berg, E., Reich, P. and Kimble, J. 1995. Global soil carbon 

resources. In: R Lal, J Kimble, E Levine and B A Steward (eds.), Soil and 

Global Change. CRC/Lewis, Boca Raton. 27–43. 

Eussen, J.H.H. 1981. Studies on the growth characteristics of alang-alang (Imperata 

cylindrica (L.) Beauv.) vegetation. Biotrop Bulletin No. 18, 1981. BIOTROP. 

Bogor, Indonesia. 24pp. 
References 

98

Eussen, J.H.H. and Wirjahardja, S. 1973. Studies of an alang-alang (Imperata 

cylindrica (L) Beeauv.), vegetation. BIOTROP Bulletin No. 6, SEAMEOBITROP, Bogor, Indonesia. 

FAO. 2001. Global ecological zoning for the global forest resources assessment 2000. 

Final report. Forest resources assessment working paper No. 056. Rome. 

FAO. 2003. State of the world’s forest. Food and Agriculture Organization, Roma, 

133pp. 

Fisher, M.J., Rao, I.M., Ayaraza, M.A., Lascano, C.E., Sanz, J.I., Thomas, R.J. and 

Vera, R.R. 1994. Carbon storage by introduced deep-rooted grasses in the 

South American savannas. Nature 371: 236–238. 

Fisher, R.F. 1995. Amelioration of degraded rain forest soils by plantations of native 

trees. Soil Sci. Soc. Am. J. 59: 544-549. 

Fitter, A.H. 1994. Architecture and biomass allocation as components of the plastic 

response of root systems to soil heterogeneity. In: MM Caldwell and RW 

Pearcy (eds.), Exploitation of Environmental Heterogeneity by Plants: 

Ecophysiological Process Above- and Belowground. 305–323. 

Fogel, R. 1983. Root turnover and productivity of coniferous forests. Plant and Soil 71: 

75–85. 

Fogel, R. 1985. Roots as primary producers in below-ground ecosystems. In: A H Fitter 

(ed.), Ecological interactions in soil. Special Publication of the British 

Ecological Society No. 4, 23–36. 

Galiana, A., Gnahoua, G.M., Chaumont, J. Lesueur, D., Prin, Y. and Mallet, B. 1998. 

Improvement of nitrogen fixation in Acacia mangium through inoculation with 

rhizobium. Agroforestry System 40: 297-307. 

Galiana, A., Mallet, B., Balle, P., Kanga, A.N., and Domenach, A.-M. 1995. In situ 

nitrogen fixation of Acacia mangium inoculated with Badryrhizobium. In: A. 

Schulte and D. Ruhiyat (eds.), Proc. 3rd Int. Cong. Soils Trop. For. Ecos. 7. 

Mineralization. Mulawarman University Press. Samarinda, Indonesia. 

Garrity, D.P., De La Cruz, R., Soekardi, M., Van Noordwijk, M., Pathak, P.S., 

Gunasena, H.P.M., Van So, N., Huijun, G. and Majid, M.N. 1997. The 

Imperata grasslands of tropical Asia: area, distribution, and typology. 

Agroforestry Systems 36 (1/3): 3-29. 

Gaudinski, J.B., Trumbore, S.E., Davidson, E.A. and Zheng, S.H. 2000. Soil carbon 

cycling in a temperate forest: radiocarbon-based estimates of residence times, 

sequestration rates and partition fluxes. Biogeochemistry 51: 33-69. 

Ginting, A.N. 2000. The progress of establishing cinnamon and candlenut 

demonstration plots in Jambi and their potential to absorb carbon. Science and 

Policy Workshop on Terrestrial Carbon and Possible Trading under the CDM. 

IC-SEA, BIOTROP, Bogor. 

Glastra, R., Wakker, E. and Richert, W. 2002. Oil palm plantations and deforestation in 

Indonesia. What role do Europe and Germany play? AIDEnvironment, 

Amsterdam, The Netherlands. http://www.fire.uni-freiburg.de/seasia/projects/ 

wwf_oil.htm. 

Golley, F.B., MacGinnis, J.T., Child, G.I., Duever, M.J. 1975. Mineral cycling in a 

tropical moist forest ecosystem. University of Georgia Press, Athens 

Grace, J., Lloyd, J., Mcintyre, J., Miranda, A., Meir, P. and Miranda, H. 1995. Carbon 

dioxide uptake by an undisturbed tropical rain forest in southwest Amozonia, 

1992 to 1993. Science 270: 778-780. 
References 

99

Greenland, D.J. and Nye, P.H. 1959. Increases in the carbon and nitrogen contents of 

tropical soils under natural fallows. J. Soil Sci. 10 (2): 284–299. 

Greenland, D. J., and J. M. L. Kowal. 1960. Nutrient content of the moist tropical forest 

of Ghana. Plant soil 12: 154-174. 

Grier, C.C., Vogt, K.A., Keyes, M.R. and Edmonds, R.L. 1981. Biomass distribution 

and above- and belowground production in young and mature Abies amabilis

zone ecosystems of the Washington Cascades. Can. J. For. Res. 11: 155-167. 

Grime, J.P. 1979. Plant strategies and vegetation processes. J. Wiley and Sons, 

Chichester, UK. 

Hairiah, K. and Sitompul, S.M. 2000. Assessment and simulation of aboveground and 

belowground C stock and dynamics. Proc. Science and Policy Workshop on 

Terrestrial Carbon and Possible Trading under the CDM. IC-SEA, BIOTROP, 

Bogor. 

Halenda, C.J. 1989. Biomass estimation of Acacia mangium plantations using 

allometric regression. NFT Res. Rpts. 7: 49-51. 

Hamburg, P.S. 2000. Simple rules for measuring changes in ecosystem carbon in 

forestry-offset projects. Mitigation and Adaptation Strategy for Global 

Change 5: 25-37. 

Hardiyanto, E.B., Ryantoko, A., Anshori, S. 1999. Effects of site management in Acacia 

mangium plantations at PT. Musi Hutan Persada, South Sumatra, Indonesia. 

In: Nambiar E.K.S., Tiarks A., Cossalter C., Ranger J., (eds.). Proc. Inter. 

Workshop on site management and productivity in tropical plantation forest, 

Kerala, India, 41-49. 

Harmon, M.E. 2001. Carbon Sequestration in Forests: Addressing the Scale Question. 

Journal of Forestry 99 (4): 24-29. 

Harris, W.F., Kinerson, R.S.Jr. and Edwards, N.T. 1977. Comparison of belowground 

biomass of natural deciduous forest and Loblolly pine plantations. In: Marshall 

J.K. (ed.), The Belowground Ecosystem: A Synthesis of Plant-Associated 

Processes. Range Science Department Science Series No: 26, Fort Collins, 

Colorado, USA, 27-29. 

Hartemink, A.E. and O’Sullivan, J.N. 2001. Leaf litter decomposition of Piper 

aduncum, Gliricidia sepium and Imperata cylindrica in the humid lowlands of 

Papua New Guinea. Plant Soil 230: 115-124. 

Hase, H. 1981. Nährstoffreserven auf Banco-Standorten der Waldreserve 

Caparo/Venezuela unter besonderer Berücksichtigung der Plantagenwirtschaft 

mit Teak (Tectona grandis). Göttinger Bodenkundliche Berichte Nr. 66. 142 

pp. 

Hendricks, C.M.A. and Bianchi, F.J.J.A. 1995. Root density and biomass in pure and 

mixed forest stands of Douglas-fir and Beech. Netherl. J. Agric. Sci. 43: 321–

331. 

Henson, E.I. 1998. Estimation gound CO2 flux and its components in a stand of oil 

palm. PORIM Bulletin 28: 1-12. 

Henson, E.I. and Chai, S.H. 1997. Analysis of oil palm productivity. II. Biomass, 

distribution, productivity and turn-over of the root system. Elaeis 9: 78-92. 

Henson, I.E. 1993. Carbon assimilation, water use and energy balance of an oil palm 

plantation assessed using micrometeorological techniques. In: Jalani Sukaimi 

et al. (eds.), Proc. Of PORIM International Palm Oil Conggress ‘Update and 
References 

100

Vision’ – Agriculture Module, Palm Oil Research Institute of Malaysia, Bangi, 

137-158. 

Hiratsuka, M., Toma, T., Yamada, M., Heriansyah, I. and Morikawa, Y. 2003. A 

general allometric equation for estimating biomass in Acacia mangium

plantations. In: Proc. International Conference on Tropical Forests and 

Climate Change, Manila, Philippines (inpress). 

Houghton, R. A. 1999. The annual net flux of carbon to the atmosphere from changes in 

land use 1850– 1990, Tellus, Ser. B. 51: 298– 313. 

Howard, D.M. and Howard, P.J.A. 1993. Relation between CO2 evolution, moisture 

content and temperature for a range of soil types. Soil Biol. Biochem. 25: 

1537-1546. 

IHM (ITCI Hutani Manunggal). 1995. Guideline for the Plantation Management of PT. 

IHM. Jakarta. Unpublished. 

IPCC (Intergovernmental Panel on Climate Change). 1996. Climate Change 1995: 

Impacts, Adaptations and Mitigation of Climate Change: Scientific-Technical 

Analyses. Contribution of working group II to the Second Assessment Report 

of the Intergovernmental Panel on Climate Change, R. Watson, M.C. 

Zinyowera, and R. Moss (eds.), Cambridge University Press, Cambridge, UK, 

880 pp. 

IPCC. 2000. Land Use, Land Use Change and Forestry. R.T. Watson, I.R. Noble, B. 

Bolin, N.H. Ravindranath, D.J. Verardo, and D.J. Dokken (eds.), A Special 

report of the IPCC, Cambridge University Press, Cambridge, UK, 377 pp. 

IPCC. 2001. Climate Change 2001: Impacts and Adaptation. O. Canziani, J. McCarthy, 

N. Leary, D. Dokken, K. White (eds.), Cambridge University Press, 

Cambridge, MA and New York, NY. 

ISME (Indonesian State Ministry for Environment). 1999. The first national 

communication under the United Nations Framework Convention on Climate 

Change, Jakarta, 33-39. 

Jackson, R.B., Mooney, H.A. and Schulze, E-D. 1997. A global budget for fine root 

biomass, surface area and nutrient contents. Proc. Nat. Acad. Sci. USA 94, 

7362-7366. 

Jentschke, G., Drexhage, M., Fritz, H-W., Fritz, E., Schella, B., Lee, D-H., Grubber, F., 

Heimann, J., Kuhr, M., Schmidt, J., Schmidt, S., Zimmermann, R. and Kuhr, 

M. 2001. Does soil acidity reduce rooting in Norway spruce (Picea abies)? 

Plant Soil 237: 91–108. 

Jones, M., Sinclair, F.L. and Grime, V.L. 1998. Effect of tree species and crown 

pruning on root length and soil water content in semi-arid agroforestry. Plant 

and Soil 201: 197–207. 

Jose, S., Gillespie, A.R., Seifert, J.E. and Pope, P.E. 2000. Defining competition vectors 

in temperate alleycropping system in the midwestern USA: 3. competition for 

nitrogen and litter decomposition dynamics. Forest Science 33: 330-346. 

Jose, S., Gillespie, A.R., Seifert, J.R. and Pope, P.E. 2001. Comparison of minirhizotron 

and soil core methods for quantifying root biomass in a temperate alley 

cropping system. Agroforestry Systems 52: 161–168. 

Kalisz, P.J., Zimmerman, R.W. and Muller, R.N.. 1987. Root density, abundance and 

distribution in the mixed mesophytic forest of eastern Kentucky. Soil Sci. Soc. 

Am. J. 51:220–225. 
References 

101

Kattenberg, A., Giorgi, F., Grassl, H., Meehl, G.A., Mitchell, J.F.B., Stouffer, R.J., 

Tokioka, T., Weaver, A.J. and Wigley, T.M.L. 1996. Climate modelsprojections of future climate. In: J.T. Houghton et al. (eds.), Climate Change 

1995: The Science of Climate Change, Cambridge University Press, 285-357.

Kawana, A. 1976. Research in forest fertilization in Balikpapan, Kalimantan, Indonesia. 

IUFRO world Forestry Congress, Oslo, Norway. 

Kawara, T., Kanazawa, Y. and Sakurai, S. 1981. Biomass and net production of manmade forests in the Philippines. J. Jap. For. Soc. 63 (9): 320-327. 

Kelting, D.L., Burger, J.A. and Edwards, G.S. 1998. Estimating root respiration, 

microbial respiration in the rhizosphere, and root free soil respiration in forest 

soils. Soil Biol. Biochem. 30: 961-968. 

Khalid, H., Zin, Z.Z. and Anderson, J.M. 1999a. Quantification of oil palm biomass and 

nutrient value in mature plantation. I. Above-ground biomass. J. Oil Palm 

Research 11 (1): 23-32. 

Khalid, H., Zin, Z.Z. and Anderson, J.M. 1999b. Quantification of oil palm biomass and 

nutrient value in mature plantation. II. Below-ground biomass. J. Oil Palm 

Research 11 (2): 63-71. 

Kicklighter, D.W., Melillo, J.M., Peterjohn, W.T., Rastetter, E.B., McGuire, A.D. and 

Steudler, P.A. 1994. Aspects of spatial and temporal aggregation in estimating 

regional carbon dioxide fluxes from temperate forest soils. J. Geophys. Res.

99: 1303-1315. 

Klinge, H. 1976. Root mass estimation in lowland tropical rain forests of central 

Amazonia, Brazil. Trop Ecol 17:79-83. 

Koeppen, W. 1931. Die Klimate der Erde. Walther de Gruyer Co., Berlin, Germany. 

Lachica-Lustica, A. 1997. Trial planting of introduced reforestration species in 

Dumarao, Capiz. In: Developments in Agroforestry Research, Book Series No. 

160: 270-281, Philippine Council for Agriculture, Forestry and Natural 

Resources Research and Development, Los Banos. 

Lal, M. and Singh, R. 2000. Carbon sequestration potential of Indian forests. 

Environmental Monitoring and Assessment 60: 315-327. 

Lamade, E. and Setyo, I.E. 2002. Characterization of carbon pools and dynamic in oil 

palm and forest ecosystems: application to environmental evaluation. 

International Oil Palm Conference, Bali, Indonesia.

Lambourne, J. 1935. Notes on the root habit of the oil palm. Malay. Agric. J. 23: 582-

583. 

Lasco, R.D. 2002. Forest carbon budgets in Southeast Asia following harvesting and 

land cover change. http://www.globalcarbonproject.org/PRODUCTS/ 

Table_of_contents_land_use%20(Canadell_Zhou_Noble2003)/Lasco_yc0055.

pdf. 26 November 2004

Lasco, R.D. and Suson, P.D., 1999. Leucaena Leucophala-based indigenous fallow 

system in central Philippines, the Naalad system. Intl. Tree Crops Journal 10

(2): 161-174. 

Lee, J., Morrison, I.K., LeBlanc, J.-D., Dumas, M.T. and Cameron, D.A. 2002. Carbon 

sequestration in trees and re-growth vegetation as affected by clearcut and 

partial cut harvesting in a second-growth boreal mixedwood. For. Ecol. 

Manage. 169: 83–101. 

Lee, K.-H. and Jose, S. 2003. Soil respiration an microbial biomass in pecan – cotton 

alley cropping system in Southern USA. Agroforestry Systems 58: 45-54. 
References 

102

Lim, M.T. 1985. Biomass and biomass relationship of 3.5-year-old open-grown Acacia 

mangium. Faculty of Forestry Occasional Paper No. 2. Serdang, Universiti 

Pertanian Malaysia, 13 pp. 

Lim, M.T. 1986. Biomass and productivity of 4.5-year-old Acacia mangium in Serawak. 

Pertanika 9: 81-87. 

Lim, M.T. 1988. Studies on Acacia mangium in Kemasul Forest, Malaysia. I. Biomass 

and productivity. J. Trop. Ecology 4: 293-302. 

Lim, M.T. and Hamzah, M.B. 1985. Biomass accumulation in naturally regenerating 

lowland secondary forest and an Acacia mangium stand in Serawak. Pertanika

8 (2): 237-241. 

Lloyd, J. and Taylor, J.A. 1994. On the temperature dependence of soil respiration. 

Func. Ecol. 8: 315-323. 

Lugo, A.E. and Brown, S. 1993 Management of tropical soils as sinks or sources of 

atmospheric carbon. Plant Soil 149: 27–41. 

Lugo, A.E. 1997. The apparent paradox of reestablishing species richness on degraded 

lands with tree monocultures. For. Ecol. Manage. 99: 9-19. 

Lugo, A.E., Silver, W.L. and Colon, S.M. 2004. Biomass and nutrient dynamics of 

restored neotropical forests. Water, Air, and Soil Pollution: Focus 4: 731-746. 

Macdicken, K.G., Hairiah, K., Otsamo, A., Duguma, B. and Majid, N.M. 1997. Shadebased control of Imperata cylindrica: tree fallows and cover crops. 

Agroforestry Systems 36 (1/3): 131-149. 

Mackensen, J. 1998. Untersuchung zur nachhaltigen Nährstoffversorgung in 

schnellwachsenden Plantagensystemen in Ost-Kalamantan, Indonesien - 

ökologische und ökonomische Implikationen. Göttinger Beiträge zur Landund Forstwirtschaft in den Tropen und Subtropen, 127. 

Makkonen, K. and Helmisaari, H-J. 1999. Assessing fine-root biomass and production 

in a Scots pine stand – comparison of soil core and root ingrowth core 

methods. Plant Soil 210: 43-50. 

Marland, G. and Schlamadinger, B. 1999. The Kyoto Protocol could make a difference 

for the optimal forest-based CO2 mitigation strategy: some results from 

GORCAM. Environmental Science and Policy 2: 111-124. 

Martin-Laurent, F., Fremont, M., Lee, S.K., Tham, F.Y., Prin, Y., Tan, T.K. and Diem, 

H.G. 1999. Effect of inoculation with selected Bradyrhizobium spp. On the 

survival and growth of Acacia mangium saplings after 20 months in the field. 

Journal of Tropical Forest Science 1 (2): 470-483. 

Metting, F.B., Smith, J.L., Amthor, J.S. and Izaurralde, R.C. 2001. Science needs and 

new technology for increasing soil carbon sequestration. Climatic Change 51: 

11–34. 

Millikin, C.S. and Bledsoe, C.S. 1999. Biomass and distribution of fine and coarse roots 

from blue oak (Quercus douglasii) trees in the northern Sierra Nevada 

foothills of California. Plant Soil 214: 27-38. 

Montagnin, F. and Porras, C. 1998. Evaluating the role of plantations as carbon sinks: 

an example of an integrative approach from the humid tropics. Envir. Manage. 

22: 459–470. 

Moraes, J.L, Cerri, C.C, Melillo, J.M., Kicklighter, D., Neill, C., Skole, D.L. and 

Steudler, P.A. 1995. Soil carbon stocks of the Brazilian Amazon Basin. Soil 

Sci. Soc. Amer. J. 59: 244–247. 
References 

103

Nepstad, D.C., De Carvalho, C.R., Davidson, E.A., Jipp, P.H., Lefebvre, P.A. , 

Negrelos, G.H., Silva, E.D., Stone, T.A., Trumbore, S.E. and Vieira, S. 1994. 

The role of deep roots in the hydrological and carbon cycles of Amazonian 

forests and pastures. Nature 372: 666–669. 

Newaz, M.S. and Millat-E-Mustafa, M. 2004. Growth and yield prediction models for 

Acacia mangium grown in the plantations of the central region of Bangladesh. 

New Forests 27: 81-88. 

Ney, R.A., Schnoor, J.L. and Mancuso, M.A. A Methodology to Estimate Carbon 

Storage and Flux in Forestland using Existing Forest and Soils Databases. 

Environmental Monitoring and Assessment 78: 291–307. 

Ng, S.K., Thamboo, S. and De Souza, P. 1968. Nutrient content on oil palm in Malaysia. 

II. Nutrient content in vegetative tissues. Malay. Agric. J. 46: 332-391. 

Nie, Z.N., Mackay, A.D., Valentine, I., Barker, D.J. and Hodgson, J. 1997. Influence of 

pastoral fallow on plant root growth and soil physical and chemical 

characteristics in a hill pasture. Plant Soil 197: 201–208. 

Nitrogen Fixing Tree Association. 1987. Nitrogen fixing trees. A training guide. 

Hawaii, USA/Bangkok, Rome, FAO. 

Noordwijk, M., Hairiah, K. and Sitompul, S.M. 2000. Reducing uncertainties in the 

assessment at national scale of C stock impacts of land use change. Proc. 

IGES/NIES Workshop on GHG Inventories for Asia-Pacific Region (ed. 

Macandog, D.B.), Hayama, Japan, 150-163. 

Nordin, L. 2002. Application of AIRSAR data to oil palm tree characterization. 

http://www.gisdevelopment.net/aars/acrs/2002/sar/038.pdf. 26 November 

2004. 

Ohta, S. 1990. Initial soil changes associated with afforestation with Acacia 

auriculiformis and Pinus kesiya on denuded grasslands of the Pantabangan 

area, Central Luzon, the Philippines. Soil Sci. Plant Nutr. 36 (4): 633-643. 

Ohta, S., Effendi, S., and Miura, S. 1992. Characteristic of major soils under lowland 

dipterocarp forest in East Kalimantan, Indonesia. Pusrehut Special Publication 

No. 2. Tropical Rain Forest Research Project JTA-9(a)-137. Japan 

International Cooperation Agency and Directorate General of Higher 

Education, Ministry of Education and Culture, Republic of Indonesia. 

Otsamo, A. 2002. Early effects of four fast-growing tree species and their planting 

density on ground vegetation in Imperata grasslands. New Forests 23: 1-17. 

Otsamo, A., Ådjers, G., Hadi, T.S., Kuusipalo, J., Tuomela, K. and Vuokko, R. 1997. 

Evaluation of reforestation potential of 83 tree species planted on Imperata 

cylindrica dominated grassland. A case study from South Kalimantan, 

Indonesia. New Forests 14: 127-147. 

Otsamo, R. 2000. Secondary forest regeneration under fast-growing forest plantations 

on degraded Imperata cylindrica grasslands. New Forests 19: 69-93. 

Papadopol, C.S. 2000. Impacts of climate warming on forests in Ontario: options for 

adaptation and mitigation. Forestry Chronicle 76:139–149. 

Parrotta, J.A, Turnbull, J.W. and Jones, N. 1997. Catalyzing native forest regeneration 

on degraded tropical lands. For. Ecol. Manage. 99: 1-7. 

Paudyal, B.K. and Nik Muhamad, M. 1990. Preliminary thinning guideline for Acacia 

mangium Willd. Plantations in Kemasul Forest Reserve, Peninsular, Malaysia. 

J. Trop. For. Sci. 3 (1): 25-34. 
References 

104

Pelley, J. 2003. Taking credit for forest carbon sinks: Is the policy getting ahead of the 

science? Environmental Science and Technology 59–63A. 

Perala, D.A. and Alm, A.A. 1990. Reproductive ecology of birch: a review. For. Ecol. 

Manage. 32:1-38. 

Peter, I. and Lehmann, J. 2000. Pruning effects on root distribution and nutrient 

dynamics in an acacia hedgerow planting in northern Kenya. Agroforestry 

Systems 50: 59–75. 

PMP-SMART (Plantation Monitoring and Planning Division-PT.SMART Tbk). 2001. 

Satuan Peta Tanah (Survai Semi Detil) Areal PT. SMART Corporation – 

Padang Halaban Estate, Kabupaten Labuhan Batu – Sumatera Utara. 1.2001 

(25/6/2001). Jakarta. 

Polomski, J. and Kuhn, N. 1998. Wurzelsysteme. Verlag P. Haupt, Bern. 290pp. 

Post, W.M., Emanuel, W.R., Zinke, P.J. and Stangenberger, A.G. 1982. Soil carbon 

pools and world life zones. Nature 298: 156–159. 

Pritchett, W.L. and Fisher, R.F. 1987. Properties and Management of Forest Soils. 

Wiley, New-York. 494 pp. 

Purbopuspito, J. and Van Rees, K.C.J.. 2002. Root distribution at various distances from 

clove trees growing in Indonesia. Plant Soil 239: 313–320. 

Purvis, C. 1956. The root system of the oil palm its distribution, morphology and 

anatomy. Journal of West African Institute for Oil-palm Research 4: 60-82. 

Raich, J.W. 1983. Effects of forest conversion on the carbon budget of a tropical soil. 

Biotropica 15: 177-184. 

Raich, J.W. and Tufekcioglu, A. 2000. Vegetation and soil respiration: Correlations and 

controls. Biogeochem. 48: 71-90. 

Ravindranath, N.H., Somashekhar, B.S. and Gadgil, M. 1997. Carbon flow in Indian 

forests. Climate Change 35: 297-320. 

Rees, A.R. and Tinker, P.B.H. 1963. Dry matter production and nutrient content of 

plantation oil palm in Nigeria. I. Growth and dry-matter production. Plant Soil

XIX: 19-32. 

RePPProT. 1987. Regional physical planning programme for transmigration. Review of 

phase I: Results, East and South Kalimantan. Direktorat Bina Program. 

Direktorat Jenderal Penyiapan Pemukiman, Departemen Transmigrasi, Jakarta, 

Indonesia. 

Retnowati, E. 1998. Kontribusi hutan tanaman Eucalyptus grandis Maiden sebagai rosot 

karbon di Tapanuli Utara (The contribution of Eucalyptus grandis Maiden 

Plantation as carbon sink in North Tapanuli). Bul. Pen. Hutan 611: 1-9. 

Roy, S. and Singh, J.S. 1995. Seasonal and spatial dynamics of plant-availability N and 

P pools and N-mineralization in relation to fine roots in dry forest habitat. Soil 

Biol. Biochem. 27:33-40. 

Ruer, P. 1967. Relations entre facteurs climatiques et nutrition minerale chez le palmier 

a huile. Oleagineux 21: 435-447. Sainju and Good 1993, 29, root distribution 

Ruhiyat, D. 1989. Die Entwicklung der Standurlichen Nährstoffvorräte bei Naturnaher 

Walderwirtshcaftung und im Plantagenbetrieb, Ostkalimantan-Indonesien. 

Diss. Forst. Univ. Goettingen. 

Ruthenberg, H. 1976. Farming Systems in the Tropics, 2nd ed. Oxford University Press, 

Oxford, UK, 366 pp. 

Sainju, U.M. and Good, R.E. 1993. Vertical root distribution in relation to soil 

properties in the New Jersey pinelands forests. Plant Soil 150: 87–97 
References 

105

Sampson, R.N. and Sedjo, R.A. 1997. Economics of carbon sequestration in forestry: an 

overview. Critical Reviews in Environmental Science and Technology 27: S1–S8. 

Santantonio, D., R.K. Hermam and W.S. Overton. 1977. Root biomass studies in forest 

ecosystems. Pedobiologia 17: l-31. 

Santer, B.D., Wigley, T.M.L., Barnett, T.P. and Anyamba, E. 1996. Detection of 

climate change and attribution of clauses. In: J.T. Houghton et al. (eds.), 

Climate Change 1995: The Science of Climate Change, Cambridge University 

Press, 406-443.

Santoso, D., Adiningsih, S., Mutert, E., Fairhurst, T. and Van Noordwijk, M. 1997. Soil 

fertility management for reclamation of Imperata grasslands by smallholder 

agroforestry. Agroforestry systems 36 (1/3): 181-202. 

Sataye, J.A., Makundi, W.R., Andrasko, K., Boer, R., Ravindranath, N.H., Sudha, P., 

Rao, S., Lasco, R., Pulhin, F., Masera, O., Ceron, A., Ordonez, J., Deying, X., 

Zhang, X. and Zoumin, S. 2001. Carbon mitigation potential and costs of 

forestry options in Brazil, China, India, Indonesia, Mexico, The Philippines 

and Tanzania. Mitigation and Adaptation Strategies for Global Change 6: 

185-211. 

Schimel, D.S. 1995. Terrestrial ecosystems and the carbon cycle. Global Change 

Biology 1: 77-91. 

Schimel, D.S., House, J.I., Hibbard, K.A., Bousquet, P., Ciais, P., Peylin, P., Braswell, 

B.H., Apps, M.J., Baker, D., Bondeau, A., Canadell, J., Churkina, G., Cramer, 

W., Denning, A.S., Field, C.B., Friedlingstein, P., Goodale, C., Heimann, M., 

Houghton, R.A., Melillo, J. M., Moore III, B., Murdiyarso, D., Noble, I., 

Pacala, S.W., Prentice, I.C., Raupach, M.R., Rayner, P.J., Scholes, R.J., 

Steffen, W.L. and Wirth, C. 2001. Recent patterns and mechanisms of carbon 

exchange by terrestrial ecosystems. Nature 414: 169-172. 

Schlesinger, W.H. 1984. Soil organic matter: a source of atmospheric CO2. In: GM 

Woodwell (ed.), The role of terrestrial vegetation in the global carbon cycle: 

Measurement by remote sensing. John Wiley & Sons Chichester, U.K,111-

127. 

Schlesinger, W.H. 1977. Carbon balance in terrestrial detritus. Ann. Rev. Ecol. Syst. 8: 

51–81. 

Schlesinger, W.H. 1991. Biogeochemistry: and analysis of global change. Academic 

Press San Diego, USA. 113 pp. 

Setyo, I.E., Purba, A. and Lamade, E. 1999. Estimation of respiration and turn over of 

DxP oil palm roots. Journal Penelitian Kelapa Sawit 7 (2): 71-86. 

Sharrow, S.H. and Ismail, S. 2004. Carbon and nitrogen storage in agroforests, tree 

plantations, and pastures in western Oregon, USA. Agroforestry Systems 60: 

123-130. 

Sitompul, S.M. and Hairiah, K. 2000. Biomass measurement of home garden. 

Proceedings of Workshop on LUCC and Greenhouse Gas Emissions, 

Biophysical Data, IPB, Bogor. 

Snelder, D.J. 2001. Soil properties of Imperata grasslands and prospects for tree-based 

farming systems in Northeast Luzon, The Philippines. Agroforestry Systems

52: 27-40. 

Soekardi, M., Retno, M.W. and Hikmatullah. 1993. Inventarisasi dan karaterisasi lahan 

alang-alang. (Inventory and characteriyation of Imperata grassland). In: 

Pemanfaatan Lahan Alang-alang Untuk Usaha Tani Berkelanjutan (The use of 
References 

106

Alang-alang land for Sustainable Farming Systems). Centre for Soil and 

Agroclimatic Research, Bogor, Indonesia, 1-11. 

Soemarna, K. and Bustomi, S. 1986. Tabel isi pohon lokal Acacia mangium Willd. 

untuk daerah Subanjeriji, Sumatera Selatan (Local tree volume table for 

Acacia mangium). Bul. Pen. Hutan 487: 41-49. 

Soepardi, G. 1980. Alang-alang and soil fertility. In: Proceedings of Biotrop Workshop 

on Alang-alang, BIOTROP Special Publication No. 5, SEAMEO-BIOTROP, 

Bogor, Indonesia, 57-69. 

Soerianegara, I. 1980. The alang-alang, (Imperata cylindrica) (L.) Beauv. problem in 

forestry. Proc. of BIOTROP workshop on alang-alang, Bogor, 27-29 July 

1976, Spec. Publ. No. 5. Biotrop. Bogor, Indonesia, 237-242. 

Soerjatna, E.S. and McIntosh, J.L. 1980. Food crop production and control of Imperata 

cylindrica on small farm. In: Proceedings of Biotrop Workshop on Alangalang, BIOTROP Special Publication No. 5, SEAMEO-BIOTROP, Bogor, 

Indonesia, 135-147. 

Sombroek, W.G., Nachtergaele, F.O. and Hebel, A. 1993. Amounts, dynamics and 

sequestering of carbon in tropical and subtropical soils. Ambio 22: 417–426. 

Sommer, R. Denich, M. and Vlek, P.L.G. 2000. Carbon storage and root penetration in 

deep soils under small-farmer land-use systems in the Eastern Amazon region, 

Brazil. Plant and Soil 219: 231-241. 

Spangenberg, A., Grimm, U., Silva, J.R.S. and Fölster, H. 1996. Nutrient store and 

export rates of Eucalyptus urograndis Plantation in East Amazonia (Jari). For. 

Ecol. Manage. 80: 225-239. 

Swamy, S.L., Mishra, A. and Puri, S. 2003. Biomass production and root distribution of 

Gmelina arborea under an agrisilviculture system in subhumid tropics of 

Central India. New Forests 26: 167–186. 

Syahrinudin. 1997. The role of undergrowth on timber estate of Eucalyptus deglupta in 

East Kalimantan. M.Sc. thesis Faculty of Forestry University of Goettingen. 

Tailliez, B. 1971. The root system of the oil palm on the San Alberto plantation in 

Columbia. Oleagineux 26: 435-447 

Tarré, R., Macedo, R., Cantarutti, R.B., de P. Rezende, C., Pereira, J.M., Ferreira, D., 

Alves, B.J.R., Urquiaga, S. and Boddey, R.M. 2001. Plant and Soil 234: 15-26.

Tinker, P.B.H. and Smilde, K.W. 1963. Dry matter production and nutrient content of 

plantation oil palm in Nigeria. II. Nutrient content. Plant and Soil XIX: 350-363. 

Trumbore, S.E., Davidson, E.A., de Camargo, P.B., Nepstad, D.C. and Martinelli, L.A. 

1995. Below-ground cycling of carbon in forests and pastures of Eastern 

Amazonia. Giobal Biogeochem. Cycles 9: 515–528. 

Tufekcioglu, A., Raich, J.W., Isenhart, T.M. and Schultz, R.C. 1999. Fine root 

dynamics, coarse root biomass, root distribution, and soil respiration in a 

multispecies riparian buffer in Central Iowa, USA. Agroforestry Systems 44: 

163-174. 

Tufekcioglu, A., Raich, J.W., Isenhart, T.M. and Schultz, R.C. 2003. Biomass, carbon 

and nitrogen dynamics of multi-species riparian buffers within an agricultural 

watershed in Iowa, USA. Agroforestry system 57: 187-198. 

Turvey, N.D. 1996. Growth at age 30 months of Acacia and Euclyptus species planted 

in Imperata grasslands in Kalimantan Selatan, Indonesia. For. Ecol. Manage.

82: 185-195. 
References 

107

Van Dam, D., Veldkamp, E. and Van Breemen, N. 1997. Soil organic carbon dynamics: 

variability with depth in forested and deforested soils under pasture in Costa 

Rica. Biogeochemistry 39: 343-375. 

Van Noordwijk, M., Hairiah, K., Partoharjono, S., Labios, R.V. and Garrity, D.P. 1997. 

Food-crop-based production systems as sustainable alternative for Imperata

grasslands? Agroforestry Systems 36: 55-82. 

Vogt, K.A., Vogt, D.J., Asbjornsen, H. and Dahlgren, R.A. 1995. Roots, nutrients and 

their relationship to spatial patterns. Plant Soil 168/169: 113-123. 

Vogt, K.A., Vogt, D.J., Palmiotto, P.A., Boon, P., O’Hara, J. and Asbjornsen, H. 1996. 

Review of root dynamics in forest ecosystems grouped by climate, climatic 

forest type and species. Plant Soil 187: 159-219. 

Voss, F. 1982. Atlas of East Kalimantan, Indonesia. East Kalimantan Transmigration 

Area Development Project (TAD). HWWA-Institut für Wirtschaftsforschung, 

Hamburg. 

Voss, F. 1983. Natural resources inventory, East Kalimantan. TAD-Report 9, Revised 

Edition. Transmigration Area Development Project (TAD). HWWA-Institut 

für Wirtshaftsforschung, Hamburg, Federal Republic of Germany. 

Voss, R. 1979. Soils and land use on the PT. ITCI concession. Weyerhauser Tropical 

Forestry Technical Report 042-1208/79/15. Weyerhauser Company, Tacoma, 

Washington, USA. 

Wakker E. 2000. Funding Forest Destruction: The involvement of Ducth Banks in the 

financing of oil palm plantation in Indonesia. Report for Greenpeace 

Netherlands. Aid Environment in cooperation with Telapak and Contrast 

Advies. 

Watson, R.T, I.R. Noble, B. Bolin, N.H. Ravindranath, D.J. Verardo, and D.J. Dokken. 

2000. Land Use, Land-Use Change, and Forestry. A Special Report of the 

Intergovernmental Panel on Climate Change. Cambridge University Press, 

Cambridge, UK. 

WBGU (Wissenschaftlicher Beirat der Bundesregierung Globale Umweltveränderungen). 1998. Die Anrechnung biologischer Quellen und Senken im KyotoProtokoll: Fortschritt oder Rückschlag für den globalen Umweltschutz? 

Sondergutachten 1998, WBGU, Bremerhaven, Germany, 76 pp., (available in 

English). 

White, A., Cannell, M.G.R. and Friend, A.D. 2000. CO2 stabilization, climate change 

and the terresterial carbon sink. Global Change Biol. 6: 817-833. 

Wichmann, W. 2001. World fertilizer use manual. BASF AG, Germany - 600 pp. 

Wright, J.O. 1951. Unusual features of the root system of the oil palm in West Africa. 

Nature 168: 748. 

Yantasath, K., Patanayibul, S., Supatanakul, W., Ungyichian, I. and Chantrasiri, S. 

1992. Field trial and multipurpose testings of selected fast-growing, nitrogenfixing trees in Thailand. Thai J. Ag. Sci. 25: 141-169. 

Yantasath, K., Supatanakul, W., Ungyichian, I., Chansawad, S., Patanayibul, S., 

Hyakitkosol, C., Prompetchara, S., Pithakarnop, N. and Chalermkin, P. 1986. 

Country Report for Thailand. NFT Res. Rpts. 3: 48-56. 

Zaharah, A.R., Sharifuddin, H.A.H., Ahmad Sahali, M. and Mohd. Hussein, M.S. 1989. 

Fertilizer placement studies in mature oil palm using isotope technique. The 

Planter 65: 384-388. 
ACKNOWLEDGMENTS 

I am very grateful to Prof. Dr. Paul Vlek, my first supervisor, for his guidance, 

support and encouragement at all stages of my work. I also thank Prof. Dr. Mathias 

Becker, my second supervisor, for his advice and sharing his idea on the manuscript. I 

could not have completed this dissertation without the generous help of Dr. Manfred 

Denich, who provided support, suggestion, and constructive comments on the 

manuscript. His technical and editorial advices greatly improved the content of this 

dissertation. For this, I am very grateful. 

I would like to express my gratitude to DAAD and GTZ for giving me the 

support during my study in Germany and my field research in Indonesia. I also deeply 

appreciate Barito Pacific Co. Ltd, Surya Hutani Jaya Co. Ltd, Rea Kaltim Plantation Co. 

Ltd and SMART Co. Ltd for allowing me doing my field work in their concessions. 

A special thank goes to Dr. Guenther Manske for helping with many 

adminstrative matters and visiting my field site in East Kalimantan, Indonesia. 

I also wish to thank Ms. Hanna Peters, Mrs. Sabine Aengenendt-Baer and 

Mrs. Andrea Berg of ZEF for their office assistant and kind help, Ms. Deborah 

Rupprecht for analyzing my samples in Bonn and Mrs. Margaret Jend for editing my 

dissertation draft and translating my abstract and summary into German. 

To all who have assisted me in this venture, I am deeply indebted. Without 

their assistance, this work would never have been completed. 

Finally, I sincerely thank my beloved wife and children for the patience and 

encouragement during all stages of my study.