Above ground biomass estimation by using variant allometric equations on various age groups of teak (tectona grandis) trees in forest plantation of mae ho phra, chiang mai province, thailand

THAI NGUYEN UNIVERSITY UNIVERSITY OF AGRICULTURE AND FORESTRY NAFILA TAUFIK ARINAFRIL ABOVE-GROUND BIOMASS ESTIMATION BY USING VARIANT ALLOMETRIC EQUATIONS ON VARIOUS AGE GROUPS OF TEAK

THAI NGUYEN UNIVERSITY

UNIVERSITY OF AGRICULTURE AND FORESTRY

NAFILA TAUFIK ARINAFRIL ABOVE-GROUND BIOMASS ESTIMATION BY USING VARIANT ALLOMETRIC EQUATIONS ON VARIOUS AGE GROUPS OF TEAK

(Tectona grandis) TREES IN FOREST PLANTATION OF MAE HO PHRA,

CHIANG MAI PROVINCE, THAILAND

BACHELOR THESIS

Study Mode: Full-time

Major: Environmental Science and Management

Faculty: Advanced Education Program

Thai Nguyen, 25/09/2018

DOCUMENTATION PAGE WITH ABSTRACT

Thai Nguyen University of Agriculture and Forestry

Allometric Equations on Various Age Groups of Teak

(Tectona grandis) Trees in Forest Plantation of Mae Ho

Phra, Chiang Mai Province, Thailand

it can also reduce pressure on timber extraction from natural forest leading to forest conversation, could contribute with the climate change mitigation attempts Among all the carbon pool of trees, above-ground biomass constitutes the major portion of carbon on trees Hence, this study used variant allometric equations that is designed

to estimate the total amount of above-ground biomass in teak trees, in the northern part of Thailand This study was carried out to distinguish the difference on pattern

from each equation by three different authors A total of 291 trees, from three different age groups of trees, 7 years, 13 years and 21 years old as plot 1, plot 2 and plot 3, respectively, were measured for above-ground biomass model comparison The sample trees were measured for its Girth at Breast Height (GBH) which then later on converted into Diameter at Breast Height (DBH), and Total Height (H) which were

necessary for the calculation Equation authorized by Ounban et al (2016), Jain and

Ansari (2013), and Mwangi (2015) that were used for the calculation, shows a total of 26.29 tC/rai, 40.62 tC/rai and 51.07 tC/rai, respectively, above-ground biomass content is stored in the measured trees from three different plots combined The results showed a significant difference on the total amount of above-ground biomass from each equation, meaning that there are some factors that needs to be considered before implementing any equation

Sink, Forest Plantation, Teak (Tectona grandis) Tree

Date of Submission 25/09/2018

ACKNOWLEDGEMENT

First and foremost, I would like to thank Allah SWT, our Almighty God, who by His grace and blessings, I had the opportunity to accomplish this study

Second, I would like to express my gratitude to my advisors, Dr Teerapong and

Dr Sa-nguansak of Faculty of Agriculture, Chiang Mai University, and Dr Ho Ngoc Son of Thai Nguyen University of Agriculture and Forestry (TUAF), for their constructive criticism and efficacious supervision, leading to the success of this study Also, to the staff officers from the Faculty of Agriculture and International Office of Chiang Mai University, for all the help during my stay in Chiang Mai Special gratitude goes to Ms Yim and Ms Linn, who spent a lot of their time assisting me despite their tight schedule Moreover, I highly appreciate all the help and effort from my Thai buddies, Mr Gene and Ms Giff, which without their guides throughout my daily lives

in Chiang Mai, would have been impossible And also, to Mr Adisorn and staff officers

of Mae Ho Phra Forest Plantation, I would like to give my gratitude for their assistance

in data collection

Finally, for the unconditional love and uncountable advice and moral support from both of my parents, Ayah and Bunda, and my two siblings, Nabila and Naufal, I would like to give my sincerest gratefulness, which without it, I would not have the courage and strength to carry out this study

Sincerely,

Nafila Taufik Arinafril

TABLE OF CONTENTS

LIST OF FIGURES vi

LIST OF TABLES vii

LIST OF ABBREVIATIONS viii

PART I INTRODUCTION 1

1.1 Research Rationale 1

1.2 Research Objectives 3

1.3 Research Questions and Hypotheses 4

1.4 Limitations 5

1.5 Definitions 5

1.5.1 Mae Ho Phra Forest Plantation 5

1.5.2 Haga Altimeter 6

PART II LITERATURE REVIEW 8

2.1 Greenhouse Gases and Climate Change 8

2.2 Forest as Climate Change Mitigation Option 9

2.3 Forest Plantation as Carbon Sequestration Potential 11

2.4 Teak (Tectona grandis) Tree 12

2.5 Land Carbon Stock 13

2.6 Carbon Cycle 15

2.7 Tree Biomass Estimation Using Allometric Equation 16

PART III METHODS 18

3.1 Materials 18

3.2 Methods 18

3.2.1 Collection Site 18

3.2.2 Transect Determination 20

3.2.3 Plot Determination 21

3.3 Tree Height and Diameter at Breast Height Measurement 22

3.3.1 Tree Height Measurement 22

3.3.2 Diameter at Breast Height (DBH) Measurement 23

3.4 Above-Ground Biomass Measurement 24

PART IV RESULTS AND DISCUSSION 28

4.1 Results 28

4.1.1 Characteristics of Trees 28

4.1.2 Above-Ground Biomass 30

4.1.3 Cluster Analysis 33

PART V CONCLUSION 42

REFERENCES 43

APPENDICES 49

LIST OF FIGURES

Figure 1 Haga Altimeter 7

Figure 2 Annual sink absorption of human carbon emissions (Gt CO₂) 15

Figure 3 (a) Map of Chiang Mai province, Thailand and (b) map of Teak plantation in Mae Ho Phra Forest Plantation 19

Figure 4 Transect locations 20

Figure 5 Sample plot 22

Figure 6 Angles for Using Haga Altimeter 23

Figure 7 (a) Tree diameter measurement using diameter tape and (b) Locating breast height 24

Figure 8 (a) Average Girth and diameter at breast height of trees and (b) Average height of trees in each plot 30

Figure 9 Total amount of above-ground biomass in each plot 32

Figure 10 Total amount of above-ground biomass 33

Figure 11 Cluster analysis dendrogram of (a) Tree Height and (b) DBH of Tree 36

Figure 12 Cluster analysis dendrogram of above-ground biomass content in (a) Plot 1; (b) Plot 2 and (c) Plot 3 41

LIST OF TABLES

Table 1 Coordination point of each transections 21 Table 2 Allometric equations comparison 27 Table 3 Diameter and Girth at Breast Height, and Height range of measured trees 29

LIST OF ABBREVIATIONS

PART I INTRODUCTION

1.1 Research Rationale

Global warming due to the increased concentration of Green House Gases (GHGs) in the earth’s atmosphere is one of the most important concerns for mankind

today (Sreejesh et al., 2013) Each of the last three decades has been successively

warmer at the Earth’s surface than any preceding decade since 1850 The period from

1983 to 2012 was likely the warmest 30-year period of the last 1400 years in the Northern Hemisphere The globally averaged combined land and ocean surface temperature data show a warming of 0.85ºC [0.65ºC to 1.06ºC] over the period 1880 to

2012 The total increase between the average of the 1850 - 1900 period and the 2003 -

2012 period is 0.78 [0.72 to 0.85] °C (IPCC, 2014a)

The rise in the carbon dioxide level in the atmosphere is mainly caused by anthropogenic activities Anthropogenic greenhouse gas (GHG) emissions since the pre-industrial era has driven large increases in the atmospheric concentrations of carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) (IPCC, 2014a)

Increasing evidence of climate change impacts and their consequences in recent years suggests the need for action Innovative approaches to assess vulnerability and adaptation, in the short and long-term, are also important In 2000, Thailand emitted GHGs equivalent to 281 million tons of CO₂ With carbon sink of 52 million tons, the net GHG emissions reached 229 million tons of CO₂ equivalent Comparing CO₂ equivalent by type of GHG in 2000, CO₂ constituted about 69% of the total, followed

by CH₄ at 26%, and N₂O at 5% (Office of Natural Resources and Environmental Policy and Planning, 2010)

The world’s forests are prominent sites to study climate change, not only in terms

of total net carbon emissions but also in terms of global storage capacity which is important for climatic regulations Processes of nutrient uptake and cycling in forest ecosystems are highly influenced by the changes in temperature or precipitation regimes

as well as by changes in the atmospheric CO₂ concentration (Terakunpisut et al., 2007)

It is estimated that the world’s forests store 283 giga-tonnes (Gt) of carbon in their biomass alone and 638 Gt of carbon in the ecosystem as a whole Roughly half of total carbon is found in forest biomass and dead wood combined and half in soils and litter combined (FAO, 2005) Forests store carbon and contain approximately 80% of the total above-ground organic carbon and 40% of the total below-ground organic carbon worldwide Deforestation and forest degradation contribute 15% – 20% of global carbon emissions, and most of this contribution comes from tropical regions Approximately 60% of the carbon sequestered by forests is released back into the atmosphere via

deforestation (Vicharnakorn et al., 2014)

United Nations Framework Convention on Climate Change (UNFCCC) has recognized the importance of plantation forestry as a greenhouse gas mitigation option,

as well as the need to monitor, preserve and enhance terrestrial carbon stocks (Updegraff

et al., 2004) Forest plantations have significant impact as a global carbon Young

plantations can sequester relatively large quantities of carbon while a mature plantation

can act as a reservoir (Sreejesh et al., 2013)

Teak (Tectona grandis) tree is a fine quality timber-yielding deciduous species

particularly suitable for rapid production of large volumes of timber, poles and fuel

wood (Kaul et al., 2010) Long rotation species such as teak has a long carbon locking

period compared to short duration species and has the added advantage that most of the

teak wood is used indoors extending the locking period further (Sreejesh et al., 2013)

In addition, production from plantation forests may relieve pressure on timber extraction

from natural forests, and thus contribute to forest conservation (Kaul et al., 2010)

With regard to the mitigation of climate change impacts, the amount of CO₂ in the atmosphere must be controlled by increasing the amount of CO₂ uptake by plants as much as possible and suppress the release (emission) of CO₂ into the atmosphere as low

as possible So, maintaining the integrity of natural forests and planting trees is very important to reduce the amount of excess CO₂ in the air (Hairiah & Rahayu, 2007)

Hence, with a large area of teak tree plantation, Mae Ho Phra Teak Plantation not only provides forest products, it also acts as a land carbon sink With 3,576.68 acre or 1,447.43 hectares area, as well as the weeds, shrubs and peat within the teak plantation area that also sequester carbon, making Mae Ho Phra Forest Teak Plantation as one of the largest carbon sinks in Chiang Mai province To study the total amount of carbon sequestrated by teak trees in this area, the researcher proposed the study “Above-Ground Biomass Estimation by Using Variant Allometric Equations on Various Age Groups of

Teak (Tectona grandis) Tree in Forest Plantation of Mae Ho Phra, Chiang Mai Province,

Thailand.”

1.2 Research Objectives

The main objective of this research is to obtain an overview of potential ground biomass and to determine the pattern of above-ground biomass changes in various age group of teak trees in Mae Ho Phra Forest Plantation

above-This research specifically aims:

1 To identify the physical appearances of teak trees age 7, 13 and 21 years old in Mae Ho Phra Forest Plantation

2 To compute the total amount of above-ground biomass content in teak trees

3 To distinguish the pattern difference on the total amount of above-ground biomass in teak trees using 3 different allometric equations

4 To see the similarity of physical appearances and above-ground biomass of teak trees

1.3 Research Questions and Hypotheses

This study wants to address the following questions:

1 What are the characteristics of teak trees age 7, 13 and 21 years old in Mae Ho Phra Forest Plantation?

2 What is the amount of above-ground biomass in 7, 13 and 21 years old of teak trees in Mae Ho Phra Forest Plantation?

3 How much is the difference in total amount of above-ground biomass in teak trees that grows older?

4 How much difference that occurs after computations using 3 different ground biomass allometric equations?

above-5 Which trees that has the closest and furthest similarities with each other in terms

of physical form and above-ground biomass content?

Limitation that were encountered throughout the study:

• The condition of plantation was not well-maintained A lot of weeds and shrubs that

hampered the researcher to gather the data and made the researcher to spend a lot of energy In the height measurement of trees using Haga Altimeter, a clear viewing angle is required between the researcher and the tree, but due to the abundance of weeds and shrubs, the researcher's point of view becomes less clear Therefore, the data measured might not be 100% accurate

• Limited time The field observation was only conducted for 3 days From May 22,

until May 24 The staff of plantation requested the researcher to work not more than 4pm, due to some dangerous factors that might occur when it gets dark, since it is a forest plantation

• Language Barrier The researcher had some difficulties on communicating with the

staff of plantation since the researcher was unable to speak Thai and the staff of plantation does not speak English

1.5 Definitions

1.5.1 Mae Ho Phra Forest Plantation

Mae Ho Phra Forest Plantation is located in Mae Ho Phra sub-district of Mae Tang district, Chiang Mai province, Thailand It was established in 1971 by the Thai

government With an area of 9,392.4 or 1,502.8 hectares, making it a large area of forest plantation in the northern part of Thailand Mae Ho Phra Forest Plantation owns 3

species of monoculture plant plantation, which is teak (Tectona grandis) with an area of 8,867.74 rai or 1,418.43 hectares, Eucalyptus (Eucalyptus globulus) with an area of 88.10 rai or 14.1 hectares and Rubber (Hevea brasiliensis) tree with an area of 436.56 rai or 69.85 hectares

Its climate is tropical, dominated by the southwest monsoon from May to October, which brings high rainfall and humidity to the region Average annual rainfall ranges from 1250 mm in the northeast to more than 4000 mm in the southern peninsula Dry season runs from November to April, with relatively cool temperatures until February March through May is dry and hot Average annual temperature is 28.90ºC (Ongprasert, 2010)

Figure 1 Haga Altimeter

PART II LITERATURE REVIEW

2.1 Greenhouse Gases and Climate Change

Over the next decades, it is predicted that billions of people, particularly those in developing countries, will face shortages of water and food and greater risks to health and life as a result of climate change (UNFCCC, 2007)

World leaders gathered in Kyoto, Japan, in December 1997 to consider a world treaty restricting emissions of ‘‘greenhouse gases’’ chiefly carbon dioxide (CO₂), that are thought to cause ‘‘global warming’’ – severe increases in Earth’s atmospheric and surface temperatures, with disastrous environmental consequences CO₂ levels have increased substantially since the Industrial Revolution and are expected to continue doing so It is reasonable to believe that humans have been responsible for much of this increase Greenhouse gases cause plant life, and the animal life that depends on the

environment, to thrive (Robinson et al., 1998)

CO₂ emissions from fossil fuel combustion and industrial processes contributed about 78% to the total GHG emission increase between 1970 and 2010 The largest sources of greenhouse gases were the sectors of energy production (34%, mainly CO₂ from fossil fuel combustion), and agriculture, forestry and land-use (24%, mainly CH₄ and N₂O) (IPCC, 2014b)

Levels of greenhouse gases in the atmosphere are rapidly increasing, warming the Earth’s surface and lower atmosphere Higher temperatures lead to climate change that includes effects such as rising sea levels, changes in precipitation patterns that can produce floods and droughts and the spread of vector-borne diseases such as malaria

(Pullaiah et al., 2015)

Actions to limit damage from climate change need to be implemented now in order to be effective Mitigation actions involve direct reduction of anthropogenic emissions or enhancement of carbon sinks that are necessary for limiting long-term climate damage also by avoiding deforestation and degradation is a priority in reducing

greenhouse gas emissions (Pullaiah et al., 2015; Tubiello, 2012) Direct options in

agriculture, forestry and other land use (AFOLU) involve reducing CO₂ emissions by reducing deforestation, forest degradation and forest fires; and storing carbon in terrestrial systems (for example, through afforestation) (IPCC, 2014b) Deforestation is having a considerable impact on the ability of the terrestrial biosphere to emit or remove carbon dioxide from the atmosphere Scientists have also determined that tropical

deforestation releases 1.5 Gt of carbon into the atmosphere each year (Gullison et al.,

2007)

2.2 Forest as Climate Change Mitigation Option

Forest vegetation and soils constitute a major terrestrial carbon pool with the potential to absorb and store carbon dioxide (CO₂) from the atmosphere The CO₂ source and sink dynamics as trees grow, die, and decay are subjected to disturbance and forest

management (Kaul et al., 2010) Forests make up around 30% of the world’s land

surface, and forest ecosystems, including their soils, store approximately 1200 giga tonnes of carbon which is considerably more than is present in the atmosphere (around

762 GtC) (Freer-Smith et al., 2007)

Forests sequester and store more carbon than any other terrestrial ecosystem and are an important natural ‘brake’ on climate change When forests are cleared or degraded, their stored carbon is released into the atmosphere as carbon dioxide (CO₂) The largest source of greenhouse gas emissions in most tropical countries is from

deforestation and forest degradation (Gibbs et al., 2007) Forests covers just over 4

billion hectares of the world’s surface According to data from the UN Food and Agriculture Organization, deforestation was at its highest rate in the 1990s, when each year the world lost on average 16 million hectares of forest As forest expansion remained stable, the global net forest loss between 2000 and 2010 was 5.2 million hectares per year During the next 20 – 30 years, the world could lose more than a million species of plants and animals – primarily because of environmental changes due to

humans (Pullaiah et al., 2015).

Tropical deforestation not only reduces the capacity of this CO₂ sink, but it also directly adds CO₂ to the atmosphere From 2005 to 2010, tropical forest carbon stocks

decreased by approximately 0.5 GtC/year (FAO, 2010 as cited in Jantawong et al.,

2017)

The total standing above-ground biomass of woody vegetation elements is often one of the largest carbon pools The above-ground biomass comprises all woody stems, branches, and leaves of living trees, creepers, climbers, and epiphytes as well as herbaceous undergrowth For agricultural lands, this includes crop and weed biomass

An estimate of the vegetation biomass can provide us with information about the nutrients and carbon stored in the vegetation as a whole, or the amount in specific

fractions such as extractable wood (Hairiah et al., 2001)

Conversely reforestation in the tropics could increase the carbon sink and remove substantial amounts of CO₂ from the atmosphere Realization of the significant contribution that tropical reforestation could make towards mitigating global climate change has led to what could be described as a global reforestation frenzy (Jantawong

et al., 2017)

The main mitigation options within agriculture, forestry and land use involve one

or more of three strategies: prevention of emissions to the atmosphere by conserving existing carbon pools in soils or vegetation or by reducing emissions of methane and nitrous oxide; sequestration - increasing the size of existing carbon pools and thereby extracting carbon dioxide (CO₂) from the atmosphere through reforestation and afforestation; and substitution - substituting biological products for fossil fuels or energy-intensive products, thereby reducing CO₂ emissions Demand-side measures (e.g., reducing losses and wastes of food, changes in human diet, or changes in wood consumption) may also play a role (IPCC, 2014a)

2.3 Forest Plantation as Carbon Sequestration Potential

Forests and trees are being planted for many purposes and at increasing rates, yet

they still account for a fairly small proportion of total forest area Forest plantations – a subset of planted forests consisting primarily of introduced species – make up an estimated 4 percent of total forest area Productive forest plantations, primarily established for wood and fibre production, account for 78 percent of these, and protective forest plantations, primarily established for conservation of soil and water, account for 22 percent The area of forest plantations increased by about 14 million hectares during 2000 – 2005, or 2.8 million hectares per year, 87 percent of which are productive forest plantations (FAO, 2005)

In 2001, FAO stated that forests in the Asia-Pacific region cover approximately

699 million hectares Of this area, some 113.2 million hectares are forest plantations, or

16 percent of the total forest resource The Asia-Pacific region accounts for some 61 percent of the world’s plantation forests The majority of the global forest plantation resource is been established in a small group of countries Five countries from Asia rank

among the top ten plantation countries in the world: China (46.7 million hectares); India (32.6 million hectares); Japan (10.7 million hectares); Indonesia (9.9 million hectares); and Thailand (4.9 million hectares) Together, these five countries account for 55

percent of the global forest plantation resource (Enters et al., 2004)

With the advent of the Kyoto Protocol and its recognition of the use of forestry activities and carbon sinks as acceptable tools for addressing the issue of the build-up

of atmospheric carbon, the potential role of planted forests as a vehicle for carbon sequestration has taken on a new significance (Sedjo, 1999)

Additionally, the emergence of tradable emission permits and now tradable carbon offsets provides a vehicle for financially capturing the benefits of carbon emission reductions and carbon offsetting activities In a world where carbon sequestration has monetary value, investments in planted forests can be made with an eye to revenues to (at least two) joint outputs: timber and the carbon sequestration services It should be noted that almost all of the studies thus far have focused on the cost of carbon sequestration as a single output, rather than as a joint output with timber (Sedjo, 1999)

2.4 Teak (Tectona grandis) Tree

Teak (Tectona grandis) is highly rated among hardwood plantations due to its

durability, mellow color, and long straight cylindrical bole It has been a popular tree species for timber production in commercial and private farmland and remains a

promising species for carbon sequestration in the seasonally dry tropics (Takahasi et al.,

2012) It is a valuable timber yielding species in the tropics especially India, Indonesia,

Malaysia, Myanmar, northern Thailand, and north-western Laos (Sreejesh et al., 2013)

According to The Forest Industry Organization (FIO) in 2010 as cited in (Ounban

et al., 2016), in Thailand, the increased demand for wood, particularly fuel wood, has

led to a rapid expansion of plantations of fast-growing species such as eucalypt and teak and of slower growing species including more than 183,000 ha of land that has been planted in the last decades Teak was mostly planted in the northern part of Thailand (94,000 ha)

The ability of teak in sequestrating carbon is determined by age class or growth level The content of biomass and carbon of teak plantations increase in every increased plant age and the quality of plantation’s growing site This is due to the increased plant age resulting from bigger plants as well as better growing areas which provide a better nutrient element Information about patterns of changes in carbon storage, in particular

on teak forests is vital and urgent so that it can be used to help as a determinant of forest management and environmental policies in order to predict and identify deposit patterns

or carbon storage and changes as early as possible, and to determine the next steps (Chanan & Iriany, 2014) Teak plantation would represent a reasonable recommendation for tree species when managing plantations with carbon sequestration and a high-quality

timber (Takahasi et al., 2012)

2.5 Land Carbon Stock

Knowledge that CO₂ is stored within and exchanged between the atmosphere and vegetation and soils has led to the suggestion that soils and vegetation could be managed

to increase their uptake and storage of CO₂, and thus become ‘land carbon sinks’ (The Royal Society, 2001) Of the total carbon dioxide emitted by human activity since 1750 about 44% remains in the atmosphere, 30% has been absorbed by the ocean and 26%

by land carbon sinks including trees, soils and fungi (refer to Figure 2) (Wilson, 2013)

Forest ecosystems are in focus as potential sinks for carbon, and carbon stocks and dynamics of soils of the forest, hereafter termed forest soils, are differ from those

of other land uses (Callesen et al., 2015) Tropical forests are a major terrestrial sink for atmospheric CO₂, absorbing about 18% of anthropogenic emissions (Jantawong et al.,

2017) The main carbon pools in tropical forest ecosystems are the living biomass of trees and understory vegetation and the dead mass of litter, woody debris and soil organic matter The living biomass included upper part and lower part of roots, trees, herb plants, bushes and ferns The dead biomass comprises litter and rough timber remains Soil makes up mineral, organic layers and turf The carbon stored in the aboveground living biomass of trees is typically the largest pool and the most directly impacted by deforestation and degradation Thus, estimating aboveground forest biomass carbon is the most critical step in quantifying carbon stocks and fluxes from

tropical forests (Gibbs et al., 2007; Chanan & Iriany, 2014)

The below ground biomass comprises living and dead roots, soil fauna and the microbial community Soil carbon, specifically in the form of soil organic matter, plays

a central role in the functioning of soils to produce a wide range of vital environmental goods and services Soils store carbon from the atmosphere as a way to mediate

atmospheric greenhouse gas levels (Banwart et al., 2015) In addition, aboveground

biomass is a key variable in the annual and long-term changes in the global terrestrial

carbon cycle and other earth system interactions (Terakunpisut et al., 2007)

The estimates of carbon stock are also important for scientific and management issues such as forest productivity, nutrient cycling, and inventories of fuel wood and pulp It is also important in the modelling of carbon uptake and redistribution within

ecosystems Thus, its dynamics must be understood if annual spatial variations are to be

related to spatial weather and climate variables (Terakunpisut et al., 2007)

Figure 2 Annual sink absorption of human carbon emissions (Gt CO₂)

Source: Burning the Carbon Sink, 2013

2.6 Carbon Cycle

Carbon (C), the fourth most abundant element in the Universe, after hydrogen (H), helium (He), and oxygen (O), is the building block of life On Earth, carbon cycles through the land, ocean, atmosphere, and the Earth’s interior in a major biogeochemical cycle (the circulation of chemical components through the biosphere from or to the lithosphere, atmosphere, and hydrosphere) (Welch, n.d)

Atmospheric CO₂ is increasing at about half the rate of fossil fuel emissions; the rest of the CO₂ emitted either dissolves in sea water and mixes into the deep ocean or is taken up by terrestrial ecosystems Uptake by terrestrial ecosystems is due to an excess

of primary production (photosynthesis) over respiration and other oxidative processes (decomposition or combustion of organic material) Terrestrial systems are also an anthropogenic source of CO₂ when land-use changes (particularly deforestation) lead to

loss of carbon from plants and soils Nonetheless, the global balance in terrestrial

systems is currently a net uptake of CO₂ (Prentice et al., 2001)

Photosynthesis and respiration are the primary processes facilitating carbon exchange between the land and the atmosphere During photosynthesis, organisms capable of carbon assimilation, mostly plants and Cyno-bacteria, absorb CO₂, and, with participation of H₂O and solar energy, they synthesize organic compounds forming the organisms’ biomass Animals and microorganisms, as the successive levels of a food chain, utilize the biomass, enabling further carbon cycling Most of the living organisms oxidize organic matter in order to generate energy necessary for them to function Besides energy, H₂O and CO₂ are the final products of the oxidation The resulting CO₂

is most often released to the atmosphere (Kuliński & Pempkowiak, 2012) The presence

of land vegetation enhances the weathering of soil, leading to the long-term but slow uptake of carbon dioxide from the atmosphere (Welch, n.d)

2.7 Tree Biomass Estimation Using Allometric Equation

Estimation of tree biomass is important for assessing productivity and carbon

sequestration and (Henry et al., 2010 as cited in Ounban et al., 2016), reported that

measurements to develop allometric equations could be carried out by either direct or indirect methods Direct methods measure the biomass by weighing trees in the field while indirect methods involve the estimation of difficult-to-measure parameters from easy-to-measure tree parameters

An allometric equation is an indirect method to estimate the whole or partial weight of the tree (stem, leaves, branches and roots), from measurable tree dimensions, including the diameter at breast height (D) and total height (H); thus, weight can be estimated non-destructively Standard allometric equation which reasonably predicts the

biomass in a tree is considered to be convenient and required in many cases, especially when allometric equations cannot be developed on site Thus, there is additional value

in deriving generalized biomass regression equations (Ounban et al., 2016)

Diameter at breast height or D (1.3 m above-ground) is the most common predictor variable and the easiest variable to measure in the field and was strongly

related to the stem and aboveground biomass for Tectona grandis Most biomass

allometric equations constructed for plantation species in Thailand have indicated that adding tree height as the second independent variable improved the biomass allometric equations which agreed with the results from the present study, while tree height alone

was the worst predictor variable for both species (Ounban et al., 2016)

The largest carbon component in vegetation comes from tree biomass, so determining the amount of tree biomass that occupies an expanse of plantations is the most important part in calculating the potential of forest carbon Biomass is expressed

in unit of dry weight Tree biomass is generally estimated indirectly by using tree biomass allometric equation, which states the relationship between specific dimensions

of the tree (e.g tree diameter or height) with the total value of tree biomass Another important component of biomass as a part of carbon component is under-growing plants and litter (Chanan & Iriany, 2014) Other computations, which require an accurate estimate of biomass along with carbon emission and carbon sequestration rates, are defining the carbon status and flux in a given geopolitical unit for the assessment, for example, of carbon taxes and similar international CO₂ mitigation measures

(Terakunpisut et al., 2007)

PART III METHODS

3.1 Materials

The study was conducted using the following materials; For data collection and data processing, notebook, pen and marker were used during and after the measurement process Plastic ropes were used to create the plots (40 m x 40 m) where the standing teak trees are measured Camera is used to take pictures of the activities, plots, trees and the areas of the conducted study Measuring tapes were used to measure the correct height for the DBH (Diameter at Breast Height) which is 1.3 m, and also to measure the length and width of each plots And Haga Altimeter was used to measure the height of trees

3.2 Methods

3.2.1 Collection Site

Mae Ho Phra Forest Plantation

Mae Ho Phra Forest Plantation, located in Mae Ho Phra sub-dsitrict of Mae Tang District, Chiang Mai Province, Thailand Mae Ho Phra Forest Plantation owns a forest plantation with an estimated area of 9,392.4 acre or 1,502.8 hectares, with 8,867.74 rai

or 1,418.83 ha of teak tree plantation, 88.10 rai or 14.1 ha of Eucalyptus tree plantation and 436.56 rai or 69.85 ha for Rubber tree plantation A total of 3 plots were chosen in different age group of teak trees plantation: 21 years age as plot 1; 13 years age as plot 2; 7 years age as plot 3, shown in the following figure:

(a) (b)

Figure 3 (a) Map of Chiang Mai province, Thailand and (b) map of teak plantation in Mae Ho Phra Forest Plantation

Source: orangesmile.com

3.2.2 Transect Determination

The study used random sampling for determining the transection where it is based

on various age classification of teak plantation for each plot It is used to represent the growth of carbon sequestrated by different group age of teak trees

Figure 4 Transect locations

Table 1 Coordination point of each transections

3.2.3 Plot Determination

Determining the plots for the sample sites is done by paying attention to the distance from the nearest road The plots for each age classification of teak trees were made with 50 meters distance from the main road to evade any human interference with the measured trees Plot size is 40 m x 40 m (1600 m² or 0.16 ha) equal to 1 rai, which

is a commonly used unit in Thailand (refer to figure 5) Teak trees in Mae Ho Phra Forest Plantation were planted at a spacing of 4 m x 4 m

Figure 5 Sample plot

3.3 Tree Height and Diameter at Breast Height Measurement

As stated by Ounban et al (2016), teak tree biomass can be measured

non-destructively by measuring tree dimensions, including the diameter at breast height (D) and total height (H)

3.3.1 Tree Height Measurement

According to Haga Hypsometer (1997), using the Haga to determine tree height can be done by the following steps:

- Select a distance, preferably 15, 20, 25, or 30 meters away from the tree, where the required point on the tree (e.g tree tip) can be seen Press the “lock”

- The “first shot”- pointing at the base of the tree and the “second shot”- pointing

at the tip of the tree

- By adding the 2 values from the “first” and “second” shot together, the result will

be the total height of the measured tree

Figure 6 Angles for Using Haga Altimeter

3.3.2 Diameter at Breast Height (DBH) Measurement

In forest inventories it is common that tree diameter is measured at 1.3 meters, called Diameter at Breast Height (DBH) Biased measurement results are common if measurements were taken above or below 1.3 meters A systematic error occurs also if the tape is not slanted around the tree with a right angle to the tree axis and has to kept tied Bark fall off in between consecutive measurements can also produce considerable measurement errors (Weyerhaeuser & Tennigkeit, 2000) The exact location to measure breast height or how to make provisions for trees growing irregular is visualized in figure 7

(a)

(b)

Figure 7 (a) Tree diameter measurement using diameter tape and (b) Locating

breast height

Source: Weyerhaeuser & Tennigkeit, 2000

3.4 Above-Ground Biomass Measurement

Standard allometric equation which reasonably predicts the biomass in a tree is considered to be convenient and required in many cases, especially when allometric equations cannot be developed on site

• Ounban, Puangchit and Diloksumpun, 2016

In their study in 2016, the study “Development of General Biomass Allometric

Equations for Tectona grandis Linn.f and Eucalyptus camaldulensis Dehnh

Plantations in Thailand” developed the allometric equation for above-ground biomass

content in teak trees:

y = 0.045(D²H)⁰·⁹²¹

Where y is the biomass of the above-ground and the tree components are measured in kilograms per tree, D is the diameter at breast height measured in centimeters, H is the height measured in meters Most references indicated that adding tree height as the second independent variable improved the biomass allometric

equations (Ounban et al., 2016) In total, 84 datasets for T grandis were gathered from

published papers The general allometric equations were then developed and the slopes and elevations were tested using ANCOVA Spacing of 2 m x 4 m, 2 m x 8 m, 3 m x 3

m and 4 m x 4 m were used as control factors

This general allometric equation gave the best fit (p < 0.01) This equation is precisely for teak trees within the specified diameter ranged which is 4.4 cm to 41.2 cm for the diameter, and 5.5 m to 31.0 m for the height If the trees are outside the specified diameter range, this model should be carefully used

• Jain and Ansari, 2013

In the study “Quantification by Allometric Equations of Carbon Sequestered

by Tectona grandis in Different Agroforestry Systems”, Jain and Ansari developed

an above-ground biomass equation as follow:

y = 3.174(GBH) – 21.27

Where y is the above-ground biomass and GBH is the girth at breast height in centi-meters Jain and Ansari used AGB to estimate carbon stock for teak trees of different age groups (1.5, 3.5, 7.5, 13.5, 18.5 and 23.5 years) This regression equation

has r²=0.898 (p <0.01) The study was conducted in Jabalpur, India The regression

equations and correlation coefficients obtained for different variables of reference teak trees were tested for statistical significance at α =0.05 Using destructive method in order

to be able to get the most accurate results, fresh weights of plant parts (leaves, branches and main stem) were determined followed by estimation of oven dry weights at 60°C - 80°C

• Juma Ramadhani Mwangi, 2015

In the study “Volume and Biomass Estimation Models for Tectona grandis

Grown at Longuza Forest Plantation, Tanzania”, Mwangi developed above-ground

biomass allometric equation as follow:

y = 0.5043 x DBH²·⁰⁶³⁶

Where y is the above-ground biomass and DBH is the diameter at breast height Mwangi stated that “the existing allometric models for accurate estimations of total tree

volume and total tree biomass for teak (Tectona grandis) has limitation of application

such as models being developed from few sample trees for model development and covered narrow range of diameters and excluded trees with small and large diameters”

This study was carried out to fill these gaps by developing biomass and volume estimation models for teak that cover a wide range of diameter A total of 51 sample trees of diameter at breast height (DBH) between 1.00 - 83.40 cm from seven compartments with ages of 2, 5, 16, 19, 21, 34 and 42 years were used for volume and biomass model development and evaluation

The sample trees were measured for DBH and total height then felled down through excavation and cross cut into manageable billets which measured, measured for fresh weight, mid diameter and length The twigs and leaves of each tree were tied into bundles and weighed A total of 16 samples per tree from stem, branches, twigs and leaves, root crown, main roots and side roots were measured for fresh weight and taken

to the laboratory for dry weight determination

Table 2 Allometric equations comparison

Where; R² = Coefficient of Determination

SE = Standard of Error

Ounban et al., 2016 AGB = 0.045(D²H)⁰·⁹²¹ 0.975 0.224 < 0.001

Jain and Ansari, 2013 AGB = 3.174(GBH) – 21.27 0.898 0.43 < 0.001

Mwangi, 2015 AGB = 0.5043 x DBH²·⁰⁶³⁶ 0.976 0.23 < 0.05

PART IV RESULTS AND DISCUSSION

4.1 Results

This chapter presents the research findings with respect to research objectives This includes the characteristics of trees; above-ground biomass total of each plots using three different allometric equations; the total amount of above-ground biomass in all plots; and the similarity of each trees in terms of physical forms and above-ground

biomass content

4.1.1 Characteristics of Trees

All standing alive trees were measured within each plot There were 96, 100 and

95 trees for plot 1, plot 2 and plot 3, respectively Within each plot site, there were 4, 0 and 5 dead trees in plot 1, 2 and 3, respectively, which were not measured Plot 1, which

is the 7 years old teak trees, already alleged by the researcher that will have the smallest GBH, DBH and height since it is the youngest plantation, with a range of 14 cm – 74

cm with an average of 45.2 cm, 4.4 cm – 23.5 cm with an average of 14.4 cm, and 3 m – 16 m with an average of 11.4 m for plot 1, respectively For plot 2, the range of GBH, DBH and height is 17 cm – 103 cm with an average of 50.2 cm, 5.4 cm – 32.8 cm with

an average of 16 cm, and 6 m – 17 m with an average of 12.1 m, respectively Plot 3 has the largest and highest, in average, in the characteristics of the trees in three measured plots, ranging from 24 cm – 90 cm with an average of 56.5 cm, 7.6 cm – 28.6 cm with

an average of 18 cm, and 11 m – 19 m with an average of 14.1 m for GBH, DBH and height, respectively (refer to Table 3)