Guadua chacoensis in Bolivia

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Guadua chacoensis in Bolivia

-an investigation of mechanical properties of a

bamboo species

Maria Lindholm

Sara Palm

December 5, 2007

Examiner: Stig-Inge Gustafsson Supervisor: Kenneth Bringzén

Department of Management and Engineering Centre for Wood Technology & Design

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Sammanfattning

Detta examensarbetete har gjorts vid CTD- Centrum för Träteknik och De-sign vid Linköpings universitet och har utförts i Santa Cruz de la Sierra i Bolivia.

Syftet med detta examensarbete är att studera de mekaniska egenskaperna och användningsområden för Guadua chacoensis, en boliviansk bambuart. Genom historien har bambu använts i en mängd olika applikationer såsom hus, verktyg, möbler, mat, bränsle, papper och land-rehabilitering. I de esta asiatiska länder är bambu en viktig resurs för små- och medelstora företag vilket skapar arbetstillfällen och motverkar fattigdom. I Sydamerika nns många länder, däribland Bolivia, vilka har stora möjligheter att utnyttja bambu på samma sätt. En av huvudidéerna med detta examensarbete är att kunna gynna den bolivianska välfärden genom att belysa denna, hittills outvecklade naturresurs.

Detta examensarbete är en Minor eld study, delvis nansierad av Sida, styrelsen för internationellt utvecklingssamarbete. Under fältarbetet genom-fördes teoretiska studier då internationell och inhemsk information om bambu, speciellt om Guadua chacoensis, samlades in. Olika områden där arten växer besöktes och hållfasthetstekniska tester genomfördes vid UPSA- Universidad Privada de Santa Cruz de la Sierra.

Genom drag-, böj- och hårdhetsprovning har det påvisats att Guadua chacoensis är ett böjligt och medelhårt material med en draghållfasthet som är jämförbar med den för Europeisk ek. Detta gör att denna bambuart lämpar sig bland annat för konstruktioner, såsom hus och broar, samt mö-beltillverkning.

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Abstract

This Master thesis has been performed at CTD- the Centre for Wood Tech-nology and Design at the University of Linköping and has been carried out in Santa Cruz de la Sierra in Bolivia.

The objective of this thesis is to study the mechanical properties and uses of Guadua chacoensis, a bamboo native to Bolivia. Throughout history, bamboo has been used in many countries for a variety of purposes. In Asia bamboo is an important raw-material for buildings and furniture. It is also used for making paper and for land rehabilitation and fuel. In South America many countries, among them Bolivia, have great potential to use bamboo in the same way. One of the key ideas with this Master thesis is to make a contribution to support the Bolivian economy and welfare by elucidate this, hitherto undeveloped, natural resource.

This thesis is a Minor eld study partly nanced by Sida- the Swedish International Development Cooperation Agency. During the eld study the-oretical studies were made, collecting local and international information about bamboo and Guadua chacoensis in particular. Laboratory tests were prepared and conducted at UPSA- the Private University of Santa Cruz de la Sierra and several localities of the plant were visited.

Through tensile-, bending- and hardness test it is found that Guadua chacoensis is a exible, medium soft material and is comparable with Euro-pean oak when it comes to the tensile strength. This leads to the conclusion that this bamboo species, among other elds of applications, can be used for constructions, like houses and bridges, and furniture manufacturing.

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Acknowledgements

The idea of doing this Master thesis was established in October 2006 which makes this a slightly more than one year long project. During this time sev-eral people have crossed our paths and contributed to our work in dierent ways.

We would like to thank our examiner Stig-Inge Gustafsson and our super-visor Kenneth Bringzén at the University of Linköping. We deeply appreciate their support and great interest in our work throughout the whole project. Furthermore we would like to thank Per Larsson and Stig Algstrand, also at the University of Linköping, for helping us to nd the right contacts in Bolivia and Kerstin Johansen at CTD, who proofread the thesis. Special thanks is directed to Per Larsson that helped us arrange the nancing of our stay in Bolivia.

Our gratefulness also goes to Gabriella A. Pinaya Johannessen at Cadefor, Santa Cruz that at all times was ready to answer questions and supported us during our stay in Bolivia. In addition, our thanks go to Gastón Mejia, Jorge Zeballos and Gustavo Quinteros at UPSA- the Private university of Santa Cruz de la Sierra that helped us with the laboratory tests.

Our deepest gratitude goes to our fellow worker and dear friend Luis Fer-nando Ortiz, who's help in Santa Cruz was inestimable. His broad knowledge of bamboo and his useful contacts were very valuable. Thanks to him our work and stay in Bolivia could not have been better. We will never forget our investigation trips and the hanging-out together!

We would also like to thank Sida, Ansgarius-stiftelsen and Sparbanksstif-telsen Alfa whose scholarships nanced our project. It would not have been possible to carry out the Master thesis in Bolivia without their economic support.

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Finally, we would like to thank everyone that made our time in Bolivia to an enriching and moving stay. Our time in Bolivia was an adventure and we will treasure the memories from this journey forever.

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Preface

During autumn 2006 the idea of going to Bolivia to do our Master thesis was arised. The possibility to do a Minor eld study in a developing country -nanced by Sida, the Swedish International Development Cooperation Agency, lead to the decision of realizing this idea. The Minor eld study scholarship nance the expenses during an eight week study in a developing country with the purpose to increase understanding of Swedish development work in countries all around the world. The fact that the University of Linköping during several years has been cooperating with UPSA- the Private Univer-sity of Santa Cruz de la Sierra lead to the choice to place our study in Santa Cruz. Santa Cruz is Bolivia's biggest city located in the east of the country, in the Tropical Amazon region.

We hope that the readers will nd the results of our endeavours, to gain a little bit of knowledge about this remarkable plant, bamboo, interesting and that the qualities of this versatile material will be appreciated.

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2.2 The Plant . . . 6 2.2.1 Rhizomes . . . 6 2.2.2 Groves . . . 7 2.2.3 Roots . . . 7 2.2.4 Culms . . . 7 2.2.5 Nodes . . . 8 2.2.6 Branches . . . 9 2.2.7 Leaves . . . 10 2.2.8 Flowers . . . 11 2.2.9 Seedling . . . 11 2.2.10 Growth . . . 12 2.2.11 Environment . . . 13 2.3 World Distribution . . . 14 2.4 Species . . . 15 2.4.1 Sympodial Bamboos . . . 16 2.4.2 Monopodial Bamboos . . . 17

2.5 Cultivation, Curing and Harvesting . . . 17

2.5.1 Cultivation . . . 17

2.5.2 Curing . . . 18

2.5.3 Harvesting . . . 18

2.5.4 Insects . . . 19

2.6 Anatomy and Mechanical Properties . . . 20

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2.6.2 Mechanical Properties . . . 21 2.7 Renement Techniques . . . 23 2.7.1 Drying . . . 23 2.7.2 Cutting . . . 24 2.7.3 Splitting . . . 24 2.7.4 Bending . . . 25 2.7.5 Joints . . . 25 2.7.6 Laminating . . . 26 2.7.7 Surface Treatment . . . 27 2.8 World Market . . . 28 2.9 Bamboo Uses . . . 28 2.9.1 Constructions . . . 28 2.9.2 Buildings . . . 30

2.9.3 Plybamboo, Laminate and Furniture . . . 30

2.9.4 Paper . . . 32

2.9.5 Ecomaterial . . . 32

2.9.6 Other Uses . . . 32

2.9.7 Recently Developed Uses . . . 33

3 Method and Performance 35 3.1 Research Approach . . . 35

3.2 Pre-Study Phase . . . 35

3.2.1 Brainstorming . . . 36

3.2.2 Mind Map . . . 36

3.3 Evaluation of Possible Working Areas . . . 38

3.4 Delimitations . . . 38

3.5 The Field Study . . . 39

3.6 Analysis . . . 39

3.7 The Quality of the Study . . . 39

3.7.1 Validity . . . 40 3.7.2 Reliability . . . 40 4 Bamboo in Bolivia 41 4.1 Distribution . . . 41 4.2 Species . . . 42 4.3 Bamboo Industry . . . 43 4.3.1 Forestal Communities . . . 44

4.4 Bamboo Uses in Bolivia . . . 44

4.4.1 Historical Uses . . . 44

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5 Guadua Chacoensis 49

5.1 The Spicies . . . 49

5.2 Distribution . . . 49

5.3 Uses . . . 50

5.4 Mechanical Properties . . . 51

6 Laboratory Tests of Guadua Chacoensis 53 6.1 Laboratory Standards . . . 53

6.1.1 Tensile test . . . 54

6.1.2 Bending test . . . 55

6.1.3 Hardness test . . . 55

6.1.4 Specimens Preparation . . . 55

6.2 Results of the Mechanical Properties Tests . . . 56

6.2.1 Tensile Test Parallel to Fibre . . . 56

6.2.2 Bending Test . . . 57

6.2.3 Hardness Test Perpendicular to Fibre . . . 57

7 Analysis 63 7.1 Laboratory Tests . . . 63

7.1.1 Tensile Test Parallel to Fibre . . . 63

7.1.2 Bending Test . . . 65

7.1.3 Hardness Test Perpendicular to Fibres . . . 65

7.2 SWOT-Analysis . . . 66

7.2.1 Strengths . . . 67

7.2.2 Weaknesses . . . 68

7.2.3 Opportunities . . . 68

7.2.4 Threats . . . 68

7.3 Possibilities for Guadua Chacoensis . . . 69

8 Conclusions and Recommendations 71 9 Reections 73 9.1 Planning of the Work . . . 73

9.2 Final Results . . . 73

9.3 Further Work . . . 74

A Glossary 81

B German Abstract 85

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D Results Tensile test Parallel to Fiber 89 D.1 Lower Parts of Culms - A . . . 90 D.2 Upper Parts of Culm - B . . . 95 E Results Bending Test 101 F Results Hardness Test Perpendicular to Fiber 107 F.1 Lower Parts of Culm - A . . . 108 F.2 Upper Parts of Culm - B . . . 118

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List of Figures

2.1 Rhizomes of a sympodial bamboo . . . 7

2.2 Internode . . . 8

2.3 Node . . . 9

2.4 Branches . . . 10

2.5 Mature culm . . . 13

2.6 World distribution of bamboo . . . 15

2.7 White, blue and black bamboo . . . 16

2.8 Microscope picture of Guadua chacoensis . . . 22

2.9 Drying bamboo . . . 24

2.10 Bamboo joints . . . 26

2.11 Dierent types of laminate . . . 27

2.12 Bamboo fence in Bolivia . . . 29

2.13 Veranda made of bamboo . . . 31

2.14 Ford and chrysler cars . . . 33

2.15 Eco-friendly laptop . . . 33

2.16 Artek bamboo table . . . 34

3.1 Mind map . . . 37

4.1 Bolivia's main bamboo growing regions . . . 42

4.2 Reinforced housewall . . . 45

4.3 Sun protection . . . 46

4.4 Family house . . . 47

4.5 Restaurant complex . . . 48

5.1 Culms of Guadua chacoensis . . . 50

5.2 Transversal cut of Guadua chacoensis . . . 50

5.3 Guadua chacoensis chair . . . 51

6.1 Mechanical properties testing machine . . . 54

6.2 Schematic gure over the tested specimens . . . 55

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D.1 Diagram of tensile test 1A . . . 90

D.6 Diagram of tensile test 1B . . . 95

E.1 Diagram of bending test 1-5 . . . 102

F.1 Diagram of hardness test 1A I . . . 108

F.2 Diagram of hardness test 1A II . . . 108

F.11 Diagram of hardness test 1B I . . . 118

F.12 Diagram of hardness test 1B II . . . 118

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List of Tables

2.1 Mechanical properties . . . 22

6.1 Result of tensile test part A. . . 59

6.2 Result of tensile test part B. . . 60

6.3 Results of bending test. . . 61

6.4 Results of hardness test part A. . . 62

6.5 Results of hardness test part B. . . 62

7.1 Table for comparison of tensile properties. . . 64

7.2 Table for comparison of bending properties. . . 65

7.3 Table for comparison of hardness properties. . . 66

7.4 SWOT-analysis of Guadua chacoensis in Bolivia. . . 67

D.1 Dimensions of specimens 1A tensile test. . . 90

D.2 Result of tensile test 1A. . . 90

D.11 Dimensions of specimens 1B tensile test. . . 95

D.12 Result of tensile test 1B. . . 95

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E.1 Dimensions of specimens bending test 1-5. . . 102

E.2 Result of bending test 1-5. . . 102

F.1 Result of hardness test 1A. . . 109

F.5 Result of hardness test 7.A . . . 117

F.6 Result of hardness test 1B. . . 119

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Chapter 1 Introduction

The following chapter introduces the reader to the Master thesis, its back-ground, objective and structure. Some advice for the reader is also given to facilitate the reading of the thesis.

1.1 Background

Throughout history, bamboo has been used in many countries for a variety of purposes. In Asia bamboo is an important raw-material for buildings and furniture. It is also used for making paper and for land rehabilitation and fuel. In South America bamboo grows in abundance but the bamboo in-dustry in these countries is not as developed as in Asian countries. Hence, Bolivia has great possibilities to develop the country's bamboo industry. One of the key ideas with this Master thesis is to make a contribution to support the Bolivian economy and welfare by elucidate this, hitherto undeveloped, natural resource.

Innovation and research are leading to development of new modern uses with large potential markets for this environmentally friendly material. A number of new technologies have been developed that enable the substitution of bamboo for wood in a large number of applications, one of those the man-ufacturing of bamboo laminates. The Bolivian wood industry is relatively well developed but the renement of bamboo has been neglected which makes this a potential business opportunity.

During several years the University of Linköping has been cooperating with UPSA and this opened a possibility to do the Master thesis in Bo-livia. During the eld work in Santa Cruz the authors were stationed at

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Cadefor- Amazonic Center for Sustainable Forest Enterprise, a service-based non-prot organization. Hopefully this Master thesis will make a contribu-tion to the bamboo industry in Bolivia by means of illuminating the potential business opportunity of this versatile material.

1.2 Objective

The objective of this thesis is to study the mechanical properties of Guadua chacoensis, one of the bamboo species that grows in Bolivia. The uses of Guadua chacoensis will briey be studied to analyze the possibility to diver-sify the elds of application of this bamboo in Bolivia. The Master thesis is intended to contribute to the development of the bamboo business area in Bolivia, serving as an aid for the country's bamboo research-work and further expansion of its bamboo industry.

1.3 Thesis Structure

Presented below is the structure of the thesis and a brief description of the contents in each chapter.

• _{Chapter one, Introduction, is a short description of the thesis and its}

objective.

• Chapter two, Bamboo -a Woody Grass, contains facts and theories concerning bamboo. The chapter is divided into Brief History, The Plant, Anatomy and Mechanical Properties, Renement Techniques and Uses.

• Chapter three, Method and Performance, describes the Research Ap-proach, the Pre-study Phase and the Field Study. The thesis limitations are set and nally the quality of the thesis is discussed.

• Chapter four, Bamboo in Bolivia, introduces the reader to bamboo in Bolivia today; where it grows, species and uses.

• Chapter ve, Guadua Chacoensis, contains facts about the species, for example its distribution, mechanical properties and uses.

• _{Chapter six, Laboratory Tests of Guadua Chacoensis, describes the}

lab-oratory tests conducted at UPSA. The results of the tests are presented to be further analyzed in Chapter seven.

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• Chapter seven, Analysis, contains the analysis of the laboratory tests. The results given by the laboratorys are compared with corresponding fugures for some Swedish woods.

• Chapter eight, Conclusions and Recommendations, after the analysis some conclusions and recomendations regarding the mechanical prop-erties of Guadua chacoensis and its uses are given.

• Chapter nine, Reections, presents the authors reections about the results, the eld study and the thesis writing.

The nine chapters are followed by a Bibliography and Appendices.

1.4 Reading Instructions

To facilitate the reading of the thesis report a glossary is attached in Ap-pendix A, which contains words and vocabulary used throughout the thesis report. Mostly this is technical vocabulary concerning bamboo and its char-acteristics. In Appendices B and C the reader will nd abstracts of the thesis content in German and Spanish.

For the reader who wants a quick overview of the thesis is the Abstract combined with the Introduction and Conclusions and Recommendations sug-gested. The frame of reference in Chapter 2 is written to introduce the reader to the bamboo plant and can be disregarded by those readers already familiar to the plant. The work carried through in the studies of this Master thesis is described from Chapter 3 and forward.

In the bibliography, the references are sorted alphabetically in the follow-ing groups: reference number [1]-[6] are books, [7]-[19] academic articles, [20]-[23] master thesises, [24]-[26] technical reports, [27]-[42] electronical sources and [43]-[44] verbal sources. The references in the text are given in brackets; before the punctuation if it has reference to the single sentence and after the punctuation if it concerns the whole section.

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Chapter 2 Bamboo -a Woody Grass

In the following chapter a frame of reference will be presented in order to cre-ate theoretical understanding of the bamboo plant and bamboo as a mcre-aterial. First an overview of the bamboo history is made to introduce the reader to the principal subject of the thesis. After that, the chapter will describe the bamboo plant and its physical- and mechanical properties followed by rene-ment techniques and bamboo uses. The theories in this chapter are chosen to cover many aspects of the subject eld of this study. The authors have chosen a rather broad frame of references to be able to properly introduce this multifaceted plant and material to the reader.

2.1 Brief Bamboo History

No bamboo fossils have been found and it is unknown for how long bamboo has been growing on the planet. The bamboo plant is one of the most primitive grasses and there are species that are believed to be more than sixty million years old. Bamboo has played an important role for humanity and will probably continuing doing so in the future. The name bamboo has in dierent countries shows the importance of the plant. Bamboo is named the "the wood of the poor" in India, "the friend of the people" in China and "the brother" in Vietnam.[3]

Bamboo is a plant that plays an important role in the daily life of about 2.2 billion people [41].

Many Asian cultures believe that humanity originate from a bamboo stem. The Philippine creation myth tells that after a great battle between the elementary forces, the rst man and women aroused from a bamboo culm. There is a similar legend in Malaysia, which tells about a man who sleeps

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under a bamboo grove and has a dream about a beautiful woman. When the man wakes up and splits a bamboo culm he nds the women from the dream inside.[39]

Farelly[3], tells about one of the most amazing stories in the bamboo history; when a grove of bamboo survived in the very epicenter of the rst atomic bomb in the city of Hiroshima. This was the only living thing close to the epicenter that held out the blast. Today a portion of this bamboo grove can be seen in the Memorial Museum for Peace, which is built at the same place where the plants once grew.

2.2 The Plant

Bamboo is the general name for members of a particular group of large woody grasses. There exists approximately 1 250 species of bamboo and those are divided into 75 groups. Most bamboos are fast-growing and reach maturity in ve years but owers very seldom. There are species of dwarf bamboo that can be as small as 10 centimetres high, but tall species can reach up to 15-20 metres. The largest known bamboo species Dendrocalamus giganteus is, fully mature, 40 metres high and has a culm diameter of 30 centimetres.[16]

2.2.1 Rhizomes

Bamboo plants are divided into sympodial (tropical) and monopodial (tem-perate) species, depending on the type of root-system, also called rhizomes, they possess [3]. The rhizomes are very important in the bamboos since they control when the culms develop and how they spread [17].

The sympodial bamboos have thick and short rhizomes, see Figure 2.1, and their culms grow in groups, which shape is decided from how the rhizomes spread under ground. The rhizomes of the monopodial bamboos are long with symmetrical internodes that are longer then they are broad. The rhizomes produce new culms and new rhizomes for up to ten years.[3] Thanks to the underground growth of the rhizomes, and the system they create in the top layer of the soil, bamboo is a great resource for soil preservation, erosion control and protection against earthquakes [21]. A healthy and still fertile rhizome is yellow-ivory coloured and has nodes from which the culms of the plant rise from. In the nodes of the rhizome nutrients are stored to be distributed to the most active part of new growth in the bamboo grove.[3]

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Figure 2.1: Rhizomes of a sympodial bamboo [37].

2.2.2 Groves

Each individual bamboo culm is often referred to as a single isolated plant. The truth is that each culm is a branch of an underground system of growth. The culms grow up from the rhizomes and all culms in a grove are thereby connected through the rhizomes. Each culm collects nutrient and liquid which is stored mutually in the rhizomes. The form of the bamboo grove depends on how the rhizomes grow below ground. The monopodial species is characterized by free-standing culms while the sympodial bamboos grow in thight clumps.[3]

2.2.3 Roots

Bamboo roots are the only part of the plant that do not grow in segments of nodes and internodes. The roots are thin and brous with a cylindrical shape. The diameter of the roots does not change when the bamboo gets older. The roots can be up to one meter long and one centimetre thick.[3]

Many bamboo species wear small roots on the culm, above ground. These roots are fading in the direction of the top of the plant. Those aerial roots are predicting the possibility that the culm will be felled by a storm or other falling plants. If this would happen, the roots will establish new culms and rhizomes at the nodes of the fallen culm.[3]

2.2.4 Culms

Depending on the species, soil, age of stand and climate the growth of the bamboo culm varies very much. Larger species can grow between 7 to 40

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centimetres a day. The documented growth-record is 120 centimetres in one 24-hour period and comes from Japan.[3] A mature culm can be from ten centimetres to 40 metres high [14]. The growth of the culm does not only depend on the climate and the soil where the bamboo grows. The maturity of the bamboo grove also inuences. When a maximum stature and productivity for each species is reached, the culms do not grow taller or thicker. The normal lifetime of a culm is ve to ten years but some species grow culms with an age of twenty years. The bamboo culm is erect and very often the tip is nodding much or slightly.[3]

2.2.5 Nodes

The node is the part of the culm from where the branches grow out [21]. The nodes makes possible a greater exibility and strength of the culm [20], and through their solid cross wall they provide the transversal connection, see Figure 2.2, between the internodes of the bamboo [6].

Figure 2.2: A split internode.

The nodes of the bamboo are very important for the growth and function of the culm. The nodes enable the necessary cross-transport of water and nutrients in the plant. The nodal structure also aect the transportation

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of liquid during drying and conservation and inuence many physical and mechanical properties.[6]

The visible nodal ridge, see Figure 2.3, is created by cell dierentiation by some cells that are compressed when a new shoot of the bamboo is emerging. When a shoot is raising the cortex is compressed by the upper portion of the new shoot and forced outwards. The morphology of the nodes varies greatly between dierent species.[6]

Figure 2.3: A node from a young bamboo culm.

2.2.6 Branches

Most species are branching at all nodes when they are pre-mature. Various species of Guadua, a South American bamboo, have thorns that can shred and cause severe damage to cloth or skin. When the culm is mature it does not wear branches at the lower nodes. Normally, the branches appear just above the nodes at alternate sides of the culm, see Figure 2.4. Like the culm itself, the branches also have nodes and the branch nodes nearest the culm is often covered with small aerial roots.[3]

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Figure 2.4: Bamboo branches.

2.2.7 Leaves

The size of the leaves of the bamboo plant varies greatly, from tiny to enor-mous [3]. According to Flores[20], there are two types of bamboo leaves:

Caulinary: These are the leaves that cover the culm from its birth until it reaches maturity. They have a brownish colour and are provided with small u as a defense system. These leaves protect the culm during its growth, embracing it until they fall of when the culm has reached maturity and the branches starts to grow out.

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Ramifying: The coating of the ramifying leaves is ribbed and has vains that stretches out from the center of the leaf. These leaves are green and the amount of sunlight they absorb decide how much water the plant take up, when it owers, when it matures and dries.

The leaf fall of many bamboo species often equals, in weight, the growth of new culms during the same year. The leaves of a bamboo fall o progressively and are replaced by new fresh leaves.[3]

2.2.8 Flowers

Most bamboos almost never ower. The normal is once in a period from 15 to 100 years [5]. The owering cycle of bamboos is much disputed and very mysterious since it is very hard to study [3]. The owering pattern of bamboos is gregarious, that is; all bamboos of the same species growing all over the planet, ower at the same time [20]. Gregarious owering can take place over small or enormous areas. Cases have been documented when the blooming started in one area and spread, taking a few years to cover the entire owering zone. The Gregarious owering can sometimes continue for as long as from ve to fteen years. Most species die after owering.[3]

During owering, the bamboo stops growing and all the energy of the plant is used for making tiny owers [3]. The ower is very small and looks like an orchid. Its colour depends on the soil where the bamboo grows and it has a very short life, approximately 48 hours.[20]

Since the bamboos ower so rarely, the phenomenon has been very poorly researched. In 1912 an investigation was carried out in Tokyo. Some seeds were sown but non of the bamboo plants, that emerged then, has owered yet.[3]

2.2.9 Seedling

A bamboo seed is very similar to a wheat grain in size and shape. When germinating, the seedling rst develops a primary root and a primary culm. The root is the rst to emerge and through cell division the culm follows. When cells grow longer in the zones of growth, the culm elongates like a tele-scope that opens up. When several culms have grown up, the rhizomes start to develop. When a seedling has developed a rhizome, it has the complete structure of a mature plant. The shape of the rhizome will transform during the maturation of the bamboo.[3]

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2.2.10 Growth

The largest reserve of bamboo grows in natural forests, which is the pri-mary habitat of bamboo. Bamboo also rise in plantations and homesteads in many parts of the world.[5] The sympodial bamboos are quite sensitive to frost since they are tropical species. The culms of the sympodial bam-boos normally grow from summer to autumn or at the beginning of the rainy season. The increment of the plant is controlled by the levels of moisture in the soil. In warm areas with frequent rainfall during the whole year, the sympodial bamboo can continue to grow all year around. The monopodial species can suer a colder climate than the sympodial ones. A monopodial bamboo can survive in temperatures around minus 20 degrees Celsius [12], and live in areas with mild winters without severe snowfall. The shooting of the monopodial species is controlled by temperature, which makes them sprout in springtime. After a bamboo has completed is growth, wich takes 80 to 120 days for a sympodial bamboo and about 60 days for a monopo-dial one, the culm hardens and matures but the height and diameter of the culm do not change. Some species grow faster during night, sometimes up to two to three times the growth by day, but other species grow faster during daytime.[3] According to Medrano[23], a Guadua bamboo can be said to have four stages of maturity:

Young culm: This phase is initiated by the growth of both primary and secondary branches. The culm is not yet so hard and has a clean surface. The coloring of the internodes is intense green and the nodes are white.

Premature culm: This stage of maturity is characterized by the fading luster of the culm and the emerging presence of fungus on it. The culm has normally reached an age of two or three years at this stage and has a high level of resistance.

Mature culm: This is the maturity stage, see Figure 2.5, when the whole culm is covered by fungus and the nodes in some places covered by moss. The mature phase normally continues for one year and during this period the culm starts to dry.

Over mature culm: The over mature bamboo has lost all its humidity and there is very little or non physiological activity in the culm, that at this stage has turned yellow. The culm has lost up to 80 percent of its resistance at this stage and starts to loose the protecting sheaths that covers the culm and branches.

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Figure 2.5: Mature culm.

2.2.11 Environment

Janssen[5], writes about studies made 1990 by Billing and Gerger, who clas-sied the impacts of bamboo on the environment. The results of the study were that the bamboo has many positive impacts on the environment, some of them are:

• Erosion. Bamboo grows fast, and in a short time develops an extended root system, supporting the soil and prevent-ing it from beprevent-ing washed away by heavy rains. The dense roof of branches and leaves protects the ground from forceful

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tropical rains. Bamboo is a lightweight material, without a need for heavy machinery for felling and transportation.

• Physical soil structure. The root system loosens up the soil, which was made hard and compact by exposure, machin-ery and cattle. The leaf roof protects the soil from further exposure.

• Ground water level. Bamboo consumes water, but this is more than compensated by the reduced evaporation created by the leaf roof, and by the layer of fallen leaves. Owing to the increased permeability of the soil, water run-o is re-duced, allowing more water to penetrate the soil and thereby more water remain in the area.

• _{Soil fertility. This is improved by protecting the soil from}

exposure and by the falling leaves providing organic mate-rial.

• Drainage by the root system and the layer of fallen leaves.

• Micro and local climate. The bamboo plant is a helping factor for stabilization of humidity and temperature.

• Feeding area and habitat for fauna. Bamboo provides a rich environment for insects, birds and some mammals.

In the study one minor negative impact was found:

• _{Bamboo Guadua is found to have a slight negative eect on}

the pH-level.

2.3 World Distribution

Bamboo has a broad weather tolerance which leads to a rather extensive distribution of the plant. Bamboo can live in areas with temperature ranges from minus 4 degrees Celsius to plus 47 degrees Celsius, rainfall extremes from 762 millimetres to 6 350 millimetres per year, from sea level to 3 658 metres in altitude and from 46 degrees north and 47 degrees south in lati-tude, see Figure 2.6.[3]

Bamboo grows naturally in North and South America, Africa, Asia, Aus-tralia and has recently been introduced to Europe as well. Asia has an old tradition to use and rene bamboo. The countries with the largest area, where bamboo is growing, are China, India, Bangladesh, Philippines and

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Thailand. In 2003 the total world bamboo forest area was more than 22 million hectares.[14]

Moisture is a determining factor for the growth of bamboo and the plant is mostly found along waterways, rice paddies or in the tropical forests and jungles and never in dry places.[3]

Figure 2.6: World distribution of bamboo [31].

2.4 Species

The classication of plants in genetic groups and families was made by Lin-naeus (1707-1778). The classication is mainly based on the reproductive structures of the plants, but since many bamboo species bloom so rarely, it is very dicult to give an exact dierentiation of its species. Bamboos have been treated as a separate family of plant by some botanists and as a subfamily of grasses by others. The correct classication of the whole group is therefore uncertain.

Since 1789, when the rst bamboo genus, Bambusa, was described, seventy-ve generic names and more than one thousand specic names have been published. Each species has a need of a various type of soil and climate and has dierent physical properties. This makes dierent species suitable for

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dierent elds of applications.[3]

The size and colour varies broadly between the species. Most bamboo species have green culms, but they can also be yellow, black, red, blue and white, see Figure 2.7. There are also canes with stripes. The blueness of the blue bamboo culms is often a product of new bloom powder on the new culms. When these culms come to maturity the blue colour may turn into dierent shades of green. An example of a white bamboo is Bambusa chungii. It got its name because the new shoots are covered in a lot of powder so that they appear white. One example of a black coloured bamboo is Bambusa lako. It is a sympodial bamboo with an upright and vertical prole.[40]

Figure 2.7: White, blue and black bamboo [40].

2.4.1 Sympodial Bamboos

The bamboo species can, according to Farrelly[3], broadly be divided into sympodial (tropical) and monopodial (temperate) species.

Three well known sympodial bamboos are:

Bambusa vulgaris: The Bambusa vulgaris is the world's most widely dis-tributed bamboo and grows in many dierent type of soil and can stand various types of weather.[3]

Bambusa textiles: The Bambusa textiles has extremely strong bres which makes it convenient for ne splitting and weaving. This makes this species

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very suitable for baskets, mats, ropes, hats and fences.[3]

Dendrocalamus strictus: Dendrocalamus strictus is the most broadly dis-tributed species of all Indian species and it is being used in a vast volume. Since it is the most distributed species it is also the most studied.[3]

2.4.2 Monopodial Bamboos

Some examples of monopodial (temperate) bamboos are:

Arundinaria amabilis: The Arundinaria amabilis is from southern China and was the most traded and used bamboo from 1880 to 1930. The large culms of this species were particularly used for shing rods, for which this species is ideal.[3]

Phyllostachys bambusoides: More than 60 percent of the bamboo harvest in Japan comes from this species. Considering that Japan has 662 species this is remarkable. It is well adapted for constructions and other industrial uses and is also exceptional for erosion control.[3]

Phyllostachys nigra: This species is a native to China. In the end of its rst season it turns into a solid black color. Thereby it got its name. Phyl-lostachys nigra is, thanks to its excellent culm wood, especially appreciated for cabinetwork and furniture.[3]

2.5 Cultivation, Curing and Harvesting

Not many bamboo species are cultivated in a controlled way. The species which are used for industrial purposes are tall growing ones whit large culm diameters. For the use in gardens, a group of small species have been domesticated.[12]

2.5.1 Cultivation

Although most of the bamboo stock in the world grow in natural forests, it can also be seen in plantations in some parts of the world [5]. The bamboo plant prefers a fertile, well drained soil that should not be to dry. Thanks to the system of rhizomes that rmly anchors the plant, the bamboo helps to prevent erosion on the slopes were it often grows. A bamboo growing in a cold climate prefers facing south, while a bamboo in a warm or mild climate

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faces north.[3]

The bamboo should be planted as small plants, cuttings or osets, at the start of the rainy season or in the beginning of spring [3]. The distance between the plants should be approximately seven metres, which equals 225 plants per hectare. For an individual farmer it is hard to grow bamboo as a crop, the cultivation of bamboo is an industrial and commercial activity. The existing plantations in the world today are owned by cooperatives or companies. A positive aspect of growing bamboo is that it can be planted at places that normally are not put to any good use. A strip of land by the side of a road or railway can be an ideal place for growing bamboo.[5] A negative aspect of planting bamboo is the plants tendency to spread out when the rhizomes elongate fairly big distances [3].

2.5.2 Curing

When starting up a bamboo plantation the selection of the site and the species that will be planted is crucial. A market survey can identify the future uses of the bamboo and thereby help select the appropriate species. When choosing the species the local climate is also an important factor.[5]

Before planting the unwanted vegetation on the site must be taken away. The small plants, cuttings or osets can be taken from a natural forest or plant nursery. Since the bamboo owers gregariously it is advisable to use planting material from various sources to avoid the possibility to lose the entire plantation at the same time, when the plants die after blooming.[5] According to Janssen[5], it is recommendable to use herbicides during the rst two years. In the third year, the bamboo can struggle with other vegetation on its own.

2.5.3 Harvesting

While timber may need more than 100 years rotation, bamboo can normally be harvested after three to seven years [14]. The yield of a bamboo plan-tation varies depending on the location, grove management, species and the time since the previous cutting. There is no standardisation of how the yield gures should be given. Sometimes the gures are for green weight of entire plants or culms and sometimes for dried bamboo. The weight given some-times is for mature culms only and somesome-times for clear cutting of all bamboo at the site.[3]

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A bamboo management problem is the over-harvest of groves at forest edges. This is due to the fact that people often chose to harvest the culms at the shortest distance from their village. A consequence of this is that the inner part of the bamboo groves grows so thick that it is impossible to reach mature culms, ready to be harvested. [5] Since sympodial bamboos grow in clumps, it is sometimes dicult to harvest those species. The oldest culms that are ready to be harvested are often surrounded by younger culms that are still growing. The solution is to cut into the grove from the direction were the fewest young culms grow. In this way, a minimum amount of young culms have to be sacriced.[3]

According to Flores[20], there is some important aspects that needs to be considerated while harvesting bamboo:

• Do not fell culm less then three years old.

• _{If possible, harvest in winter when the insects hibernate.}

• Make the cut at a maximum height of 25-35 centimetres from ground level and always above the node. This is to avoid uid gathering in the culm that would aect the rhizomes negatively.

• Do not harm the shots and small plants that surround the chosen culm.

• _{Before felling the culm, be aware of the age of it and its future use.} • Facilitate the drying of the culm by leaving it in a vertical position,

leaning on its branches or towards a support, at the site of felling.

• Just cut the culms that has been chosen for use.

• When felling the culms, make sure to leave enough mature culms to protect the smaller plants against wind and direct sunlight.

• Remove the felled culms in 10-15 days after felling.

• Store the felled culms vertically in a covered and protected place.

2.5.4 Insects

If bamboo is not treated with wood preservatives or kept very dry, it is easily attacked by insects [39]. There are various kinds of insects that can attack bamboo. The attacks reduce the vitality of the plant and prevent the in-crement. The insects that attack the bamboo have natural enemies, which

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control the populations of these insects in natural stands of bamboo. Be-cause of this natural control of the insects, the attacks are not considered serious in natural stand of bamboo that has a good biodiversity and stable population. In Asia, more than 800 species of insects that attack bamboo has been recognized.[36]

In Asia, there exists more than 50 species of insects that can destroy n-ished bamboo products or felled culms. This should be considered a serious threat to the Asian bamboo industry because the damages can have a big economical impact, for example in big constructions.[36]

Unfortunately, in most cases the insect attacks are prevented with the help of non-environmentally friendly and poisonous products.

2.6 Anatomy and Mechanical Properties

The mechanical properties of a bamboo culm are determined by its anatom-ical structure [6]. Below, the anatomanatom-ical structure of bamboo is briey de-scribed before its mechanical properties are presented.

2.6.1 Anatomical Structure

According to the anatomic study of bamboo made by Liese[6], the variation between dierent bamboo species can be seen as rather small. These dif-ferences between the species are of taxonomic value and they have inuence on properties and processing. Bamboo has no radial cells, like trees have rays, to transport liquids and nutrients. In the bamboo plant it is the node that provides the transportation of those substances. The outer part of the culm, the cortex, acts as a tissue protector and water blockader. The cells are dierent in dierent part of the culm; they are vertically along the culm length and transversally across the culm wall.[6]

Structure of the Internode

Most species possess hollow internodes where a culm wall is surrounding a large cavity, but few species have solid internodes. A culm consists of approx-imately 52 percent parenchyma, 40 percent bres and 8 percent conducting tissue. The outer third part of the culm contains about 50 percent of all the bres of the stem.[6]

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Structure of the Node

The nodes of a bamboo culm are the repeated scars in the sheath that covers the whole culm. A young bamboo has white nodes which can clearly be seen in contrast to the green internodes.

The cells in the nodal area dier signicantly in size and form from the cells in the internodes [6]. The essential chemical components of bamboo are cellulose, hemicellulose and lignin [10]. Hemicellulose and cellulose make up more than 50 percent of the total chemical components in bamboo [7]. Lignin is also an important chemical component which acts as a binder for the cellulose bres.[10]

The nodes have an immense inuence on the mechanical strength of the culm. The shorter bres and distorted vascular bundles of the node lead to higher density, lower volume shrinkage and lower tensile strength than the internodes.[6]

2.6.2 Mechanical Properties

Bamboo is an anisotropic material; the properties in the longitu-dinal direction are completely dierent from those in transversal direction. In the longitudinal direction there are the cellulose bers, which are strong and sti. In the transversal direction there is lignin, which is soft and brittle. Therefore, bamboo is a unidirectionally reinforced composite with comparatively little tangential capacity.[5]

The density decide the mechanical properties of a culm [6]. According to the studies of Liese[6], the density of the bamboo depends on the bre content, bre diameter and cell wall thickness. Therefore the mechanical properties vary signicantly within a culm and between species. The density varies ap-proximately between 0,5 and 0,9 g/cm3_{. The bre distribution varies in the} culm; the outer part of the culm has denser distribution of bres than the inner part, see Figure 2.8, which means that the outer part has a far higher density than the inner part.[6]

The base is the hardest and most resistant part of the bamboo culm [13], and the bending strength is two to three times higher on outer parts than inner parts. The density increases upward the culm, thanks to the thinner culm wall with a higher compactness of vascular bundles. Older culms have

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Figure 2.8: Microscope picture of Guadua chacoensis.

higher density than young culms.[6] In Table 2.1 some mechanical properties of bamboo can be seen.

Density [kg/m3_] _600-800 Young's modulus [MPa] 15 000-20 000 Tensile strength [MPa] 160-320 Compressive strength [MPa] 60-100 Flexural strength (modulus of rupture) [MPa] 80-160 Elongation [%] 2.88-3.52

Table 2.1: Mechanical properties of bamboo [33].

In spite of the fact that bamboo is a grass, it has many similarities to wood. The cell construction and the properties of bamboo resemble the structure of wood. Like earlier mentioned, the bamboo culm is harder on the outer parts then the inner. The wood has reverse structure with a hard cen-tre and is weaker in the outer parts. This is an advantage for bamboo, which grounds a more stable construction.[42] Another advantage is that bamboo does not have rays liker woods. Rays are channels necessary for

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transporta-tion of food, mainly sugar, but they weaken the material. This leads to the fact that bamboo often is stronger than wood.[5]

When bamboo is being compared with construction steel, one important aspect is that constructing in steel needs 50 times more energy than bamboo. Bamboo is a good alternative to steel when it comes to tensile loading. This is due to the fact that bamboo has a six times higher quotient between tensile strength and density than steel. When the humidity content increases the physical and mechanical properties also increases.[11]

2.7 Renement Techniques

When it comes to the processes of rening bamboo, very few books and articles are available. This is the result of that the knowledge about how to rene bamboo in traditional ways, has been passed on from father to son for centuries. The knowledge has not been transcribed to be published and spread to others. The following section gives a very brief overview of the most common renement techniques.

2.7.1 Drying

Depending on the species, site of growth and felling, a green bamboo culm can have very high moisture content. In comparison to wood, bamboo take longer time to dry and since there is a risk of deformation a quick drying is preferable.[28]

Kiln Drying: Whole culms that are kiln dried often shows cracking and therefore kiln drying is not recommended in these cases. However, kiln dry-ing is usable for split bamboos.[28]

Air Drying: Depending on the initial moisture content in the culm and the wall thickness, air drying takes approximately six to twelve weeks. In some species non-uniform shrinkage and excessively shrinkage causes collapse that makes the culm useless. Those problems are most often seen in drying of young culms, hence it is recommended that only mature culms are used for drying. Fewer problems are seen in drying of split bamboos. Split bamboos can even be dried in open sun-light without any problems. To accelerate the drying of whole bamboos they can be dried in an upright position, see Figure 2.9. Split bamboo can protably also be dried placed in an upright position.[28]

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Figure 2.9: Bamboo culms drying.

2.7.2 Cutting

The easiest way to cut bamboo in desired lengths is with a saw [3]. It is im-portant that the tools are sharp, since this prevent tearing and splitting [4]. A common belief in many countries where bamboo grows, is that the phase of the moon during which the bamboo is felled, is correlated with the possibility to latter insect attacks. There is no scientic basis to this belief.[4]

2.7.3 Splitting

Dierent splitting techniques have been developed in dierent countries. Those are often very simple and depending on the thickness of the culm wall, dierent tools are used.[4] The most common tool for splitting bamboo is a sharp machete. The blade is forced through the culm to separate the pieces from each other. To be able to fasten the process of splitting bam-boo, techniques have been developed for dealing with large amounts of raw material.[3]

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2.7.4 Bending

According to Farrelly[3], bamboo can be bent by heating it or by soaking it rst. When heating the bamboo, the mortar holding the bers becomes exible and it is possible to bend the material to a desired shape. The shape to which the bamboo is formed is preserved after cooling.

2.7.5 Joints

The best placements for joints are near nodes, since the internodes are hol-low and can therefore break relatively easy. Making joints in bamboo is not trivial since the culm is hollow, not perfectly circular and has nodes at vary-ing distances. All these restrictions have to be considered while designvary-ing a joint.[5] Typical jointing can be seen in Figure 2.10.

Janssen[5], arranges the dierent joints into eight groups, depending on how the jointed pieces are arranged in relation to each other, and if jointed from the inside or outside of the culm. In the groups, dierent ways of putting the pieces together exists; lashes of dierent types and pins of steel or wood. Four of the groups Janssen mentions are:

• Full cross section. This group is characterized by contact of the full cross-section of the bamboo culm. Mostly lashing is used to keep the bamboo culm in position.

• From inside to an element parallel. In most cases, the hollow of the bamboo is lled with material like cement, mortar or a piece of timber, after which the jointing moves into the better known area of joints between steel bars or wooden pieces.

• From inside to an element perpendicular.

• For split bamboo. This too is a modern development. Thin pieces of galvanized steel fastened with nails. Used in prefab-ricated housing. Besides glue, nails or pieces of galvanized steel also can act as jointing material.

Janssen[5], further tells that scaoldings made of jointed bamboo culms, are an extraordinary example of good jointing. The culms are jointed to-gether with lashes of bamboo and it is important to apply the strips wet, so that the shrinkage leads to a perfect bonding.

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Figure 2.10: Bamboo joints.

2.7.6 Laminating

In general, laminated bamboo boards are manufactured from monopodial bamboos. The boards are close to wood when it comes to the qualities and appearance. Laminated bamboo is very suitable for ooring and fur-niture and can replace wood in doors and window-frames and many other applications.[8]

The process of laminating bamboo begins with the translation of the bamboo culms into strips with a uniform rectangular shape. After drying the strips into the right moisture content an adhesive is applied on the sides of each one. The strips are pressed together to get a good bonding. When laminating, the strips can be placed against each other in two dierent ways.

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Depending on the position of the strips the laminate is denominated vertical or horizontal.[8] In Figure 2.11 vertical and horizontal laminates can be seen.

Figure 2.11: Vertical and horizontal laminates.

When manufacturing bamboo laminates, the wall thickness and the di-ameter of the culm have inuence on the manufacturing process and the end result. These two parameters limit the size of the bamboo strips which are glued together when making laminates. According to Bansal et.al [8], the colour of the laminate can be darkened by steaming the bamboo strips be-fore drying them. The temperature of the steam and the time of steaming decide the nuance developed. A higher temperature and a longer steaming time gives a darker colour.[8]

2.7.7 Surface Treatment

The nishing method depends on the end-use of the bamboo and also the specic product. Some possible surface treatments are smoking, lacquering and painting.[4]

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2.8 World Market

The bamboo world market had in 2003 reached a level of 10 billion US dollars and is growing, thanks to the increasing demand of environmentally friendly green bamboo products. Today the bamboo industry has an important role in providing food, housing and income generation for about 2.2 billion people in the world.[19]

The world population and economy are growing at the same time as the demand for wood and wood products are increasing and the world forests are shrinking. One possible solution to this problem is broader exploitation and use of wood substitutes.[14] Bamboo has an immense potential as wood substitute as it is fast growing. In this area, as wood substitute, bamboo's potential is strengthen by the fact that it is a wide spread, low cost and environmental friendly plant.[19] Suitable areas for further development and penetration are ooring, furniture, buildings, constructions, panels, paper and bamboo for plywood.[12]

2.9 Bamboo Uses

In terms of diversity, distribution and uses, bamboo is the unri-valled leader in the world of plants. There are over 1 500 docu-mented uses for bamboo, and more are being discovered by mod-ern science and technology.[6]

Bamboo can be rened in small craft based companies at village level but also in more modern high technological industries. Bamboo and bamboo bre can be used in a wide range of applications, from simple handicrafts to more advanced bre-based products.[19]

2.9.1 Constructions

Bamboo products are hard and durable, which makes the material a suit-able substitute for wood in many elds of application. One example is constructions.[12]

Bridges: In China and Asia there are bamboo bridges of many designs. Cables of bamboo bres were the rst material used for suspension bridges. Five centimetres thick bamboo cables can be spanned up to 76 metres and manage to support four tons without central support.[3]

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Waterstorage: Cement tanks reinforced with bamboo have been used as an alternative to aluminium tanks. The cement tanks proved to be four times cheaper than galvanized steel tanks of equal size. Other uses are wa-terwheels, water pipes and water systems.[3]

Fences: Farrelly[3], gives examples of how bamboo can be used in the garden; functional walls around properties, fences for animals and decora-tion. In Figure 2.12 a typical fence for animals can be seen.

Figure 2.12: A fence of bamboo in Bolivia.

Scaolding: In many countries in Asia is bamboo used for construction of scaoldings. In comparison to steel scaolding, the scaolding made out of bamboo are well known for its low costs and ability to resists hurricanes.[5]

Cases are known wherein bamboo scaolds survived hurricanes that blew away steel ones as if they were matchsticks.[5]

In spite of these advantages, bamboo scaolding faces strong competition from steel scaolding. If bamboo scaolding is going to be spread to other parts of the world it is very important with a standardized system.[5]

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2.9.2 Buildings

Since hundreds of years, bamboo is used for constructions like houses, build-ings and other structures [15].

Housing: The qualities and distribution of bamboo make it an excel-lent material for easy built and cheap houses. Like earlier mentioned, it is a lightweight material with a strength that is large in relation to its weight.[5] Today approximately one billion people in the world live in bamboo houses [9]. One negative aspect is that the bamboo should not be in contact with wet soil, see Figure 2.13. Therefore the bamboo culms need to be extended at the lower end, for example with concrete, to prevent decomposition.[5]

In many parts of the world bamboo is still considered as the poor mans timber and Janssen[5], writes about examples were people have made their bamboo houses look like concrete houses. These processes, mixing bamboo with concrete, weaken the structure of the houses and expose the lives of the people living there to danger. The problem is the bonding between the bamboo and the concrete. The bamboo wants to absorb water when the concrete is poured around it. When the concrete dries and gets harder, the bamboo also dries and shrinks.

Janssen[5], gives an example of a calculation that has been made. It is calculated that 70 hectare of bamboo plantation is sucient to build 1 000 bamboo houses per year. If these houses were built with timber instead, 600 hectare of natural forest would have been devastated each year.

Storerooms: One also important area that Farrelly[3], writes about is how bamboo is being used for building simple, low-cost, small-scale systems for storage and preservation of crops. These storerooms are important for enlarging the supply of food and make it more available to people.

Temporary Shelter: Bamboo is also a well suited material for building temporary shelter that can be put up in only a few hours.[3]

2.9.3 Plybamboo, Laminate and Furniture

Plybamboo: Plybamboo is plywood made of bamboo. A positive aspect is that the process of manufacturing plybamboo can start at village level and end up in a modern factory.[5]

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Figure 2.13: A bamboo veranda.

Laminate: A future possible large eld of application is laminate. New techniques of lamination can be of importance to modern industrial design.[3] Examples of applications for bamboo laminate are furniture and ooring.

Furniture: Bamboo has since a long time been used for furniture, often it is the straight culm that is used. Furniture is a good example of a product that can be made with simple tools at village level.[5]

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2.9.4 Paper

Paper made out of bamboo has a nearly two thousand year long tradition in Asian countries. The rst seventeen hundred years the paper was made by hand. The following centuries new methods and processes for paper making were developed, and today India leads the bamboo paper production.[3]

Bamboo matures very fast in comparison with woods. This leads to the fact that bamboo can provide two to six times as much cellulose per area compared to pine. It is predicted that the quantity of bamboo pulp will increase dramatically because of the advantages bamboo has.[3]

2.9.5 Ecomaterial

Bamboo has several important ecological roles such as ood tamer, soil binder, windbreaker and earthquake neutralizer. It can also be used for fuel production and as carbon dioxide converter.

Fuel: Farrelly[3], explains that bamboo is an environmental friendly ma-terial and that the harvesting does not disturb the soil, which makes it well suited for fuel production. Another positive aspect is that bamboo is a re-newable energy source with an annual increase of 10 to 30 percent.

Carbon dioxide converter: Bamboo consists of cellulose and lignin that both contain much carbon. This means that bamboo needs a lot of car-bon to grow. Bamboo acts as a carcar-bon dioxide converter that absorb carcar-bon from the air and store it in a process called carbon sequestration.[5]

Bamboo generates up to 35 percent more oxygen then the same amount of trees [30]. In a project run by the Environmental Bamboo Foundation, individuals are given a way to balance their personal carbon dioxide output by buying a share of a bamboo forest.[29]

2.9.6 Other Uses

Because of bamboo's rich amount of elds of application all uses can not be mentioned. But some other uses of bamboo worth mentioning are: food, health products, medicines, decoration and utensils.

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2.9.7 Recently Developed Uses

Ford Motor Company has recently presented a concept car, see Figure 2.14, with a futuristic combination of materials: bamboo, aluminium and carbon-bre. On the Tokyo motor show 2005 the car company Chrysler presented an idea of a future car, see Figure 2.14, with interior in recyclable material and bamboo ooring.

Figure 2.14: Ford concept car [32], and Chrysler future car [35]. The computer hardware company Asus has developed an eco-friendly lap-top, see Figure 2.15. The laptop case is covered in bamboo and all the plastic in it is labelled and recyclable. There are no paints or sprays used on its com-ponents and the upgrading of comcom-ponents has been made easier.

Figure 2.15: Asus eco-friendly laptop with a bamboo case [38]. The Finish furniture company Artek has recently released a collection of bamboo furniture, consisting of tables and chairs, see Figure 2.16.

For spring 2007, the clothing rm Northface added new bamboo clothes to their ecoCloth Collection. The cloths consists of cotton and bamboo bres.

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Chapter 3 Method and Performance

The following chapter describes the method and performance of the Master thesis. The delimitations of the thesis are also presented.

3.1 Research Approach

Bamboo is probably the fastest-growing and highest yielding nat-ural resource and construction material available to mankind [18]. In spite of the statement above, bamboo has not yet reached its fully po-tential in Europe. Just recently, European engineers and designers have dis-covered this multifunctional highly environmentally friendly material. Both authors of this Master thesis are students of Industrial Engineering, spe-cialised in Wood Technology. Although bamboo is a grass, this material is highly interesting to anyone working with wood and wood-products. During autumn 2006 the authors of this report read several articles about the intro-duction of bamboo products on the Swedish market, mostly ooring, hence the interest of studying bamboo for the Master thesis. The fact that bam-boo does not grow in Sweden and the co-operation beteween the University of Linköping and UPSA led to the choice of going to Bolivia to learn more about bamboo.

3.2 Pre-Study Phase

The Pre-study phase began in Sweden in January 2007 at the University of Linköping. During spring, litterature studies were carried out to obtain more knowledge about bamboo. Both books and a large number of academical articles were reviewed. Preliminary contacts in Bolivia were established to

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be able to visit forest communities and companies working with bamboo in the Santa Cruz region. In April the same year the authors attended to a course in Gothenburg, which was arranged by Sida, to get information about how it is to live and work in a developing country.

3.2.1 Brainstorming

Once in Santa Cruz the research objective of the Master thesis was to be decided. The authors brainstormed about possible areas to work within to be able to determine the course of the study. The brainstorming was carried out together with Mr. Luis Fernando Ortiz, an Industrial Engineering student at UPSA, also doing his Master thesis on the subject of bamboo.

3.2.2 Mind Map

The brainstorming process was summarized in a mind map, see Figure 3.1, to give an overview of the conceivable areas of the study. The subhead-ings are listed without any relative order. Some areas discussed during the brainstorming process are not included in the mind map due to their vague relevance for the thesis's outcome.

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3.3 Evaluation of Possible Working Areas

After summarizing the possible working areas in the mind map, an evalua-tion of each category was made. This evaluaevalua-tion was conducted verbally by the authors together with Mr. Luis Fernando Ortiz. The possible working areas were discussed and evaluated with consideration for the relevancy and the accessible resources, both monetary ones and those concerning the space of time, for the Master thesis. Furthermore, the authors personal interests were taken into account when choosing the working area of the thesis.

The country's lack of information about the mechanical properties of native bamboos lead to the choice of studying this area. After the discussion and evaluation of possible working areas the objective in Section 1.2 was formulated.

3.4 Delimitations

The thesis's frame of reference, in Chapter 2, is deliberately extensive to get a wide-ranged knowledge about bamboo. This makes it necessary to delimitate the research to a specic objective hence many interesting areas described in the frame of reference are not further investigated. The total amount of time accessible to carry out the Master thesis is 20 weeks, 13 of those consists of the eld study in Santa Cruz. The restricted time-frame and the available equipment constitute themselves in important limitations for the research work.

The authors chose to study the mechanical properties of Guadua chacoen-sis, a bamboo species native to Bolivia. A brief study of the uses of Guadua chacoensis will be carried out. No market research will be made concerning bamboo. The market of bamboo products will only be briey discussed. There are no existing standards about how to conduct mechanical properties test of bamboo. Therefore the authors used standards for wood as a guid-ance. Due to the limited time and resources the number of specimens tested had to be limited. For the same reasons the mechanical tests were limited to; tensile test parallel to bre, bending test and hardness test perpendicular to bre.

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3.5 The Field Study

Between 4th of July and 19th of September 2007 the authors were stationed in Santa Cruz, Bolivia, to carry through the eld study. Cadefor oered the possibility to a working place at their head quarter oce in Santa Cruz and the knowledge and experience of the employees was available during the whole stay. UPSA made laboratory equipment available to facilitate the mechanical properties tests supervised by Gastón Mejia, Jorge Zeballos and Gustavo Quinteros. The contacts in Santa Cruz, made by the University of Linköping, and intermediated by Stig Algstrand, were used to get useful information about bamboo in Bolivia.

During the eld study theoretical studies were made, collecting local and international information about bamboo and Guadua chacoensis in particu-lar. The laboratory tests were prepared and conducted during a period of nine weeks. To get a deeper understanding of the material and its origin several localities of the plant were visited, among them Buena Vista and Ascención de Guarayos.

3.6 Analysis

The results of the mechanical properties tests were analysed through compar-ison with corresponding mechanical properties of oak, birch, ash, beech and pine. To give further references to the reader some comparison with steel and aluminium alloys were made. Steel and aluminium are common construction materials and are also used in many other applications that are the same as for bambu. Since there exist many dierent steels and aluminium alloys the comparison was made with the types that have uses similar to those for bamboo.

To be able to analyse the future possibilities of Guadua chacoensis in Bo-livia a SWOT-analysis was made followed by brainstorming, where dierent elds of application were discussed.

3.7 The Quality of the Study

To be able to utilize the results given by this Master thesis in a suitable way, it is important to do an analysis of the quality of the study. The validity and the reliability of the thesis are discussed in the following section.

Guadua chacoensis in Bolivia