Bamboo research and development in Thailand - Rungnapar Pattanavibool

Scientist, Royal Forest Department, Bangkok, Thailand.

Topography

Thailand is located in the central part of the Indochina Peninsula, between latitudes of 5°37N and 20°27N and longitudes of 97°22'E and 105°37'E. The total area of the country is 513 115 km². The longest dimension of the country is 1640 km which is measured in the North-South direction from Amphoe Mae Sai in Chiang Rai to Amphoe Betong in Yala. The widest as well as the narrowest dimensions of the country are found in East-West direction. The widest dimension measured from the Three-Pagoda Pass at Amphoe Sangklaburi in Kanchanaburi to the Mek Pass at Amphoe Phibun Mangsahan in Ubon Ratchatani, is 780 km. The narrowest area of the country is only 64 km. It is named the Isthmus of Kra and located at Ban Wang Duan in Prachuapkhiri Khan.

The country shares its borders with 4 neighbouring countries (Fig. 1); Myanmar to the north and west, Laos to the north and northeast, Kampuchea to the east, and Malaysia to the south. The land boundaries with Myanmar, Laos, Kampuchea, and Malaysia are 2202, 1750, 798, and 576 km long, respectively. The narrow strip bordered by a long mountain chain in the west separates the country from the east Myanmese territory. Thai-Laos boundary includes both land and Maekong River boundaries, with total lengths of 640 and 1110 km, respectively. In addition to land boundaries, the country also has coastal boundaries along the Gulf of Thailand and the Andaman Sea which are 1878 and 937 km, respectively.

The country can be divided by topography into five major regions: North, Northeast, Central-West, East and South (Fig. 1). The upper part of the country is hilly where the four main tributaries of Chao Phraya River flows southward, the important river of Thailand. The Chao Phraya flows through the alluvial plain of the central part of the country to the Gulf of Thailand. This results in the formation of a great central plain of the alluvial fan known as the Chao Phraya Delta. The long stretch of the peninsula southwards separates the Pacific Ocean from Andaman Sea to the West and the Gulf of Thailand to the East. One third of the upper part of the land mass forms a large plateau stretching eastwards which is known as the Northeast Highland or Korat Plateau sloping eastwards to the famous Maekong River.

Fig. 1. Map of Thailand, five regions

Climatic conditions

The climate for the whole country is influenced by the Southwest monsoon during the wet season (May-November) and the Northeast monsoon during the dry season (December-April). The distribution of wet months ranges from 2 to 7 months yearly, with about 1000-4000 mm of annual rainfall. In some areas, the day temperature may reach 42°C during the dry season, during March and April, and may drop to 0-10°C in the cool-dry season, from December to January. However, the average temperature of the whole country all the year round ranges from 24 to 34° C.

Population

The Thai population reached 60 million in January 1997. Annual growth rate in 1995 was approximately 0.6% (Data Center 1995). Ethnic Thais comprise about 75% of the population; 14% are Chinese, and the rest are Malays, Khmers and hill tribesmen.

Forest types and forest areas

Forests of Thailand can be broadly classified into two main types, Evergreen and Deciduous forests, based on dominant and subdominant species of the top canopy. The Evergreen forests include Tropical Evergreen forests, Hill Evergreen forests, Dipterocarp forests, Coniferous forests and Mangrove forests whereas those included in Deciduous forests are Mixed Deciduous forests and Dipterocarp deciduous (or Dry Dipterocarp) forests. Minor forest types such as Scrub forests, Beach forests and Swamp forests are found in some particular areas. Tropical Evergreen forests are the richest in their total species and a high proportion of Dipterocarpaceae is commonly found covering over 55% of the area. However, the occurrence of the Evergreen forests is limited to only some areas where the moisture is adequate. The Deciduous forests dominate the greatest forest areas in Thailand (Table 1). Both Mixed and Deciduous Dipterocarp forests are found throughout the country, except in the South. Many commercially important species, including Dipterocarpus spp., teak and bamboos, are commonly found in the deciduous forests.

Table 1. Forest type and area in each region of Thailand (1982)

Source: Data Center, Royal Forest Department, 1996, Ramyarangsi, 1987.

Type of Forest	North (km2)	Northeast (km2)	East (km2)	Central (km2)	South (km2)	Total (km2)
Evergreen forest	25 568	9 305	6216	12 449	14 323	67 861
Mixed deciduous forest	25 006	2 618	1 113	5 192	0	33 929
Dry dipterocarp forest	34 318	13819	253	540	0	48 930
Mangrove forest	0	0	418	335	2 119	2 872
Pine forest	2018	144	0	0	0	2 162
Grove forest	846	0	0	0	0	846
Total	87 756	25 886	8 000	18 516	16 442	156 600

Forests are sources of timber, wood products, food, fuel and other minor forest products as well as medicinal plants. These products were amply available in the past for domestic consumption and for export but their supply is dwindling at present due to over exploitation, mismanagement and uncontrolled expansion of shifting cultivation areas. Major losses of the forest lands in Thailand occurred during last 40 years. The forest area was about 50% in 1951, which was reduced every year and is now only 25.6% (Table 2). To increase the forest areas in Thailand, the government banned logging since 1989, and since then reforestation as well as management and development of the forests and degraded lands have been promoted.

Land use pattern

Being an agricultural country, approximately 78% of the land is used for farming. Presently, the major exports of agricultural commodities such as rice, maize, cassava and so on reflect the country's dependency on agriculture in spite of its reputation as a teak timber exporter during the last two decades. It is well recognized that while agricultural farm lands increase year by year the forest lands decrease at an alarming rate leading to the shortage of wood and fuel materials and has caused environmental deterioration. Rapid depletion of forests during the past ten years in the tropical zone, especially in Southeast Asia, caused great loss of species and diversity of plant resources. The deforestation crisis, certainly, caused the reduction of abundance of bamboos.

Distribution and utilisation

In Thailand, bamboo is one of the most socioeconomically important species. They grow incredibly fast and well known as “pioneer species”. They can rapidly invade into any kind of land, including degraded areas/Being pioneer species, they are frequently found in open land throughout the country (Figs. 2 and 3). They are normally found associated with teak (Tectona grandis) trees in Mixed deciduous forests. Those species are Dendrocalamus membranaceus and D. strictus. Some species of bamboos, e.g. Dendrocalamus brandisii, D. giganteus and Cephalostachyum pergracile grow in Tropical evergreen forests while Thyrsostachys siamensis, occasionally grows in Dipterocarp deciduous forests. Bamboos are multipurpose species for many uses of basic living including food, household construction, supporting poles, baskets, handicraft making, firewood and paper pulping, etc.

There are 13 genera and 60 species of bamboos recorded in Thailand and most of them are “sympodial type”. A list of 10 important commercial bamboos species in Thailand is shown (Table 3).

The important species of bamboo in Thailand may be divided into three groups according to their utilization; for shoot and stem production.

1. Bamboos for shoot production (for food) such as Dendrocalamus asper (Pai Tong), D. brandisii (Pai Bongyai), D. strictus (Pai Sangdoi), Bambusa blumeana (Pai Seesuk), Thyrsostachys siamensis (Pai Ruak), T. oliverii (Pai Ruakdum) and Gigantochloa albociliata (Pai Rai).

2. Bamboos for stem production (for construction and supporting poles) such as B. bambos (Pai Pha), B. blumeana, B. nana (multiplex) (Pai Liang), D. asper, D. strictus, D. membranaceus (Pai Sangnuan), T. oliverii and G. hasskarliana (Pai Phaak).

3. Bamboos for stem production (for basketing and handicraft) such as B. blumeana, B. nana, T. siamensis, T. oliverii, G. hasskarliana, Schizostachyum humilis (Pai Griab) and Cephalostachyum virgatum (Pai Hiae) (Figs. 11-13).

Planting by rhizome: Propagation of bamboo is well known and planting of culms with attached rhizomes (offset planting) is the best method. The most vigorous sprouting activity is seen in one-year-old culms (after budding). Cut culms with two to three nodal buds are planted in the soil which produce rhizomes, roots and culms. This method is successful in bamboo species with thick walls such as Thyrsostachys siamensis and Melocalamus compactiflorus.

Table 2. Forest Area in Thailand from 1985 to 1995

Source: Data Center, Royal Forest Department, 1996

Region	Total Area	National Forest Reserves	Forest area
			1985		1988		1989		1991		1993		1995
	(km2)	(km2)	(km2)	%	(km2)	%	(km2)	%	(km2)	%	(km2)	%	(km2)	%
North	169 644.288	111 964.78	84 126	49.59	80 402	47.39	80 222	47.29	77 143	45.47	75 231	44.35	73 886	43.55
Northeast	168 854.333	55 333.40	25 580	15.15	23 693	14.03	23 586	13.97	21 799	12.91	21 473	12.72	21 265	12.59
Central and West	67 398.703	20 414.15	17 685	26.24	17 244	25.59	17 233	25.55	16 616	24.65	16 408	24.34	16 288	24.17
South	70 715.187	28 183.15	15 485	21.90	14 630	20.69	14 600	20.65	13 449	19.02	12 808	18.11	12 455	17.61
East	36 502.500	14 474.91	7 990	21.89	7 834	21.46	7 786	21.33	7 691	21.07	7 634	20.91	7 591	20.80
Whole Kingdom	513 115.011	230 370.39	150 866	29.40	143 803	28.03	143 417	27.95	136 698	26.64	133 554	26.03	131 485	25.62

Table 3. Ten important commercial bamboos in Thailand

	Local name	Botanical name
1.	Pai Tong	Dendrocalamus asper Back.
2.	Pai Ruak	Thyrsostachys siamensis Gamble (Syn. T. regia Bennet)
3.	Pai Seesuk	Bambusa blumeana Schult.
4.	Pai Liang	B. nana Roxb. (Syn. B. multiplex Raensch)
5.	Pai Ruakdum	T. oliveri Gamble
6.	Pai Pha	B. bambos Voss
7.	Pai Saangnuan	D. membranaceus Munro
8.	Pai Saang	D. strictus Nees
9.	Pai Wan	B. burmanica Gamble
10.	Pai Kaolaam	Cephalostachyum pergracile Munro
more species	Pai Rai	Gigantochloa albociliata Kurz
	Pai Bongyai	D. brandisii Kurz
	Pai Phaak	G. hasskarliana
	Pai Griab	Schizostachyum humilis
	Pai Hiae	Cephalostachyum virgatum Kurz

Growth of culms is good at the onset of monsoon (June to October). The new rhizomes and culms generally develop from the one-year-old parent culm. About three to seven large buds of the one-year-old parent culm tend to grow simultaneously but only one or two of them would grow completely. This is the limitation of rhizome plantings. Besides this method of propagation is too expensive for large-scale plantations. However, a rhizome can be well utilized by skillful cutting or fertilizing.

Culm cutting: This is an effective method for propagating thick-walled and large-sized bamboos (8-12 cm in diameter) such as Bambusa blumeana, B. vulgaris, Dendrocalamus latiflorus, etc. One-year-old culms are suitable for culm cutting. The cuttings should have one or two nodal segments. For single node propagation, culms about 40 cm long with a node in the middle are used as explants. They are planted at an angle of about 45° and at a depth of 20 cm in the rooting medium. Node sections are placed at the same level of the rooting media with a bud exposed on the top side. Watering is done twice a day. Sprouting of new shoots can be seen after two to four weeks. Water, fungicide and insecticide are regularly applied for 6-12 months before transplanting.

This method is not very popular because it is expensive. In addition, there is limitation of using one-year-old culms which can be put to other uses.

Branch cutting: Propagation by branch cuttings is a useful, practical and effective method. It is a good method for raising commercial large-scale plantations as in the case of Dendrocalamus asper. The species has aerial roots at the base of the lateral branch. Bigger branches have more potential for rooting than small ones. Rooting is abundant in rice husk charcoal medium, the roots are slender, thin and long, whereas those in soil are bigger and clustered. The rooting efficiency of each species is different and depends on culm size and wall thickness. Thick-walled bamboos posses potential for higher sprouting and rooting probably due to more food reserves in the culm.

Propagation by tissue culture techniques: Tissue culture research on bamboos was carried out in the Central Laboratory of the Division of Silviculture, Royal Forest Department. The investigation can be divided into two parts, one dealing with callus induction and differentiation, and the other with multiple shoot induction.

Callus induction and differentiation

This study was conducted to induce callus from nodes of aseptic seedlings of Dendrocalamus membranaceus. Mature seeds collected from Kanchanaburi province were surface-sterilized with 75% ethanol for one minute dipped into 10% sodium hypochlorite solution for 15 minutes and then rinsed thoroughly in sterile water. Seeds were aseptically cultured on a medium containing MS components. Cultures were kept under fluorescent light of 2000 lux, in a 12/12 h day/night regime and at a constant temperature of 25 ± 2 C. Nodal segments of aseptically grown seven-day-old seedlings were cut to 2-2.5 cm and implanted on semi-solid MS media containing different concentrations of 2,4-di-chlorophenoxyacetic acid (2,4-D) ranging from 0 to 8 X 10^-5M and 6-benzylaminopurine (BAP) from 0 to 0.8 X 10^-5M. Callus formed in 4-6 weeks on medium containing 1 to 1.5 X 10^-5M of 2,4-D and 0.2 X 10^-5M of BAP. On media with higher concentrations of 2,4-D, the callus developed slowly with dark brown soft masses. After six to seven months, the white and fresh callus was transferred to a medium with a lower concentration of 2,4-D (0.5 to 1 X 10^-5M). Embryogenic callus formed within three to four months.

Multiple shoot induction

The experiment was conducted to investigate the sprouting possibilities of Dendrocalamus membranaceus and D. brandisii seeds. The seeds of D. membranaceus were cultured in MS basal media supplemented with BAP at different concentrations ranging from 0 to 6 X 10^-5M, with 1% agar and 3% sucrose. After 15 days the seeds germinated and produced multiple shoots in all media containing BAP. The best result was obtained with 2 X 10^-5M BAP in which three to five multiple shoots were produced 1 to 3.5 cm in length. However, after three weeks the base of seedlings turned brown. Subculturing was done every month on the same medium. The maximum number of multiple shoots (25-30 shoots) were obtained in the medium supplemented with 0.5 to 2 X 10^-5M of BAP within three to four months. Concentrations of BAP higher than the optimum level produced lower number of multiple shoots. However, rooting was not obtained in this medium. For rooting, MS medium with 1 X 10^-5M NAA was used. The use of BAP in the root induction media inhibited root formation.

In case of D. brandisii, vigorous multiple shoots (20-30) could be induced in MS medium supplemented with 2 X 10^-5M of BAP. The multiple shoots showed sustained growth when subdivided and transferred to fresh medium of the same composition. Root formation occurred when the multiple shoots were transferred to MS medium containing lower BAP concentrations or to basl MS medium without any growth regulators. Rooting could also be induced in sterile vermiculite soaked with water. The plantlets were suitable for transplanting in soil after 4 months and grew well under nursery conditions.

Many of the plants raised by tissue culture are growing in the field. No abnormalities are noticed even after 4-6 years.

Bamboo research station

A cooperative bamboo research programme in Thailand was initiated in 1965 between the United Nation Development Programme (UNDP) and the Royal Forest Department (RFD) of Thailand. The major objective of this programme was to estimate the annual production of bamboo for pulp and paper industries. The estimation was made on resources in natural forests, particularly in the Western part of Thailand. A research centre was set up in Kanchanaburi province where bamboo is the dominant forest species (Figs. 2, 3). In this research programme, a series of studies on ecological aspects and the management of bamboo forests, vegetative and the generative propagation of bamboo, techniques of bamboo plantation establishment, etc. were intensively conducted. In 1972, the joint UNDP/RFD bamboo research project was terminated and bamboo research activities since then have been operated solely by the RFD.

Since 1983, the RFD bamboo research programme received support from the International Development Research Centre (IDRC) of Canada. The major objective of this programme was to establish living bamboo collections as sources for establishing future bamboo plantations as well as demonstrate establishment to farmers. The living bamboo collections were established and model bamboo plantations (or bamboo farms) were set up in 4 locations representing each region of the country. Apart from the plantations for research, bamboo arboreta or bamboo gardens were also established in many areas along the highways throughout Thailand by Department of Highways. These arboreta are very useful for studying bamboo growth as well to provide materials for propagation. In addition to the establishment of bamboo plantations, a number of studies on propagation including sexual, vegetative as well as tissue culture, genetics, taxonomy, flowering phenomenon, silvicultural practices, eco-physiological aspects, utilization and preservation of bamboo wood etc. were conducted. Main institutes responsible for research studies and projects are Kasetsart University and The Royal Forest Department, Bangkok.

Bamboo seeds are collected in Kanchanaburi area every year. At the research station they are sorted separating the good seeds from bad ones, packed in plastic bags and sent to headquarters in Bangkok, where they are stored in cold room (Figs. 6-10). Some of the seeds are illustrated. Bamboo splits are used for making baskets (Figs. 11-13).

Private plantations

Dendrocalamus asper is not a native of Thailand. It was introduced to the country approximately 70 years ago (personal communication with farmers, Tanurak 1996), and is the most important species for shoot production (Figs. 4, 5). It was primarily planted in Prachinburi province where it grows very vigorously and abundantly. It is a well adapted species to local conditions. In 1994, the cultivation of this species was extended covering 67 provinces out of the total of 76, with a total planting area of 424 169 rai (1 rai = 0.16 ha) (Table 4). At the end of 1994, this species flowered and died throughout Thailand. The flowering crisis brought an economic disaster to bamboo shoot production in the country. The export of bamboo shoot products, mainly of D. asper, involved more than thousand million bahts in 1996 and 1997 (Table 5). This resulted in Thailand losing that much revenue in 1998 and following years. A new cycle of this bamboo species, was started using seeds in 1995. Thai government is supporting many projects to recultivate this species and support Thai farmers in different provinces.

Table 4. New planting areas and yields of Dendrocalamus asper in Thailand from 1990 to 1994

Source: Tanurak, 1996

Items	Year
	1990	1991	1992	1993	1994
Total area (rai)	180 155	236 426	344 296	391 499	424 169
Ave. shoot production (kg/rai)	1 309	1 312	1 338	1 343	1 353
Total shoot production (ton)	131 490	172 805	206 678	259 614	300 518
Ave. stem production (ton/rai)	3 850	3 855	3 848	3 852	3 858
Total stem production (ton)	497 840	612 720	767 480	997 310	1 221 071

Table 5. Quantity (ton) and value (million baht) of bamboo shoot exportation from 1990 to 1994

Source: Tanurak, 1996

Items	1990		1991		1992		1993		1994
	Quantity	Value	Quantity	Value	Quantity	Value	Quantity	Value	Quantity	Value
Bamboo cans	42 639	693.1	66 960	1 421.2	48 683	956.0	64 658	1 124.7	71 199	1 110.9
Dry shoots	31	3.6	30	4.2	34	4.7	16	7.5	109	6.2
Fresh shoots	168	3.1	105	3.0	29	0.9	33	1.6	54	2.0
Total	42 808	699.8	97 095	1 428.4	48 746	961.6	64 707	1 133.8	71 362	1 119.1

References

Data Center. 1995. Forestry Statistics of Thailand. Information Office, Royal Forest Department. Bangkok. 150 p.

Data Center. 1996. Forestry Statistics of Thailand. Information Office, Royal Forest Department. Bangkok. 149 p.

Ramyarangsi, S. 1987. Bamboo research in Thailand. Pp. 67-69 in Recent Research on Bamboos, Proceedings of the International Bamboo Workshop, Hongzhou, October 6-14, 1985. (A.N. Rao, G. Dhanarajan and C.B. Sastry, eds.). CAF, Beijing and IDRC, Singapore.

Tanurak, S. 1996. Economic Bamboos. Horticultural Crop Promotion Division, Department of Agricultural Extension. Bangkok. 78 p. (in Thai)

Figs. 2. Natural distribution of Thyrsostachys siamensis in Kanchanaburi and Nam Now province in Thailand.

Figs. 3. Natural distribution of Thyrsostachys siamensis in Kanchanaburi and Nam Now province in Thailand.

Fig. 4 Dendrocalamus asper plantation in Prachinburi area.

Fig. 5 Shoot production.

Bamboo seeds

Fig. 6. Bambusa bambos

Fig. 7. Dendrocalamus membranaceus

Fig. 8. Gigantochloa albociliata

Fig. 9. Thyrsostachys siamensis

Fig. 10. Cleaning and sorting bamboo seeds.

Figs. 11. Preparing bamboo splits for making baskets. And baskets ready for marketing. The machine used for splitting is also locally made; Thyrsostachys siamensis and Bambusa sp. used mostly

Figs. 12. Preparing bamboo splits for making baskets. And baskets ready for marketing. The machine used for splitting is also locally made; Thyrsostachys siamensis and Bambusa sp. used mostly

Figs. 13. Preparing bamboo splits for making baskets. And baskets ready for marketing. The machine used for splitting is also locally made; Thyrsostachys siamensis and Bambusa sp. used mostly