NEEM (AZADIRACHTA INDICA A. JUSS) IN THAILAND¹

by

E. B. Lauridsen², C. Kanchanaburagura³, S. Boonsermsuk⁴,

I. INTRODUCTION

Neem (Azadirachta indica A. Juss) is a species of considerable international interest. As a consequence of this interest exploration of the species in Thailand was initiated jointly by the Royal Forest Department (RFD) and the DANIDA Forest Seed Centre (DFSC) (amongst others). The objectives were to explore the species throughout its natural range in Thailand as a basis for the collection of seeds for provenance trials and needed activities.

II. BACKGROUND

Neem has been singled out as a high-priority species i.a. at the following international meetings:

• The fourth session of the FAO Panel of Experts on Forest Gene Resources, held in Canberra, Australia, 1977;

• The ESCAP/FAO/UNEP Expert Group Meeting On Fuelwood and Charcoal held in Bangkok, Thailand, 1981;

• The IUFRO Special Programme for Developing Countries-organized Asian Regional Workshop on Increasing the Productivity of Multipurpose Tree Species held in Kandy, Sri Lanka, 1984;

• The IUFRO Special Programme for Developing Countries-organized Research Planning Workshop for Africa (Sahelian and North Zones), held in Nairobi, Kenya, 1986;

• The IUFRO Special Programme for Developing Countries-organized Research Planning Workshop for Latin America, held in Huaraz, Peru, 1987.

In Thailand, Neem is included in a comprehensive genetic and silvicultural research programme coordinated by the Forestry Faculty of the Kasetsart University, Bangkok. The programme has been implemented as a follow-up to the Kandy workshop. It is financially supported by F/FRED⁵.

The problems of transport and storage of the recalcitrant Neem seed cause severe difficulties for any activities within the field of genetic improvement of Neem (see e.g. Roederer & Bellefontaine, 1989). Although recommendations for further research to solve the problems have been specified by a number of authors the problem still remains largely unsolved.

¹ Manuscript received June 1991.

² DANIDA Forest Seed Centre, Denmark.

³ Central Research Center, Kanchanaburi, Silvicultural Research Sub-Division, Royal Forest Department, Thailand.

⁴ Central Forest Research Lab. & Training Centre, Royal Forest Department, Thailand.

⁵ Forestry/Fuelwood Research and Development Project (USA)

III. NATURAL DISTRIBUTION OF NEEM

The natural distribution of Neem has not, to date, been accurately determined.

Troup (1921), writes about Neem: “It is common in the open shrub forests of the dry zone of Burma, and it is found apparently wild on the Siwalik Hills; … if wild anywhere in India, it is probably so in the forests of the Carnatic and parts of the Deccan. In the Saharanphur Siwaliks I have found it in some quantity on the inner ridges in places where it is difficult to believe it could have spread from cultivated trees. It is cultivated all over India and Burma, more especially in the drier parts of the country, and has evidently become wild in many localities as an escape from cultivation.…”

Jacobs (1961), indicates that Neem is natural to Upper Myanmar (and cultivated throughout India), Sri Lanka, the Indo-Chinese Peninsula (except Malaya), and from Eastern Java to Sumbawa Islands.

The National Academy of Sciences (1980), describe Neem as native to the dry forest areas of Pakistan, India, Sri Lanka, Myanmar, Thailand, Malaysia and Indonesia.

According to Bhumibhamon (1987), Neem is indigenous to India, Myanmar, Java and the Lesser Sunda Islands.

IV. VARIATION AND GENETICS

So far, little is known about genetic variation of Neem, particularly about provenance variation. This is at least partly due to the fact that difficulties in storing and handling seeds of Neem have almost preclude systematic sampling and subsequent field trials.

Little information is also available on the genetics and population structure of the species. However, based on the wide distribution of Neem from Thailand (Laos, Cambodia) in the East to Pakistan (Iran) in the West, considerable genetic diversity may be expected. This variation could provide a basis for genetic improvement.

V. EXPLORATION IN THAILAND

The exact occurrence of Neem in Thailand is not well known. In April 1987 the Royal Forest Department (RFD), Bangkok, and the Danida Forest Seed Centre (DFSC), initiated a small-scale experiment with Neem seed. In parallel with these activities exploration was carried out in 1988 in the Provinces of Ratchasima and Kanchanaburi, including demarcation and description of four provenances. These activities were continued during the winter of 1989 and were finalized at the end of 1989. Totally, 27 provenances were described following a detailed survey, and 15 provenances were defined and described through a less detailed survey.

The field survey was carried out by a staff member of the Silvicultural Research Sub-Division and the Central Forest Research Lab. & Training Centre of the RFD in collaboration with a staff member of DFSC.

Activities included identification and exploration in natural forests with occurrence of Neem, and in areas where Neem was found extensively on farmland. The work also included interviews with staff of the local forest services, residents and farmers, concerning the past and present occurrence of Neem, and local utilization of the species. Selected locations were visited, and representative populations of Neem were identified selected and mapped. At the sites where detailed surweys were carried out, the number of Neem trees was recorded in randomly selected sample plots. Also phenologial data and fruit production (when the season permitted) were estimated. An example of provenance description is given in Annex 1.

In North-Eastern Thailand only a very approximative survey was carried out, without sample plots and with the assessment of tree density based on ocular estimates instead of enumeration.

VI. NEEM IN THAILAND

A. Varieties

Only two varieties of Neem occur in Thailand. One is Azadirachta indica var. siamensis Valenton, which has larger leaves and appears more robust and vigorous than the other variety, which belongs to the holotype known primarily from India and introductions to Africa. The latter variety has two types, one type with white-flushing inflorescences, and another type with red-flushing inflorescences. The flowers of the white type are often collected and used for food. The wood of the red type is considered more resistant to insects and is accordingly the preferred type for manufacture of furniture, in particular of beds.

The holotype of Azadirachta indica - in Thailand called “Sadao india” or “Quinine” - has been valued primarily for its medical uses. This holotype is considered as having better medical properties than var. siamensis.

The two varieties of Azadirachta indica can also be differentiated based on differences in pollen morphology and isozyme-patterns. Boonsermsuk & Jitjamnong, (1989), studied the peroxidase isozyme-patterns and pollen morphology, of what was then considered to be three varieties of the species, Azadirachta indica - with the names in Thai: Sadao Thai, Sadao india, and Sadao Thiam (Sadao Chang). The study identified the variety Sadao Tiam as Azadirachta exelca (Jack) Jacobs. It differed from the two varieties of Azadirachta indica for a number of the examined characteristics. The two varieties of Azadirachta indica were distinguished from each other mainly based on their different isozyme-patterns. The pollen differed in thickness of the pollen membrane, but all other pollen characteristics were identical.

Near Prachuab Khiri Khan on the Peninsula (see Figure 1) the two above varieties hybridize resulting in a progeny of intermediate characteristics. A little north of this location no hybridization occurs due to asynchronous flowering of the varieties.

B. Occurrence and distribution in Thailand

The distribution and characteristics of Neem in Thailand, both var. siamea and the holotype, have been described in Glover & Adams (Ed.), (1990).

Azadirachta indica var. siamensis has a wide natural distribution in Thailand (Figure 1) with the densest populations occurring on termite mounds and ridges in paddy fields (Figure 2 and 3) or scattered in some of the dry Dipterocarp forests. With a few exceptions the variety does not occur in moist deciduous forests or at altitudes above 200 meters.

In South-Eastern Thailand, Azadirachta indica var. siamensis seems occur naturally only along the Western coast in a 30–40 kilometres wide belt. According to local people Neem occurred naturally in the moist deciduous forests until large clearings were made for agricultural production, 20–40 years ago. Neem does not occur East of the town Klaeng, and only very sparsely outside the town. In the East along the border to Cambodia, Neem is not found until, the Sa kaoe town, on highway 33 leading from Bangkok to Aranyaprathet. No information is available on the occurrence of Neem in Cambodia.

In the Central-North, the variety occurs commonly and often in dense populations of as many as 5 trees per hectare.

The distribution of Neem in the North-East close to Laos has not been established yet; the species appears only in isolated occurences, and is rare.

In the North and North-West, Neem has spread naturally through the valleys along the rivers Mae Nam Ping, Mae Nam Yom, and Mae Nam Nan, and has reached 19° Northern latitude.

In the West, the densely forest-covered mountains along the border to Myanmar, have prevented Neem from naturaly spreading from Thailand into Myanmar and vice versa. It is uncertain whether Neem in Myanmar belongs to the holotype or to the var. siamensis. At one locality, near the town Tak, a “dense” population of Neem trees is located deep in a moist mixed deciduous, teak-bearing forest, which is unusual. There is no other Neem in the vicinity of this stand.

In South-Western Thailand, Neem extends up to approximately 9° Northern latitude. The Northern limit of the species Azadirachta exelca (Jack) Jacobs, is 50 kilometres further to the South. The latter species is utilized and appreciated by local communities, in the same way as Neem is in other parts of the country. Azadirachta exelca (Jack) Jacobs, grows into a large tree of fine form and is considered as having wood characteristics similar to those of Khaya senegalensis, and the same resistance to insect attacks as Neem. At the Malaysian border further South, a border village is called Sadao, the local name for Neem. However, in this area the name Sadao is often confused with Azadirachta exelsa (Sadao Chang), Acrocarpus fraxinifolius (Sadao Chang), or Chukrassia sp., and it is unlikely that Neem occurs naturally in the moist evergreen forest in this area.

In Southern Thailand the holotype of Azadirachta indica (local name: “Sadao india” or “Quinine”) is found isolated, mostly in temple compounds, where it has been introduced primarily for its medical uses.

C. History of Neem in Thailand

Even though man has influenced the distribution of Neem in Thailand significantly, most villagers interviewed in the 1988/89 survey, stated that Neem normally established itself and was rarely planted. Furthermore, the species occurs isolated in natural forests, and is spreading rapidly after forest clearings (bats are largely responsible for disseminating the fruits). According to local farmers and monks in South-Eastern Thailand, Neem occurred naturally, but only in scattered occurrences, in the moist deciduous forests until large scale forest clearings took place 20–40 years ago. Information given by residents of other regions was less clear. Generally, Neem seems to have been spreading slowly and gradually from existing populations, through a natural process. Mans contribution to the spread of Neem in Thailand seems to have been to pave the way through forest clearing and land preparation, and to leave the tree to developed. Thus, most Neem populations in Thailand may be considered as natural populations, which have spread slowly and relative recently.

The naturally occurring populations of Neem in Thailand are threatened in several ways:

• Large areas of suitable soil and climatic conditions, are used for rice fields. Most of these fields were traditionallt small and separated by soil ridges. Trees and bushes were grown on the ridges for provision of wood, fuel, and other products. Neem was a favoured species and has, as mentioned above, its main distribution in these areas (Figure 2 and 3). However, many rice fields are now being converted to sugar-cane production or, for the drier sites, to Cassava. These farming systems do not have room for any tree crops. In several areas, large populations of Neem are expected to disappear within a few years. In a number of areas earlier rich in Neem, only scattered occurrences can be found today.

• Neem of unspecified origin (often also the Sadao india) has been utilized in large-scale roadside plantings. As a consequence, natural populations may be polluted by pollen of unknown provenance (Figure 4).

• With good roads and communication between regions, Neem with special properties is being moved over large distances to replace the existing natural populations, which are not conserved in parallel with such activities.

Regarding the holotype of Azadirachta indica (the Indian type), an old monk in a monastery near Sattahip noted, that he had not seen this type until the naval base at Sattahip was established in the twenties. He suggested that the Thai Navy had introduced it. This was also suggested by an old farmer who living near Chonbury, and who was in the navy before the Second World War.

There are no indications that this type of Neem is spreading naturally beyond its present locations. The above mentioned roadside planting schemes may, however, cause its rapid expansion throughout Thailand.

LITERATURE

Bhumibhamon, S. 1987 Melia and Azadirachta in the Tropics - Basic Information; Melia and Azadirachta Research Series no. 1, National Research Council, Bangkok. (Cites: Burkill, I.H. 1966: A Dictionary of the Economic Products of the Malay Peninsula, Vol II.) (3)

Boonsermsuk, S. & Jitjamnong, P. 1989 Pollen morphology and pattern of variation in isozyme system of Azadirachta indica Juss. and A. indica siamensis Valenton. Resh. Doc. Tech. Work on Biomass & Biochemistry, Central Forest Research Lab. & Training Centre, Royal Forest Department, Thailand. (4)

ESCAP 1982 ESCAP/FAO/UNEP Expert Group Meeting On Fuelwood and Charcoal held in Bangkok in 1981. Proceedings, New York, 1981.

FAO 1977 Report of the Fourth Session of the FAO Panel of Experts on Forest Gene Resources (held in Canberra). Report: FO:FGR/4Rep., FAO, Rome, 1977.

Glover, N. & Adams, N. (Eds.) 1990 Tree improvement of multipurpose species. Multipurpose Tree Species Network Tech. Series, Vol. 2, Winrock International Institute for Agricultural Developemnt, Arlington, U.S.A., 1990.

Gøtzsche-Larsen, J. 1987 Memorandum on the IUFRO research planning workshop for tropical Latin-America. Travel report, DANIDA Forest Seed Centre, Denmark, 1987.

I.U.F.R.O. (Compil. Carlson, L. W. & Shea, K. R.) 1986 Increasing productivity of multipurpose lands. IUFRO research planning workshop for Africa Sahelian and North Sudanian Zones, Nairobi, Kenya, 1986.

I.U.F.R.O. 1981 XVII IUFRO World Congress. Congress Report, Japan, 1981.

I.U.F.R.O. 1984 Planning workshop for Asia on forest research and technology transfer. Theme: Increasing productivity of multipurpose species. Kandy, Sri Lanka, 1984.

Jacobs 1961 The genetic identity of Melia exelca Jack, The Gardens' Bulletin, Vol XVIII, Singapore, 1961 (3)

National Academy of Sciences Firewood Crops, 1980 Shrub and Tree Species for Energy Production. National Academy of Sciences, Wash. D.C., 1980.

Roederer, Y. & Bellefontaine, R. 1989 Can Neem seed be expected to keep their germinative capacity for several years after collection? Forest Genetic Resource Information no. 17, FAO, Rome 1989.

Palmberg, C. 1981 Genetic Resources of arboreal fuelwood species for the improvement of rural living. In: FAO/UNEP/IBPGR Technical Conference on Crop Genetic Resource, Rome, 1981.

Troup, R.S. 1921 The Silviculture of Indian Trees, Vol. I, Oxford Clarendon Press (3)

Figure 1. Distribution of Azadirachta indica in Thailand.

	Figure 4. Azadirachta indica planted along highway Denchai-Phrae. An “Indian” type can be seen in the foreground and a “Thai” type in the center; (Photo: E.B. Lauridsen, March 1989).
fIGURE 2. Azadirachta indica var. siamensis growing in paddy field. Ban Lai Hin, Chiang Mai. (Photo: E.B. Lauridsen, March 1989).
Figure 3.  Azadirachta indica var. siamensis growing in paddy field; South of Uttaradit; Provenance Ban Dan Sa Kaeo. (Photo: E.B. Lauridsen, March 1989).

ANNEX 1

P R O V E N A N C E     D E S C R I P T I O N

Provenance name : Doi Tao

Species (botanical) : Azadirachta indica A. Juss.

(vernacular): Mai Saliam, Neem, Nim.

1. Original provenance

1.1 Location

Map ref.: Thailand 1:50,000, ed. 2-RTSD, 1979, series L 7017, sheet 4744 IV. Thailand Highway Map, 1:1,000,000, Roads Assoc. of Thailand, 1988. World (S.E. Asia) 1:1,000,000, Series 1301, Ed. 7-TPC, sheet NE 47, 1971 (Figure 1 and 5).

Detailed description of location: Along road 1103 from Thoen - Mae Li - Hod. In Amphoe Doi Tao at sharp bend at temple where the highway turns due north, follow smaller road to the west towards the bank of the river Mae Nam Ping. The provenance extends about 400 meters north from this road until a laterite road running east-west.

The total area of the provenance has been calculated at 150 hectares.

1.2 Origin

Villagers say that Neem here “has come by itself”; thus it is natural.

1.3 Site description

The aspect is gentle west; the topography is slightly undulating. The soil is eroded, yellow-red podzolic, with exposed laterite.

The rainfall is around 1250 mm per year, with a dry season during the months of November-April. Detailed description of the climatic conditions is available upon request. Nearest weather station is at Chiang Mai (Latit.: 18° 47' North, Longit: 98° 59' East).

1.4 Stand description

The stand is a degraded moist deciduous forest without teak, and with extensive farming and cattle grazing in the area. The trees do not exceed 12 meters in height.

The tree species association is the following:

Albizia lebbeck (Ton), Cassia garettiana Craib. (Sa Mae San), Flacourtia indica, Horsfieldia macrocoma, Morinda citrifolia, Shorea obtusa, Shorea siamensis, and Terminalia mucronata, Ziziphus sp. (Lep njeo).

Neem (Azadirachta indica) occurs at the rate of 0-15-23 groups of trees per hectare with an average of 1.9 trees per group. The average height of the trees is 10 meters, varying from 8 to 12 meters. Regeneration (here defined as any tree of less than 6 meters height and not bearing fruits) is ample with 0-8-27 groups of seedlings per hectare with about 2 seedlings per group. Also, coppicing is plentiful with 0-10-37 groups per hectare, each group with 2 ½ trees. Only around 1–2 trees per hectare produce fruits.

The above statistics stem from a survey along a randomly selected 700 × 30 meter line traversing, by chance, the highest lying and poorest part of the area. The Neem trees are larger in the lower parts, and fruit bearing is also more abundant there.

1.5 Demarcation, isolation

The area has easily recognizable boundaries formed by all-weather roads to the east and south, and partly to the west. To the north a dirt road forms the easternmost boundary, whereas an imaginary line is the border towards southwest.

There is no foreign Neem, i.e. introduced plants, in the vicinity of the area.

2. EXTENSION OF PROVENANCE

Seed collection may be extended to an area to the east, north and south of the Amphoe Doi Tao town to cover a total area of 400–500 hectares.

3. SEED COLLECTION

3.1 Seed production:

Neem (Azadirachta indica): Only around 1–2 trees per hectare produce fruits in sufficient quantity, i.e. a minimum of 100 fruits per tree. The production is higher in the lower parts of the area. The provenance may thus produce some 23000 fruits per year, or enough for around 10 hectares. Inclusion of the extension would increase production to more than 100,000 fruits, or around 40 hectares per year. Generally fruit production is better in the extension area, because the trees are larger there.

3.2 Accessibility

The area is accessible from all-weather roads, or tracks.

3.3 Labour availability

The area is close to the town of Doi Tao and labour is easily available in the seed collection season.

3.4 Contacts for access to area

The area comes under the jurisdiction in part of the Forestry Department (Amphoe), and in part of the Electricity Board of Thailand. Contact is through the Royal Forest Department, Silvicultural Research Sub-Division, Bangkhen, Bangkok 10900.

4. CONSERVATION NEEDS

The area has status of reserved forest, but protection is difficult. There is a need for good protection of the area to ensure regeneration, and to limit fuelwood extraction. The extended seed collection area (extended provenance) may, or may not, maintain its status depending upon if, and how fast, the farmers convert from rice farming to growing cashcrops like sugarcane or cassava.

Description on March 6. 1989 by:

Figure 5. Location of the provenance Doi Tao