Previous Page Table of Contents Next Page

Teak improvement in Indonesia - Dr. Hendi Suhaendi

Hendi Suhaendi

Forest Tree Improvement and Development Institute

Yogyakarta, Indonesia.

Matured teak plantation in Java, Indonesia.


Teak is the most important commercial tree species in Indonesia. There are 0.6 million ha of production plantations and most are based on seed from these production areas. Teak improvement work started in 1974, stimulated by earlier reports of genotypical races, based largely on wood and stem qualities and on some morphological characteristics. Provenance trials commenced in 1932 and observations drew conclusions such as: future exotic teak planting was not required since Java teak was as good as any exotic, although in windy or dry areas it was better to plant Malabar and Myanmar or Thailand teak. Of the exotics, Lao teak had best form and branching; best height was of Lao and Malabar teak; Lao, Malabar and Thailand teaks had the best girth growth. Further provenance trials are operational. Seed Production Areas cover 3,700 ha. Over 136 trees have been selected on the basis of height, DBH, volume, crown, straightness, pruning ability, branch diameter, branch angle, disease resistance, age, and wood characteristics. Teak is vegetatively propagated by grafting and tissue culture. As of 1995, 1,139 ha of clone banks and clonal seed orchards have been established. Progeny trials from open pollinated parents (189 families) showed significant differences in height and diameter at a very early age. Cardinal points in setting up tree breeding programmes are: that a real need is evident; objectives are clearly defined; results will be put into practice; the programme is carefully planned; the programme has adequate financing.

Key words: Tectona grandis, Indonesia, provenance trials, tree improvement, seed production areas, clone banks and orchards.


Teak (Tectona grandis L.f.) is one the most important commercial tree species in Indonesia. It is planted extensively in Java by Perum Perhutani, a state forest enterprise established by the Act No. 36/1986, and which is responsible for the management of teak. Teak plantations cover over one million ha and the annual cut is about 8,000-10,000 ha (Hardiyanto et al., 1992). Rahardjo (1993) noted that Perum Perhutani is also responsible for managing some 0.5 million ha of protection forest and approximately 2.0 million ha of production forests, both in Java. About 1.8 million ha of production forests are plantations comprising: teak (0.6 million ha), pine (0.2 million ha) and other species such as Agathis, mahogany, rosewood, Paraserianthes falcataria, Acacia mangium and Gmelina arborea. Despite the fact that teak has been widely planted, the use of genetically improved seed has not been practiced and current plantations utilize seeds from production areas. Teak improvement activities are now under way to obtain genetically improved seed in programmes carried out by the Forest Research Institute, Perum Perhutani and universities.


Forest tree improvement planning commenced in 1930 (Wind, 1930; Thorenaar, 1930), some 17 years after the establishment of the Forest Research Station and 33 years after the formation of the Forest Service in 1897. Improvement work started with teak (Soerianegara, 1974) and was stimulated by the finding that there are several types of Javanese teak (Wind, 1930; Gresser, 1932). Thorenaar (1930) described some examples of genotypes and geographical races.

Coster (1931) reported on the flowering biology of teak. This study marked the beginning of teak tree improvement. This was followed by provenance trials in 1932 using seed from Lao (Indo-China), Thailand (Siam), Myanmar (Burma), India and Indonesia (Coster and Eidmann, 1934). Although definite results were obtained (Daryadi, 1959), they were not used for further tree improvement work or for large scale seed production.


Variations in Java teak

There are several genotypic and geographic types of Javanese teak, (Wind, 1930; Gresser, 1932). Gresser (1932), Coster and Eidmann (1934), and Beekman (1949) considered that these variations can be grouped by either wood properties or by bole form or stem characteristics. Based on wood properties, there are four types:

The second group is based on bole form or stem characteristics, such as: 1) knobby or knotted stem teak (Jati knobbel, Jati gembol) with knobs on the stem; and 2) straight stem teak (Jati gladstam, Jati batang licin).

Soerianegara (1974), Simatupang (1964), and Sandermann and Simatupang (1966) in studies of the wood chemistry of teak, found significant differences between the various types and provenances of teak from Java, India, Myanmar, Thailand and Lao. Tectoquinone, the most important extractive which creates durability against termites, varies between 0.3-1.3% in Java teak. The caoutchouc content, which is responsible for low abrasion and resistance to mineral acids, varies between 0.1-5%. Spaan (1911) listed 12 varieties of teak tree descriptions originating in Madiun, but the lack of replicability in appearance and growth performance and other characteristics limits these varietal integrities, which may be caused by differences in location or certain diseases. According to Hedegart (1976), what is called Java teak is a variety mostly caused by environment.

Busgen (in: Hamzah, 1976) stated that many varieties of Java teak generally have characteristic high seed stability and, therefore, seed origins should be noted in teak improvement programmes. Ten Oever (1916) speculated that differences among varieties might accidentally appear (e.g., in streaked teak and knotted stem teak), but that on the other hand, calcareous teak and oily teak are a different matter. Thorenaar (1930) reported that Java teak contained more lime compared to Myanmar and Thailand teak. Bianchi (1936) stated that the technical quality of Java teak wood is in the same class as Myanmar and Thailand teak. Variations among populations is also reported by Eidmann (1934) based on seed origin comparisons: Java teak has a big leaf, 60-70 cm long with green and fresh surface, either without or having a very small petiole, and with a strong grooved internode; the Indian variety has a small and stiff leaf, 45-55 cm long, dark green up to the blush leaf with a shiny surface; the stem smaller, not so grooved, and the young internode often bluish-green in color.

Gresser (1932) reported that smooth stem teak has a small seed with a diameter of less than 14 mm, and represents a desired variety. Murthy (in: Muniswami, 1977) also reported that in Java teak, good characteristics from difference races are related to seed size. Beekman (1949) recognized teak provenances based on the thickness of exocarp and mesocarp, as well as pericarp properties. Seed from Java and Muna has a thin exocarp and mesocarp; seed from India (Godavari, Madhya Pradesh and Malabar) has a very thin mesocarp; seed from Java and Myanmar is bigger than seed from India.

Provenance trials

Coster (in: Coster and Eidmann, 1934) described the teak improvement program as a preparatory activity, namely the study of the flowering biology and tree improvement activities, comprising: a) provenance trials; and b) mass selection. Due to the difficulties and the length of the time required to conduct controlled crosses and progeny tests, these activities were excluded from the program. A brief description of the material used in the provenance trials is presented in Table 1. The provenance and variety trials were conducted on two sites: Nglambangan (Bojonegoro) and Kesamben (Blitar), in eastern Java in 1932. Details of the climate and soils of the experimental sites are given in Table 2.

Table 1. Teak provenance and varieties trial (planted in 1932, assessed in 1957 at 25 years of age)

Provenances and Varieties


Soil and Topography


Annual Rainfall (mm)

Dry Months

1. India

1.1 Malabar




Loose laterite, valley, 30 m a.s.l

1.2 Godavari




Sandy loam, hill, 400 m a.s.l

1.3 Central Prov.




Sandy loam, 500 m a.s.l

2. Burma - Insein





3. Thailand - Phrae




Sandy soil

4. Lao - Paklay




265 m a.s.l

4.1 Gray teak (Kay)

Loam, hill

4.2 Brown teak (Kouai)

Sandy loam, plain

4.3 White teak (Kouoc)

Sandy loam, plain

4.4 Hard teak (Hinh)

Sandy loam, plain

5. Indonesia

5.1 Muna




Brown loam over gray sand, 5-10 m a.s.l

5.2 Tjep




Dark brown loam, fertile

5.3 Pati (Regaloh)




Volcanic sandy soil, fertile

5.4 Gundih




Margalitic soil, very infertile

5.5 Ponorogo




Dark clay loam, infertile

5.6 Streaked teak (Doreng), Bangilan




Red, old lateritic soil

5.7 Knotted-stem teak, Margasari




Loamy sand, moderately fertile

5.8 Smooth-stem teak, Ngliron




Humous margalitic soil, sandy to loamy

Sources: Coster and Eidmann, 1934; Daryadi, 1959; Soerianegara, 1974.

Mons. = monsoonal.

Table 2. Locations of the 1932 Java provenance trials



Soil and Topography


Annual Rainfall (mm)

Dry months

1. Nglambangan (Bojonegoro) 7°12’S and 111°45’E




Black, calcareous loamy soil, plain, 150 m a.s.l

2. Kesamben (Blitar) 8°10’S and 112°22’E




Volcanic ash soil, fertile plain, 200 m a.s.l

Source: Coster and Eidmann, 1934; Daryadi, 1959; Berlage, 1949; Soerianegara, 1974. Mons. = monsoonal.

Initial results and observations from these two trials after two years were reported by Coster and Hardjowasono (1935) as follows:

Substantial results and observations from these two experiments were reported by Daryadi (1959) after 25 years. The main points are summarized below (Soerianegara, 1974).

A. Stem form and branching

The best foreign provenance was from Lao, except for brown (Kouai) teak; the worst was from Godavari. The Malabar (India) variety has the greatest number of branches. Indonesia teak is of moderate quality, except for knotted stem teak. Progenies of the smooth stem teak from Ngliron (Randublatung) did not reproduce the properties of their parent trees.

B. Height

Malabar (the best) and Lao, especially the Hinh (hard) and the Kouoc (white) teak provenances, attained average heights of over 28 metres. Indonesia teak types having similar growth rates were from Pati (streaked teak) and Cepu (smooth stem teak), especially in the Nglambangan (Bojonegoro) area.

C. Girth

Malabar, Lao and Thailand provenances all reached 110 cm (35 cm diameter) and over. Almost all the Indonesian types attained 110 cm girth; the most vigorous were derived from seed collected from Pati, Cepu, and Ponorogo, and also from streaked teak.

D. Wood quality

The wood quality of the varieties has still to be investigated. However, observations made at both of the experimental sites suggest that the appearance of the streaks in streaked teak depends on site conditions. At Nglambangan (Bojonegoro), where the soil is margalitic (black calcareous), the occurrence of streaked progenies is 100 percent, while at Kesamben (Blitar), on volcanic ash soil, it is only 37.5 percent.

As a consequence of the Teak Sub-Commission of the Fourth Session of the Asia-Pacific Forestry Commission (APFC) meeting in Bandung in 1957, the Forest Research Institute (now, Nature Conservation and Forest Research and Development Center) at Bogor began a special series of FAO teak provenance trials in 1959. The purpose of the studies is to investigate the growth of different teak provenances on poor soil. Teak provenances under investigation are from India (Malabar), Myanmar, Thailand, Lao, Togo, and Cepu (Indonesia). Trees were planted at three locations in Cikampek (Western Java), Bangsri (Central Java), and Wonorejo (Eastern Java). Details of the climate and soils of the experimental areas are presented in Table 3. Results of height and diameter growth based on inventories made in 1963 and 1964 follow Table 3.

Table 3. Experimental area for the 1959 FAO teak provenance trials



Soil and Topography


Annual Rainfall (mm)

Dry months

1. Tjikampek (West Java) 6°25’S and 107°28’E




Red podsolized latosol, plain, 60 m a.s.l

2. Bangsri (Central Java) 6°31’S and 110°46’E




Red podsolized latosol, plain, 90 m a.s.l

3. Wonorejo (East Java) 7°58’S and 114°15’E




Brown mediterranean soil and grumosol, slope, 60 m a.s.l.

Source: Soerianegara (1974)

The result based on inventories carried out in 1963 and 1964 were reported by Soerianegara (1974) as follows:

1) At Cikampek (Tjiampek) the best height and diameter growth are obtained from Malabar (India) and Myanmar provenances. At 4 years the Malabar teak had an average height and diameter of 4.4 m and 5 cm respectively; figures for Myanmar teak were 3.5 m and 4 cm. In 1968, the Malabar provenances at Cikampek had a mean height of 10.8 and 9.9 m and mean diameters of 14.2 and 13.2 cm. Unfortunately, the remaining trees in the experiment were cut illegally.

2) At Bangsri, the Malabar and Cepu provenances were the most vigorous, and at 5 years they had attained a mean height of 6.1 and 5.8 m, and mean diameters of 7.6 and 7.9 cm respectively. Trees from the Myanmar and Togo seed sources died.

3) At Wonorejo, trees from Myanmar seed sources also died. Provenances showing the best growth were those from Cepu and Thailand. At 5 years they had a mean height of 4.4 and 3.9 m, and mean diameters of 5.4 and 4.6 cm respectively.

Recently, the Faculty of Forestry, Gadjah Mada University, assessed a trial of 21 teak provenances established in 1988-1989 in Wanagama, Yogyakarta. Differences among provenances were apparent for both height and diameter at ten months age (Table 4).

Assignment of Seed Production Areas.

The main purposes in assigning a Seed Production Area by Perum Perhutani are: 1) to obtain better quality seed; 2) to concentrate the collection of seed in a smaller area which can be specially managed so that seed collection can be arranged and supervised easily; and 3) to increase the seed collecting capacity at that site and improve the germination capacity of this seed (Wirjodarmodjo and Subroto, 1983).

Seed Production Areas are selected from Compartments or sub-Compartments which have been assigned as seed stands. Actually, a Seed Production Area is a plus stand, or a young plantation of the required parent seed origin which will be upgraded and opened later after the removal of all unwanted trees, and managed as a seed source. Seed Production Areas can supply improved seed until seed orchards are capable of producing seed in sufficient quantities.

Seed Production Areas were designated for selected stands in 1983: 453.3 ha in Central Java, 377.7 ha in East Java, 41.5 ha in Ciamis, West Java, 22.4 in Indramayu, West Java, and 10.6 ha in Purwokerto, Central Java (Satjapraja and Suhaendi, 1992). At present, Perum Perhutani had selected 3,700 ha teak Seed Production Areas (Perum Perhutani, 1995).

Table 4. Height and diameter growth of 21, ten-month-old teak provenances, Wanagama


Height (cm)

Diameter (mm)

1. Malabar (India)



2. Godavari (India)



3. Kay (Lao)



4. Kouai (Lao)



5. Central Prov.(Ind.)



6. Thailand



7. Kouoc (Lao)



8. Myanmar



9. Muna (Celebes)



10. Soe (West Timor)



11. Cepu



12. Margasar



13. Gundih



14. Java



15. Pati



16. Bangilan



17. Ngliron



18. Ponorogo



19. Deling



20. Blora



21. Randublatung



Source: Hardiyanto et al., 1992

Selection of plus trees

Plus trees can be found in natural as well as in plantation forests, but in order to facilitate work, plus trees selection carried out by Perum Perhutani has only been from plantation forests.

The first selection of plus trees was made by van der Kloot (1951) and 77 plus trees were selected (Daryadi,1959; Sastrosumarto and Suhaendi, 1985; Satjapraja and Suhaendi, 1992). From 1982 to 1993, Perum Perhutani selected 136 plus trees in Central and East Java (Perum Perhutani, 1995). The phenotype characteristics evaluated were: height, breast height diameter, tree volume, crown, straightness, pruning ability, branch diameter, branching angle, resistance to disease, age, and wood characteristics. Evaluation of characteristics, except of wood characteristics, follow the North Carolina State University system (Wirjodarmojo and Subroto, 1983).

Vegetative propagation


Teak can be easily propagated through bud and cleft grafting (Sastrosumarto and Suhaendi, 1985; Satjapraja and Suhaendi, 1992). According to Hardjono et al. (1959), successful bud grafting of teak depends on the age of the bud donor. Bud grafting at 20-50 years age can give 70% success, whereas trees of 50 years age and over have a take of about 60%. Trials at the Forest Research Institute, Bogor, showed an 80% success, which indicates that a large-scale bud grafting programme is possible.

Cleft grafting is also promising according to a study reported by Harahap (1972), which concludes that bud and cleft grafting can be recommended for establishing a teak clonal seed orchard. According to Muniswami (1977), the famous basic method for teak in India is bud grafting with two-open-flap. This method has been tried by Perum Perhutani in Indonesia. This material was used for establishment of a clone bank (Wirjodarmodjo and Subroto, 1983).

Tissue culture

Since 1979, Perum Perhutani has cooperated with the Institut Teknologi Bandung (Bandung Institute of Technology) on teak tissue culture research (Wirjodarmodjo and Subroto, 1983). Noerhadi and Wirjodarmodjo (1980) reported research results on teak tissue culture as follows:

1) Callus growth from stem and petiole gave a predominant type response. The explant after 3 weeks, and treatment with BAP hormone, was planted in a modification of JS and MS medium; hormone 2 4-D in concentration up to 3.5 ppm produced a better and larger callus compared with NAA hormone with concentration up to 10 ppm.

2) A cut young leaf and pedicel also produced callus, but at a very low rate and not consistently, compared with callus from stem and leaf stalk.

3) Root formation from the explant is noted after 2 months planting in the same medium, with additional NAA and BAP hormones of concentration 3.5 ppm and 0.25 ppm respectively.

Establishment of Clone Banks

Even though teak plus trees have been identified, they might be lost because of theft, forest fire, natural disasters, etc. To preserve genetic sources and their characters, it is important to make an archive, or copy tree, using vegetative propagation techniques. These copies of the plus trees are kept in a special site - a clone bank. The function of the clone bank, besides preserving genetic characters of the plus trees, is also to serve as a bud source when needed in vegetative propagation to establish clonal seed orchards. Clone banks are located in safe locations that are supervised, visited often, and on flat terrain.

Perum Perhutani has 5 clone banks. In each one, there are ten replications of the plus trees, so every plus tree is copied 50 times. If/when the parent plus tree disappears, its genetic characters are safely preserved. Clone banks are located at Cepu and Randublatung Forest Districts, Central Java, and in Bojonegoro, Parengan, and Saradan Forest Districts, East Java. Any selection of a plus tree is always followed by establishing it in a clone bank (Perum Perhutani 1992, 1995).

Establishment of Clonal Seed Orchards

The establishment objective of clonal seed orchards is to obtain high genetic quality seed. The trees in clonal seed orchards are derived from vegetative propagation (bud grafting) of the sum of plus trees. The site of a clonal seed orchard must be remote from other teak forests to avoid pollen contamination, thus ensuring that pollination occurs only between plus trees in a completely randomized block design.

Clonal seed orchards of Malabar and Java teak have been successfully established by the Forest Research Institute at Kesamben and Saradan in Eastern Java (Hardjono et al., 1959; Soerianegara, 1974). Another clonal seed orchard of Java teak was established by Perum Perhutani in 1983. Perum Perhutani planned to establish 1,200 ha of teak clonal seed orchards, and by 1993, 1,139 ha were established at Cepu, Padangan, and Randublatung Forest Districts (Perum Perhutani, 1995).

When establishing a clonal seed orchard, buds from the plus trees are taken at the end of the dry season (August/September). Same-day grafting is made onto previously prepared rootstock, which is then planted in a plastic bag filled with soil and a little fertilizer. These bags are kept at the nursery for approximately three months, until December-January when they are planted in the orchard. Orchard planting is done by the taungya method with a spacing of 10×10 m. Additional tilling ground is provided for forest farmers to plant a second crop (Perum Perhutani 1992).

Progeny testing

The first progeny test by Perum Perhutani took place in 1987 in the Cepu, Kendal, and Saradan Forest Districts. A total of 122 teak plus trees had been planted by 1991. Random block designs were used to analyze height and diameter growth, tree form, stem and crown and resistance to disease (Perum Perhutani, 1992). Another progeny test of 189 families was carried out in 1988 by the Faculty of Forestry, Gadjah Mada University, in Wanagama, Yogyakarta. Seed for this was collected from open pollinated parent trees from plantations in Java and Nusa Tenggara Timur (West Timor). At the age of three months, differences among families in height and diameter were significant (Hardiyanto et al., 1992).


Soerianegara (1974) states that progress in teak improvement will only be achieved provided: a) there is a real need for such a programme; b) the objectives are clearly defined at the start; c) the results will be put into practice; d) the programme is carefully planned; and e) the programme is adequately financed. This assessment is strongly supported.

Teak improvement programmes are being undertaken by many institutions both within and outside Indonesia. Teak Networking is a requirement at national, regional and international levels.


Beekman; H.A.J.M. 1949. Houtteelt in Indonesia (Silviculture in Indonesia). H. Veenam and Zonen, Wageningen.

Berlage, H.P. 1949. Regenval in Indonesia (Rainfall in Indonesia). Verhandel. No. 37, Directorate of Meteorogy and Geophysics, Jakarta.

Bianchi, T.J. 1936. Vergelijkend onderzoek van Java, Burma, en Siam teak (Comparison research between Java, Myanmar and Thailand teak wood). Tectona 29: 871-873.

Coster, C. 1931. Bijdrage tot de Bloembiologie van den djati, Tectona grandis L.f. (Scientific contribution in flowering biology on teak, Tectona grandis L.f.). Tectona 24: 768-792.

Coster, C. and F.E. Eidmann. 1934. Selectie-onderzoek van den djati, Tectona grandis L.f. (Selection of teak, Tectona grandis L.f.). Short Comm. No. 40, Forest Research Institute, Bogor.

Coster, C. and M.S. Hardjowasono. 1935. Selectie-onderzoek van den djati, Tectona grandis L.f. II. De groi gedurende het tweede levensjaar (Selection of teak, Tectona grandis L.f. II. Growth during the second year). Short Comm. No. 49, Forest Research Institute, Bogor.

Daryadi, L. 1959. Penyelidikan seleksi jati, Tectona grandis L.f. (Selection of teak, Tectona grandis L.f.). Comm. No. 70, Forest Research Institute, Bogor.

Eidmann, F.E. 1934. Germination of teak (Tectona grandis L.f.). Short Comm. No. 42, Forest Research Institute, Bogor.

Gresser, E. 1932. Over den knobbeldjati (About knotted teak). Tectona 25: 269-271.

Hamzah, Z. 1976. Sejarah pemuliaan pohon jati (History of teak tree improvement). Dalam Proc. Simposium Ilmu Pemuliaan dalam Bidang Pertanian Pertama, 14-16 December 1976, Universitas Padjajaran, Bandung.

Harahap, R.M.S. 1972. Percobaan orientasi pembiakan vegetatif beberapa species pohon (Orientation trial of vegetative propagation on some tree species). Laporan No. 15, lembaga Penelitian Hutan, Bogor.

Hardiyanto, E.B., O.H. Suseno and S. Danarto. 1992. Tree improvement programs in Indonesia. Dalam Prosiding Seminar Nasional Status Silvikultur di Indonesia Saat ini, 27-29 April 1992, Wanagama, Yogyakarta. p. 63-78.

Hardjono, R., Djodjo and L. Daryadi. 1959. Percobaan okulasi jati, Tectona grandis L.f. (Budding experiment on teak, Tectona grandis L.f.). Comm. No. 68, Forest Research Institute, Bogor.

Hedegart, R. 1976. Breeding systems, variation and genetic improvement of teak (Tectona grandis L.f.) In: J. Burley and B.T. Styles (Eds.), Tropical trees: variation breeding and conservation. p. 109-121. Linn. Soc. Symp. Ser. No. 2, London: Academic Press.

Muniswami, K.P. 1977. Population improvement and hybridization - teak. In: Proc. Third World Consultation on Forest Tree Breeding, Canberra, Vol. 2: 507-544.

Noerhadi, E. and H. Wirjodarmodjo. 1980. Vegetative Propagation of Tectona grandis L.f. and Pinus merkusii Jungh. et De Vriese using tissue culture techniques. In: Proc. IUFRO Symposium and Workshop on Genetic Improvement and Productivity of Fast Growing Tree Species, August 25-30, 1980.

Perum Perhutani. 1992. Forest tree breeding done by Perum Perhutani. Paper presented in the Senior Officials Meeting on the Cooperation Between Indonesia and Thailand on Forestry, 17-18 February 1992, Jakarta. 8 pp.

Perum Perhutani. 1995. Tree improvement in Perum Perhutani. Paper presented in Seminar on Integrated Forest Tree Improvement Program in Indonesia, 22 March, 1995. Forest Tree Improvement Research and Development Institute, Yogyakarta.

Rahardjo, P. 1993. Strategi pemuliaan pohon di Perum Perhutani (Strategy of tree improvement in Perum Perhutani). Dalam Prosiding Lokakarya Pemuliaan dan Perbenihan Pohon Hutan, 25-26 August 1993, Purwobinangun, Yogyakarta. p 145-152.

Sastrosumarto and H. Suhaendi. 1985. Suatu tinjauan mengenai program pemuliaan jati (Tectona grandis L.f.) di Indonesia (A review about teak improvement programme in Indonesia). Pusat Penelitian dan Pengembangan Hutan, Bogor.

Satjapradja, O. and H. Suhaendi. 1985. Forest tree improvement (breeding) in Indonesia. In: Proc. of the First Project Advisory Committee Meeting of UNDP/FAO/RAS/91/004 Project, 27-29 May 1992, Manila, Philippines. p. 65-77.

Soerianegara, I. 1974. Forest tree improvement in Indonesia. In: R. Toda (Ed.), Forest Tree Breeding in the World, p. 146-153. Government Forest Experiment Station of Japan, Meguro, Tokyo.

Spaan, W.J. 1911. Aantekeningen over de in het boschdistrict Madiun voor komende djativarieteiten (Note on teak varieties which occurred at Madiun Forest District). Tectona 4: 473-477.

Ten Oever, H. 1916. Code De Djatibosschen ov Java (Teak forest in Java). Tectona 34: 1-95.

Thorenaar, A. 1930. Over selectie bij djati (About teak selection). Tectona 23: 826-837.

van der Kloot, W.G. 1951. Verslag van een Dienstreis naar Middenoost Java 20 Februari tot 14 Maart 1951.

Wind, R. 1990. Overzicht van de onderzoekingen en algemeen werk-plan van het Boschbouwproefstation (General features of researches and common workplan from Forest Research Institute). Tectona 23: 782-795.

Wirjodarmodjo, H. and P.M. Subroto. 1983. Teak improvement by Perum Perhutani. Duta Rimba 63-64/IX: 3-13.

Previous Page Top of Page Next Page