Log Qualities, Wood Properties and Processing of Teaklog

Home , Heat bending of wood, Sawmill, Teak, Tectona, Wood

Present Utilization of Small-Diameter Teak Log from Community Teak Plantations in Java and Eastern Indonesia

Technical Report ITTO PPD 121/06 Rev. 2(I)

Prepared by Eko B. Hardiyanto T.A. Prayitno ITTO

Contents

Contents ….………………………………………………………….………………...... ii Preface …. ………………………………………………………………………… …...iii 1. Introduction …………………………………………………………………………1

2. Data collection .. …………………………………………………………………...... 1

Field survey … …………………………………………………………………………2 Literature review …………………………………………………………………….2 3. Community-grow teak plantation ……..………………………………………….4

Site conditions ……………………………………………………………………………4 Size and productivity …………………………………………………………………4 Silvicultural practices ……………………………………………………………..…11 Stem form …...... ……………………………………………………………………… 14 The need for stem quality improvement …... ………………………………………15 4. Log quality and wood property … …………………………………………….17

Log quality ….. ………………………………………………………………………..17

Wood property .…..…………………………………………………………………….26

Mechanical property …… …………………………………………………………..26

Longitudinal variation …...…………………………………………………….28

Radial variation …..………………………………………………………… ….28

Interactions between factors .….………………………………………………29

Physical property .…..………………………………………………………………31

5. Wood processing .. ………………………………………………………………..34

Sawing technique ..…..…………………………………………………………………34

Wood drying ..….……………………………………………………………………….35

Manufacturing . ….……………………………………………………………………..37

Wood processing in the surveyed areas .….…………………………………………38 The need for wood proceessing improvement ..… ………………………………...42 6. References.……..……………………………………………………………………..44

Preface This technical report has been prepared as part of the output of ITTO PPD 121/06 Rev 2(I) titled ‘Development of value‐adding processes for short‐rotation, small‐ diameter community teak plantations in Java and eastern Indonesia’. The information presented in this technical report is derived from the survey and study as well as existing literature.

Many individuals and institutions have generously assisted in the survey, testing wood sample and the preparation of the report. We are particularly grateful to the following: • International Tropical Timber Organization (ITTO) provided the funding. • The Dean of the Faculty of Forestry Gadjah Mada University provided facilities and support. • J. Suranto, Navis Rofii, Ermy Erene Koeslulat, Elma, Vendy, Rifky and a number of students carried out field surveys and data inputs. • In Yogyakarta, Ambar Polah Wood Drying shared information on wood drying. • In Gunung Kidul, Mr. Darmanto, owns a small wood processor, offered time and shared information on wood processing; Mr. Supoyo, the Head of Batur Agung Cooperative provided information on teakwood manufacturing, marketing and challenges. • In Wonogiri, Mr. Bambang Wahyu of the Forestry, Estate Crop and Mining District Office helped for arranging the field survey. • In Pacitan, Mr. Suyitno of the Forestry and Estate Crop District Office helped for arranging the field survey. • Forest District of Timur Tengah Selatan, East Nusa Tenggara helped for arranging field surveys • In South East Sulawesi, Mr. Suntoro offered help for arranging the field survey. The Forestry Cooperative (Koperasi Hutan Jaya Lestari‐KHJL) shared generously their time and information. • In South Sulawesi, Mr. Djohan Perbatasari and Mr. Budi Santoso from FORDA Forestry Research Institute, provided information and facilities for field survey. • Many farmers and wood processors in the surveyed areas in Gunung Kidul, Wonogiri, Pacitan, East Nusa Tenggara, South Sulawesi and South East Sulawesi spent their time and provided information on their teak plantations and teaklog processing.

iii

• Perum Perhutani of Cepu District provided access to the information on its teak plantation and wood processing unit.

Eko B. Hardiyanto T.A. Prayitno

Introduction

Teak (Tectona grandis) is one of the worldʹs premier hardwood timbers, rightly famous for its mellow color, fine grain and durability. It occurs naturally only in India, Myanmar, the Lao Peopleʹs Democratic Republic and Thailand, and it is naturalized in Java, Indonesia, where it was probably introduced some 400 to 600 years ago (Troup 1921).

Indonesia has a long history of growing teak as an exotic plantation. The species is believed to be introduced the first time in 14th century by Hindus (Simatupang 2001). Currently Indonesia is one of the world’s largest teak grower. Most of the plantations have been grown in Java, where the largest grower is Perum Pehutani (state‐owned forest corporation) which manages over 1 million ha of teak‐bearing plantation with a net area of teak estimated to be around 6,00 000 ha. Community‐grown teak plantations have been becoming of importance in producing teak log, not only in Java, but also in eastern Indonesia such as South Sulawesi, South East Nusa Tenggara and East Nusa Tenggara. The trend of teak planting by farmers has been continuously increasing in recent years due to decreasing the log supply from state forest managed by Perhutani while the demand of teaklog is steadily increasing.

Teak log harvested from community‐teak plantation has been stated to have low quality and consequently low price as well due to be harvested at much younger ages around 15‐20 years compared with that of traditionally known of teak log from the state forest harvested at least at 40 years old. However, complete information on the productivity, log quality, wood properties and processing of teak log harvesting from community‐grown teak plantations in Indonesia is still lacking. The present study is intended to gather this information with a particular reference to Java and eastern Indonesia which have a large size of community teak plantations .

Data Collection

Field survey

Field surveys were carried out in major community‐grown teak plantations in Java and eastern Indonesia. In Java surveys included the following districts: Gunung Kidul (Yogyakarta Province), Wonogiri (Central Java), Pacitan (East Java). In eastern Indonesia surveys covered the following districts: Konawe Selatan and Muna (South East Sulawesi Province), Timur Tengah Selatan and Belu (East Nusa Tenggara Province) (Figure 1).

The field survey was designed to gather base‐line data on community‐grown teak plantations such as size, productivity, quality, silviculture practices (planting pattern, density, maintenance etc.) In every designated district a minimum of 20 plots were made and in each plot 20‐30 trees were measured (tree height, stem diameter) and evaluated (stem form, cylindricity, fluting). Stem form was classified as follows: straight, sweep, bow, sinuous, wobble, kink and fork (Figure 2). The stand selected for sampling was at least 10 years old.

The field surveys also collected information on a wide range of log dimensions and qualities at selling time harvested from short‐rotation community teak plantations. During field surveys interviews with teak growers and processors were also conducted.

Literature review

An extensive literature search was carried out in order to collate all sources of data and information related to community‐teak grown plantations and teaklog utilization harvested from the community teak plantations.

Figure 1. The location of survey of the community-grown teak plantations indicated by red stars

Figure 2. Classification of stem form used in the survey

Community-grown teak plantations

Site conditions

The site conditions where the major community‐grown teak plantations has been developed vary. Mostly the soil belongs to vertisol and alfisol derived majority from limestone and sediment. Annual rainfall ranges from around 1,200 mm (East Nusa Tenggara) to more than 2,850 mm (South East Sulawesi). All of the sites where teak has been grown have monsoonal season, namely wet and followed with dry season (Table 1). The amount of rainfall and the length of wet season will affect the growth and quality of teak wood. Some sites can be categorized as fairly good, like in Konwale Selatan (SE Sulawesi). In contrast, other sites are very poor, stony soil having very shallow soil, like in some parts of Gunung Kidul, Wonogiri and many parts of Pacitan. The elevation of the surveyed sites ranged from 0 to 300 m above sea level.

Table 1. Site conditions of selected community teak growing areas Location Soil Rainfall Length of dry Type Parent material (mm/yr) season (month) Gunung Kidul Vertisol, Alfisol Limestone, marl 2,145 6 Andesitic sediment Wonogiri Vertisol, Alfisol Limestone, marl 2104 6 Pacitan Vertisol, Alfisol Limestone 1,892 6 E.Nusa Tenggara Vertisol, Alfisol Limestone 1,286 7 S. Sulawesi Alfisol Limestone, marl 1,620 5 SE Sulawesi Alfisol, Vertisol Sediment 2,850 5

Size and productivity

It is not easy to assess the accurate size (ha) of the community‐ grown teak plantations for various reasons. Teak is planted in various patterns by farmers: planting block either pure or mixed with other tree species, a mixture of different ages, edge rows planting along the borders of farm land, scattered trees in home garden.

A survey carried out in 2003 (Central Bureau of Statistic 2004) revealed that teak was the most favoured tree species grown by farmers amounting to 79.7 million trees, followed by Paraserianthes (59.8 million trees), mahogany (45 million trees), and acacia (32 million trees). There were over three million households growing teak all over Indonesia. The majority of community‐grown teak plantation is located in Java. Three major growing areas of community teak plantation in Java are Central Java (26.5 %), Yogyakarta (8.9 %), and East Java (21.3 %). Outside Java teak is grown by farmers in high quantity in East Nusa Tenggara (6.8 %), South Sulawesi (4.5 %) and South East Sulawesi (2.2 %). In these major community teak plantations some of the trees are ready for harvest (Table 2).

Total teak log production from the community teak plantations in Java in 2006 amounted to 758,720 m3 (Table 3), which is much higher than teak log produced by Forest State Enterprise, Perhutani in the same year around 486,948 m3. Teak log production from community forest can vary from year to year since harvesting plan does not exist and it is based more on the economic need of the farmer. Figure 3‐5 illustrate the community teak plantations, while Figure 6 shown the teak plantation managed by Forest Estate Enterpise, Pehutani.

Table 2. The size of community-grown teak plantation in major growing areas in Java and eastern Indonesia (Central Bureau of Statistic 2004) Province Number of Number of trees household Total 1 Ready for harvest2 West Java 171,907 4,053,909 (5.09) 1,216,096 (6,54) Central Java 926,748 21,099,806 (26,47) 4,054,652 (21.98) Yogyakarta 253,164 7,089,864 (8,89) 1,522,888 (8,26) East Java 964,758 16,963,633 (21.28) 510,770 (24.45) East Nusa Tenggara 193,076 5,458,148 (6.83) 775,830 (9.63) South Sulawesi 112,996 3,551,805 (4,46) 1,405,706 (7,62) South East Sulawesi 29,653 1,765,981 (2.24) 436,644 (2,37) 1 The numbers in bracket are the percentage of total teak trees grown in the community plantations in Indonesia; 2 The numbers in bracket are the percentage of trees ready for harvest from the total trees in the respective province

Table 3. Teaklog production from community teak plantation in Java in 2006 Province Log production (m3) References West Java 11,486 West Java Forest District (2007) Yogyakarta 98,650 Forest and Estate District of Yogyakarta (2007) Central Java 248,111 Cental Java Forest District (2006) East Java 400,473* Perhutani Unit 1 East Java (2007) Total 758,720 * = estimated

Figure 3. Community teak plantation in: (a) Gunung Kidul and (b) Wonogiri

Figure 4 Community teak plantation in: (a) Pacitan and (b) East Nusa Tenggara

Figure 5. Community teak plantation in: (a) South Sulawesi and (b) South East Sulawesi

Figure 6. Teak plantation in the state forest managed by Perhutani

An inventory conducted in a village of Pringsurat, Gunung Kidul, Yogyakarta revealed that the potential of teakwood produced from the community plantation was approximately 60.5 m3 per ha (Awang 2006).

It is not easy to obtain accurate data on tree growth of community teak plantations due to a number of reasons: a mixture of trees of different ages, unknown tree age, mixed planting with other species, a mixture of different methods of regeneration, different stocking etc. Table 4 shows the rate of teak growth at different locations. The data should be treated cautiously and used as an indicative teak growth in the community plantations.

Teak growth in the community plantation seems to vary dependent upon the site condition and genetic material of planting stock. In Gunung Kidul, Wonogiri, Pacitan and East Nusa Tenggara teak had slow growth rate, but comparable with that of Perhutani in Cepu. Genetically poor planting stock, poor soil conditions and poor maintenance likely contributed to this less growth. In contrast, in Konawe Selatan (South East Sulawesi) teak had rapid growth, reaching 0.88 – 2.70 cm in stem diameter per year which is attributable to more fertile soil condition and a longer rainy season than other areas being surveyed. Bhat (2006) reported a similar finding in India in that trees from wet sites had faster growth than dry sites. Teak responds very well in terms of growth and girth increment in areas where the trees received at least sufficient moisture throughout the year than growth in monsoonal areas.

Table 4. Growth rate of community teak plantation Location Mean annual increment Height (m/yr) Stem diameter (cm/yr) Gunung Kidul 0.58-1.36 0.90-1.69 Wonogiri 0.38-1.19 0.52-1.30 Pacitan 0.45-1.10 0.68-1.29 East Nusa Tenggara 0.31-0.68 0.80-1.69 South East Sulawesi 0.70-1.62 0.88-2.70 South Sulawesi 0.40-1.34 0.70-1.40 Cepu (Perhutani)* 0.50-0.70 0.86-1.22 *) Forest state enterprise

Silvicultural practices

The community‐grown teak plantations are established using a variety of planting materials, including seed, seedling, stump and coppice. Mostly the planting materials are from genetically unimproved seeds and often unknown seed sources. Only recently some farmers have been using some planting materials purchased from seedling growers that claim their planting materials are of improved ones. Seeds may be picked off from the ground from trees in the surrounding areas and directly planted at the early rainy season. Seeds may also grown first in the polybag before planting in the field. Seeds may also collected from available stands nearby belonging to the state forest, for example in Gunung Kidul and South East Sulawesi. The wildlings growing under stands are often allowed to grow. Stump is often prepared from the wilding from surrounding areas or other locations and then planted. Coppice system is also used in many community teak plantations in a number of locations.

The use of wildings and coppice are for example found in Gunung Kidul, Wonogiri, Pacitan, East Nusa Tenggara and South Sulawesi. Coppice method of regeneration is very common found in Bulukumba (South Sulawewi) (Figure 7).

The use of wilding is particularly causes for concern due to the possibility of inbred seed which results in low productivity and poor quality of the plantation. Seed bearing trees per a unit area in the community teak plantation may be not many or scattered. The crossing rate of such trees are likely not good, resulted in producing inbred seeds. In addition, due to the best trees are usually harvested by farmers to get quick income, and leaving the poor ones, this practice could results in deterioration of tree growth and quality in the future plantations.

Coppice regeneration when unsingled and leaves more than one stems also results in poor growth and stem form (sweep and fluting). Also, tree growth from coppices is poor when they are unfertilized.

At the time of planting the majority of the growth of community‐grown teak plantations are unfertilized so that their productivities are mostly low, except at the site where inherent soil fertility is relatively high such as at Konawe Selatan (SE Sulawesi). Nutrient inputs after planting are rarely applied. No single tree spacing is adopted. When teak is planted as planting block it may be spaced 2 m x 2 m, 3 x 2 m; 4 x 2 m etc. Teak may also planted between agriculture crops, known locally as tumpangsari (taungya system), using spacing distance of 2 m within rows and 4‐6 m between rows. Teak may be planted purely or mixed

with other tree species. Teak may also be planted in the edge of garden (border planting) which are often in close spacing (1 m apart).

b a

Figure 7. (a) Wilding and (b) coppice are often used for regeneration in community teak plantations

Pruning is seldom done or if it is practiced the pruning method is incorrectly applied (Figure 8). If performed incorrectly, pruning can reduce the quality of stem wood even more than failing to prune at all. Incorrect pruning can also damage the quality of wood by inviting disease or insect. For example leaving long brunch stub which eventually leads to loose knots in the stem or branch size is already too big when pruning is done leaving the a large size of scars. Therefore, pruning is required to keep tree trunk free from knots that reduce quality and to increase merchantability height.

Figure 8. (a) Pruning is rarely done resulting in trees with poor stem form or big knot, (b) Thinning is sometime practiced and cut logs a are sold (photo from infojawa.org)

Thinning practice varies dependent on the knowledge of the farmer. Generally small holder farmers are reluctant to undertake silvicultural thinning. They believe that all trees have economic worth and are reluctant to cut trees unless the log can be sold. However, in some locations, for example in certain parts of Gunung Kidul and Wonogiri thinning has been practiced (Figure 8). Farmers who thin their stands expect earlier income from thinning and better growth and quality of the remaining trees in the future. On the other hand, some farmers feel reluctant to cut their trees because of additional cost with no economic return and always think that thinning will be a loss in their investment. With no

thinning has been practiced particularly during the first ten years in densely growing stands, trees’ growth potentials are lost. The high competition in dense stand will result in smaller stem diameter classes which reduces the price each log can generate.

Farmers use their teak trees as a form of savings. Harvesting is done using a principle of the need of the farmer. Whenever farmers need a large sum of money, for instance to pay their children’s education, wedding ceremonies, medical emergencies etc., then they will cut their trees, usually the biggest ones in their land which commands highest price.

Stem form quality

The important property requirements of teak wood include straight bole with least taper, reduced fluting (irregular involution and swelling) and knot‐free volume. Results of the survey in the community teak plantation revealed that trees have different types of stem form. Higher percentages of trees in the community plantation did not have straight bole, except in South East Sulawesi. In the later location the majority of trees had straight stem. Compared with teak plantation grown by forest state company (Perhutani) in Cepu, the stem form of teak plantation grown by farmers was poorer, except that from SE Sulawesi (Table 5). High percentages of trees had flutes both in the community grown teak plantations as well as in the Perhutani plantation. Stem cylindricity was mostly categorized as moderate, except in Pacitan where most of the trees had poor stem cylindricity. Teak in Perhutani had better stem cylindricity than community‐grown teak plantations (Table 6).

Overall community teak plantations had poorer stem form compared with those of Forest State Enterprise, Perhutani. As mentioned in the preceding section that community‐grown teak plantations were mostly established using genetically poor planting stocks and often unknown origin. The combined poor planting material and poor maintenance resulted in poorer stem form compared with that of Perhutani’s plantation. The later had used better planting material at least the seeds come from seed production area.

Table 5. The percentage of tree with different types of stem form Location Trees with different type of stem form (%) Bow Fork Kink Sinuous Straight Sweep Wobble Gunung Kidul 10.9 15.4 3.0 9.6 57.1 1.7 2.0 Wonogiri 14.1 6.7 1.0 9.6 57.4 9.3 1.9 Pacitan 7.8 11.5 14.7 35.3 22.5 5.3 3.9 E. Nusa Tenggara. 11.4 11.7 9.4 9.0 49.0 9.1 0.3 South Sulawesi 13.8 8.3 6.0 32.3 36.8 12.3 4.9 SE Sulawesi 4.6 11.2 6.3 9.9 74.5 5.0 0.0 Cepu (Perhutani)* 6.7 10.8 4.4 10.0 67.5 0.0 0.3 *) Forest state company

Table 6. Stem cylindricity and butt fluting Location Tree with cylindrical form (%) Tree with butt fluting (%) Good Moderate Poor Gunung Kidul 52.0 27.0 20.0 74.9 Wonogiri 17.8 60.2 22.0 71.0 Pacitan 15.0 18.8 66.1 41.6 E. Nusa Tenggara. 2.6 64.8 32.6 9.6 South Sulawesi 43.7 51.8 10.6 95.2 SE Sulawesi 74.2 21.7 7.6 93.1 Cepu (Perhutani)* 69.7 27.3 0 85.5 *) Forest state enterprise

The need for stem quality improvement As mentioned in the preceding section that stem quality of the community‐ grown teak plantation is still low. Therefore, the improvement of stem form of the teak plantation grown by farmers are needed. This can be done in a number of ways. Genetically improved planting materials should be used. In teak stem form has been reported to be strongly under genetic control (Kaosa‐ard 2000, Danarto and Hardiyanto 2001).

Genetically improved planting materials are now available. Perhutani through its tree breeding program has produced improved planting materials which are also available for sale. Perhutani owns 1,300 ha of clonal seed orchard (CSO) varying in age from 11 to 23 years which produce 20 tons of seed annually. In 2006 the CSO of Perhutani produced 41 tons of clean seeds, 33 tons for own use, 3 tons for public relation and 5 tons are available for public sale (Purwanta, pers. comm.).

In South East Sulawesi seed production areas (SPA) have been established by the government on state forest, for example in Buton (50ha) and Muna (37 ha). A new SPA has also been established in Konawe Selatan, but it is yet to produce seed (Midgley et al. 2007).

It is recommended that seed used for planting at least from seed production area and whenever possible to get seed from the CSO of Perum Perhutani. The use of wilding, seedling or stump from unknown source should be avoided. Coppice method of regeneration should not be practiced.

In addition to the use of better planting materials, proper silvicultural practices should also be practiced to improve productivity and stem quality of community teak plantations. Spacing, pruning and thinning should be practiced properly. Training or extension activities on better growing teak plantations for small‐ holder farmers are urgently needed.

Log Quality and Wood Property

Log quality Commercial teak woods harvested from community plantations in Gunungkidul, Wonogiri, Pacitan, East Nusa Tenggara and South East Sulawesi showed different quality when they were compared to the commercial teak wood harvested from the teak plantations of Forest State Enterprise, Perhutani. Generally teak logs from community plantations were smaller in diameter, higher portion of sapwood and occurrence of knots along the stem, poorer stem‐ form and more stem defects than those of Perhutani’s plantation. Detailed observations on teak logs from community plantations revealed that heart rot occurred even the trees were still relatively young.

The average log diameter of the community‐grown teak plantations in Java, for example ranged from 22.0 cm to 26.2 cm. This is much smaller than teak logs harvested from the Forest State Enterprise, Perhutani in Cepu which had the average diameter of 40 cm.

The heartwood portion was determined by measuring the area of heartwood compared to area of two cross section of the stem obtained from two ends of the log. The average heartwood portion of log from community teak plantations ranged from 52 % to 78 %. The average log with flute varied from 3.6 % to 51.3 %, while the average log with end split ranged from 23.1 % to 61.1 %. In comparison logs from Perhutani’s plantations in Cepu had the average heartwood percentage of 72 %, the average log with flute of 17 % and the average of log with end split of 11 %. The high percentage of heartwood of teak log from South East Sulawesi is possibly related to the rapid growth of teak plantation in the area (see Table 4). Fast growth of teak is previously reported to correlate with high percentage of heartwood and strength (Bhat 2000, Bhat et al. 2001). The higher quality of teak log from Perhutani’s plantation can be understood as the logs had larger diameter and were harvested from older teak plantations, normally at 60 years old, even tough at certain cases the harvesting age has been reduced to younger ages, around 40 years old.

Figure 9 shows samples of teak logs from different sites. The high percentages of sapwood (light color wood appearing in the outer portion of logs, near the bark) are attributable to small diameter logs and young ages when the trees were harvested. The heartwood portion was significantly lower than that of teak logs harvested from Forest State Enterprise Perhutani’s teak plantation which harvests its plantation at 40‐60 years of age (Figure 10c). Prayitno (2001) studied the changes in teak wood quality of Perhutani’s plantations and found that the decreased wood quality in its teak plantation was due to the cutting age. Older age teak trees having bigger stem diameter produced greater portion of heartwood. Okuyama et al. (2003) reported that the heartwood ratio was related to stem diameter not age.

In addition, log defects were found in logs harvested from community teak plantations, such as knot with variation of its diameter, flute, and heart rot downgraded the log. As a consequence, logs form the community‐grown teak plantation are sold at lower prices than those from Perhutani.

a b

c d

Figure 9. Teak logs harvested from community teak plantations: (a) Gunung Kidul, (b) Wonogiri, (c) Pacitan and (d) East Nusa Tenggara

a b

Figure 10. Teak logs harvested from community teak plantations: (a) South Sulawesi, (b) South East Sulawesi, (c) Forest State Enterprise, Perhutani in Cepu for comparison

The low percentage of heartwood has a consequence, that is, the low price of the teak log. It could drop to one third up to one half of regular price of the log per cubic meter. For example, the price of Perhutani’s teak log with the same diameter but having almost full heartwood could be sold at Rp 20 million, while that of teak log from community plantation is only Rp 6 up to 10 million per cubic meter. This situation becomes worse when the buyer already knows that the sapwood is not quite durable compared to heartwood. In the field the teak log price varies widely due to market mechanism, namely supply and demand of the teak log. When the teak supply falls short, the teak log price soars up, in contrast when the teak log is abundant then the price goes down.

Detailed information on the quality of logs coming from community teak plantations are presented below according to the location.

Gunung Kidul Twenty five enterprises were surveyed in the district, all of them were small in scale and managed as family‐run enterprise. They generally have log yards for collecting logs before being processed or sold. They do not have large amount of capital, high quality and sophisticated machineries. Typically the processor have only small amount capital with traditional and semi manual‐processing machineries.

Table 7 presents the teak wood log quality found in the log yard of each processor surveyed in Gunung Kidul. The average log diameter was 26 cm. The average minimum log length was 1.89 m, while the average maximum log length was 4.08 m. This range of log length is suitable for producing door and window frames, short beam for house constructions and furniture components. However, it is much shorter compared with commercial tropical wood species from Kalimantan. The commercial tropical hardwoods (Kalimantan hardwood species) such as meranti, keruing, belangeran are produced in a 6 m log‐length or longer. The differences could be traced back to the quality of teak plantation owned by the community teak growers. The striking factor affecting this log length was the branching habit of the trees. The branch has been found so low on the stem making the log length produced from the trees is less than 2 m.

Teak logs harvested from community plantations in Gunung Kidul had a variety of defects. The common defect found was the existence of large knots

and sometimes distributed along the stem, which significantly downgrade the quality of logs. It was also found high percentages of logs with flute, end‐split and heart rot in the log cross section. The average diameter of knot was about 4.28 cm, and the average log length free of knot was 2.23 m. The average percentages of log with flute, split and heart rot were was 51.3 %, 23.1 % and 5.5 % respectively.

Table 7. Teak log quality in the log yard of traditional, small scale industries in Gunungkidul Industry name Diameter (cm) Log length (m) Heart Knot Log length Log with Log with Log with Min Max Ave. Min Max wood diameter free of flute (%) heart rot end split (%) (cm) knot (m) (%) (%) Kurnia Jati 17 42 26 1.8 2.9 0.62 4.9 1.4 53.3 10.0 6.7 Karya Jati 12 44 29 0.5 3.0 0.64 4.0 1.2 20.0 10.0 3.3 Mutu Jati 11 40 19 2.0 3.1 0.46 2.8 1.8 26.7 26.7 3.3 Dwi Bangun 12 31 21 1.7 3.0 0.61 3.4 1.9 50.0 10.0 3.3 Gasing Jaya 20 34 26 1.6 2.6 0.61 5.5 1.6 70.0 30.0 40.0 Sinar Mulia 22 45 29 1.0 2.9 0.62 3.5 1.7 36.7 0.0 26.7 Sumber Rejeki 23 37 29 2.0 4.0 0.57 5.2 2.1 76.5 0.0 0.0 Suminar Jati 23 73 37 1.5 6.0 0.74 5.6 2.9 64.7 0.0 17.6 Nugroho 20 36 27 2.5 5.0 0.60 0.0 2.2 75.0 0.0 0.0 Widodo 13 41 26 1.5 4.5 0.64 3.7 2.7 36.7 10.0 26.7 Sumber Jati 20 28 25 2.0 3.0 0.61 3.7 1.8 40.0 10.0 10.0 Kabul Santoso 14 43 26 1.4 3.5 0.57 4.4 1.4 45.4 18.2 18.2 Jati Unggul 14 22 19 2.5 3.0 0.40 2.7 2.4 50.0 5.0 35.0 Israk Mebel 14 37 23 2.0 3.5 0.53 4.5 1.8 23.1 0.0 23.1 Mandiri 17 35 27 3.0 4.0 0.60 6.0 2.9 68.7 18.7 0.0 Batur Agung 19 52 34 1.3 4.0 0.67 5.7 2.2 52.9 0.0 23.5 Bukit Seribu 15 48 32 1.0 6.5 0.65 5.7 3.1 54.5 4.5 22.7 Karya Manunggal 16 30 22 2.0 2.0 0.48 4.3 1.2 28.6 0.0 100.0 Average 17 40 26 1.9 4.1 0.59 4.3 2.2 51.3 5.5 23.1

Wonogiri Wonogiri district is located at the east side of Gunungkidul. It has similar site conditions as those of Gunungkidul. Surprisingly the teak logs observed in ten log yards in Wonogiri showed better qualities than Gunungkidul. The average log diameter was 22 cm. With regard to log length being sold, or the debugging policy of the wood seller, teak logs in this area were cut at length ranging from 0.9 m to 3.0 m. These log lengths were much shorter than those found in Gunungkidul (1.4 ‐ 4.5 m). Compared with the teak log observed in Gunungkidul, teak logs in Wonogiri had less defects. The average heartwood

portion found in the cross section of teak logs was 62% compared to 59 % in Gunung Kidul. The knot diameter was also much smaller (0.99 cm) compared to 4.28 cm in Gunungkidul, while the length of free‐knot log was shorter in Wonogiri (1. 53m) compared to Gunungkidul (2.23 m). The logs with buttress and heart rot incidence were considerably lower in Wonogiri, but the percentage logs with split end percentage was higher in Wonogiri (Table 8).

Table 8. Teak log quality in the log yard of traditional, small scale industries in Wonogiri Industry name Diameter (cm) Log length (m) Heart Knot Log length Log with Log with Log with Min Max Ave. Min Max wood diameter free of knot flute (%) heart rot end split (%) (cm) (m) (%) (%) Sido Lancar 14 33 22 1.0 2.5 0.67 0.56 2.0 26.7 0.0 30.0 CV. Kartika 10 32 21 1.0 2.5 0.60 1.32 1.4 16.7 0.0 33.3 Kayu Mas 14 29 21 1.0 2.5 0.49 1.50 1.3 23.3 3.3 30.0 UD.Cinta Abadi 14 28 22 0.7 2.1 0.54 1.37 1.2 23.3 0.0 43.3 Sugeng Surupan 10 27 18 0.9 2.5 0.62 1.00 1.3 16.7 0.0 26.7 UD. Maju Jaya 15 35 24 1.0 3.0 0.62 0.53 1.7 6.7 6.7 13.3 UD. Jati Mas 14 35 24 1.0 3.0 0.74 1.17 1.7 13.3 3.3 16.7 Karya Baru 10 32 22 1.0 2.5 0.64 0.00 1.4 26.7 0.0 30.0 Delanggeng 14 32 23 1.0 2.5 0.68 0.93 1.5 10.0 3.3 23.3 Mutiara Jati 13 32 23 1.0 2.8 0.62 1.50 1.6 10.0 10.0 16.7 Average 13 32 22 0.9 2.6 0.62 0.99 1.5 17.3 2.7 26.3

Pacitan Pacitan has similar site conditions to those of Gunung Kidul and Wonogiri (see Table 1). Teak log qualities observed in Pacitan were slightly lower that those found in Gunungkidul or Wonogiri. The average log diameter was 23 cm. The average minimum length of teak log found in a number of log yards was 1.45 m. As mentioned the preceding section that the debugging policy at each location is different, indicating that the minimum log length is dependent on the market demand or the end product dimension. Teak log length in Pacitan was shorter than Gunungkidul but similar to Wonogiri, which ranged from 1.0 m to 2.5 m.

The growth and quality of community teak plantations in Pacitan were significantly poorer that those found in the adjacent districts (Wonogiri and Gunung Kidul) producing teak logs of much lower qualities. The heartwood percentage of teak log in Pacitan was only 52% which is lower compared to that of Gunungkidul and Wonogiri. The average diameter of knot was found to be

larger (8.42 cm) than Gunungkidul (4.28cm) and Wonogiri (0.99 cm), while the average length of knot‐free log was much shorter (0.98 m) compared to Gunungkidul (2.23 m) and Wonogiri (1.53 m) (Table 9).

Teak logs obtained from Pacitan had lower percentage of log with flute, possibly due to site conditions and plantation management. The average percentage of log with flute was only 26.8 % compared to that of Gunungkidul (51.3 %). The same condition occurred for log splitting behavior. The average percentage of log with end split was 51.1 % which is very high when it is compared to that of Gunungkidul (23.1 %) and Wonogiri (26.3 %). These findings confirm the results from informal interviews with wood processors that teak log quality in Pacitan was lower than Gunungkidul and Wonogiri. .

Table 9. Teak log quality in the log yard of traditional, small scale industries in Pacitan Industry name Diameter (cm) Log length (m) Heart Knot Log length Log with Log with Log with Min Max Ave. Min Max wood diameter free of knot flute heart rot end split (%) (cm) l(m) (%) (%) (%) Marjuki Arjosari 12 26 20 2.0 2.0 0.51 6.7 0.85 0.0 30.8 69.2 UD. Wahyu Jati 10 51 29 1.2 2.0 0.61 9.6 0.90 50.0 30.0 50.0 Abdul Romi 11 38 22 1.5 2.0 0.45 7.6 0.94 0.0 23.1 46.1 TPN Desa Candi 12 32 20 1.5 2.5 0.39 7.0 1.10 40.0 30.0 50.0 UD Tri Rukun 12 52 27 1.0 2.5 0.65 11.2 1.10 0.0 20.0 90.0 Average 11 40 23 1.4 2.2 0.52 8.4 0.98 18.0 26.8 61.1

East Nusa Tenggara Teak log qualities from East Nusa Tenggara were inferior to those previously reported from southern part of Java (Gunungkidul, Wonogiri and Pacitan). The average log diameter was 18 cm. The average minimum length of teak log available in the industry was 1.2 m, while the average maximum length was 2.8 m, which is shorter than Gunungkidul, but longer than Wonogiri. The average heartwood percentage was the same as that of Pacitan (52%), and lower than Gunungkidul (59%) and Wonogiri (62%). Knot diameter average was considerably very high (10.52 cm). The average knot‐free log was very short, in fact the shortest among the four locations has been reported so far (Table 10). This indicates that the knots appeared on the entire log length.

Table 10. Teak log quality in the log yard of traditional, small scale industries in East Nusa Tenggara Industry name Diameter (cm) Log length (m) Heart Knot Log length Log Log with Log with Min Max Ave. Min Max wood diameter free of knot with flute heart rot end split (%) (cm) (m) (%) (%) (%) Bengke Bahtera 12 32 20 1.1 3.8 0.57 6.4 0.28 10.0 13.3 36.7 Karya Setia 16 21 17 1.5 2.0 0.52 9.2 1.01 0.00 0.00 0.0 Zona Dewata 9 20 14 1.3 3.2 0.51 14.2 0.94 3.33 6.7 53.3 Buana Kelu 12 22 17 1.0 2.0 0.51 15.2 0.55 0.00 20.0 40.0 Mitra Kencana 13 19 21 1.0 2.8 0.47 6.3 0.13 4.76 4.8 33.3 Average 12 23 18 1.2 2.8 0.52 10.2 0.58 3.62 8.9 32.7

South Sulawesi Teak logs harvested from community plantations in South Sulawesi had relatively similar quality to those in Java (Gunung Kidul and Wonogiri). The average diameter log was 24 cm. The average minimum log length was 1.6 m, whereas the avearge log length was 3.0 m. The average heartwood percentage was suprisingly quite high (73.0 %) (Table 11).

Table 11. Teak log quality in the log yard of traditional, small scale industries in South Sulawesi Industry name Diameter (cm) Log length (m) Heart Knot Log length Log with Log with Log with Min Max Ave. Min Max wood diameter free of knot flute heart rot end split (%) (%) (m) (%) (%) (%) Haji Damang 16 41 26 1.9 2.9 82.0 0 0 0 0 0 Usaha Mujur 14 44 29 1.6 2.7 48.0 11.9 0.4 7.0 7.0 10.0 Jati jaya Mandiri 13 40 19 1.2 3.1 60.0 5.0 1.1 3.0 10.0 7.0 Panrita M. 12 30 21 1.7 2.9 80.0 7.9 - 3.0 3.0 0 Samsurya 20 33 26 1.7 3.2 95.0 0 0 0 0 0 Average 15 38 24 1.6 3.0 73.0 8.3 0.8 4.3 6.7 8.5

South East Sulawesi As mentioned previously that community teak plantations in South East Sulawesi grew faster and showed better stem quality than other surveyed areas. The teak log quality indicators such as heartwood percentage, log without knot or buttress, incidence of heart rot and end split determine the good management in the community teak plantations. Table 12 shows the information of teak log quality in Southeast Sulawesi.

Table 12. Teak log quality in the log yard of traditional, small scale industries in South East Sulawesi Industry name Diameter (cm) Log length (m) Heart Knot Log length Log Log with Log with Min Max Ave. Min Max wood diameter free of knot with flute heart rot end split (%) (cm) (m) (%) (%) (%) Marsuki 15 44 24 1.60 2.15 73 na na na na na Darmokusumo 17 46 26 1.17 2.40 82 na na na na na Average 16 45 26 1.39 2.28 78 na na na na na na = not available

Wood property

Teak logs harvested from community teak plantations were collected from 5 locations, namely Gunungkidul, Wonogiri, Pacitan, East Nusa Tenggara and South East Sulawesi. The logs were then sawn to make samples for determining the physical and mechanical properties according to the ISO 1975 standard. Results of the assessment of wood properties are reported in details below.

Mechanical property Teak wood is used for structural purposes in house constructions as well as in boat and ships. In order to assess if community‐grown teak plantations have the required strength properties for those end‐uses, mechanical strength of wood samples collected from 5 locations were determined.

Table 13 presents the results of assessment of mechanical strength of teak wood from different locations. Teak wood strength differed between locations. Generally, teak wood from South East Sulawesi showed greater mechanical strength compared to other four locations (Gunungkidul, Pacitan, Wonogiri and East Nusa Tenggara). The strength difference might be due to specific conditions of each location. Site condition and plantation management have been known to have pronounced effects on physiological activities in trees, which in turn affect tree growth and wood quality. The mechanical strengths of teakwood originated from South East Sulawesi were 58.4 N/mm2; 80.5 N/mm2; 30.7 N/mm2; 119.4 N/mm2 and 11,537.8 N/mm2 for compression parallel to grain, tension parallel to grain, shear, modulus of elasticity (MOE) and modulus of rupture (MOE), respectively.

Table 13. Average teak wood mechanical properties from different locations Compression Tension Shear Location MOR MOE strength // to strength // to strength (N/mm2) (N/mm2) grain (N/mm2) grain (N/mm2) (N/mm2) Gunung Kidul 47.0 95.9 26.8 104.1 9,184.2 Wonogiri 52.7 99.8 24.2 107.4 8,942.2 Pacitan 41.7 78.9 23.7 93.7 9,590.7 E. Nusa Tenggara 46.0 73.0 22.5 83.4 6,745.1 S. E. Sulawesi 58.4 80.5 30.7 119.4 11,537.8

Earlier studies on wood mechanical properties teak wood taken from a plantation of 17 years old in Java reported that the MOE was 10,729 N/mm2, while the MOR was 76.2 N/mm2 (Putro and Sutjipto 1989). A similar study in Thailand using logs taken from 20 year old plantation and tested according to ISO 3129‐1975 (E) found that compression and tension parallel to grain and shear strength were 35.2 N/mm2 , 81.8 N/ N/mm2 and 0.83 N/ mm2 respectively (Ruksasupaya et al. 1995).

Results of this present study are not much different from a similar study in India reported by Bhat (1997) who found that the MOR and MOE of 27 year old trees were 112.4 and 11,179 N/mm2, respectively. Similarly the bending strength of community teak plantations reported in the present study was not inferior to the older trees. Bhat (1997) reported the MOR and MOE of 52 years old trees were 103.6 and 12,985 N/Nm2, respectively. Other published reports on mechanical properties of natural‐grown teak and plantations present the same variability, in particular, a wide range of MOE and MOR values ranging from 8600 to 13400 N/mm2 for the first MOE and from 58 to 148 N/mm2 for MOR (Trockenbrodt and Josue 1999). Teak log normally attains maturity mechanical maturity by 20‐21 years (Bhat 2000, Bhat et al. 2001) which is coincident with the cutting age of mostly community teak plantations in Java.

An analysis of variance for mechanical properties reveals that the only factor affected significantly on the mechanical strength of teak wood was location. The location had profound influence on the structure and anatomy of teak wood which in turn resulting in different strength properties. The other factors such as axial positions (butt, middle and top portion of the stem) as well as radial position of sapwood and heartwood did not affect the mechanical strength

significantly. As mentioned in the preceding section the wood from South East Sulawesi had greater percentage of heartwood than other locations which contributed to the differences in mechanical strength.

Longitudinal variation Longitudinal variations in teak log have been reported in various publications. At higher positions of log (top portion of tree), the strength tends to have lower value compared to near the base (butt portion). Significant longitudinal variation of teak log strength harvested from the community teak plantations was not observed in this study (Table 14). More detailed observations reveals the reason behind this finding. Teak logs from community teak plantations were harvested at young ages, typically at 15‐20 years old, they had more branches at the lower positions of the stem, compared to those cut from Forest State Enterprise, Perhutani’s teak plantations. The log length of community teak plantations sold commercially was in a range of 3 m for each axial portion. This means that the whole log length is only about 6 m or less. Consequently, the mechanical strength of teak logs from community teak plantations is more or less the same along the axial direction.

Table 14. Average teak wood mechanical strength at the axial position Longitudinal Compression Tension Shear MOR MOE position strength // to strength // to Strength (N/mm2) (N/mm2) grain (N/mm2) grain (N/mm2) (N/mm2) Butt 49.3 89.2 26.1 101.5 7,791.7 Middle 48.2 80.9 25.1 104.0 9,937.7 Top 50.0 86.7 25.5 99.4 9,870.6

Radial variation The sapwood of teak wood is characterized with light color, while the heartwood is dark, brown yellowish in color. The higher percentage of sapwood is normally found in the cross section of stem of young trees. This has been used by the user for determining the commercial price of wood. The higher percentage of sapwood found in the stem (cross section of log), the lower the price per cubic meter will be.

There was no clear relation between the sapwood proportion and mechanical properties. The sapwood strength was not always inferior to the heartwood. Table 15 shows that the heartwood portion was only more superior than sapwood in tension strength parallel to grain and modulus of elasticity (MOE), while in the other mechanical properties were not much different and had no practical values.

Table 15. Average teak wood mechanical strength according to radial position Radial Compression Tension Shear MOR MOE position strength // to strength // to strength (N/mm2) (N/mm2) grain (N/mm2) grain (N/mm2) (N/mm2) Sapwood 49.7 82.6 25.9 103.0 8,909.5 Heartwood 48.6 88.6 25.2 100.2 9,490.5

Interactions between factors In this study, the effect of interactions between two or more factors involving location, axial and radial position was tested. Table 16 presents the mechanical properties according location and axial direction, whereas Table 17 depicts the mechanical properties according to location and radial direction. Results of the analysis variance reveals that only location exerted significant effect on the mechanical strength. Other factors and their combinations did not affect significantly on the strength of the wood (Table 18) . Published data on a similar study but on matured trees report that the effect of axial and radial potions their effect is significant on the mechanical properties. The different results reported in this study might be caused by the age of trees. All of the tree samples in the current study represented the commercial teak wood when they were sold by the farmer.

Table 16. Average teak wood mechanical strength according to location and axial position Compression Tension Shear Longitudinal strength // to strength MOR MOE strength Location position grain // to grain (N/mm2) (N/mm2) (N/mm2) (N/mm2) (N/mm2) Butt 45.7 101.9 29.2 108.2 7,890.4 Gunungkidul Middle 45.6 99.5 24.2 99.5 9,263.6 Top 49.8 86.2 26.9 104.7 10,398.5 Butt 53.3 91.5 24.3 104.6 7,986.1 Wonogiri Middle 51.9 91.2 24.9 110.2 9,765.8 Top 52.9 116.8 23.3 107.4 9,074.6 Butt 43.4 86.5 22.1 102.6 9,115.5 Pacitan Middle 38.6 73.2 24.4 91.7 10,652.2 Top 43.0 76.9 24.8 86.8 9,004.5 Butt 46.5 79.6 23.6 80.8 4,350.5 East Nusa Middle 45.2 67.0 19.9 93.9 8,110.6 Tenggara Top 46.4 72.6 23.9 75.4 7,774.2 Butt 57.7 86.8 31.3 111.1 9,616.3 South East Middle 59.7 73.8 32.1 124.7 11,895.9 Sulawesi Top 57.7 80.8 28.8 122.4 13,101.2

Table 17. Average teak wood mechanical strength according to location and radial position Compression Tension Shear Location Radial strength // to strength MOR MOE strength position grain // to (N/mm2) (N/mm2) (N/mm2) (N/mm2) (N/mm2) Sapwood 47.0 89.7 26.4 107.3 9,091.5 Gunungkidul Heartwood 47.1 102.0 27.1 101.0 9,276.9 Sapwood 53.8 97.3 24.0 109.7 9,741.0 Wonogiri Heartwood 51.7 102.3 24.3 105.1 8,143.3 Sapwood 41.6 83.8 24.0 91.7 8,317.4 Pacitan Heartwood 41.7 73.9 23.5 95.7 10,864.1 E. Nusa Sapwood 48.3 66.1 23.3 91.4 7,346.3 Tenggara Heartwood 43.7 79.9 21.7 75.4 6,143.9 Sapwood 57.9 76.1 31.9 115.1 10,051.4 S.E. Sulawesi Heartwood 58.9 84.8 29.4 123.7 13,024.3

Table 18. Analysis of variance of teak wood mechanical properties Significance Source df Compression Tension Shear strength // to strength // strength MOR MOE grain to grain Location (L) 4 ** ** ** ** ** Axial (L) 2 ns ns ns ns ** Radial (L) 1 ns ns ns ns ns L x A 8 ns ns ns ns ns L x R 4 ns ns ns ns ns A x R 2 ns ns ns ns ns L x A x R 8 ns ns ns ns ns ** = significant at 0.01, ns= not significant

Physical property The physical properties assessed in this study consist of wood specific gravity, shrinkage and swelling. Three factors were involved in the study, namely the locations of teak wood taken from the teak plantation, three levels axial positions (butt, middle and the top portion) and radial position (sapwood and heartwood).

Table 19 presents the average wood specific gravity and shrinkage behavior of teak wood from different sites. Teak logs from five locations relatively had the same physical characteristics. The highest wood specific gravity was found in teak wood coming from South East Sulawesi. The oven dried wood specific gravity of teak wood from this area was 0.69 and decreased slightly when it was measured in air dry condition. On the other hand, the lowest wood specific gravity was obtained in teak wood from East Nusa Tenggara. The oven dried wood specific gravity was 0.55, while the air dry specific gravity was 0.53. Teak wood from Java (Gunungkidul, Wonogiri and Pacitan) had oven dry wood specific gravity of 0.63, 0.64 and 0.60 consecutively, while their air wood specific gravities were 0,60; 0.62 and 0.57 for Gunungkidul, Wonogiri and Pacitan respectively.

Table 19. Physical characteristics of teak wood from different locations Location Oven dry Air dry Radial Tangential Longitudinal specific specific shrinkage shrinkage shrinkage gravity. gravity (%) (%) (%) Gunungkidul 0.63 0.60 2.40 6.65 0.72 Wonogiri 0.64 0.62 2.40 5.76 0.41 Pacitan 0.60 0.57 2.27 5.86 0.49 East Nusa Tenggara 0.55 0.53 1.99 3.80 0.52 South East Sulawesi 0.69 0.66 2.14 4.94 0.28

The higher wood specific gravity tends to have the higher wood strength. The lowest oven dry wood specific gravity in this study which was found in teak wood from East Nusa Tenggara, which had also the lowest wood mechanical strength. The highest wood specific gravity found in South East Sulawesi produced the highest mechanical strength.

Shrinkage behavior of teak wood from community plantations agrees with the universal rule of shrinkage and swelling. The highest shrinkage value from the green condition to oven dried state was at the tangential direction, followed by radial direction and the lowest was at the longitudinal direction. The tangential direction shrinkage was almost twice radial shrinkage. Among the five locations, Gunung Kidul and Wonogiri produced teak wood with high and similar shrinkage values, namely 2.40 %. The values of tangential shrinkage were 6.65 % and 5.76 % respectively for Gunung Kidul and Wonogiri. Pacitan had slightly lower radial shrinkage (2.27 %) and tangential shrinkage (5.86 %) than Gunung Kidul and Wonogiri.

A different result in wood shrinkage was found in teak wood collected from South East Sulawesi. Among five locations studied, it had the highest wood specific gravity in oven dry and air dry conditions, but the shrinkage values were relatively low. It was lower than the shrinkage values of teak wood from Java (Gunung Kidul, Wonogiri and Pacitan). The low shrinkage values were found in three directions, namely radial, tangential and longitudinal. It might be attributable to the high percentage of heartwood of the logs harvested from this area.

Earlier studies on wood shrinkage of teak wood taken from a 17 ‐ year old plantation in Java reported that that the radial shrinkage was 2.19 %, while the tangential shrinkage was 3.55 % (Putro and Sutjipto 1989).

The shrinkage values of log from community teak plantation observed here are markedly lower than those reported from a similar study using logs harvested from a 20 year old plantation in Thailand which found that radial and tangential shrinkage values were 4.1 %, and 10.7 % respectively (Ruksasupaya et al. 1995). Other published data on shrinkage of teak wood range from 2.5 % to 3.0 % in the radial direction, 3.4 % to 5.8 % in the tangential direction (Trockendrodt and Jouse 1999). The shrinkage values of the log from the community teak plantation in Java and eastern Indonesia were practically within the ranges mentioned above.

An analysis of variance was also conducted for shrinkage data as it was in mechanical strength. Three factors were involved in the analysis namely location, axial and radial directions (Table 20). The wood specific gravity was affected significantly by combination of location and axial and radial directions, indicating that each location has a different effect on axial and radial variations on wood specific gravity.

Table 20. Analysis of variance of physical properties of teak wood Significance Source df OD wood AD wood Radial Tangential Longitudinal spec. gravity spec. gravity shrinkage shrinkage shrinkage Location (L) 4 ** ** ns ns ns Axial (A) 2 ** ** ns .ns ns Radial (R) 1 ** .** ns ns ns L x A 8 ** ** .ns ns ns L x R 4 ** ** ns ns ns A x R 2 ns ns ns ns ns L x A x R 8 ns ns ns ns ns ** = significant at 0.01, ns= not significant

Wood Processing 5

In every area being surveyed there were teak wood processing units run by local people. They were typically small sized enterprises, traditional, and had low capital. Surprisingly there were many people involved in the teak log marketing and processing. Some were involved in marketing logs only, some were involved in marketing logs and processing, the others were involved in processing and marketing products. The small enterprises were generally initiated by the availability of opportunities, personal communication or family heritage. They have not been managed professionally.

Information gathered from the survey reveals that there were two types of enterprise working on teak wood. The first type is called teak log buyer. They are involved in buying trees from the community teak growers in the villages, collecting and putting logs in log yards and then selling the teak logs to wood processors. The teak buyer usually owns log yard for sorting and piling logs. The second type is teak businessmen who are involved in teak log processing and/or producing end product of teak wood such as furniture, housing components and other ordered items. They have the wood processing site such as sawmill, drying facilities, and other processing machineries. Interviews were also carried out with the teak log buyers (first type of enterprise) to collect additional more information on log qualities.

Sawing technique Almost of the observed sawing techniques in the rural or community teak wood industry were traditional, and very simple. The log was reduced to all lumbers of tangential type. The advantages of this sawing technique are very fast sawing, efficient, and no time required to turn logs for specific dimension of sawn lumber. All products of processing these tangential lumbers are for making furniture. However, the technique could produce lumber prone to defect such as splitting, bowing, and cupping.

Some community industries used band saw for breaking down the logs, the others employed large diameter of circle saw (Figure 11). The first sawing type is more efficient in processing and producing high yield, while the second one produces lower yield due to high sawdust waste.

The data on the recovery rate of sawing is lacking. Most of the small sized processors did not assessed the yield from sawing the log. Observations on the sawmill reveals that the recovery rate of most of the sawmill processing teak log form community plantation was low, below 40 %.

a b

Figure 11. Examples of sawing tools used by small sized processor : (a) band saw, and (b) circular saw

Wood drying The drying technique employed by the community teak wood processing in the surveyed area is mostly air drying ‐ traditional and also simple (Figure 12a). It does not require much effort to do it. This type of drying technique is only done by arranging the lumbers in arrow, almost vertically leaning to a wall or leaning to the center bar. By this technique the teak wood processors have earned a lot of benefits, such as low cost, easy to work on, requires less area to dry. However, this drying method has a number of disadvantages. It needs longer time to dry, can not be controlled in such a way to produce specific moisture content, and very high variability of moisture content in the wood.

However, some industries, for example in Gunung Kidul have employed a relatively high technology of drying wood, which is so‐called heating type by a wood heater (Figure 12 b and c). This drying technique is done by burning wood waste or lignocellulosic materials that is considered as waste in a box like burner and then the hot air is supplied to the drying chamber. The lumbers are stacked or piled in such a way that hot air could pass through the inter lumber space and could remove water from the lumber quite fast. This technique will shorten the drying time but if it is not done carefully would produce more percentage drying defects.

a1 a2

b c

Figure 12. Drying techniques employed by small sized processors: (a1 and a2) air drying, (b) hot- air drying, (c) hot-water drying

Manufacturing

Teak logs from community plantations were processed and manufactured by small sized industries mainly for furniture. Some are used for house components such as frame, door and window (Table 13). A very small percentage is used for light construction of houses. However, exact data on the end products are currently not available.

Figure 13. Housing components and furniture made of teak log from community teak plantations by the small sized industry in Java, mostly for domestic market

Wood processing in the surveyed areas Gunungkidul Twenty five industries were visited and surveyed during the study. It is noted that the majority of industries found in Gunung Kidul had sawmill. Mostly they employed air drying technique to dry the wood. Some of them used heater, but no kiln dryer found in the district (Table 21). From 25 processors surveyed, there were 19 companies who broke down teak logs into sawn wood by themselves. The remaining 6 companies might ask for help to other companies or the third parties to break down their logs. It was found 11 companies who dried their sawn wood using the oldest technique of wood drying, namely air drying. Some companies (5 industries) have been studying how to improve the drying technique by heating the wood with hot air circulated in a chamber. The heat was obtained from burning the wood waste in the mill. The other form of heating is warm water to be circulated around the wood chamber. Table 18 shows that among 25 industries, more than half worked for furniture production.

Table 21. Teak wood processing conditions in Gunung Kidul Manufacturing No Industry Name Sawing Drying furniture, housing Air Heater Kiln Combination components 1 UD. Kurnia Jati √ √ √ 2 Karya Jati √ 3 Mutu Jati √ √ √ 4 Dwi Bangun √ √ √ 5 Gasing Jaya √ 6 UD. Sinar Mulia √ √ √ 7 Sumber Rejeki √ 8 UD. Suminar Jati √ √ 9 CV. Nugroho √ √ 10 UD. Widodo √ 11 UD. Sumber Jati √ 12 UD. Kabul Santoso √ 13 UD. Jati Unggul √ √ √ 14 Israk Meubel √ √ √ 15 UD. Mandiri √ 16 Batur Agung Furniture √ √ √ 17 UD. Bukit Seribu √ 18 UD. Karya Manunggal √ √ 19 Jati Murni √ √ 20 UD. Mebel Hartini √ √ 21 Sunan Jati √ √ √ 22 PT. Kurnia Jaya √ 23 CV. Dua Dimensi √ √ √ 24 UD. JATI SARI √ √ √ 25 UD. Hasta Karya √ √ Total 19 11 5 16

Wonogiri A similar situation to Gunung Kidul was observed in Wonogiri. There were 29 processing companies surveyed, but not all of them processed teak logs. Those companies who were not involved in wood processing, usually they only obtained teak trees from farmers and then sold the log to the wood processor locally or nationally. There were 9 companies who acted as teak log buyer. The remaining 20 enterprises, could be categorized into the second type purchased logs from farmers and then processed them into end products. Almost the same type of wood products as in Gunungkidul was found in this district.

Table 22 shows that out of 29 companies in this district, 5 companies processed teak logs in to sawn logs. The industries still used the traditional wood drying technique, namely air drying. Surprisingly the number of companies have improved the drying technique by heater exceeded the number of companies used the air drying technique. Almost all industries in the district manufactured furniture and housing components.

Pacitan Table 23 presents the total number of industries processing teak wood surveyed in Pacitan. However, out of 18 industries surveyed only 5 owned log yard for storing their raw materials. Most of the industries in this district worked for breaking down the teak logs into sawn timber. The air drying was the most popular technique for drying teak wood in this district. No heating technique has been introduced in the wood industries. A great deal number of industries manufactured furniture and housing components, namely 15 out of 18 being surveyed.

East Nusa Tenggara In this province most of the companies being surveyed worked on sawmilling the teak logs. Air drying was the only technique employed for drying the wood or sawn wood. No kiln drying was applied and no improved technique was available for drying the wood. Most of the industries manufactured furniture, housing components and others (Table 24). East Nusa Tenggara is located in eastern part of Indonesia. The province consists of a number of islands. It is still an underdeveloped province with limited infrastructures. The market for high quality of wood products is still limited in the province. Most of the teak wood harvested in the province has to be marketed outside the province, mainly Java in the form of flitch.

Table 22. Teak wood processing conditions in Wonogiri Drying Manufacturing Industry Name furniture, housing No Sawing Air Heater Kiln Combination components 1 Sido Lancar* 2 CV. Kartika* 3 Kayu Mas* 4 UD. Cinta Abadi* 5 Sugeng* 6 UD. Maju Jaya* 7 UD. Jati Mas* 8 Karya Baru* 9 Delanggeng √ 10 UD. Mutiara Jati* 11 UD. Bowo √ √ 12 CV. Sinar K √ √ 13 Parjo Mebel √ √ 14 UD. Giri Usaha √ √ 15 CV. Permata 7 √ √ 16 UD. Sari Madiri √ √ 17 UD. Mandiri √ √ 18 Ais Furniture √ √ 19 UD. Jati Mulyo √ √ 20 Rimba Mulya √ √ 21 Lilis Sejati √ √ 22 Kusuma Jati √ √ 23 Layar Emas √ √ 24 Mebel Kayu √ √ 25 UD. Bowo √ 26 Sarwo Jati √ 27 Tunggal Jati √ 28 UD. Kartika Jati √ 29 UD. Sari Laut √ √ Total 5 6 9 15 * = first type of enterprise

Table 23. Teak wood processing condition in Pacitan Drying Manufacturing No Industry Name Sawing furniture, housing Air Heater Kiln Combination components 1 Marjuki √ √ √ 2 P. Dirman √ √ √ 3 Abdul Romi √ 4 UD. Tri Rukun √ √ √ 5 Juni √ √ √ 6 Bahrudin Suhadi √ √ 7 Juli √ √ √ 8 UD. Maju Lancar √ √ √ 9 UD. Aagung Jati Mulya √ √ √ 10 UD. Wahyu Inti Jaya √ √ √ 11 UD. Jati Mandiri √ √ √ 12 Muh. Adnan √ √ √ 13 CV. Anis Rahayu √ √ √ 14 Pangat √ √ √ 15 S. Boyman √ √ √ 16 Marfi √ √ √ 17 UD. Wahyu Jati Iindah √ √ √ Total 17 16 15

Table 24. Teak wood processing condition in East Nusa Tenggara Drying Manufacturing No Industry Name Sawing furniture, housing Air Heater Kiln Combination componets 1 UD. Sinar Cahaya Jepara √ √ √ 1 Bengkel Bahtera √ 3 Oesena Bersahabat √ √ √ 4 Mebel Jepara Indah √ √ 2 CV. Karya Setia √ √ 3 CV. Zona Dewata √ 4 CV. Buana Belu √ 5 CV. Mitra Kencana √ √ 9 Karya Putra Jepara √ √ 10 Usaha Bani √ √ 11 Dokehia √ √ 12 Rubadeo Mebel √ √ 13 Mebel Amasat √ √ Total 8 7 10

South East Sulawesi By Indonesian standard South Sulawesi is an underdeveloped province. The infrastructure is limited and the economy remains small, very little manufacturing and only modest trade are available. Almost all of the wood processing industry in the province comprises of sawmill, with only small adding‐value facilities (furniture, carpentry) to meet local need. Most teak wood leaves the province as green, rough‐sawn lumber or flitch.

The need for wood processing improvement

The current teak wood processing observed in the small sized industries is mostly considered traditional, less efficient and using simple and often traditional tools for wood processing. There are a wide range of opportunities to improve the current wood processing to achieve the high quality of teak wood products. The following areas in wood processing are suggested: 1. The sawing technique.‐ The technique employed should consider the log quality and the price of sawn timber. This combination factor will generate high revenue of sawmilling. The current sawing technique is mainly tangential lumber type sawing. This sawing method does not consider the log quality or log defects along the stem. Consequently, the lumber quality and its yield are not predictable. 2. Sawing machine. ‐ The proper use of sawing machine and type of saw blade should be employed in the sawing system. By doing so the recovery rate can be increased significantly and the waste percentage can be minimized. 3. Drying technique.‐ The proper drying technique should be introduced to the community wood industry. The setting up location of air drying with wood piling above the ground and covered by roof would minimize the effect of high humidity of soil and high humidity of air during night. Since wood is hygroscopic material, then it could attract moisture from the air and soil easily. The current air drying conducted by rural people or community wood processors is merely vertical arrangements of teak lumbers in rows in an open area without roof or only laying the lumbers in a declining position. The base lumber directly touches the soil. This technique of wood drying produces wide variabilities in the moisture content of wood and longer time to reach a certain moisture content. A relatively modern wood drying

such as heating the wood piling to a certain temperature is an effort to reduce the drying time and smaller variations of the moisture content. This system seems to do well and requires small investment to build, but the drying defect is relatively high. Hot water drying system needs a bit high capital to set up the machine, however it will produce uniform moisture content and lesser drying defects. 4. The improvement of color appearance of sapwood.‐ The light color of teak sapwood, which is whiter than the heartwood should be reduced as much as possible for increasing the teak wood value. One of the known methods to make this sapwood portion do not appear is to change its color to the similar color of heartwood. This could be done by heating the wood. The heat treatment has shown a good promise to reduce the heterogeneity of wood color, meaning the color differences between heartwood and sapwood become less. 5. More efficient use of logs.‐ All teak logs procured from community teak plantations should be processed into useful products. This can be done by reconstituting the waste to become an acceptable dimension of wood products. A small dimension of log cut, log end, log with knots and end‐splits, and other defects are glued together side by side to make lumber or beams. This lamination technique should be introduced to the small sized wood industry of the community. 6. Product diversification.‐ Moving the conventional and commercial products of furniture to the high products of housing components such as beam, truss, window frames and other items will increase the revenue of the community teak wood processors.

References 6

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