F. Tesoro
Florentino Tesoro is Director, Forest Products Research and Development institute, National Science and Technology Authority, the Philippines.
Faced with growing populations and rising housing needs, the countries of Southeast Asia are devoting increasing amounts of their forest resources to meeting domestic demand. At the same time, a diminishing natural forest resource is creating a need to find new sources and new processes for wood-based construction materials. This article reviews the present and future use of wood for construction in several ASEAN (Association of Southeast Asian Nations) countries and suggests that future requirements will be met from some unconventional sources and with increased use of new technologies.
· Although indigenous construction materials such as cement, bricks and tiles abound in the various Southeast Asian countries, and significant amounts of iron and steel bars are imported by most of them, wood remains the most important construction material that is available in the region in substantial quantities. In the coming years wood will continue to be a major construction material, but in a variety of new forms and from a number of unconventional sources as the declining supply of traditional tropical species is supplemented through the increased use of plantation trees and lesser-known natural species, supported by technological advances in wood processing.
The total forest resources of the region are shown in Table 1. Between them, Indonesia, Malaysia, the Philippines and Thailand have a reported area of 168.56 million hectares. This represents about 7.33 percent of the total world forests and about 14.11 percent of all tropical forests (CTFT, 1983). In addition to these natural forests there are about 3.169 million ha of man-made forests.
The latest data on log production in the ASEAN countries are shown in Table 2, totalling 42.5 million m3. By comparison, the total log production in the ASEAN region in 1980 was 58.5 million m3 (or about 45 percent of the total tropical timber production). The reason for the reduction in log production in these countries is their desire to conserve their remaining forests. As a result, most of the countries ban log exports. The current level of log production is expected to be maintained for some time, with a strong possibility of further reduction.
Production and consumption of wood-based construction materials
The number of wood-processing plants/mills and installed capacities in the various ASEAN countries are shown in Table 3. The five countries have a total of 3 551 sawmills with capacities of more than 500 m3 each per year. The particle-board plant capacities of the two mills in Singapore were not available, but the combined capacities of the other plants in the region total 327 000 m3. Total fibreboard mill capacity amounts to 127000 m3.
The actual production of lumber and panel products in 1981 in these same countries is shown in Table 4. The actual particle-board production of Indonesia and Singapore and the lumber production from Singapore were not available.
The wood-based industries in Southeast Asia are basically export oriented although part of their outputs are channelled to local markets to meet demands for construction and other uses. In 1983, Indonesia used locally almost 4.1 million m3 of lumber or 77 percent of its lumber output while Malaysia and the Philippines utilized about 55 percent of their lumber production of 3.4 million m3 and 0.66 million m3, respectively. Thailand's lumber output of 0.9 million m3 had to be supplemented with about 0.4 million m3 of imported lumber to meet local requirements (CTFT, 1983). Singapore's utilization of its lumber production is not available.
In plywood utilization, Malaysia reduced its plywood export from 78 to 75 percent in 1981 to meet demands by its housing/construction industry. The Philippines likewise showed increased local consumption of plywood in 1980 over the previous year, utilizing 204000 m3 but this dropped in 1981 and the local market remained depressed in succeeding years. This was brought about by the recession (FAO/UNDP, 1983). Likewise, Thailand noted a general decrease in plywood consumption as a result of subdued construction activity, no doubt brought about by the recession. The other panel products such as particle boards and wood cement boards are mainly for local consumption with very little foreign trade.
Housing needs in Southeast Asia
The most important construction need in Southeast Asia is the provision of shelter for its growing populations. The Southeast Asian countries (excluding Brunei) have an estimated population of close to 270 million as of 1982. The population of the region has a range of from 4000/km2 in Singapore to 45/km2 in Malaysia, and a population growth rate of 2.3 percent per annum with a high of 3.0 percent in Malaysia and a low of 1.5 percent per annum in Singapore.
Table 1. Area of natural forests and extent of plantation in ASEAN countries
|
Country |
Forest land area |
Annual forest loss |
Plantation area |
|
(1000 ha) |
(1000 ha) |
(1000 ha) |
|
|
Indonesia |
122 000 |
550 |
12 000 |
|
Malaysia |
20 200 |
230 |
59.2 |
|
Philippines |
10 700 |
101 |
653.0 |
|
Thai land |
15 660 |
333 |
451.9 |
|
Total |
168 560 |
1 214 |
3 169.1 |
1Only on the island of Java.
Table 2. Latest data on log production in ASEAN countries
|
Country |
Year |
Volume |
|
Indonesia |
1982 |
3 103.0 |
|
Malaysia |
1983 |
33 200.0 |
|
Philippines |
1983 |
4 430.0 |
|
Thailand |
1983 |
1 788.1 |
|
Total |
|
42 521.1 |
Table 3. Number of mills and production capacities of various ASEAN countries for construction materials
|
Country |
Sawmills1 |
Plywood |
Particle board |
Fibreboard | |||
|
|
|
No. |
1 000 m3 |
No. |
1000 m3 |
No. |
1 000 m3 |
|
Indonesia |
1 736 |
95 |
5327 |
6 |
283 |
1 |
3 |
|
Malaysia2 |
904 |
44 |
690 |
2 |
4 |
- |
- |
|
Philippines |
390 |
32 |
1 500 |
1 |
10 |
1 |
54 |
|
Singapore |
23 |
11 |
500 |
2 |
n.a. |
|
|
|
Thailand |
498 |
8 |
100 |
3 |
30 |
3 |
70 |
1Sawmills with capacities of more than 500 m3/yr.
2Including Sarawak and Sabah.
Sources: FAO, 1980; CTFT, 1983; IWPA, 1985.
Table 4. Production wood construction materials in ASEAN countries in 1981 (1 000 m3)
|
Country |
Lumber |
Plywood |
Particle board |
Fibreboard |
|
Indonesia |
5 257 |
1553 |
n.a. |
1 |
|
Malaysia |
6 943 |
490 |
3 |
|
|
Philippines |
1218 |
457 |
5 |
69 |
|
Singapore |
n.a. |
482 |
n.a. |
|
|
Thailand |
934 |
106 |
9 |
30 |
Sources: CTFT. 1983; Wardle. 1983.
Wood will continue to be a major construction material, but in a variety of new forms and from a number of unconventional sources.
BUILLDING A COMMUNITY CENTRE IN SUMATRA domestic needs are rising / A. MOYSE
Because of high population and growth rate, the ASEAN countries have difficulty meeting housing and other infrastructure requirements. Indonesia needs over one million dwellings to be built every year for the next 20 years to provide adequate housing for its population (Hidayat, 1984). Malaysia on the other hand required a total of 923300 housing units from 1981 to 1935. Of these, 284 400 units are to meet the backlog in housing stock, approximately 365 300 units are required by new families and 273 600 are needed to replace old and unusable dwellings (Sa, Salleh and Soon, 1984). In Thailand, the estimated housing needs for the period from 1982 to 1986 are 743 998 units or a yearly average of 148 799 units (Sinsuwong, 1984). The National Housing Authority of Thailand, however, has planned to construct for the period from 1982 to 1986 only 96 500 units. In the Philippines as of June 1984 it was estimated that there is a backlog of about 1.2 million units and an annual demand of about 200 000 units (Anon., 1983). Should the population increase to 70 million by the year 2000 the estimated total housing units required would be about 10.5 million units (NEPC, 1977).
Developments in wood-building components
While the forests of Southeast Asia are basically rain forests and common or similar species are found in the various countries of the region, the type and nature of the raw materials from forests are changing. In the past, when forest resources were still abundant, large-diameter trees were usually utilized. Harvesting was also confined to a few commercial species. With the resources declining rapidly, smaller trees and a wider number of species are being utilized. Furthermore, more attention is being given to higher productivity so that fuller utilization of trees is being attempted. This has led to the development of diversified wood products for construction.
Lesser-known and small-diameter species A common feature of the tropical rain forests in the timber-producing countries of Southeast Asia is the abundant forest growth. An enormous number of plant species can be classified as timber-producing In Indonesia, there are believed to be about 4 000 species, while about 2 500 timber species are reported in Peninsular Malaysia and about 3800 species in the Philippines. It is estimated that Thailand's forests hold similarly large numbers of timber species. However, only a small percentage of these have become commercially important. In Indonesia only 400 tree species have been utilized in various ways and of these only 120 are known in domestic and foreign trade (Martawijaya and Kartasujana, 1981). Likewise, in Malaysia there are only 400 species, and in the Philippines about 200 species of any commercial value. The Royal Forest Department of Thailand reported a production volume of 128 species which could mean that these species are those commercially important in Thailand (Thailand, 1983).
The constraint in using lesser-known species for construction and similar purposes is the lack or inadequacy of information on their properties.
A TOW OF LOGS IN KALIMANTAN, INDONESIA the demand for lesser-used species increasing / C. COSSALTER
The very low percentage of the number of species commercially utilized from Southeast Asian forests indicates the presence of a large number remaining that could potentially be used for construction purposes. Almost all of these are sparsely distributed, have low volume and relatively small diameters. As a consequence, their properties and uses have not been fully studied and classified. However, with the diminishing supply of the more common and popular species the demand for these lesser-utilized species is increasing, and more and more of them are being used for construction, either in lumber form or as plywood. (If they are used in lumber form, however, preservatives may need to be applied to improve their durability.) Other construction materials can be manufactured from these species, such as particle boards, fibre-boards or cement-bonded boards. Their reconstitution into panel products of various types overcomes some of their shortcomings for construction purposes.
The use and promotion of the lesser-known species have been the subject of several symposia and workshops (ESCAP, 1982; PCARRD, 1983). Guidelines have been published for the improved utilization and marketing of tropical wood species, emphasizing the use of lesser-known species (FAO, 1980a), using criteria based on fundamental properties such as modulus of rupture (MOR), durability, treatability, specific gravity, workability, shrinkage, seasoning, finishing, etc. for determining potential end-uses, A series of reports in Malaysia (Lim, 1982, 1983; Wong, 1977) has identified the potential end-uses of lesser-used species for construction as well as the substitute species for the popular timbers for various building components.
Plantation-grown species Slash-and-burn agriculture and logging have brought rapid decline to the natural forest area of Southeast Asia. As a result, forest departments in the region have adopted various measures to reforest logged-over, open and denuded areas. The demand for fuelwood and pulpwood has also prompted the establishment of plantations for these purposes. The average rate of annual forest loss and estimates of plantation areas in the region are shown in Table 1.
The main plantation species are the fast-growing Eucalyptus spp., Albizia spp., Acacia spp., Leucaena leucocephala, Casuarina spp., Gmelina arborea, etc. Other species planted are mahogany (Swietenia spp.) and teak (Tectona grandis).
Although these plantation species have been intended primarily for fuelwood or pulpwood or merely as a cover crop to protect the forest soil from erosion, some of them have been utilized for construction purposes. Albizia spp. was planted on purpose in the southern Philippines to meet the raw-material requirements of a pulp and paper mill for pulpwood. However, Albizia has been utilized for veneer and plywood production as well as for non-load-bearing construction purposes. Although Leucaena leucocephala is used primarily for fuelwood it is also utilized for lumber and has been made into particle boards.
As the demand for construction material continues to increase and the supply from the natural forests continues to diminish, substitute species from plantation sources will be utilized to meet this demand. The constraint in using lesser-known species for construction and similar purposes is the lack or inadequacy of information on their properties. However, as more information on basic and technological properties is generated, more and more of these species will find their way into construction. Knowledge of processing properties such as sawing, drying, treatability, machinability and finishing together with mechanical properties will become essential.
Rubber is another plantation species that has become a potential source of construction material. In Southeast Asia, the area of rubber plantations is estimated to be about 2.2 million ha. Malaysia has the most extensive area with about 1.72 million ha. Indonesia has about 427 000 ha of government plantations and the Philippines about 53 000 ha. Since a large proportion of these plantations is more than 30 years old the rubber trees have become unproductive and are scheduled for replacement. It is estimated that in Malaysia alone the volume of rubberwood from replacement planting is close to 9 million m3 per year, while in Indonesia replacement plantings are close to 5000 ha a year with an estimated wood volume of 720000 to 1 095 million m3 annually.
Malaysia has made the most extensive studies of the properties and uses of rubberwood. These studies show that it is easy to saw and can be machined smoothly but is prone to bowing and end-splitting (Seng and Ten, 1983). Likewise, rubberwood has been shown to be susceptible to fungal and insect attack. It stains easily upon cutting. However, it can be treated easily even with non-pressure methods (Hong et a/., 1983). Other studies have found rubberwood suitable for blockboard cores, for lumber, for furniture, particle-board manufacture, glued laminated products, parquetry and flooring (Hing and Choh, 1983).
Cement-bonded boards Wood in various forms and sizes such as chips or particles or narrow long strips like woodwool has been bonded with cement to produce panel products for construction. Research on this type of panel was undertaken more than 20 years ago in Europe but only now is it being seriously considered in the ASEAN countries. Malaysia, Indonesia and Thailand have in fact already gone into commercial production of this material. Malaysia produces woodwool cement boards and particle boards bonded with cement. Cement-bonded boards can be used for external walling, have sound and heat insulating properties and are resistant to the attack of insects and fungi. They also have great potential for low-cost housing because cost is competitive with other materials (Anon., 1984). Wood cement board is light with a density of only 600 kg/m3. The thermal conductivity of cement-bonded boards is lower than resin-bonded particle boards and comparable to fibre insulating boards.
Glued laminated wood The use of glued laminated timber as a structural component has been limited primarily to beams and arches in Southeast Asia. In the late 1950s and early 1960s a private construction firm in the Philippines was producing laminated beams but the use of this material had little success. Recently, however, there has been renewed interest in wood-laminated structural components and wood lamination has been identified as a priority research area in Malaysia.
As sources of wood construction materials change from large-diameter, high-quality logs in natural forests to small-diameter and lower-quality logs in plantation forests, the wood-lamination process permits the latter to be converted into high-quality construction components. Ten or more years ago the cost of laminated timber was prohibitive and it was therefore unpopular. However, with the increasing cost of conventional timber, laminated materials have become more competitive.
A variation of laminated timber is laminated veneer lumber (LVL). It consists of veneers laminated in such a way that the veneer grains lie in the same direction. LVL was used in the 1960s in Japan for furniture and pianos (Sasaki, 1981). LVL manufacture permits low-grade logs and those from thinnings to be used. Although these types of logs have severe knots their influence on strength may not be important if the ply number is large enough and the knots are distributed at random (Sasaki, 1981).
The production of LVL can be an extension of plywood manufacture. At least two plywood plants in the Philippines are already producing LVL classified as uniply but for export to Japan. Further studies must be conducted on various small-diameter and plantation species to develop processing techniques and the effect of butt joints, lathe checks, glue-line, and veneer thickness on mechanical properties must be studied. Production costs also need to be reduced to competitive levels in order to exploit LVL further.
There has been renewed interest in wood-laminated structural components.
Palmwood for construction Palmwood is one of the newer construction materials. The lumber from the coconut stem (Cocos nucifera) has so far been most studied and used. Although palmwood does not come from the traditional dicot stem, the large quantities of it in Asia, Africa and Latin America make it a highly potential material for construction.
The coconut is grown as an agricultural crop in Indonesia, Malaysia, the Philippines and in Thailand. Coconut trees become unproductive after 50 years when they are replaced. In the Philippines, it is estimated that the total land area planted to coconut is about 3.16 million ha with approximately 411 million coconut trees. The Philippines alone has close to 84 million mature coconut palms. India, Indonesia, Malaysia, Sri Lanka and Thailand have an aggregate of about 96.6 million mature palms (Mosteiro, 1985). At an estimated 0.28 m3 of lumber yield per stem the total estimated volume of lumber from coconut in Asia, including that of the Philippines, would be about 50.6 million m3. This volume could supplement conventional wood for construction.
The importance of coconut lumber in Asia and the Pacific was emphasized in the workshops held in the Kingdom of Tonga in 1976 (Anon., 1976) and in the Philippines in 1979. Since then, several training projects and programmes have been undertaken and sponsored by FAO and UNIDO in Asian countries on the properties and processing of coconut. Monographs on coconut-wood processing and use have also been published (FAO, 1985).
The cocostem has been used for secondary transmission poles, bridges and posts. However, it has a very low durability and deteriorates within three years when in contact with the soil. Consequently, outdoors and when in contact with the ground, treatment with preservative is essential.
In the Philippines cocotimber is now found in local lumber outlets. At present, cocolumber is about 40 percent cheaper than conventional lumber. With better understanding of its properties and better handling and application, its use in construction is expected to increase appreciably.
Oil-palm has also been planted extensively in Southeast Asia, especially in Malaysia, where it is estimated that there are about 1 000 000 ha of oil-palm plantations. (The Philippines has a very limited area planted to oil-palm.) Malaysia is studying the basic and technological properties of oil-palm for future utilization.
Wood will continue to be a major construction material in subsequent decades in Southeast Asia. A large part of the volume used for construction will be in the form of lumber and plywood but more and more reconstituted wood-panel products will be used in the form of fibre-boards particle board and wood-cement boards. The decreasing wood supply from natural forests will be supplemented by wood from plantations and secondary or lesser-used species will be adopted more and more as construction materials.
Non-traditional materials will also be used more extensively in the future. Rubberwood looms as an important source for both household furniture and construction. The palm stem, especially that of coconut, will also be used to a large extent for house construction, particularly for low-cost housing. Laminated products will also become important as the supply of large-diameter wood declines further.
A more extensive use of nontraditional materials will depend largely on advancing technologies in processing to promote productivity and economy. Likewise, supplementary technologies such as the production of high-quality adhesives and finishing materials from materials indigenous to the region will improve the quality of the wood construction products themselves.
ANON. 1976 Coconut Stem Utilization Seminar. 25-29 Oct. 1976. Sponsored by the Govt New Zealand. Tonga Island.
ANON. 1983 Building for man: the National Shelter Programme in the Philippines. Reader's Digest (juin).
ANON. 1984 Trend of building material in Malaysia 1970-2000 Min. Housing and Local Govts, Malaysia.
CTFT. 1983 Regional study for the commercialization of the timber resources in ASEAN countries. France. Centre technique forestier tropical.
ESCAP. 1982 Technical properties and possible end-uses of lesser-known species of tropical timbers. Report on utilization of lesser-known species of tropical timber (Southeast Asia). Los Baños Laguna ESCAP.
FAO. 1980a Guidelines for the improved utilization and marketing of tropical wood species.
FAO. 1980b Production capacities: plywood, particle board and fibreboard. 1980. Rome.
FAO. 1985 Coconut wood processing and use. Etude FAO: Foretstry Paper No 57. Rome.
FAO/UNDP. 1983 Proc. Technical Consultation on Wood-based Panels. 13- 17 Jan 1983. New Delhi.
HIDAYAT, B.Y. 1984 The prospect of agro-residues for building materials in Indonesia. Paper presented to the Seminar and Workshop of Agro-Residues for Low-Cost Building Materials, July 1984, Manila
HING. L.W. & CHOH, S.H. 1983 Rubberwood - present and potential utilization. Proc. Rubberwood Utilization Seminar p. 49-54. 15 June 1983. Malaysia.
HONG L.T., SAJAN, M.A. COH. T.A. & SINGH. K.D. 1983 Preservation and protection of rubberwood against biodeteriorating organisms for more efficient utilization. Proc. Rubbenwood Utilization Seminar p. 20-36. 15 June 1983. Malaysia.
IWPA. 1985 Indonesian Wood Panel Association. Jakarta.
LIM. S.C. 1982 End-uses of Malaysian timbers. II. Wall panels and partitions. The Malaysian Forester, 45 (2): 263 269.
LIM, S.C. 1983 End-uses of Malaysian timbers. IV. Flooring. The Malaysian Forester 46 (2): 278-285.
MARTAWIJAYA, A. & KARTASUJANA, I. 1981 The potential use of Indonesian timbers. Indian Agric. Res. Dev. J.. 3 (4): 108-116.
MOSTEIRO, A. 1985 The need for industrial utilization of coconut wood. Los Baños. Laguna, Philippines. (Unpubl.)
NEPC. 1977 National Environmental Protection Council. Philippine Environmental Quality Report, p. 153. Manille, the Philippines.
PCARRD. Proc. 1983 Symp. on the Production of Lesser-used Species and Small-Diameter-Sized Timber. Philippine Council for Agriculture and Resources Research and Development. Los Baños Laguna, Philippines.
PCARRD. 1985 The Philippines Recommends for Coconut Timber Utilization. PCARRD Technical Bulletin Series 60. Los Baños Laguna, Philippines
THAILAND. 1983 Forestry statistics of Thailand. Royal Forest Department
SAX. S.K.. SALLEH, R. & SOON, C.K. 1984 State of the art in housing in Malaysia. Paper presented to the Seminar and Workshop of Agro-Residues for Low-Cost Building Materials, July 1984, Manila
SASAKI. H. 1981 Recent Developments in Laminated Wood Products in Japan. Proc. XVII IUFRO World Congress. Div. 3 Forest Products p. 146- 156.
SENG, H.K. & TEN, C.K. 1983 Processing of rubberwood. Proc. Rubberwood Utilization Seminar p. 11-19. 15 June 1983. Malaysia.
SINSUWONG, C. 1984 State of the art in housing in Thailand. Paper presented to the Seminar and Workshop of Agro-Residues for Low-Cost Building Materials, July 1984, Manila
SWEE, H.P. 1984 Low Cost Housing in Malaysia. Régional Meeting on Strengthening Engineering Capabilities for Low Cost Mass Housing p. 158-166. 29 Oct.-2 Nov. 1984. Jakarta/Bandong, Indonesia, CESAP.
WARDLE, P. 1983 Trends in production and trade of wood-based panels. Proc. FAO/UNDP Technical Consultation on Wood-based Panels, p. 309-318. 13- 17 January 1983.
WONG. T.M. 1977 Prospects for Timber in Housing. The Malaysian Forester. 40 (2): 101-1O8.
