One impediment to the sustainability of forests and forest industries is the low wood utilization efficiency and the amount of residues, which occur both in the forest and during wood processing. Wood residues have emerged as a major potential raw material and, if more efficiently used, could contribute to a reduction in areas logged every year. The extent of logging waste reported in the literature generally range from 30 percent to 50 percent of the extracted volume. Wood volume losses or wastes also occur at roadside landings, mill yards and in manufacturing itself. Mill process yields have been reported to be as low as 33 percent of delivered log volume.
This assessment for China forms part of a regional study commissioned by the Asia-Pacific Forestry Commission. The overall objectives of the study are to:
present an overview of the availability of wood residues in the processing chain (including harvesting, transport, storage and processing) of major forest product industries, from the standing tree to the final and semi-final product; and
assess the raw material in terms of its source: natural forests, plantations (including trees outside forests).
Background to the forestry sector
The national forest resource inventory (1989 to 1993) indicates a forest cover of 128.5 million ha (excluding plantations), only 13.92 percent of the total land area of China. The total growing stock is about 11.8 billion m3. Natural forests (naturally in origin with a tree crown cover of more than 30 percent) cover about 108.6 million ha (84.5 percent), 16.1 million ha (12.5 percent) are classified as economic forests (designated for the production of timber and non-timber forest products) and 3.8 million ha (2.95 percent) are bamboo forests. About 63.0 million ha of wasteland are to be afforested. The total growing stock in China is about 10.7 billion m3 (excluding the forest resources of Taiwan Province and that beyond Tibet's control line).
The most extensive forest area with the largest industrial wood resources is the natural forests of the northeast provinces. Other important forests are natural forests in the southwest and plantations in the southern provinces (Table 1). Forest ownership is mixed; about 45 percent of the forest is owned by the State and administrated by the State Forestry Administration. The remainder is owned collectively but managed according to forest laws and monitored by the State Forestry Administration.
In recent years, about 5 million ha have been reforested annually. The man-made forests cover 34.25 million ha (26.7 percent of the total forest area) (Tables 2 and 3). About 4.5 million ha are fast-growing and high-yielding timber plantations. They will provide raw material for industries in the future.
Forestry in China has developed into an industrial sector. More than 52 000 organizations are engaged in afforestation, forest management and harvesting, and wood processing. In 1998, the total output of the sector reached 84.87 billion yuan RMB, accounting for 1.07 percent of gross domestic product. The total number of employees in the sector is about 2.36 million. The total staff numbers of the state-owned units are 2.07 million, and have recently decreased.
1 Chinese Academy of Forestry, Beijing, China
Table 1. Forest cover by region (million ha and million cum)
|Region||Standing stock||Forest area||Forest stand growing stock||Timber forest growing stock|
|Northeast/Inner Mongolia||3 476.5||32.4||36.6||28.4||3 002.7||33.1||2 683.8||39.8|
|Sichuan and Yunnan||222.8||26.3||20.9||16.3||2 410.6||26.5||1 398.8||20.7|
|Collective forests in 10 southern provinces||1 826.6||17.0||46.6||36.3||1 457.7||16.0||1 225.9||18.2|
|Tibet||1 262.1||11.8||4.0||3.1||1 231.1||13.6||878.3||13.0|
|Other provinces and municipalities||1 347.7||12.5||20.4||15.9||985.1||10.8||556.6||8.3|
Source: Forestry Yearbook of China, 1994.
Table 2. Distribution of plantations by region (million hectare)*
|Sichuan and Yunnan||3.7||10.9|
|Collective forests in 10 southern provinces||18.3||53.4|
* including timber plantations, shelterbelts, economic forests, and planted bamboo forests
Table 3. Distribution of timber plantations by region (in million hectare and cum)*
|Sichuan and Yunnan||2.02||11.5||55.08||9.5|
|Collective forests in 10 southern provinces||10.06||57.4||357.14||61.7|
* man-made forests for supplying wood for pulp and paper, panel products, furniture and other industrial purposes
Table 4. Exports and imports of forest products in 1997 (value in US$ 1,000)
|Volume||Value||1997 as percentage of 1996||Volume||Value||1997 as percentage of 1996|
|Chips||1.95 mill. tons||154 370||105||95||2 100 tons||1 029||19||75|
|Logs||63 300 m3||29 455||99||100||4.47 million m3||677 788||140||148|
|Sawn timber||387 200 m3||193 049||101||100||1.32 million m3||267 823||142||149|
|Particleboard||14 700 m3||9 271||162||197||12 810 m3||28 484||137||143|
|Fiberboard||34 500 m3||9 146||66||83||432 m3||105 937||136||151|
|Plywood||437 900 m3||151 536||248||243||1 488.5 m3||605 498||84||94|
|Wood pulp||16 400 tons||8 648||139||108||1 529 ton||741 000||105||97|
|Paper and paper board||269 100 tons||269 250||5 524 tons||2 827 012|
|Waste paper||3 500 tons||311||66||68||1 618 tons||175 750||118||91|
Since the 1990s, the Government has taken a series of significant measures to promote sustainable forest management. This includes the formulation and implementation of various key programs and policies, such as the Forestry Action Plan for China's Agenda 21 and the Outline of China's Ecological Development Program. The 2010 development goal is to raise the level of forestry to that of countries with a medium forestry development level.
The results of excessive overcutting and annual consumption levels exceeding annual growth are reduced growing stocks and environmental degradation. Since 1990, China has increased its forest area and stock volume. The Government has adopted a quota system for logging operations and strictly controls resource consumption to ensure that annual removals do not exceed annual growth. The quotas are determined once every five years. The Government appoints forest resource commissioners and organizations that are stationed in key forestry provinces and forest industrial enterprises to control log volumes, amount of timber transported and timber sales. In 1997, the national logging quota was about 226 million m3, although far less was actually harvested. Approximately 85 percent of the logged volume is sourced from natural forest.
To prevent further degradation of the environment, the Government has decided to phase out logging gradually in key ecological areas and to adopt selection and improvement cutting systems. The national cutting quota for the year 2000 has been reduced by 16 million m3 compared to the 1997 quota. The goal is that by 2010 about half of the timber will be sourced from plantations and by 2050 timber supply from the plantation is envisioned to increase to 70 percent.
Logging operations vary among different parts of China. In the more mountainous southern provinces, trees are pre-processed and cut into shorter logs to facilitate transport. In the northern forest areas, whole trees are transported. In the State-owned forest areas, the forest bureaus are responsible for logging, wood transportation and storage. In the collective forest areas, the forest departments establish working stations for purchasing logs harvested by collective units and individual forest farmers. The timber is transported to the mills by train, truck, and via water bodies (in the south) (Annex 1).
The average percentage of mechanization in forest harvesting and timber transport is around 87.7 percent; 90 percent in the northeast forest region and 40 to 80 percent in the rest of the country. The degree of mechanized felling (refers mainly to the use of chainsaws) is 91 percent in the northeast and 40 to 60 percent in other parts of the country. The degree of mechanized yarding is 83 percent in the northeast, Inner Mongolia and Jilin and reaches only about 25 percent in the southwest and south. Regeneration and silvicultural treatments are mainly manual.
At present, tree fellers use mainly YJ4 and GJ85 chainsaws that are produced in China. YJ4 chainsaws are mainly used in the southern provinces and the more powerful GJ85 chainsaws with long handles, stable performance and low oil consumption are widely used in the northeast. Cableways and tractors are mainly used in skidding operations. Over 85 percent of the cableways are used in the south and tractors are used in the north. Most yarding equipment is produced in China. According to a national study conducted in 1995, most of the equipment currently in use is out-dated. Only 17 percent can be considered advanced.
The wood-processing sector
The wood-based industry in China plays an important role in social and economic development. The total annual consumption of roundwood (including fuelwood) is about 250 million m3 and is comparable to the consumption levels of steel and plastic. Due to insufficient forest resources, the use of wood residues and plantation timber as raw materials in the wood-based panel industry is crucial. The production of wood-based panels in 1997 was 16.49 million m3 (Table 5).
Sawmilling: The annual log production is about 65 million m3, of which 40 to 50 percent are sawlogs. There are about 2 000 sawmills in China with a total capacity of about 25 million m3. Most are small or medium size with annual processing capacities below 5 000 to 10 000 m3. Sixty percent of the milling equipment was installed during the 1950s and productivity is low.
Wood residues are used for the production of parquet, toothpicks, chopsticks, and woodchips mainly for the domestic market. The production of chips and parquet in 1997 was 5.29 million m3 and 18.94 million m2, respectively.
Table 5. Production of forest products in China (1,000 cum)
|Year||Sawn timber||Wood-based panels||Pulp (1 000 t)||Paper & paper board (1 000 t)|
|1981||13 011||996||351.1||568||--||77||4 063||5 402|
|1985||15 908||1 616||538.7||895||50||182||6 153||9 112|
|1990||12 849||2 359||758.7||1 172||87||428||8 350||13 719|
|1995||41 838||16 846||7 592.6||2 164||537||4 351||18 620||24 000|
|1997||20 120||16 490||7 584.5||2 759||1 059||3 604||17 380||27 436|
|1998||17 876||10 563||4 465.2||2 195||--||2 663||--||--|
Wood-based panels: The wood-based panel industry is quite technology-intensive and has benefitted from the import of foreign equipment since 1980. However, the average capacity of mills is low compared to world standards (Table 6), which limits efficiency to some extent. At present, the number of mills is about 3 000, of which 240 have an annual capacity of over 10 000 m3. Data for overall capacities in the wood-based panel industry are very limited. Estimates for plywood are 10 million m3, blockboard 2 million m3, particleboard 4 million m3, medium-density fiberboard (MDF) 3 million m3 and hardboard 0.7 million m3.
Table 6. Average capacity of wood-based panels mills (1,000 m3/year)
Plywood: In 1997, plywood production reached 7.58 million m3, accounting for 45 percent of the total panel production. At present, 2 000 plywood mills are operating. More than 100 mills exceed an annual capacity of 10 000 m3 and 7 mills exceed 100 000 m3 capacity each. Most mills are located in the more developed eastern coastal region. Both local and imported equipment is used. Some smaller mills still rely on out-dated equipment.
Particleboard: There are about 550 particleboard mills in China. Only one mill exceeds a capacity of 100 000 m3, 17 mills manage about 50 000 m3 each. There are 120 smaller mills, with an average annual capacity of 10 000 m3 each. The small units account for approximately 62 percent of total production. Some new mills are equipped with advanced technologies. Particleboard uses low-grade raw materials and has various applications with promising prospects.
Fiberboard (including hardboard): There were 400 mills with a capacity of 2 000 to 15 000 t/year in operation. At present, only 70 mills operate because of water pollution concerns.
Medium-density fiberboard (MDF): MDF production started in the early 1980s and the sector has developed rapidly. Forty sets of foreign machinery with annual capacities of 30 000 to 50 000 m3 each were imported (total capacity of 1.5 million m3). Seventy sets of locally made equipment with an annual capacity of 15 000 to 30 000 m3 each are also operating. By the end of 1996, 108 plants were producing MDF with total annual capacity of 2.77 million m3. This makes China the second largest MDF-producing country in the world. It was estimated that MDF capacity in the country would reach 4 million m3 by the end of 2000.
Surface finishing and other panel products: Production of surface finishing products started in the 1960s. At present, the production reaches 150 million m2. In 1997, production of other panels, including blockboard, wood cement particleboard and wood gypsum particleboard, reached 2.8 million m3.
Further efforts need to be made to improve the quality and variety of products. A 1994 study indicated that only 8 out of 10 plywood mills complied with national quality standards. Tests conducted between 1995 and 1997 showed that only 36.6 percent of particleboard and 62.5 percent of MDF were of high quality. Major defects include problems with dimension, density, swelling and formaldehyde emission.
Pulp and paper: Since 1980, paper and paperboard production has increased by 10.1 percent annually. In 1997, production reached 27.4 million tons of 600 paper products. Import figures are as follows: 1.54 million tons of wood pulp, 5.52 million tons of paper and paperboard and 168 000 tons of waste paper. Total consumption reached 27.33 million tons, which makes China the second highest paper and paperboard consumer in the world.
Forest harvesting and regeneration were covered by the legal system when the “Forest Law” was enacted in 1984 and the “Provisions of Rules and Regulations of the Forest Law” were published in 1996. In 1987, the “Regulation for forest cutting and regeneration” was formulated. This regulation prescribed harvesting operations and silvicultural treatments in various ways. In the revised “Forest Law,” promulgated in July 1998, the Government stipulated that the following measures were to be encouraged and adopted:
Quotas for forest harvesting; tree planting and afforestation of hillsides and expansion of forest cover
Provision of funds or long-term loans for collective and individual plantings and silviculture
Comprehensive and efficient use of wood and development and use of wood substitutes
Strict controls of harvested volumes
Harmonized annual timber production plans
Control of various forms of selective, clear and shelterwood cutting for mature stands
Issuance of cutting licenses
China advocates efficient wood use and encourages the development and utilization of wood substitutes. Since 1980, the Government has financially supported the modernization of wood-based panel enterprises. In 1990, the forestry department issued a notice to encourage forest enterprises to reduce and use wood wastes. Since 1991, the State Tax Office provides 3-year tax breaks for State-owned forest enterprises of the northeast and Inner Mongolia forest regions, which use wood wastes as raw materials in the production process. These policies have encouraged the wider use of logging and mill residues.
The availability of large dimension timber from the natural forest is declining and the total amount of timber, in general, is also insufficient. This has triggered a shift from sawntimber and plywood to non-veneer wood-based panels and paper products. Also, production will shift gradually from cities to the timber producing areas to increasingly add value locally.
Sawmilling industry: Sawmilling in the timber-producing regions will be promoted. This will include drying and preservation. Value-added processing, including finger jointing and laminating, will be developed. The percentage of artificial timber drying will be increased from the current 20 percent to 50 percent.
Wood-based panel industry: MDF, structural particleboard, bamboo plywood and other new products will be developed. It is expected that capacity will be increased by 520 000 m3. The particleboard and hardboard industry will benefit from the expansion of raw material resources, modernized technologies, improved pollution control, and better product qualities. The raw material base for plywood production will be broadened and attention given to the development of sliced thin veneer, if raw materials are available.
Pulp and paper industry: China aims to produce 30 million tons of paper and paperboard by 2000. Pulp production will reach 25 million tons (3.32 million tons derived from wood as a raw material). Consumption of pulp per capita is expected to increase from 23.4 to 26 kg. Every effort will be made to increase the raw material base for paper production, including the use of logging and mill residues. In 2010, the production of paper and paperboard is expected to reach 40 million tons and production of wood pulp 14 million tons.
To increase efficiencies in the logging and wood-processing sectors, the former Ministry of Forestry formulated the “Policy Outlines on Forestry Equipment” in 1996. Its objective is to foster a modernization process for forestry equipment by the year 2010. In particular, more attention will be directed at:
Development of appropriate logging equipment to improve efficiency and reduce logging residues.
Quality of forestry operations to improve logging and increase recovery rates.
Development of energy-efficient technologies.
Development of effective processing technologies based on wood waste.
Formulation of favorable policies to encourage research and development by forestry enterprises to improve their technical skills.
Training of forest workers to raise technical level in the forestry sector.
Information on recovery rates by forest type does not exist. Table 7 provides average figures for State-owned wood harvesting and processing enterprises. Estimates for the private sector are not available.
Table 7. Recovery rates of State-owned forestry enterprises (percent)
|Item||Recovery rate of sawntimber*||Utilization rate of harvested forest resources**|
* Production of sawn timber/consumption of logs
** Production of logs/stocking volume of harvested forests
Although the forestry sector suffers from a shortage of raw materials, large quantities of logging residues are potentially available for use. The industrial utilization rate of wood residues may be as low as 17.4 percent. The main uses of logging residues include:
Production of wood chips, particularly because smaller dimensions from thinnings become increasingly available. Wood chips are an important raw material for the panel and paper industries. Exports of wood chips from Heilongjiang Forest region total about 3 000 tons (oven dry) annually.
Use of small-dimension wood and production of small wooden products such as carvings, tool handles, wooden boxes, toys, parquet, furniture, balls, etc.
Production of charcoal.
Chemical processing of wood to produce feed, feed additives, protein, vitamin, resin, turpentine, tannin extract, yeast, alcohol, etc.
The following problems hinder the increased use of logging residues:
Logging residues are quite scattered, harvesting operations are seasonal and working conditions are poor. Felling, skidding, transport and storage pose additional difficulties. The transport cost per cubic meter of logging residues to the mill is 50 to 60 yuan (RMB) excluding management costs. Therefore, the use of logging residues is financially unattractive.
Logging residues are often available in hilly areas and alternative uses have to compete with firewood.
Product diversity and low quality.
Lack of supportive policies. Wood processors criticize the high costs of wood chips, which are probably due to high taxes for logs (30 percent of the purchasing price) and the high transport and chipping costs (about 30 percent of the purchasing price) since most forest farms are located in the hills. As a result, large quantities of logging residues remain underutilized. The Government should formulate favorable tax policies to make logging residues more attractive.
According to a 1995 study in Daxinganling Forest region, logging residues include brushwood; tree tops, withered and damaged wood, and low-quality wood. The volume of logging residues (over 5 cm in diameter and over 1 m in length) is 8.44 m3/ha. Losses also occur during collection, loading and transport. The loss rate is about 7 percent, i.e. 0.59 m3/ha. Therefore, the usable volume of residues is reduced to 7.85 m3/ha. In Daxinganling Forest region, the timber production is about 70 m3/ha, which means that usable residues make up only about 11 percent of the harvested volume. Accordingly, a forest bureau with annual production of 350 000 m3 of timber can obtain 39 250 m3 of logging residues.
The same study also indicated that workers of the forest farm use 6 to 8 m3 of wood as firewood annually per household. About one-third of the firewood could be used as sawntimber and the other two-thirds could be chipped, which would result in greater economic benefits. However, that would deprive people who do not have any alternatives of an important energy source.
Lack of skills also lead to an increase in logging residues. A common problem is high stumps. In some areas stump height can reach 90 cm. Smaller logs are at times left behind or good quality logs mixed with firewood resulting in avoidable wastes.
According to a study by the Lushuihe Forest Bureau (Jilin Province), 792 m3 of wood is wasted every year. This includes small logs and short pieces (less than 2 m in length and less than 8 cm in diameter). Also, over-mature and partially rotten trees are left uncut. The total additional volume potentially available amounts to 10 459 m3.
Another study showed that logging residues in Jilin were about 15 percent of total log production. Sixty percent of the residues could have been used. Improvements in bucking could also make a considerable difference. Off-cuts often amount to 30 percent of the total log production and 90 percent of the wastes could be avoided. Another study in Fujian highlighted that logging wastes account for 40 percent of the harvested volume, although not all of the material can be used. Branches account for 14, bark for 20, butts for 4 and off-cuts for 2 percent, respectively.
The usable logging residues, including branches over 3 cm, and off-cuts account for 10 percent of log production (Table 8). However, economically usable wastes are only about 7 percent.
Table 8. Usable rate of logging residue in Fujian (percent)
|Percentage of log production|
|Small-size poles||Small-size logs||Pulpwood||Total|
|Over 3cm branches||1.4||-||4.6||6|
Wood waste from processing includes mainly strips, sawdust and other wastes. In the forest areas, some strips are used for cooking and heating. The amount of strips is about 15 percent of the volume of sawntimber produced. Eighty percent of this amount can be utilized. Sawdust is difficult to collect and the useable amount is about 6 percent of sawntimber produced. Fifty percent of it can be economically used for energy production and other purposes.
The amount of wastes generated during wood processing is determined by the quantity of wood processed and the processing itself, i.e. the equipment used. Recovery rates in the different wood-processing sub-sectors range from 50 to 93 percent (Table 9). The average recovery rate is about 65.5 percent. Assuming a log production of about 60 million m3 and a weighted recovery rate of 60 percent, 12.38 million m3 of waste is generated every during wood processing.
Table 9. Average recovery rates (percent)
|Utilization rate of harvested forest resources||Logging||Wood processing (average)||Sawmilling||Plywood||Particleboard||MDF||Blackboard||Finger jointed wood|
The highest wood utilization rates are obtained by the MDF, particleboard and parquet sub-sectors. The role of technology and equipment used in the production process is very important (Annex 1). It determines not only the quality of the final products but has also a considerable influence on the generation of wastes. For example, the Fuzhou MDF plant with an annual production of 120 000 m3 has received numerous First Class, Second Class and Special Class awards for producing high standard boards. It relies on raw materials composed of wood chips and logging and mill residues (sawdust, waste fiber, wood powder, slabs, off-cuts). In 1995, the mill imported a continuous flat-pressing process MDF production line from Germany. Wastes generated during the production process are used for energy production. The wood chip consumption per cubic meter of board has gradually decreased (Table 10).
Table 10. Consumption of wood chips in MDF production at the Fuzhou mill
|Consumption of wood chips (m3)||70 955||83 950||82 494|
|MDF production (m3)||41 754||53 335||53 261|
|Unit consumption of chips per cum panel (m3 /m3)||1.70||1.57||1.55|
* includes only January to October
Usable volume of logging and mill residues
There are considerable differences in logging residue generation depending, among others, on stocking density, volume of branches and trees species. For example, the tree branches in Wanqing Forest Bureau (Jilin Province) make up 10.43 percent of the total stock volume. In Tieling Forest Bureau (Heilongjiang Province), this ratio reaches 20.68 percent. Huge differences exist even for the same tree species. Branches of larch make up 5.96 percent of the total stock volume in Huzhong Forest Bureau (Daxinanling), 24.09 percent in Dashiton Forest Bureau (Jilin Province) and 23 percent in Shangganling Forest Bureau (Heilongjiang Province).
National log production is estimated to decrease from 63 948 000 m3 in 1997 to 47 950 000 m3 in 2000, i.e. a decrease of about 16 million m3. In forest cutting areas in the northeast, Inner Mongolia and the southwest, the potentially usable logging residues (Ln) and economically usable logging residues (Lne) are 15 percent and 9 percent of the total log production, respectively. Log production of these forest regions is 48 percent of the total national production. Therefore, the Ln and Lne can be calculated as follows:
Ln = 47 950 000 × 48% × 15% =3 452 400 m3
Lne = 47 950 000 × 48% × 9% =2 071 400 m3
On the basis of figures from Fujian Province, Ls and Lse of logging residues of the remaining forest regions are set at 8 and 5.6 percent, respectively. Total log production is 52 percent of total national log production. Accordingly, Ls and Lse can be calculated as follows:
Ls = 47 950 000 × 52% × 8% = 1 994 700 m3
Lse = 47 950 000 × 52% × 5.6% = 1 396 300 m3
Therefore, the total volume of potentially usable Lf and economically usable Lfe (excluding tree tops) for all of China in 2000 can be calculated as follows:
Lf = 3 452 400 m3 + 1 994 700 m3 = 5 447 100 m3
Lfe = 2 071 400 m3 + 1 396 300 m3 = 3 467 700 m3
According to a study conducted in Jilin Province, Lb and Lb of cutoff tree tops is about 3 and 2.7 percent of the log production, respectively. Thus, Lb and Lb can be calculated as follows:
Lb = 47 950 000 m3 × 3% = 1 438 500 m3
Lb = 47 950 000 m3 × 2.7% = 1 294 700 m3
The total potentially usable and economically usable logging residues are therefore 6 885 600 m3 and 4 762 400 m3, respectively. In other words, nearly 10 percent of the residues generated during timber harvesting are real wastes in the sense that the materials have a direct economic value.
The volume of mill residues is determined by log consumption and the recovery rates in the different processing sub-sectors. According to various studies, average recovery rates are 34.4 percent of the log production for processing (Table 11), i.e., every 10 000 m3 of logs processed will generate 3 440 m3 of wastes. Strips, wood shavings, waste veneers and cutoff tops make up about 71 percent or 2 442 m3. Sawdust accounts for the remaining 29 percent or 998 m3. The sawmilling sub-sector accounts for about 60 percent of log production. Hence the volume of sawmilling residues can be calculated as follows:
47 950 000 × 60% = 28 770 000 m3
Taking account of log imports (about 4 million m3), the total production of wastes from processing in the whole country in 2000 is estimated to be:
(28 770 000 m3 + 4 000 000 m3) × 34.4% = 11 272 880 m3
Under the present conditions, 80 percent of this amount, i.e. 9 018 304 m3, can be economically used. This means that while logging and wood processing generate about 18 158 480 m3 of residues, only about 13 780 704 m3 can be used economically. This is about 27.7 percent of the log production in 2000.
Table 11. Ratio of residues in different operations (percent)
|Operation||Location||Amount of residues/log production||Ratio of usable residues||Usable residues/processed logs|
|Logging||Northeast, Inner Mongolia and southwest forest regions||15||60|
|Logging+Bucking||All the other regions||10||70|
Necessary conditions for reducing residues
The following aspects need to be considered to effectively reduce logging and mill residues:
Development of appropriate logging equipment to improve efficiency of harvesting operations.
Upgrading of timber harvesting management aimed at reducing butt heights and collecting usable wood raw materials.
Reduction in firewood use.
Development of processing technologies, especially for utilizing sawdust.
Training for all forestry operations, especially for tree fellers.
Due to a lack in nation-wide data, the diversity of forest harvesting operations and equipment employed in the forest and wood processing sub-sectors, the estimates presented in this report have to be treated with care. However, based on numerous case studies and a careful consideration of the observed differences, it can be concluded that the amount of wastes generated by the forest sector is substantial. Logging and wood processing generate about 18 158 480 m3 of usable residues, although only about 13 780 704 m3 can be used economically (Table 12). This is still about 27.7 percent of the log production in 2000. The potential to make use of this amount as raw materials in the pulp and paper and wood-based panel sub-sectors is considerable.
Table 12. Estimates of useable wood residues (million cum)
|Usable residues||Economically usable residues|
Management must be strengthened to improve efficiencies in most sub-sectors and recovery rates in logging operations need to be increased through better collection and transport. Further impetus for reducing wood residues can be provided through appropriate training and the modernization of ailing enterprises. Some of China's wood-based panel enterprises have integrated the use of wood wastes in their production processes. However, there are still quite a number of old and inefficient wood-processing mills. Many small-scale enterprises contribute substantially to the generation of wastes and need to be either upgraded or closed down.
To increase efficiencies in the logging industry and the wood-processing sector, the following activities are recommended:
Develop appropriate logging equipment to improve efficiency of harvesting operations;
Improve management aimed at increasing recovery rates in forest harvesting;
Reduce the reliance on firewood as an energy source;
Develop processing technologies that can profitably make use of wood wastes, including sawdust and bark;
Provide training for forestry workers in forest management, particularly in harvesting;
Formulate favorable tax policies to support the use of logging residues; and
Design policies to support the large- and medium-scale wood-processing enterprises in establishing high-quality timber plantations, especially in the south and coastal areas.
Utilization of wood residues at typical mills
|Unprocessed logs||185||100% from plantations|
|Amount of other raw materials||0|
|Recovery rate of wood (percent)||100|
|Technology & equipment||Schenck, Germany|
|Product standard||Enterprise standard|
|Total wood raw materials used||178|
|Ratio of logs used (percent)||100|
|Recovery rate of wood (percent)||100|
|Technology & equipment||Imported from Germany|
|Annual capacity||1,800||(10 000 m3)|
|Product standard||Enterprise standard|
|Total wood raw materials used||36|
|Ratio of logs used (percent)||99.7|
|Recovery rate of wood (percent)||99.69|
|Unprocessed logs reached transported by trains||12.4||Shut down||100% from natural forests|
|Amount of other raw materials:|
|branches||25 330||86 928 t|
|Recovery rate of wood (percent)||70.6||90|
|Technology & equipment||Imported||Shut down|
|Total wood raw materials used in||12.4|
|which ratio of logs (percent)||100|
|Recovery rate of wood (percent)||30.7|
|Technology & equipment||Imported|
|Total wood raw materials used||25.3||47.5|
|Recovery rate of wood (percent)||90||90|
|Technology & equipment||Bison|
|Annual capacity/production||30/ 22.5|
|Total wood raw materials used||39.4|
|Recovery rate of wood (percent)||90|
|Unprocessed logs arrived transported by trains||4.86||4.85||All from natural forests|
|Recovery rate of wood (percent)||52.9||43.2|
|Technology & equipment||Locally made||Locally made||Shut down|
|Total logs used||2.58||1.8|
|Recovery rate (percent)||66.2||65.2|
|Technology & equipment||Some imported||Some imported||Shut down in 1998|
|Total logs used||37.6||38.3|
|Recovery rate (percent)||41.8||34|
|Technology & equipment||Some imported||Some imported||Equipment rejected in|
|Product standard||Enterprise||Enterprise||Only use waste veneer|
|Recovery rate of wood (percent)||70||70||of the mill|
|Wood used, in which||5.4||7.9|
|Chips (percent)||35||All from plantations|
|Sawmilling waste (percent) transported by trucks||2|
|Recovery rate of wood (percent)||83||98|
|Technology & equipment||Local||Imported|
|Recovery rate of wood (percent)||83||98|
|Unprocessed logs reached transported by trains||110||760||100% from natural forests|
|Amount of other raw materials:|
|Branches||15%||from plantations & single trees|
|Recovery rate of wood (percent)||94||95||96|
|Technology & equipment||Local||Local||Local|
|Total logs used||80||40||8.5|
|Recovery rate of wood (percent)||75||75||71|
|Technology & equipment||Local||Local||Local|
|Annual production||12||10 National||3|
|Total logs used||30||34||3.06*|
|Recovery rate of wood (percent)||41||98|
|Technology & equipment||Local||Bison||Bison|
|Total wood used, in which||14||23.8||21.1|
|Recovery rate of wood (percent)||71||71||71|
|Technology & equipment||Siempelkamp|
|Total wood used, in which||216||From plantations|
|Recovery rate of wood (percent)||95|
|Technology & equipment||Local|
|Total wood raw materials used, in||5.3|
|which ratio of logs (percent)|
|Recovery rate of wood (percent)||78|
|Finger jointed wood|
|Technology & equipment||Local||Local||Local|
|Total wood raw materials used||1.052||2.134||1.052|
|Recovery rate of wood (percent)||95||95||95|
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A. Ng. Gintings1 and Han Roliadi2
In Indonesia, biomass residues include the materials left in the forest after logging; over-aged and unproductive plantation species that need to be replaced by young seedlings; and mill wastes (residues) generated during wood processing. Disposal of these residues by burning has encountered objections mainly because of environmental concerns. Residues may also have a considerable economic value. If they are used more efficiently, dependency on conventional and regular wood materials could be reduced, and timber extraction might be scaled down.
For these reasons, wood residues should be managed properly. The purpose of this study is to assess the potential of wood residues in Indonesia, and to propose efforts to deal with them. The Indonesian case study forms part of a regional study commissioned by the Asia-Pacific Forestry Commission. The overall objectives of the study are to assess the availability of wood residues availability in the processing chain (including harvesting, transport, storage and processing) of major forest products industries; and to evaluate the raw materials in terms of its source (e.g. natural forests, estate sector, and wood processing industries).
The Indonesian forestry and estate crops sectors
Indonesia has 144 million ha of forestland, classified as 18.8 million ha conservation forest, 30.3 million ha protection forest, 30.5 million ha conversion forest, and 64.4 million ha production forest (Anon, 1998a). The production forests are allocated for the extraction of timber or non-wood products (e.g. rattan, cayeput oil, dammar, resin/turpentine, gutta percha).
Forestry in Indonesia is an important social and economic sector (Anon, 1999a). Forest porducts not only help to develop the nation's economy but also provide income to people living in and around the forests. The contribution of the forestry sector to the Indonesian gross domestic product (GDP) increased from Rp. 14.43 trillion in 1993 to Rp. 16.69 trillion in 1997, although in relative terms the contribution of the forestry sector to the GDP has decreased from approximately 4.29 percent (1993) to 3.82 percent (1997). In addition, Indonesia's forests provide valuable local and global environmental services (Schweithelm, 1998).
Rubber plantations, oil-palm estates, and plantations of other estate crops (e.g. clove, tungseed, nutmeg, and cashew nut) cover 3.5 million ha, 2.2 million ha and 1.2 million ha, respectively (Statistical Estate Crops, 1997). The Indonesian production of rubber increased from about 1.4 million tons in 1993 to 1.6 million tons in 1997. The role of rubber in the nation's economy is regarded as important. This is reflected by the increase in exports from 1.2 million tons (valued at US$ 977 million in 1993), to 1.3 million tons (valued at US$ 1.9 billion in 1996). Palm oil is also an important commodity in social and economic terms (Anon, 1998b). In 1997, Indonesia produced 5.4 million tons of crude palm oil (CPO). CPO exports totaled 3.3 million tons, valued at US$ 1.5 billion. The oil-palm sector employs some 3.4 million families. By the end of 1998, the oil-palm estate sector had increased from 2.2 million ha to about 2.6 million ha, capable of producing 5.9 million tons of CPO.
1 Director of Forest Product and Socio-economic Research and Development Centre (FPRC) and Coordinator for this paper
2 Senior Research Staff of FPRC and Secretary/Draft formulator of this paper
Other estate crops cover approximately 1.2 million ha. In 1995–1996, annual exports totaled about 690 tons of cloves, 9 536 tons of nutmeg, 27 886 tons of cashew nuts, and 137.9 tons of tungseed, which were valued at US$ 1.7 million, US$ 19 million, US$ 23.8 million, and US$ 787 000, respectively (Statistical Estate Crops, 1997).
Forest harvesting and wood processing
The 64.4 million ha production forests consist of mangrove forests, swamps, lowland and mountain forests. Lowland tropical forests make up about 26 percent of the total area (Dennis, 1998). As lowland forests are the most accessible, they are more affected by logging (timber harvesting) than other types of production forest.
Timber extracted from the production forests is partially exported, with the remainder supplying domestic wood-processing industries. Log production between 1992/1993 and 1996/1997 averaged 27 739 400 m3 per year (Forestry Statistics of Indonesia, 1997/1998).
Indonesia's wood-processing industries can be categorized into two types, i.e. the primary industries (e.g. sawmills, veneer/plywood, particleboard/flakeboard, fiberboard/medium-density fiberboard (MDF), and pulp/paper), and secondary industries (e.g. furniture, handicrafts and toys, crates and containers, household articles and kitchen utensils, housing components, and other solid wood products). The wood-processing industries that are officially listed and significantly consume wood raw material include sawmills, veneer/plywood, and pulp/paper manufacturers. Their products are in demand domestically and some are exported. Indonesia is also a major producer and exporter of secondary processed wood products (Johnson, 1997).
Indonesian policies on sustainability and environment
The Indonesian Government has classified natural forest according to conservation, protection, production, and conversion objectives. Due to overcutting, illegal logging and forest fires, the forest sector has experienced numerous difficulties in recent years. In response, conversion forests have been allocated for industrial forest plantations (timber estates) to raise raw material supplies for some affected sub-sectors.
To reduce air pollution and the risk of widespread fires, the burning of old and unproductive rubber trees and oil palms is discouraged by the Government and alternatives are currently sought. The dumping of wood wastes into water bodies is also discouraged to reduce water pollution. Primary and secondary wood-processing industries are encouraged to treat wastes and residues by means other than burning to reduce air pollution.
In general, environmental policies take the form of suggestions or encouragement, and unfortunately still remain weak. However, the recently disastrous Indonesian forest fires have raised the awareness of the Government and the Indonesian people (Anon, 1998a). Hence, wood waste generation and disposal are now receiving more attention by Indonesian authorities.
According to information on logging operations predominantly in the lowland forests of Sumatra, Kalimantan, Sulawesi, and Maluku (Idris, 1995; Martawijaya and Sutigno, 1990; Kliwon et al., 1995), average log production is 65.6 m3 per ha. This includes trees with diameters of 50–160 cm. Logging residues average about 82.2 m3 per ha and are composed of various products (Table 1). Wood residues thus constitute 125 percent of the timber removed during harvesting. Assuming a logging rate of 363 415 ha per year in lowland production forests (Idris, 1995), about 23.84 million m3 of logs are produced and logging residues constitute approximately 29.8 million m3 annually from this forest type. Detailed studies on logging rates and waste generation have not yet been conducted for other forest production types (e.g. mangrove forests, swamps, and mountain forests). The lack of data from other forest types makes it difficult to calculate the total amount of logging wastes. Hence the figures in Table 1 should be viewed cautiously.
Table 1. Composition of logging residues*
|Component||Amount (m3 per ha)||Amount (percent)|
|Upper portion of the tree trunk including branches, smaller branches and twigs||37.29||45.35|
|Damaged standing trees, due to felling and skidding||3.96||4.82|
|Commercial wood logs of unacceptable qualities, due to knots, crooks, reaction woods and other defects||15.66||19.05|
|Unknown or non-commercial tree species||1.33||1.62|
* Based on observations and assessments in lowland production forest (Idris, 1995)
The crops described here are those dominating in terms of area and production, i.e. rubber and oil palm. Rubber plantations and production increased slightly between 1993 and 1997 (Table 2).
Table 2. Indonesian rubber production between 1993 and 1997
|1993||3 405 023||1 475 438||0.433|
|1994||3 472 379||1 499 424||0.432|
|1995||3 495 901||1 573 303||0.450|
|1996||3 518 441||1 574 026||0.447|
|1997||3 516 571||1 548 609||0.441|
Source: Statistical Estate Crops of Indonesia, 1997
The replanting rate of old and unproductive rubber plantations is about 3.33 percent per year (117 500 ha) of the total rubber plantation area. Felled rubber trees can potentially produce some 35 m3 of wood material per hectare (Albaladejo, 1997; Anon, 1978; Susila et al., 1988). Hence, 4.11 million m3 of wood, currently regarded as wastes, could be produced per year.
The Indonesian oil-palm estate covers an area of about 2.6 million ha. The replanting rate of unproductive oil-palm trees is about 5.46 percent per year (120 000 ha). What is currently regarded as wastes can potentially produce 78 m3 of raw material (i.e. woody items) per hectare (Anon, 1998b; 1998c; and Statistical Estate Crops, 1997) or about 9.36 million m3 per year.
Discussed here in brief are the primary wood-processing industries (i.e. sawmill, veneer/plywood, and pulp/paper); and those of secondary type.
In 1995, 330 sawmills operated in Indonesia with a total installed capacity of about 4.3 million m3 (Syafii and Sudohadi, 1996). Indonesian production of sawnwood between 1992/1993 and 1996/1997 ranged from 1.7 to 3.5 million m3 per year (Forestry Statistics of Indonesia, 1997/1998), on average about 2.6 million m3 per year. A study of five sawmills in Kalimantan indicates recovery rates between 40 to 60 percent (by volume) of the raw material intake (Martawijaya and Sutigno, 1990; Sarajar, 1989). On average, 54.24 percent (by volume) of the sawnwood production was turned into wastes. These figures are comparable to the 40 to 60 percent recovery rates employing conventional sawmilling techniques in other mills (Tsoumi, 1993).
About 120 veneer/plywood factories operate in Indonesia. Their total production capacity is around 12 million m3 per year (Syafii and Sudohadi, 1996). The domestic production of veneer/plywood between 1992/1993 and 1996/1997 ranged from 8.1 to 10.9 million m3 per year, with an average of 9.6 million m3 (Forestry Statistics of Indonesia, 1997/1998). Studies of several veneer/plywood factories in Java, Sumatra, and Kalimantan reveal recovery rates for plywood of about 40 to 55 percent (by volume) of wood input (Martawijaya and Sutigno, 1990). The estimates are comparable with results from other mills in the country that use conventional technologies (Haygreen and Bowyer, 1989; Tsoumi, 1993). On average, about 57 percent of the raw materials is turned into wastes.
Pulp and paper
Wood is the principal raw material for the pulp and paper industries. A few companies also use bamboo, agricultural residues, or waste paper (Anon, 1999b). In 1995, 71 pulp and paper mills operated in Indonesia, with a total installed capacity of 2.0 to 3.8 million tons of pulp and paper per annum. Six of them were State- or Government-owned factories, while the rest were operated by the private sector (Syafii and Sudohadi, 1996).
Since most of the Indonesian pulp and paper mills use wood (i.e. mostly hardwood or short-fibered wood species), chemical pulping processes are used. Their recovery rate is assessed to be about 45–50 percent (Smook and Kocurek 1982; Tsoumi 1993). A study of 11 private pulp/paper mills with a total production capacity of 3.5 million tons (as output) per year indicates that they exploit about 685 532.5 ha of plantation forests, which potentially produce about 15.06 m3 of wood material per hectare (or 10.3 million m3) per year (Anon, 1997a). This translates into about 5.2 million tons of wood (as input). Recovery rates are therefore about 67 percent and much higher than the rates quoted above.
Residues in the pulp and paper processing may be in the form of log butts, sawdust, and fines (Anon, 1995; Haygreen and Bowyer, 1989). In total, the portion of residues reaches some 40 percent of the wood material input (Sarajar, 1989; Suchsland and Woodson, 1986).
Other primary processing facilities
Other primary processing facilities include the particleboard and MDF industries. In 1996, there were about 39 particleboard factories with a total of production about 470 000 m3 per year. Six MDF mills were officially recorded with a total production of approximately 550 000 m3 per year. There are no data on recovery rates for these mills (Anon, 1997a; and Syafii and Sudohadi, 1996). In comparison to the major wood processors, particleboard and MDF production is not very significant. In addition, they generate less waste, as smaller wood dimensions can be utilized (FAO, 1963; Tsoumi, 1993).
Secondary wood processing
Secondary wood processing includes the manufacturing of furniture, handicrafts and toys, and housing components. In 1995, about 553 units produced secondary processed wood products with a total production capacity of 2.5 million m3 per year (Syafii and Sudohadi, 1996). Data on residue generation do not exist, although rough estimates are in the order of 25 percent (Sarajar, 1989).
Assessments of residues generated from forestry, estate sector, and wood industries
Forest harvesting and estate crops residues
Forest harvest/logging residues
Logging residues were as much as 82.0 m3 per ha, and the rate of forest logging (timber harvest) was about 0.36 million ha per year (Idris, 1995). Therefore, the total amount of logging residues is about 29.8 million m3 per year. Residues are generally left in the forest to decay. Attempts to utilize logging residues are currently being investigated. Small amounts of residues are used by local people for construction, housing, firewood, or other purposes.
The total amount of residues from unproductive rubber trees and oil palms is 13.44 million m3 per year. Residues from other estate crops (e.g. clove, tungseed, nutmeg, and cashew nut) are negligible.
The total amount of residues generated during timber extraction and the regeneration of rubber and oil-palm plantations is about 43.14 million m3 per year (Table 3). In reviewing the estimates, one has to keep in mind that they are based on only a small number of studies. Also, it is not possible to consider illegal logging operations, and timber plantations were excluded from the analysis. Hence, the actual total amount of residues is likely to be even higher and the figures below should be viewed as very conservative.
Table 3. Residues generated during logging and by the estate sector
|Wood residues source||Amount (million m3/year)|
|Forest logging (a)||29.70|
|Old rubber trees||4.11|
|Unproductive oil-palm trees||9.33|
|Total from plantation||13.44|
|Overall total (a + b)||43.14|
Sources: Idris, 1995; Statistical Estate Crops of Indonesia, 1997
Residues from wood-processing industries
Primary wood industries
The Indonesian sawmilling industry produces about 2.6 million m3 of sawnwood per year. On average, residue generation is estimated at 54.24 percent of sawnwood production (Martawijaya and Sutigno, 1990; Sarajar, 1989). Therefore, the total volume can be estimated at 1.4 m3 per year. Based on a recovery rate of 43 percent (Martawijaya and Sutigno, 1990), the plywood/veneer sector generated 4.6 to 6.2 million m3 per year, or an average of 5.5 million m3 of wastes.
On average, 2.6 million tons of pulp and paper are produced annually (Anon, 1997a, 1997b, 1999b). Therefore, approximately 10.3 million m3 of wood materials are required each year as input. Residue generation in this sector is about 4.1 million m3 per year.
Secondary wood industries
Secondary wood processing generates about 562 000 m3 per year.
The total amount of residues generated by the wood-processing industry reaches 11.57 million m3 per year (Table 4).
Table 4. Generation of residues by the wood processing sectors
|Wood industries||Outputs of production (ranges and averages)||Approximate amount of residues (m3/year)|
|I. Primary wood-processing|
|Sawmills1||1 729 839 – 3 534 3563||938 265 – 1 917 035|
|(2 589 826)6||(1 404 722)|
|Veneer/plywood1)||8 066 400 – 10 947 6333||4 597 848 – 6 240 151|
|(9 586 889)||5 464 521)|
|Pulp/paper2||1 314 300 – 4 267 0004||2 102 880 – 6 859 200|
|(2 586 280)||(4 138 048)|
|Total (I)||7 638 993 – 15 016 385|
|(11 007 291)|
|II. Secondary wood-processing||2 500 0005||375 306 – 766 814|
|(i.e. furniture, handcraft and kitchen utensils, crate and containers, other solid wood products)||(561 889)|
|Overall total (I + II)||8 014 299 – 15 783 199|
|(11 569 180)|
1) From 1992/1993 – 1996/1997;
2) From 1994 – 1998;
3) Unit = m3/year;
4) Unit = tons/year;
5) In 1996
6) Figures in parenthesis are average values
Suggested efforts to minimize the generation of wood residues
Improvement of forest harvesting practices
Two main approaches to improving forest harvesting have the potential to reduce wastes during log extraction, i.e. technical and institutional approaches.
Numerous improvements can be made in timber harvesting operations. Foremost are reductions in stump height and the introduction of directional felling that have the potential to considerably decrease damage to the residual stand. Furthermore, improved road planning and construction can also help to reduce damage and waste. Better skidding techniques, such as the use of arches on skidders, will also minimize the breakage of logs.
The introduction of penalties could also result in waste reduction. For example, loggers could be fined Rp. 50 000 if they generate more than 1 m3 of waste per ha (Idris, 1995). Royalties can also be adjusted upwards for poor logging operations. Such disincentives should ensure that wasteful harvesting operations are discouraged.
Possible improvement in the wood processing
A number of innovations could raise sawmill efficiency, such as reducing kerf and variability in thickness. Milling technologies also need to be optimized and logs accurately positioned for the cutting process (Haygreen and Bowyer, 1989). Several ways should be considered in improving the efficiency of veneer/plywood processing, including methods of production, log characteristics, and wood shrinking/swelling (Tsoumi, 1993).
The amount of residues generated in pulping is not only affected by the pulping processes, but also by improving methods, such as wood preparation, debarking, chipping, and chip screening (Anon, 1995; Smook and Kocurek, 1982).
Utilization of wood residues
Wood residues can also be converted into useful products (Haygreen and Bowyer, 1989; Peterson and Leenhouts, 1997; Sjostrom, 1981; Tomich et al., 1998; and see Annex 1):
Solid wood products: furniture components, handicrafts/toys, sports items, household appliances;
Housing and vehicle parts, crates, and containers;
Wood composites: veneer and plywood, particle/flake board, wood-cement board, strain board, and glued-laminated beams;
Pulp and paper: paper, liner board, tissue paper, corrugating medium, sack paper, and paperboard;
Products chemically derived/converted from wood material: rayon/artificial silk, celluloid, cellulose acetate, charcoal, wood gas, alcohols, acetic acid, furfural, and wood tars; and
Fertilizer: being biodegradable, woody biomass residues can be utilized as organic compost for soil conditioning or improving soil fertility.
Converting residues into useful products not only solves disposal problems but can also influence logging rates in that less timber needs to be harvested. This is important because the recent Indonesian forest fires reduced the production forest area to 62 percent of its original size (Anon, 1998a). However, the increased utilization of residues will not come about if technical, socio-economic, political and enviromental aspects are not considered properly.
Technical aspects on the utilization of wood residues into useful products
Residues from forest-logging and wood-processing industries
The Indonesian tropical rainforests are characterized by their biodiversity and boast a variety of timber species with different properties and sizes.
The strength of the wood is affected proportionally by its specific gravity which, for Indonesian tropical timber, can range from 0.25 to slightly above 1.00. The variation in specific gravity results in different strengths. Information about strength is necessary to convert wood residues into useful products, such as solid-wood structures, laminated beams, veneer/plywood, wood composites, and mechanical pulp.
The chemical characteristics of wood residues are important for pulping. Wood with low lignin concentration is easier to process into unbleached and bleached pulps since it requires less processing chemicals. Understanding the aspects of related chemical substances (e.g. types and concentrations) is crucial if wood residues are to be chemically converted into products like pulp and paper or other cellulose derivatives.
Most Indonesian wood residues consist of short fibers that produce pulp and paper with lower strength properties than the longer fibers of softwoods. This aspect needs to be considered in promoting the use of wood residues of Indonesian hardwoods.
Information about the utilization or conversion of wood residues in Indonesia is limited. Recent research indicates that the properties of wood residues are generally comparable to those of regular woods. However, due to various characteristics as listed below, wood residues remain classified as low grade (Koch, 1960; Sandwell, 1960; Syafii and Sudohadi, 1996):
available only in small sizes (i.e. diameter and length);
presence of defects such as knots, shake, rot, insect damage.
These undesirable characteristics need more attention if wood residues are to become more attractive to wood processors. The following steps can be taken to improve the situation: removal of defects followed by reassembly into pieces of desirable dimensions; addition of other materials to enhance strength; mechanical flaking, chipping, or grinding followed by reconstitution (with additives); and chemical digestion and reformation, which results in a variety of pulp and paper products, each with special properties.
Residues from estate crops
Utilization of rubber and oil-palm residues is still being researched (Albaladejo, 1997). Rubberwood possesses a number of properties adequate for further processing but requires intensive treatment to enhance its durability (Budiman, 1978). Oil-palm residues can be used for a variety of products such as particleboard. Conversion of rubber to pulp remains difficult as the pulping process requires significant amounts of chemicals, yields are low and pulp negatively affects metal equipment (Anon, 1998c).
The conversion of residues into useful products is hampered by a number of constraints, e.g. “weight losing”3 usually occurs in or during processing; residue supplies are often scattered at their source location and only available in small quantities; and raw material continuity is difficult to ensure. The potential of using residues is determined by raw material characteristics, mill size and location, investment requirements, manufacturing costs, and profitability (FAO, 1963; Sandwell, 1960; Suchsland and Woodson, 1986). Although difficulties remain, they are not insurmountable as the industry is in urgent need of raw materials, and wood composites produced from residues can meet standard requirements and have become acceptable to consumers (Musttaqin and Soedjatmiko, 1998).
3 Weight losing is the weight loss that occurs during processing.
The Government is also encouraging the use of logs of smaller diameters (especially of less known and non-commercial species) and wood residues by charging a reduced royalty to Rp. 4 000 per m3 (Anon, 1997c). This compares with a royalty of Rp. 11 000 to 21 000 per m3 for logs with diameters above 50 cm.
Conclusions and recommendations
The logging operations, the estate crop sector (mainly unproductive rubber and oil-palm plantations), and wood-processing industry (i.e. primary and secondary processors) are the main sources of biomass residues in Indonesia.
The total amount of residues generated during timber extraction/logging and the replanting of old and unproductive rubber and oil-palm plantations is about 43.14 million m3 per year. The total amount of residues generated by the wood-processing industry reaches 17.78 million m3 per year. There is a concern about their disposal, which can lead to air and water pollution. Although the wood industry in Indonesia is to some extent facing supply shortages of raw materials, residues are still insufficiently used. Operators in the forests and managers in the wood industries should pay serious attention to remedy this situation rather than resort to over-cutting and illegal procurement of logs.
In reviewing the estimates, one has to keep in mind that they are based on only a small number of studies. Also, it is not possible to consider illegal logging operations, and timber plantations were excluded from the analysis. Hence, the actual total amount of residues is higher and the assessed figures as obtained should be viewed as very conservative.
Although there are a number of ways in which residues could be used more efficiently, various constraints have until now hampered attempts to make their widespread use more acceptable. Among the policy options to improve the current situation are the following:
strict law enforcement;
provision of incentives to reduce open-burning and to encourage the utilization of residues for energy generation;
providing a conducive environment for processing residues into useful products; and
raising awareness for technical options among the general public, policy-makers and industries.
The financial support from the Asia-Pacific Forestry Commission for carrying out the study is gratefully appreciated. The authors are also grateful for the assistance of Kayano Purba, Paribotro Sutigno, Askari, and Gustan Pari who all have sought and provided some significant and beneficial data and information. Further appreciation is extended to Syarief Hidayat, Djudju Djuhariah, Ida Srimulyati, and Eko Martianingsih who provided useful supplementary assistance.
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|Sources/location of generation||Types of wood residues (and/or their composition)||Potential uses|
|Forest logging (timber harvest)||• Remaining standing stumps||• Veneer/plywood|
|• Upper portion of the tree trunks, with branches, smaller branches, etc.||• Solid wood structures (lumber and laminated beams)|
|• Wood logs of unacceptable qualities||• Packing materials|
|• Damaged standing trees||• Chips (for pulp/paper/fiberboard)|
|• Unkown or in commercial species||• Particle and flake boards|
|Unproductive estate crops, trees||• Predominantly rubber and oil-palm plantations||• Chips|
|• Solid wood structures|
|• Particle/flake boards|
|Primary wood processing|
|• Sawmills||Log ends||• Small-size lumber|
|• Packing materials|
|Pith and small dimension wood materials||• Packing materials|
|• Small-size lumber|
|Trimming materials||• Joints and laminated wood materials|
|Sawdust and bark||• Charcoal|
|• Veneer/plywood||Log ends||• Lumber core|
|• Packing materials|
|Core||• Lumber core|
|• Packing materials|
|Rejected veneer||• Particleboard|
|Rejected plywood||• Packing materials|
|• Core materials|
|Trimmed plywood||• Core materials|
|• Pulp/paper||Log butts||• Chips|
|Oversize chips (after rechipping)|
|Sawdust and fines|
|Secondary wood-processing||Trimming and ripping materials||Chips|
|(e.g. handcraft, moulding, furniture, housing parts, and other solid wood products)||Rejected materials||• Core materials|
|Cutter removal materials||• Packing materials|
Sources: Ahmad, 1989; Haygreen and Bowyer, 1989