2.1. Forest management and fuelwood supply
2.2. Natural forest for fuelwood
2.3. Forest types for charcoal-making
2.4. Fuelwood plantations
2.5. Cost of plantation establishment
2.6. Fundamental factors in fuelwood supply
Charcoal is made from wood and generally about five tons of wood produce one ton of charcoal. Therefore, charcoal-making can only be an on-going industry where the wood raw material resource is managed to provide a continuing supply. For every person in a community who uses charcoal for heating and cooking about 0.5 ha of natural high forest has to be set aside to provide that wood supply in perpetuity. If the wood comes from well managed fuelwood plantations a tenth of the above area would be adequate. However, plantations require a commitment to proper management and the allocation of better quality land which may be needed for food production.
Although wood used for charcoal may sometimes be derived from sawmill waste or land clearing operations, this does not ultimately alter the long term forest land or plantation requirement for fuelwood. The logistics of supplying that fuelwood is the concern of this chapter.
The objective of resource management of fuelwood supply for charcoal-making is, simply stated, to reduce the land area committed to produce the necessary fuelwood for the projected charcoal production. The two major ways to achieve this are to make the forest more productive by improving growth and reducing waste in harvesting and to improve the conversion ratio of raw fuelwood to finished charcoal at the user's door.
Decisions in the resource management area to be fully effective have to be made at a national level. At the level of the charcoal burner, the decision is normally made in a simple exploitive way. Managers of large areas of natural forest or plantations can usually make a more far-sighted decision. But whatever decisions are made and acted upon at whatever level, they will ultimately be expressed at the national level in the form of an adequate, or otherwise, charcoal supply situation. The necessity for a national fuelwood policy, as pointed out in chapter 1, is inescapable. In this chapter we are concerned with maximising the long-term growth/yield of the forest resource. Later chapters are concerned with efficient wood harvesting, carbonisation and distribution of the finished product.
The science of forest management is too complex to be elaborated in this manual. It is sufficient to point out some features of natural forest growth and yield which affect fuelwood supply. A natural forest is a resource which, in the economist's jargon, grew without labour inputs from man. The aim of forest management is to harvest a maximum timber crop from such a forest without destroying its productivity as an on-going ecosystem and, at the same time, minimise the inputs needed to achieve this. The result of this process is expressed in the mean annual allowable out of the forest, usually measured in cubic metres per hectare. Theoretically, one could remove a volume equal to this each year and the forest would maintain itself. In practice, the intervention of man produces long-term changes in the forest, especially in the tropics, changing the species composition and the diameter glasses of the mature, natural forest after harvesting and regeneration. Wherever possible, a forest should be managed to produce the product mix of highest value - sawlogs and veneer logs are first priority. (15). Fuelwood has the lowest value; it is wood which cannot normally be sold for any other purpose. Its price is usually below pulpwood for the paper industry.
The normal method of harvesting a forest is to divide it into compartments or management areas and selectively fell the trees in each compartment in turn, working through the whole forest over a period of 30-50 years, which is called "the rotation". The objective is that the harvested compartments will be ready for harvesting again at the end of the rotation period and, hopefully, will be as well stocked with saleable timber as they were when in their natural state. Rarely is this objective achieved in practice because a rotation (perhaps forty years or more) is a long period in terms of a country's development process. Population grows, national priorities alter, the mix of saleable forest species and products changes and the power of the administration controlling forest operations fluctuates. Although the objective of rational management of natural forests is rarely attained and almost never optimised, it is still possible to estimate in general terms over a whole region or country - providing inventory figures of forest area and type are available - what the total annual harvest of fuelwood could be without harming the forest's ability to recover and produce timber indefinitely. However, even in countries where the annual harvest per hectare over a region appears to be supportable indefinitely - usually due to the uneven intensity of harvesting, mainly due to population density differences the forest ecosystem is in part being destroyed or damaged. The ultimate consequence of this process is not difficult to imagine.
The usual compromise achieved - even in countries where forest management is strong and well-oriented - is that a certain area of forest is allocated for fuelwood supply with the annual allowable offtake, or cut set at a level believed sustainable from the knowledge available at the time. The fuelwood harvesting enterprise then endeavours to stay within the prescribed cut and to maximise the harvest by making effective use of branchwood, dead timber and small diameter wood of poor quality, etc., which is not normally included in the assessed standing volume for yield calculations. To avoid damaging the forest system, however, there needs to be constant monitoring and measurement by the forest management authorities to ensure that target regeneration and growth rates are being achieved and decide if the allowable cut may be increased or must be reduced.
A study of traditional-charcoal-making practices throughout the developing world indicates clearly that the preferred forest type for charcoal-making is dry, well stocked savannah forest rather than dense humid rain forest. Savannah forests are preferred for a number of reasons. The wood is usually dense, slow-growing and highly lignified, which gives a good charcoal yield when carbonised. The quality of logs available for sawmilling is generally low, due to poor form of the trees and this means that most of the wood is only saleable as fuelwood, which tends to keep wood prices low. The terrain is usually easy, which simplifies harvesting. A short, wet season, and correspondingly long, dry season, means that charcoal operations can continue most of the year and fuelwood dries out quickly with minimum loss through insect attack and fungal decay. The only major limitation in some areas is the low yield of wood per hectare. Typical yields considered good practice are about 35 cubic metre/ha. Marginal commercial operations show wood yields down to 20-25 m³/ha. The classic charcoal production areas of Africa, South America and Asia are nearly all savannah-type forests. As savannah-type forests have become overcut and uneconomic, the charcoal industry has tended to move into the humid rain forest type. These forests have high available quantities of fuelwood per hectare. It is not unusual for fuelwood yields of 100 m³/ha to be obtained even after saw and veneer logs have been removed. This gives low wood costs at the side of the kiln. In the wet humid climate, however, the fuelwood is mostly of low to medium density, not highly lignified and commonly prone to rapid decay and attack by insects. The rainy season is longer and more severe and, in some areas, there may be two rainy seasons per year, which make it very difficult to dry the fuelwood before carbonisation. Instead, the fuelwood usually rots or is destroyed by insects before it dries sufficiently for optimum carbonisation. Therefore, when making charcoal in humid tropical rain forests it is necessary to carbonise the wood at a higher initial moisture content than is typical in savannah-type forests. This avoids the wood deteriorating, as it is left to dry only a few weeks before carbonising. The yield is lower because more wood must be burned in the kiln to dry out the wood before carbonisation can start. A typical moisture content of wood charged to the kiln under these circumstances can be 50-100 percent, depending on the density of the wood and the weather conditions at the time. Yields fall to one ton of charcoal per six tons of wood or more (on a volume basis about one cubic metre of charcoal to 2.67 to 3 steres of fuelwood). Despite the disadvantages, the increasing unavailability of suitable dry type forest resources are forcing more and more charcoal operations to be shifted to humid rain forest, even though yields and production costs are much higher than the traditional savannah forests.
Fortunately, given the problems of fuelwood and charcoal supply in many developing countries where natural forests have been cleared, or otherwise devastated, forest science has developed systems for cultivating man-made plantations of quick growing forest trees. The eucalypts native to Australia have been widely adopted and modified by selection for this purpose throughout the world. FAO's book "Eucalypts for Planting" (11) provides a wealth of information in this field and is essential for anyone seriously interested in this area.
There are many species of eucalypts used in plantations, allowing adaptation to particular local conditions, and, fortunately all make excellent fuelwood and charcoal. Where plantations are established and managed correctly on suitable sites, growth can be rapid. Mean Annual Increments (MAI) of 15-20 m³ per ha over 12-20 year rotations are not uncommon.
Establishment and management of fuelwood plantations is a specialised branch of forestry and should only be attempted when specialist advice has been obtained. To be successful it is necessary that land of suitable fertility be set aside for the plantations, that a suitable tree species be selected and that a proper system of dedicated management be set up. The first crop will not be produced until 12 - 15 years have passed which makes the development of man-made forests a job for government, well organised cooperatives, or a large private corporation.
Producing wood for charcoal from plantations demands that the cost of producing the fuelwood on the stump be carefully calculated to ensure that such a long-term investment is, in fact, worthwhile. On the other hand, the cost or stumpage of wood from natural forests is arbitrary and is set, in effect, by ordinary market forces, somewhere between zero cost where a small-scale charcoal producer gathers wood without payment from vacant forested land, and the cost of producing equivalent fuelwood from plantations. State forest services sometimes attempt to set fuelwood stumpage by calculating the management cost of the natural forest from which the wood is taken. Sometimes private natural forest owners set a stumpage rate as a percentage of the value of the charcoal produced. Around ten percent is a typical charge. Government stumpages are usually less than this when expressed on the same basis.
As an example of the detailed cost items of eucalypt plantation establishment, we have drawn on the valuable experience of the charcoal iron industry of Brazil perhaps world leaders in the production of industrial charcoal derived from plantation-grown fuelwood. Under Brazilian conditions (1977) the costs can be summarised as follows:
A normal value of US$ 100/hectare has been used for calculation. At this value land cost has little influence on the final cost of fuelwood.
The costs of afforestation with eucalyptus trees are shown in Table 3. The trees are planted from seedlings and are first out after eight years. Six or seven years later they are re-cut and after a further six or seven years, are re-cut a second time. This gives a total cropping cycle of 20-22 years, after which time the stumps are uprooted and new trees planted.
In a highly mechanized operation the expense per hectare during the first year of a reforestation project represents 50 percent of the total expenses of the complete cycle of 20-22 years, which is US$ 500 of a total expense of US$ 1,000. The expenses during the first of the three cycles represent US$ 700 or 70 percent of the total rotation time of 20-22 years. For manual reforestation the expenses during the first year represent US$ 800 or 60 percent of the total expenses of US$ 1 300. Salary for rural workers in 1977 was US$ 80 per month. The cost of salaries has been included for the first planting and three years maintenance.
The resulting final cost of forestry for the three cycles is US$ 4.99 per cubic metre of charcoal (equivalent to US$ 19.96 t), when using maximum mechanization. This corresponds approximately to 30 percent of the 1977 commercial price of charcoal. The tax incentives have not been considered, as they have been decreasing in the course of the last years and may in future become insignificant. However, in 1977 they still represent a saving of 17.5 percent.
It is assumed that, after the third felling, the eucalyptus forest must be replanted. No figures are yet available for Brazilian conditions for sucker growth after the third felling. Coppice regeneration after two rotations may give variable results. For further information on coppice systems see (11).
Table 3. Costs of Forestry Operation in Brazil with Eucalyptus Trees (excluding tax incentives)
With Maximum Mechanisation
|
Cycle |
Total Yield |
MIA |
Land Cost |
Equipmt. Cost |
Labour US$/ha |
Fuelwood Cost |
Charcoal Cost |
||
|
st/ha |
st/ha. A |
US$/ha |
US$/ha |
a |
b |
US$/ha |
US$/st |
US$/m³ |
|
|
Planting |
- |
- |
100 |
200 |
200 |
- |
500 |
- |
- |
|
2-8 yrs. growth |
176 |
22 |
- |
100 |
- |
100 |
200 |
- |
- |
|
First cut after 8 yrs |
176 |
22 |
100 |
300 |
200 |
100 |
700 |
3.94 |
8.74 |
|
Second cut 13-15 yrs. |
152 |
22.25 |
- |
65 |
- |
85 |
150 |
0.98 |
2.15 |
|
Third cut 18-22 yrs |
112 |
16-19 |
- |
65 |
- |
85 |
150 |
1.34 |
2.95 |
|
TOTAL 20-22 yrs |
440 |
20-22 |
100 |
430 |
200 |
270 |
1,000 |
2.27 |
4.99 |
|
All Operations Manual |
|||||||||
|
First cut |
176 |
22 |
100 |
100 |
600 |
800 |
4.34 |
9.99 |
|
|
Second cut |
152 |
22-25 |
- |
50 |
200 |
250 |
1.64 |
3.61 |
|
|
Third cut |
112 |
16-19 |
- |
50 |
200 |
250 |
2.23 |
4.91 |
|
|
TOTAL |
440 |
20-22 |
100 |
200 |
1 000 |
1 300 |
2.95 |
6.49 |
|
Notes:a. Plantingb. Maintenance
c. Costs include land, preparation of soil, roads, tree nurseries, tree planting and maintenance
d. m³ ch. = m³ charcoal produced from 2.2 st. of wood
Fuelwood supply is, in the long run, the most fundamental aspect in charcoal-making. With an adequate wood supply charcoal production becomes a problem of social and technical management. Where the wood supply is inadequate, no technical "fix" can provide the charcoal needed of the population. It is surprising how often this fundamental point is ignored or glossed over and too much attention incorrectly focussed on charcoal production details.
A permanent and hopefully expanding supply of fuelwood for charcoal is essentially a long-term problem of land resource allocation and management. Proper management is basic since the crop cycle of trees, whether in plantation or natural forest, is measured in decades. Management must pay close attention to the social interaction between a rural population and forests, if their existence and productivity are to be maintained. The fertility of the forest soils must be maintained, with use of fertilizers if necessary. The long-term effect, for example, of removal of bark from plantation forests on nutrient balance, needs to be studied. The advantages and disadvantages of Coppice rotation on eucalyptus forests as related to production of higher priced products such as poles, saw and veneer logs, must be carefully evaluated. Finally, the choice of species for charcoal most suited to a particular region is important. What matters in the long run is the yield of charcoal that can be obtained per hectare, expressed in available heat units, delivered at the door of the final user. Choice of species and the way the plantation is managed play an important role, which is only now beginning to be appreciated. Although eucalyptus species are the most widely planted for charcoal and fuelwood, the advantages of other hardwoods and pine species which, in certain cases, may give higher returns by yielding a higher priced wood mix than fuelwood alone, always need to be studied closely when determining a plantation establishment policy.
