by E.E.F. UHART, FAO Technical Assistance Officer, Iran
OUTSTANDING in forest utilization in those Middle or Far Eastern countries that receive technical assistance from the United Nations is the substantial amount of wood used for charcoal as compared with the relatively small amount of saw timber extracted. This is characteristic of Iran and Syria, Turkey and Iraq and is also found on a smaller scale in Pakistan and India (where wood is more normally used for fuel); but towards China and neighboring countries, it is seen once more at its worst. Here, a partially burnt charcoal is used for cooking; it burns slowly, but is troublesome because it smokes.
Charcoal-burning is also practiced throughout the Malay Peninsula, Thailand and Indochina, where it plays an important part compared with saw timber extraction which is carried out on a modest scale in relation to existing forest resources. In all these countries charcoal production is primarily intended for local consumption and is only occasionally exported to adjacent regions.
What we shall proceed to describe for Iran will apply with slight variations to the countries mentioned above.
One instance is enough to illustrate the point: Iran, according to official statistics, annually consumes 400,000 metric tons of charcoal made from roughly 4,000,000 m3 of wood, whereas saw timber extraction only amounts to 200,000 m3, one-twentieth of the volume converted into charcoal.
This extensive use of charcoal is due, in the first place, to methods of cooking (grilling mutton over hot coals) and heating. These methods came to be employed because complicated stoves are not necessary for burning charcoal, which is an inexpensive fuel, easy to use and available wherever there are forests. They date from the time when a fire, still a rarity, could be kept alight by live charcoal embers underneath the ashes.
The switch-over from charcoal to oil or coal will be a long and difficult process because of the high price of the latter and the difficulty of transportation over bad roads.
Finally, it is significant that Tehran, with a population of 1,200,000, consumes 200,000 tons of charcoal a year, half the country's total consumption, despite the concurrent use of oil, fuelwood and coal.
On the whole, Iran has a dry, continental-type climate with the exception of its coastal areas, notably the Caspian area, which has a good rainfall. This has given rise to two large forest zones:
1. North Slope of the Caspian area, where rainfall is heavy (11.50 m. per year) and where there are also snowfalls. On account of its climate this area still has some fine forests with species of a Caucasian-European type, the most important of which are: Quercus castaneifolia, Parrotia persica, Fagus, Ulmus, Fraxinus, Carpinus, Populus, Buxus, Juniperus, etc.
2. Remainder of the country, where rainfall is low (from 400-120 mm. in the south). Here Pistacia lentiscus and, in particular, Quercus persica, predominate, the latter an excellent drought-resistant species adapted to the climate of the region, which grows well from stumps.
The first area, which includes mature trees and stands which have deteriorated through widespread grazing and uncontrolled charcoal burning, still possesses timber worth extracting.
The second area, on the contrary, needs to be made a reserve area immediately, with the sole object of protecting the existing forests on account of the general paucity of timber. Only when these forests have been rehabilitated can good forest management be undertaken.
Confining ourselves to Iran - since the same methods are employed in the other countries - the systems of charcoal-burning can be reduced to two.
In the Caspian and Azerbaijan forests, stone and earth kilns are used; these are roughly put together with faggots and billets under a vault of beaten earth, and are for the most part protected by a rough roof from rain and storm. The capacity of the kilns varies from 3 to 10 or 15 m3 of wood and they are filled through openings at both ends of the covering vault and emptied of charcoal from below, with 1 to 3 vents to assist the draught.
In the Shiraz area the system is even more primitive and consists in digging a pit in the ground, reinforcing it inside with flat stones, particularly on the side with the opening, to avoid it caving in. Wood is cut in 50 cm. lengths and stacked alongside the opening. The pit is fired by dropping burning kindling into the hole and covering it with the wood. The hole is then covered over with a lattice of billets ("charbonettes" - small logs not over 66 cm. in length) which act as a support for a covering of damp earth which is applied when the fire is put out.
There is no need to dwell upon these primitive ovens which are found with slight variations in Asia, Africa and Latin America. The Chinese type, for instance, consists of a hole dug in the ground, sometimes with stone walls, with a slanting door for loading and unloading and several openings for the draught.
The principle is the same: the wood is charred, that is to say, a part of the wood burns slowly and gives forth enough heat to distill the remainder and convert it into charcoal. It is all a question of experience and personal skill. In order to obtain good charcoal, the burning must be stopped when all the wood is charred and, above all. the pit must be hermetically sealed.
From a practical forester's point of view, there are three drawbacks common to all these methods of charcoal burning:
1. The charcoal yield is very poor - about 10 percent - which means that a great part of the wood burnt is a total loss. The optimum yield varies between 22 and 25 percent by weight of the charred wood (distillation in a retort).
2. Methods of working the forest are poor; the wood cutters have poor equipment and as a result do not make full use of the timber. Generally, they only take the branches up to 25 cm. in diameter, and leave the trunks to rot on the ground. The trees are either uprooted or, more usually, cut at 1 meter to 1.50 meters from the ground, with the result that no new shoots sprout and the forest disappears.
Present felling methods destroy the existing forest without making full use of its wood and absolutely prevent regeneration by shoots.
3. In most of the countries under consideration, charcoal-burning places are badly located and choice of site is completely uncontrolled. This involves destruction throughout the stands and the resultant disappearance of the forest, especially where there is unrestricted grazing and shifting cultivation.
Erosion removes the top soil from the slopes and exposes the rock; and, in the tropical regions, laterization takes place, with all its consequences.
This gloomy picture is no exaggeration. Its truth can be checked by flying over the Middle East countries, the Deccan Plateau in Central India, or China.
Iranian kiln in the Caspian region, showing the two openings through which the kiln is stoked; note the trench from. which the kiln its emptied and the charcoal put into sacks.
A similar kiln. without roof: a forest ranger points to the opening trough which the kiln is emptied.
Although this section deals more particularly with the action taken in Iran, the remedies found useful there can serve in others with minor changes.
1. In order to increase the charcoal yield to a reason able level, it has been suggested that the local kilns be replaced by mobile metal ovens of the Magnein-Tranchant type. These have the advantage that they can easily be made locally and even unskilled labor can be readily taught to handle them; but, more important, their average yield varies between 18 and 20 percent. This, in theory, would reduce wood consumption by half. The charcoal obtained from this type of oven is of better quality, since it is completely charred and burns out for lack of oxygen instead of having to be put out with water as is too often the practice.
The cost of manufacturing these ovens in Iran is at present 1,000 Tomans (U.S. $125) per unit. They should be used in a set of four, operated by ten men. Their average service life is two years. Taking into account the depreciation over this period, the additional profit from each set of ovens is 3,000 Tomans. Moreover, the quantity of wood consumed would be approximately twice as small as by the old method in order to produce the same quantity of charcoal.
2. Felling would be improved by the use of simple but good quality hand tools: axes, billhooks and cross-cut saws for bucking and metal wedges and sledge hammers for splitting trunks; the use of such tools would make it possible to fell trees efficiently and, above all, at ground level. This latter practice would ensure stand regeneration by stool-shoots in the form of coppice or coppice with standards. Further, a cutting cycle needs to be established for all forested areas, in the case of the Caspian forest, this would be 10 years.
The advantage of this would be to limit charcoal production to low altitude forests (those below 500 m.), the others being reserved as high forest fulfilling a protective role both as regards climate and for preserving soil water, in addition to constituting a source of timber. We are convinced that the coppice system will also contribute to soil conservation, on account of the closeness of the stand, and will at the same time have a favorable effect on the improvement of water regimes, although the amount of water evaporation which takes place in a deteriorated high forest, as compared with the coppice which replaces it, is always a debatable point.
3. In order to concentrate charcoal-burning activities and make their supervision easier, sound legislation needs to be enacted and enforced, above all, to limit charcoal-burning to carefully chosen areas, with due regard for supervision and transport facilities (roads) and the comparatively low density of the stands.
These suggested remedies would probably have to be varied for other countries in the light of economic conditions (consumption and transport facilities), while remaining generally very similar. In the more highly developed countries, for instance, stationary metal or masonry ovens could be erected and supplies of wood brought either by road or by water. Apparatus could be added for the recovery of by-products, which have a high market value when available in large quantities. Among the by-products which could be put to immediate use are tar to provide creosote for impregnating railway sleepers and telegraph poles, and acetic acid in the form of lime acetate for dyes for the textile industry.
Felling could be partially mechanized by the use of band-saws, and haulage improved by cableways.
The implementation of such a plan, which would entirely revolutionize local customs, would require the full support of government and public opinion.
Legal and financial planning would obviously vary according to the existing forms of forest ownership, social conditions and the financial resources of the particular country.
The legal structure would need to be either a state enterprise, a co-operative system where holdings are small, or private enterprise.
In the author's opinion, the first of these would be most suitable for Asia; that is, the establishment of state-controlled charcoal-burning companies managed by competent forest service agents, but financially independent. They would be state trading monopolies.
The funds that would be needed to finance them could be raised in several ways. The time required for carrying out such a plan would naturally vary according to the country in the case of Iran, ten years.
The profits from such enterprises would be used to equip the forests with roads, houses for rangers, sawmills, plantations, etc.
In this rapid survey an attempt has been made to stress the widespread nature of the charcoal problem. Similar drawbacks require similar remedies. Briefly, by introducing modern ovens a better yield will be obtained. The forests will be managed, thus ensuring their conservation and a better return. Forest conservation will indirectly affect the climate and the soil's water resources and will also help to check erosion. The zoning off of charcoal-burning areas will make it possible to utilize the other forest areas - as, for example, montane forests - for other purposes such as protection and the production of saw timber. The improvement of the latter will assist the rational utilization of industrial wood to feed both the home and export markets.
One example is worth quoting: as a result of the establishment of a charcoal-burning center in Cambodia at the village of Dang Tong, a mixed stand with a preponderance of "sralao" (Lagerstroemia) was converted valuable teak (Tectona grandis), after the other species had been removed. A small sawmill used the "sralao" for making boards and building timber.
This is an example to be followed and it is reasonable to conclude that, with proper charcoal-making arrangements and practices, the population can be kept supplied with charcoal and the tropical and subtropical forests enriched with valuable species, thus helping to meet timber shortages and to raise standards of living.
Kiln in the Shiraz region, out of action.
Kiln in the Shiraz region , in action.
Metal oven and regenerators of local manufacture at the Agricultural University of Karadj (near Tehran).