Afforestation within reduced boundaries: The development of Hungarian forestry, 1950-1980

Béla Keresztesi

Béla Keresztesi is Director-General of the Forestry Research Institute, Budapest, Hungary.

After the First World War, Hungary lost 67 percent of its total land area, 58 percent of its population and 85 percent of its forests. Gone were the heavily forested Carpathian mountains. The new Hungary consisted mainly of plains and hills cut by the River Danube, and the annual volume of wood felled was less than 9 percent of its pre-war level. A new approach to national forest management was needed if Hungary was not to become totally dependent upon wood imports. What could be done?

The systematic development of Hungarian forestry - silviculture, the timber industry and timber marketing - began after the First World War, which marked the fall of the Austro-Hungarian monarchy. The Treaty of Trianon (4 June 1920), which fixed the post-war frontiers of Hungary, ratified the reduction of its territory. Those parts where non-Hungarians were in a majority were transferred to neighbouring countries or given to the new countries that had emerged from the same events. The country's total area (without Croatia) decreased from 28.3 million to 9.3 million ha, while its population fell from 18 million to 7.6 million.

Much of the territory detached from pre-1920 Hungary consisted of forest-covered mountains. The country's forested area was therefore reduced from 7.4 million to 1.1 million ha. This loss of 6.3 million ha had considerable consequences, for the area of the new Hungary yielded less than 9 percent of the wood volume harvested in the old Hungary.

The forests of the plains and hills within the new frontiers (which comprise the forest resources of present-day Hungary) had formerly played only a minor role in supplying wood. Before the First World War, requirements in coniferous roundwood and sawnwood had been amply covered by the Carpathian forests. For this reason, during the nineteenth century and at the beginning of the twentieth, even the large forest estates had limited themselves to applying the coppice system to produce fuelwood and small-sized timber. Before the Treaty of Trianon, 24 percent of Hungary's forests consisted of conifers; in 1920 conifers accounted for only 4.1 percent. It therefore became necessary to make up the deficit by imports.

This unfavourable situation gave rise to concern in forestry circles, and the foresters, under the direction of Károly Kaan, a well-known Hungarian forester and a state secretary, drew up a forest policy adapted to the new conditions. Among the priority objectives of this policy were afforestation of the Great Plain, reforestation of degraded land, replacement of clear-felling by a shelter-wood compartment system and, finally, a new law that gave the forestry administration authority to make the application of these management plans obligatory even for private forests. However, this policy conflicted with the interests of the owners of the private forests, so between the two world wars its application was limited.

A modern forestry serving the interests of the entire national community became possible after the Second World War. It was then that Hungary, having adopted a socialist regime, nationalized its forests: this was to make it possible to implement a forest policy with a long-term perspective.

On the initiative of the Minister of Agriculture, a scientifically planned forest-development policy was launched in 1954. A series of decrees gave this policy the force of law (cf. Ministerial Decree No. 1040/1954, relating to the development of forest production, and Ministerial Decree No. 3009/1955, relating to the development of the wood industry and to wood economy).

These decrees, intended to run for six years (1955-1960), are still in force today. They brought together, for the first time, socialist guidelines for forest management and the primary transformation of wood, with the following main objectives:

· reproduction and expansion of the country's forest capital;

· improvement in the quality of the timber produced;

· multi-purpose use of the forest resources;

· mechanization of forestry by the widespread application of industrial methods;

· reconstruction and development of the wood industry in line with the country's wood resources.

At the beginning of the 1950s, it was thought that the forest capital could be increased by reducing fellings - then thought to be excessive - and by a considerable expansion of the wooded areas. Decree No. 1040 ran counter to this concept in that it gave great importance not just to the extension of the wooded areas but to maintenance operations (cleaning, thinning, artificial pruning) and to regeneration of the existing forests, mainly the natural forests, which played a major role in supplying the country with wood. It also provided for a considerable increase in fellings.

The programme for afforestation of the Great Plain gradually led to an afforestation programme for the entire country on a modern ecological basis.

It may be said that up to the end of the eighteenth century, forests and ecological conditions for silviculture in Hungary were still relatively favourable. The situation deteriorated in the nineteenth century owing to extensive deforestation and to major flood-control projects - although these efforts did make it possible to protect a total area of about 2 million ha from flooding, representing a large part of the country. (It is the largest area protected from floods in Europe, followed by areas in the Netherlands and Italy of 1.4 million and 0.7 million ha respectively.) After 1920, total forest area - which at the end of the eighteenth century stood at 2.8 million ha - was reduced to 1.1 million ha (see Table 1).

The period between the wars brought few essential changes. However, after the Second World War, the environment began to undergo a favourable change, thanks to extensive afforestation work, the establishment of non-forest plantations and the development of watershed management. The territory protected from flooding is now considered to form one vast ecosystem. The forestry and water-management work carried out and kept under permanent control has created favourable conditions for agricultural and forestry production and the security of settlements and communications.

Results While the afforestation work carried out between 1925 and 1938 in the Great Plain increased the wooded area by only 15200 ha, plantations effected between 1946 and 1980 have increased it by 486000 ha. The Great Plain is the area most affected: the forested area increased by only 4.7 percent between 1925 and 1938 but by 134.8 percent between 1946 and 1979, after the national plan was applied.

Table 1. Changes in Hungary's forest area, by region (In thousands of hectares)

Year	Transdanubia	Great Plain	North Hungary	Total
1800	1878.7	329.5	557.6	2765.8
1925	591.6	180.6	318.6	1090.8
1938	598.6	189.1	318.3	1106.0
1946	607.7	199.1	317.4	1124.2
1950	619.9	245.0	301.0	1165.9
1955	644.0	315.3	298.1	1257.4
1960	665.4	343.0	297.8	1306.2
1965	729.9	376.8	314.8	1421.5
1970	745.5	366.6	358.6	1470.7
1975	743.6	438.0	363.7	1545.3
1980	769.8	466.5	373.9	1610.2

Note: The regions shown lie within the present boundaries of Hungary Prior to the Treaty of Trianon (1920), the country's total forest area was much larger, since it included millions of hectares in the Carpathian mountains

REFORESTATION IN THE PILIS FOOTHILLS - aiming at self-sufficiency in timber

Another consequence of the government decree was the application of a new silvicultural system in the natural forests. This system, worked out after tests lasting several decades in the Sárvar oak stands, was intended to maximize the production of high-quality wood assortments. The implementation of this new system was connected with the considerable increase in the yield from intermediate fellings.

The highest yield was obtained in 1960, with 47.8 percent of the volume harvested coming from secondary fellings. The shelter-wood compartment system, which makes it possible to conserve biosystems and forest stands built up over centuries, was rarely used in private forests before 1945. The 1954 decree ordered that this system be made general. During the period 1950-1955, increased regeneration through plantations was carried out within the framework of natural regeneration. No distinction was made between regeneration by suckers and shoots and that by seeding. In the second period, 1960-1965, natural regeneration gained ground, because all the necessary conditions were present: financing, labour, technically trained foresters, machines and vehicles' making possible felling and extraction that did not damage the stands or the soil.

But the Hungarian economic reform of 1968 did not guarantee sufficient support for a natural regeneration period of 15 to 30 years. Long-term forestry projects were therefore pushed into the background in the third period (19701980), the sole or dominant indicator being the financial success of the enterprises, or profitability. The abundance of game, which greatly exceeded cynegetic capacity, also caused considerable damage to the regeneration. In the third period, therefore, regeneration by suckers and shoots again gained ground.

At the beginning of the 1950s, it was feared that the forests were being overcut.... Today, the yield capacity is not even fully used.

Hungary has established 1 million ha of artificial stands, many of them practically identical to the natural forests.

Improvement in quality Hungarian forest products are not much in demand on the international market. The hardwood timber that is exported is of medium quality, and there is little processing of wood. It is mainly the present crisis that has made it possible to see clearly that In order to succeed on the international market, it is necessary to produce better-quality timber.

The efforts made to improve forest plants have given good results. The National Council for Agricultural Variety Testing has so far accepted 10 varieties of poplar, 5 of willow, 10 of robinia, a Scotch pine, a Norway spruce and an elm. Special efforts have been made to obtain, among other things, good stem shape and to increase the proportion of timber and industrial wood in total volume of wood produced. But in future the accent will have to be put on faster growth and resistance to diseases.

Since the 1950s, the improvement of fast-growing trees, in particular poplars and black locust, has been one of the concerns of the Hungarian Forestry Research Institute. It is useful to describe here briefly what has been done with respect to the black locust (Robinia pseudoacacia L.).

Black locust makes up 18.2 percent of the country's total forest area at present (see Unasylva, Vol. 32, No. 127, p. 23-33). This species has been closely linked with agriculture ever since its acclimatation: even today, 60 percent of the black-locust stands are managed by agricultural-production cooperatives and state farms. Before the Second World War, black locust was the favourite species of the small self-sufficient peasant farms, which used their wood to meet highly varied needs. After the collectivization of agriculture, the wood of the existing black-locust forests proved difficult to utilize in the wood industries because a considerable proportion consisted of inferior-quality material. Improvement of black locust was, in fact, encouraged as much by the wood industry as by beekeepers.

To effect improvement through selection, the best plots - and within these plots, the elite trees - were selected from all of the country's black-locust forests. Varietal trials were then conducted with their vegetative progeny, and the best were selected for cultivation tests. The 10 varieties of black locust that qualified can be classed into three groups, according to the purposes they serve:

· For the production of saw logs: R. pseudoacacia cv. Nyirségi, R. pseudoacacia cv. Kiskunsági, R. pseudoacacia cv. Jászkiséri, R. pseudoacacia cv. Appalachia, R. pseudoacacia cv. Pénzesdombi and R. pseudoacacia cv. Ullöi.

· For the production of poles and stakes (mining timber, supports for vines and fruit trees, fences, hop stakes): R. pseudoacacia cv. Zalai, R. pseudoacacia cv. Császártöltési and R. pseudoacacia cv. Szajki.

· For the improvement of bee-keeping: Robinia ambigua decaisneana cv. Rózsaszin A.C. (rose-colour A.C.).

Some of these varieties are useful for both forestry and bee-keeping purposes: R. pseudoacacia cv. Kiskunsági, R. pseudoacacia cv. Jászkiséri, R. pseudoacacia cv. Zalai and R. pseudoacacia cv. Császártöltési.

These varieties have been evaluated on the basis of data obtained from trials in the Gödöllö arboretum and classed in four categories:

· trees with straight, cylindrical trunks, producing high-quality timber and industrial wood;
· trees with straight trunks, producing medium-quality timber and industrial wood;
· trees with curved trunks, the wood from which serves for the production of small articles;
· trees with very curved trunks and crown, ramifying at a low level and providing fuelwood.

The proportion made up by the first two classes is decisive in evaluating exploitability. Assortments of timber and industrial wood at exploitable age have been calculated on the basis of the quality classes with the help of Antal Dérföldi's procedure for the planning of timber and industrial wood according to size groups. The total value of these assortments in forints gives the compound exploitation value - the presumed value of the forest at exploitable age. It can thus be seen that the exploitation value of the improved black-locust varieties providing sawnwood exceeds that of the common black locust now being cultivated by 26 to 54 percent. The value of the varieties intended for the production of poles and stakes also exceeds it, by 37 to 52 percent (with the exception of Robinia pseudoacacia cv. Császártöltési).

Production of honey The black-locust forests constitute the basis for commercial honey production in Hungary. In years favourable to flowering, 50 to 60 percent of the honey produced comes from black locust. In 1982, honey exports brought in US$16.5 million. The Hungaronektár firm gives financial backing to improving late-flowering varieties of black locust producing large quantities of nectar. Rose-colour A.C. black locust comes into flower a week later than common black locust. While the sugar value of common black locust - the sugar content of the nectar produced by one flower in 24 hours - varies from 0.8 to 1.0 mg, and the values of the varieties Császártöltési, Kiskunsági, and Jászkiséri, are 1.8,1.56 and 1.48 mg respectively, rose-colour A.C. reaches a sugar value of 1.9 mg.

Because of the economic importance of honey exports, the National Planning Office allocated special funds in 1982 for the establishment of 1000 ha per year of new forests of improved varieties of black locust.

Plantations When the total yield of the forests, and of planned wood production in particular, is calculated, it can be seen that forests created by people (through artificial stands) give the best results.

In this connection, a World Symposium on Man-Made Forests and Their Industrial Importance, sponsored by FAO, was held in April 1967 in Canberra, Australia.

The documents prepared for this conference make it possible to draw up a list of the countries that are in the forefront with regard to artificial plantations; that is, those that have at least 0.5 million ha of such stands. A classification of the countries in order of percentage places Hungary and the United Kingdom at the head of the list (see Table 2).

Table 2. Countries with the highest ratio of plantation to total forest area

Country	Total forest area (millions of ha)	Plantation area (millions of ha)			Plantations as percentage of total forest area
		Coniferous	Deciduous	Total
Hungary	1.39	0.14	0.86	1.00	71.9
United Kingdom	1.76	0.91	0.36	1.27	71.9
China a	96.38	-	-	30.00	31.1
Japan	25.05	6.38	0.71	7.09	28.3
Bulgaria a	3.62	-	-	1.00	27.6
Republic of Korea	6.69	0.48	1.15	1.63	24.2
South Africa	4.10	0.42	0.50	0.92	22.5
Italy	6.03	0.50	0.33	0.83	13.9
Poland	7.69	-	-	0.76	9.9
France a	11.60	0.98	0.12	1.10	9.4
New Zealand	7.36	0.43	0.03	0.46	6.3
Spain	26.70	1.49	0.11	1.60	6.0
United States	307.10	9.67	0.68	10.35	3.4
USSR a	929.59	15.15	3.73	18.88	2.0
Indonesia a	121.18	0.14	1.14	1.28	1.6
India	68.95	0.02	0.93	0.95	1.4
Brazil	352.10	0.07	0.43	0.50	0.1
Total	1977.28	36.78	11.07	79.62	4.0

Source: FAO (1967).
a. Estimate.

Note: These figures, which are 17 years old, may not reflect the results of major new plantation efforts in certain countries. For example, the proportion of forest area accounted for by plantations in Bulgaria has increased from 27.6 to 50 percent, according to the article by Grouev.

Comecon countries

Table 3. Forest resources of Comecon countries

Country	Year	Forest area (thousands of ha)		Year	Felled volume (millions of m³)		Annual felled volume per hectare of forest (m³)
		Total	State forests		Total	Coniferous
Bulgaria	1977	3284	3284	1975	5.1	1.2	1.5
Hungary	1977	1575	928	1975	7.5	0.4	4.8
German Democratic Republic	1977	2690	1709	1975	8.6	6.4	3.2
Cuba	1977	1595	1595	-	-	-	-
Mongolia	1977	15219	15219	1975	9.2	8.5	0.6
Poland	1977	8577	6988	1974	23.8	19.4	2.8
Romania	1977	6149	6148	1971	16.4	4.3	2.7
USSR	1973	771964	748808	1977	639.3	404.5	0.8
Czechoslovakia	1978	4515	4327	1975	14.7	10.8	3.3

Source: Tzehmistrenko & Feofilov (1979).

In fact, Hungary has established 1 million ha of artificial stands well adapted to the natural conditions, many of them practically identical to the natural forests. The period after the Second World War is considered the golden age of Hungarian silviculture.

As for the productivity of the stands, Table 3 gives data on the annual harvested volume per hectare in the Council for Mutual Economic Assistance (Comecon) countries. The Hungarian forests produced the highest yield, 4.8 m³ per hectare per year. At the beginning of the 1930s, annual yield was only 2.0 m³ per hectare.

Although the main aim of Hungarian forestry development for more than 50 years has been to overcome the shortage of wood in order to reduce imports, an earlier forestry law called for multi-purpose use of the forests. In a socialist society, the objective to be attained is the common good. Forests and forestry make a very large contribution to this, particularly through public-welfare forestry, which considers the forest as not just a source of wood and other material but also an essential part of the physical environment of the people, who therefore maintain and utilize it according to the principles of multi-purpose use. The advantage of this type of utilization is obvious: it makes it possible to share expenses, reducing the specific costs per user, and at the same time to increase effectiveness. Those who have user rights are classified by order or priority. They benefit from advantages or are obliged to limit their demands, as the case may be.

In 1974, when the national development plan for forest stands was being prepared, an inventory was made of the forests intended for the production of wood and of those intended for protection of the environment - protection plantations, green belts, forests and plantations intended for the protection of soils, water, the landscape and nature - as well as of those intended for leisure and tourism (see Table 4). According to this inventory, special-purpose forests formed only 5.9 percent of the total in 1965; by 1980 they already accounted for 18.8 percent.

Table 4. Breakdown of Hungarian multiple-use forests according primary purpose

Primary purpose	1965		1980
	Area (thousands of ha)	Percentage share	Area (thousands of ha)	Percentage share
Production of wood	1305.4	94.1	1290.1	81.2
Recreation	6.3	0.4	54.9	3.5
Protection of the environment	66.3	4.8	174.3	11.0
Protection of nature	4.5	0.3	24.0	1.5
Hunting	2.8	0.2	41.9	2.6
Experiments	2.5	0.2	3.2	0.2
Total	1387.8	100.0	1588.4	100.0

After the Second World War, a shortage of labour, caused by a series of social changes - industrialization, rural exodus, development of the tertiary industry, a rise in salaries - increased the mechanization of forest work, not only in Europe but in all countries in which forests were exploited. The difficulty of operations and their high cost also helped to give forest work an industrial character. The application of modern techniques made it necessary to accelerate the development of forest roads.

Advantages of autonomy To facilitate implementation of forestry decrees, very detailed directives were formulated by the Forestry Research Institute, covering everything from seed management to harvesting operations. This was in line with the system for controlling the economy in force at the time, based on centralization.

RED DEER FORAGING IN WINTER maintaining the wildlife resource

But after the economic reform of 1968, the forest enterprises acquired great autonomy. Today they rely essentially on their own judgement in applying the results of research and choosing their technical inputs and production technologies. Toward the mid-1970s, the Forestry Research Institute suggested the introduction of wood-production systems analogous to modern agricultural-production systems, and these were instituted.

Forest enterprises rely on their own judgement in applying the results of research and choosing their technical inputs and production technologies.

The most advanced forest enterprises quickly became interested in these innovations and entered into long-term contracts with the Forestry Research Institute for the development of wood-production systems.

· The West Hungarian Forestry Combine entrusted it with preparing an industrial-type system for the production of conifers.

· The Forestry and Wood-Processing Enterprise of the Southern Great Plain contracted for a system for the production of Scotch pine.

· The Forestry and Wood-Processing Enterprise of Nagykunság sought systems for the production of black locust, poplar and conifers.

The Nagykunság black-locust production system was the first to be completed; its operation was authorized by the Ministry of Agriculture and Food in April 1982.

The purpose of the system is to achieve industrial-type production of black locust by concentrating efforts and applying a long-term policy, using the results of research as well as advanced technologies aimed at improving the quality and increasing the output of wood and other forest resources in order to obtain the best financial results.

It is a long-term system for improving production, because it is based on forest enterprises and agricultural cooperatives operating in their own interests to ensure professional and disciplined application of modern technologies. In turn, the organizer of the system ensures the provision of modern machines and the necessary maintenance, as well as professional advice and professional training of local staff.

The black-locust production system was drawn up using interconnected subsystems. These sub systems cut the long production cycle into short sections that correspond to the branches of production in forestry. The system does not cover the entire production cycle, but only a period of 5 to 12 years, which includes logging plant, production, regeneration and primary thinning - the phases most decisive for the life of a forest. The system therefore consists of four subsystems. In addition, the production work carried out in the subsystem can be evaluated separately, from the economic point of view.

Wood-based panels Decree No. 3009/1955 on the development of the primary wood-processing industry and the timber economy provided for modernization of the existing sawmills and plywood factories, the initiation of fibreboard and particle-board manufacture and the replacement of wood by other materials. The manufacture of fibreboard and particle board was developed by the Western countries to use the waste from coniferous timber. But Hungarian specialists decided to use fuelwood - small-sized hardwood - to manufacture boards. This was Hungary's most important innovation for better industrial use of the inferior-quality wood intended for the domestic market.

Summarized data on Hungarian forestry in recent decades

	1950	1975	1980
Forest area (thousands of ha)	1166	1545	1610
Standing timber (millions of m³)	117	238	257
Allowable cut (millions of m³)	2.6	7.5	7.7
Harvested gross volume (millions of m³) including industrial wood	3.1	6.7	7.5
Industrial wood (millions of m³)	0.9	3.1	3.7
Processed timber (millions of m³)	0.8	3.2	3.6
Consumption of industrial wood (millions of m³, roundwood equivalent)	2.6	7.2	7.0
Consumption of firewood and charcoal (millions of m³)	2.4	2.1	2.4
Total consumption (millions of m³ net)	5.0	9.3	9.4
Rate of domestic production (percentage)	54.7	59.5	66.7
Timber imports (millions of m³, roundwood equivalent)	2.9	5.6	4.9
Timber exports (millions of m³, roundwood equivalent)	-	1.5	13

EURO-AMERICAN POPLAR CULTIVARS ready to float down the Danube

Overall assessment After a quarter of a century, what are the results of the application of the two decrees originally meant to run for only six years? Even before 1945, forestry education and research in Hungary had a great tradition, with recognized international status. The professional foresters and forest agents were equipped with modern professional knowledge. But, as previously mentioned, it was very difficult to apply forest policy at that time because of the system of ownership then in force. The 1954 and 1955 decrees were therefore welcomed with real enthusiasm by the foresters. These two decrees constituted a big step forward. In fact, they formed the basis of Law VII of 1961 on forestry and game management, which contained many of the same objectives and defined them in practically the same terms.

After 30 years, the situation in forestry development can be summarized as follows (see box): while the standing timber in the forests at the end of the Second World War amounted to about 117 million m³ today, thanks to intensive silviculture and expansion of the forest area, the timber in the forests intended for the production of wood exceeds 257 million m³. The financial value of this standing timber - if it is taken as being equivalent to the contribution for the maintenance of the forests - amounts to 141000 million forints.

WOOD DISTILLATION PLANT AT TOLMÁCS keeping Hungarian industry supplied

At the beginning of the 1950s, it was feared that the forests were being overcut. In 1950, for example, 3.1 million m³ were harvested, as against an allowable cut of 2.6 million m³. Today, 30 years later, the yield capacity is not even fully used. In 1980, of the 7.7 million m exploitable, only 7.5 million m³ were harvested. During the last three decades, total wood consumption has almost doubled. In 1950, the resources of the country were sufficient to cover only 54.7 percent of overall requirements. In 1980, the proportion had risen to 66.7 percent. In 1950, Hungary did not export any wood. In 1980, exports already amounted to 1.3 million m³.

These figures show that Hungarian forestry has achieved considerable development, even by world standards. This is a result of which the present generation of foresters can be proud, given the difficulties with which forestry has been faced in Hungary as a result of two world wars, and their consequences, in less than half a century.

Hungary relies extensively on plantations - LARCH-BEECH STAND IN BÖRZSONY MOUNTAINS...

Hungary relies extensively on plantations... - BLACK LOCUST PLANTATION AT ÜLLÖ

Bibliography

FAO. 1967	World Symposium on Man-Made Forests and Their Industrial Importance. Unasylva (FAO), 21 (86-87) (special issue).
HOMAN-SZEKFÜ. 1935	History of Hungary. Budapest. Királyi Magyar Egyetemi Nyomda. 5 vols. (In Hungarian.)
KAÁN, K. 1920	Problems of forest economic policy. Budapest. "Patria" Irodalmi Vállalat és Nyomdai Rt. (In Hungarian.)
KERESZTESI, B. 1971	Hungarian forests. 2nd ed. Budapest. Akadémiai Kiadó. (In Hungarian.)
KERESZTESI, B., ed. 1967	Oaks. Budapest. Akadémiai Kiadó. (In Hungarian.)
KERESZTESI, B., ed. 1978	The cultivation of poplars and willows. Budapest. Mezögazdasági Kiadó. (In Hungarian.)
KERESZTESI, B., ed. 1982	Hungarian forestry 1954-1979. Budapest. Akadémiai Kiadó.
KERESZTESI, B. & SOLYMOS, R., eds. 1978	The cultivation of conifers and utilization of their wood. Budapest. Akadémiai Kiadó. (In Hungarian.)
LESENGI, F. 1936	History and actual situation of Hungarian forestry. Budapest. "Pátria" Irodalmi Vállalat és Nyomdai Rt. (In Hungarian.)
TZEHMISTRENKO, A.F. and FEOFILOV, V.A. 1979	The fundamental directions of forestry development in the countries of the Council for Mutual Economic Assistance. Lesnoie Hosiaistvo, 11: 12-17. (In Russian.)

How endangered are the world's tropical forest?

What can be done to save them?

FAO's answers are here, in two widely quoted recent books on tropical forest resources

FAO FORESTRY PAPER No. 30 (1982) - tropical forests resources (available in English, French and Spanish)

FAO FORESTRY PAPER No. 37 (1982) - conservation and development of tropical forest resources (available in English and Spanish)

FAO - FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS