Forest resources of the world

In 1953 FAO carried out a second world forest inventory. The preliminary results are summarized in the following article which also indicates the scope and limitations of the inventory, and, some of the principal problems encountered. The detailed results will be published shortly under the title "The 1953 World Forest Inventory." The final figures will show some slight changes as compared with the figures quoted below, since several important returns have not yet been received, so that the data included below in respect of those countries may be several years out of date.

Conclusions

A sound national forest policy aims at the rational development and exploitation of forest resources on the principle of the greatest good for the greatest number. To formulate such a policy as precise a knowledge as possible of the wood resources of the country is required. These data a forest inventory must provide. To furnish all the elements necessary for policy formulation, the inventory should yield information on the forested area, ownership, composition and management status, as well as estimates of the volumes of standing timber, annual growth, fellings and removals.

Two factors give rise to the need for world-wide inventories. First, the population of the world is increasing steadily, on average by one and a half percent annually; forest resources, on the other hand, are in the short term relatively fixed, at any rate in extent. On a world scale efforts are necessary to ensure that forest output rises commensurately with world needs. Secondly, forest needs are by no means coterminous with forest resources, since the factors which determine forest distribution transcend political boundaries. Hence the need arises for the co-ordination of national forest policies. In other words, the peoples of all nations and regions are becoming increasingly conscious of their interdependence, of the existence of "one world."

FAO is alive to this, and not only because the forests are a repository of important raw materials, but also because they play a decisive role in agricultural economy, by protecting crop lands and regulating the water regime. Thus a knowledge of the world's forest resources is vital to the execution of the program of FAO in its broader aspects, and not merely to that of its Forestry Division alone. It was for these reasons that FAO, at the second session of its Conference in 1946, decided to undertake an inventory of the forest resources of the world, asking all member countries to supply their most recent available data. The results of that enquiry were published in Unasylva. ¹

¹ See "Forest Resources of the World," Unasylva Vol. II, No. 4, 1948 and Vol. IV, No. 2, 1950.

Clearly this kind of enquiry must be repeated at intervals. Forest area and output can be modified, the economic conditions of exploitation change with improved transport facilities, with technical progress in both extraction and utilization, with the utilization of hitherto non-commercial species and with the growth of population; moreover national statistics are steadily improving. Thus not only are forested area, growing stock, growth and fellings constantly changing; so is the accuracy with which they are measured. Hence periodical reviews are necessary, and for this reason the sixth session of the FAO Conference, in 1951, recommended that the organization should, at five-yearly intervals, collect and publish available information on the forest resources of the world, the next inventory to be undertaken in 1953.

Following this recommendation, experts met in Geneva in 1952 to consider definitions and determine the scope of the 1953 inventory. Forms were agreed and despatched to all member countries, including dependent territories. At the same time FAO staff gathered information from both official and unofficial sources concerning the resources of non-member countries.

Of the 212 countries and dependent territories which may be distinguished, 12 have a land area of less than 10,000 hectares, while 44 have a forested area not exceeding 10,000 hectares.

Responses to the 1953 questionnaire, together with the results of the first inventory, supplemented by data collected with the aid of authorities in member countries, official reports, and FAO Technical Assistance field experts, have made it possible to assemble data, especially concerning forested area, in respect of 198 countries. In the remaining 14 countries and territories forests are either non-existent or negligible in extent. Thus the 1953 Inventory provides the most comprehensive picture of the extent of the world's forests which has so far been published. The sources of the information included are set out below in Table 1.

Table 1. - Details of information sources

Source of information	Number of countries	Percentage of world forested area
Replies to 1953 questionnaire	109	69
Replies to 1947 questionnaire	12	3
Official statistics	71	27
Unofficial reports	6	1

No attempt has been made to compare the 1947 and 1953 inventories, since no valid comparison is possible. Apart from changes in definition, ² there are many other facts which invalidate a comparison. For each world inventory, countries report the results of their most recent national inventory. Some countries including several with important forest areas, have made no new inventory since 1947, thus the changes which have taken place there in the last seven years have not yet been recorded. Moreover, many countries which had suffered during the war were unable in 1947 to estimate accurately the effects of overcutting and forest destruction, and could return only provisional figures; the increase in precision which their more recent figures afford overshadows the real changes which have taken place. The statistical service in many countries, especially in the less developed regions, has improved out of all recognition in recent years.

² A short account of the principal changes is given later in this article, a full discussion will appear in The 1953 World Forest inventory.

Finally, in the overwhelming majority of countries, even to-day, there has been no complete inventory, but only estimates based on partial inventories. Thus for the world as a whole, and for most individual countries, the differences between the figures reported in 1947 and 1953 reflect primarily improvements in statistical coverage and accuracy; it is therefore quite impossible to draw firm conclusions about real changes which have taken place in the forests. Some of these factors are transient, deriving from special difficulties experienced in the immediate postwar period. The steady progress now being made, together with increasing uniformity in approach and clarity in definition, offer the hope that valuable conclusions may be drawn when the results of the 1958 inventory are compared with those of the current one. The 1947 inventory was largely experimental. The pattern of future world inventories is not likely to depart substantially from that established in the 1953 inventory.

A world inventory cannot provide answers to all the questions which a national inventory must pose. It can afford indications of the extent of the world's forests, and of the wealth of resources they contain. It cannot ascertain whether the forests are well distributed for fulfilling their productive and protective role; it cannot hope to afford a comprehensive picture of age and species distribution, or to reflect the effects of silviculture on the quality of output. These, and many other questions, a national inventory will seek to answer. They are not appropriate to a world inventory, which must confine itself to eliciting a limited range of salient facts.

Information sought

The experts who designed the 1953 questionnaire had to find an acceptable compromise between the need to preserve continuity with the earlier inventory and- the need for modifications arising from past experience and from the very real progress which has been achieved in national forest statistics in recent years.

The 1947 inventory had demonstrated clearly that the distinction drawn therein between productive and unproductive forests was an arbitrary one; many countries found it impossible to submit reliable information classified in this way. For this reason, the primary classification in the 1953 enquiry is into accessible and inaccessible stands, the former category including, but separately distinguishing, "unexploited, but accessible" stands. For similar reasons, the more detailed information required in 1953 relates only to "forests in use"; in 1947 it related to all accessible productive forests.

Because the inventory in 1953 concentrates on forests in use, which are fairly well-documented, and because of the considerable progress made in forest statistics since 1947, it was decided to collect several important categories of information which did not appear in the earlier inventory, e.g. concerning the present status of forest management (area of forest under working plans, cutting practices, allowable cut). To clarify the distinction between fellings and removals, questions were asked about logging and floating losses. A separate section deals with roundwood supply from trees outside the forest, of considerable importance in many countries, particularly in Europe and the Mediterranean basin. A further new section dealt with changes in forest area (inaccessible forests becoming accessible, afforestation, losses to other land categories), all factors influencing future roundwood supply. Thus the 1953 inventory includes information falling into the following main groups:

forest area in relation to other land categories;
forests in use: management, standing timber, growth, fellings and removals;
accessible forests: yield and ownership;
other roundwood sources;
changes in forest resources. ³

³ Not discussed in this article.

The definitions which had been adopted in the 1947 questionnaire leaned too heavily on the experience of advanced countries, where the agricultural and forested areas are distinct and where the forests have for the most part long been under rational management. They were not always valid for less developed countries, nor did they allow for some important differences in concept which exist even among the advanced countries. Accordingly the 1953 questionnaire contained revised definitions, and made provision for detailed explanation by countries of the ways in which their own definitions differed from those set out. ⁴ Nevertheless certain difficulties arose, and a brief account of some of the more important ones may not be out of place since it throws light on the problems attached to the taking of a world forest inventory.

⁴ Space does not permit the inclusion in this short; article of the statistical qualifications which attach to the individual and summary figures quoted below. In The 1953 World Forest Inventory, all figures are annotated in detail.

Forest is defined as land bearing vegetative associations dominated by trees of any size. But in many parts of the world - in Africa, for example - dense forests shade off into open stands with a continuous sheet of grass, finally passing into shrub and thorny formations. Where does the forest end and brushland begin? The answer to this question frequently depends on local administrative convenience, so that areas classified as forests may in fact bear only a few small and deformed trees per hectare, along with scattered thorny shrubs of no economic value. Grazing grounds, whether grazed by wild or domestic animals, if they occur within the forest area are more often than not classified as forest, since they usually come under the supervision of the forest administration. Thus the term "forest" in this inventory covers stands of very different densities. Shifting cultivation - the alternate use of the soil for forest and agricultural crops - presents another problem; some countries classify these lands (which are subject to burning and clearing on an indefinite rotation) as forest, others as brushlands, and others as agricultural land. Because shifting cultivation is important in many parts of the world, a future inventory will have to pay special attention to this problem.

Accessible forests are as forests within reach of economic management or exploitation. But the accessibility of a forest depends not only on transport facilities and communications; it depends on cutting practices and on the product sought. A forest may be accessible for fuelwood extraction by the inhabitants of a remote village, but inaccessible for exploitation on a significant scale for industrial wood. A hand-sawyer may work where modern mechanical equipment cannot penetrate. Thus accessibility is an arbitrary as well as a transient concept (though presenting fewer practical difficulties in arriving at estimates than did the earlier concept "productive forests"), and this has to be borne in mind in interpreting the results of the inventory.

Evidence of differences in national practice was perhaps most striking in the methods of calculating the volume of standing timber in forests in use; these differences, of course, applied equally to estimates of growth and allowable cut. In extreme cases only trees over 40 years old or over 40 cm. diameter at breast height were included. Some countries included, others excluded, tops, stumps and branches. Table 2 indicates the practice followed by the 57 countries which were able to give full details:

Table: 2. - Estimate of growing stock

Type of growing stock	Number of countries
	Including in estimate of growing stock	Not including in estimate of growing stock
All trees in the forest	30	27
Branches	10	47
Tops above merchantable diameter	23	34

A few examples will illustrate the divergency in practice. In Belgium, the volume of growing stock excludes spruce and Douglas fir under 30 years old and other conifers under 20 years; in Sarawak, all fuel trees are included but timber trees of less than 50 cm. diameter are excluded; in Sierra Leone, branches of trees yielding industrial timber are excluded, but those of trees used for fuel included. These examples serve to emphasize the danger of drawing international comparisons from reported figures without paying careful attention to the exact meaning of the figures reported. A further complication is that felling and removal statistics often include trees or parts of trees excluded from standing timber and growth statistics, weakening any comparison between net growth and fellings, a relation vital to sustained yield management.

Whereas in Europe and North America and in certain countries in other regions all forest species are marketable, in many tropical and sub-tropical forests only a limited number of species has any commercial value. Extraction is selective, and the bulk of the growing stock is left in the forest, some to be used ultimately as fuelwood, but most to rot. Species not to-day marketable are frequently left out of account altogether in national estimates of growing stock, growth and allowable cut. Here again not only are international comparisons invalidated; the relationship between growth and removals becomes meaningless, especially since locally used fuelwood may appear in felling statistics while, excluded from growth figures. Hence the fact that in Liberia, for example, fellings are roughly double net growth does not necessarily mean that there is evidence of overcutting, since the two categories of information are not statistically comparable.

Bark presents another problem, since here again practice differs widely. The difference which the inclusion or exclusion of bark can make may be appreciated when it is realized that, according to species and diameter, bark may account for anything from 5 to 50 percent of standing timber volume. On the basis of information submitted by countries or collected by the FAO staff from various sources, an attempt has been made to present some of the published figures in a form capable of bearing international comparisons. Thus figures of growing stock, gross increment, natural losses, net growth and allowable cut are presented with bark; figures of annual cut, logging and floating losses and removals are presented without bark. In Table 19 which presents the relationship between net growth, allowable cut and fellings, however, all figures are presented on a without bark basis. The procedures adopted to secure comparability are described in detail in The 1953 World Forest Inventory.

Finally, it has to be borne in mind that in many countries where the forest service is not highly developed the official statistics relate only to recorded fellings. These may be only a fraction of total fellings, including illicit cuts. Frequently estimates of unrecorded fellings, based on sample enquiries, have been made; where available these have been included. For many countries, however, unrecorded fellings have necessarily been excluded. The significance of this aspect of the published figures will be recognized by those who appreciate that unrecorded and illicit fellings have been largely responsible for the destruction of forests in the past.

This short and by no means exhaustive account of some of the problems encountered in compiling the 1953 world forest inventory leads us to two important conclusions. First, it is necessary to exercise extreme caution in interpreting the published figures, especially in drawing international comparisons and in relating growth to drain. Secondly, in spite of the considerable progress made in forest statistics in the last seven years, we are still very far from the goal of comprehensive, systematic and comparable statistics relating to the world's forest resources.

Response

The present state of knowledge about national forest resources is brought out clearly by the figures set out in Table 3.

Table 3. - Countries reporting on national forest resources

All or nearly all the 110 countries completing the 1953 questionnaire were able to provide information relating to the forest area, afforestation and removals; about two-thirds furnished data relating to growing stock, fellings and areas lost to other land uses; less than half could give figures for net growth. For allowable cut, a figure of the highest importance for forest management on sustained yield principles, only 42 countries were able to provide an estimate.

It has to be remembered that national forest inventories are a comparatively recent innovation, though inventories of individual forests as a recognized basis of forest management have been taken in various countries for almost a century. Thus many countries which do not have basic information on a national scale, nevertheless possess comprehensive figures for some of their more important forests. On the other hand, even in countries where comprehensive, nation-wide data are available, these figures are sometimes insecure, resting on partial inventories and on sample surveys whose scope has been limited by the funds available. Very few countries have been able to establish precise figures based, for example, upon a modern combination of air and ground survey techniques.

Moreover, Table 3 gives only the reporting countries' response to certain key questions relating to forests in use. Much less is known about inaccessible stands and accessible stands not yet exploited.

Some of the implications of the uneven response to the 1953 inventory are touched on at the end of this article, in the paragraphs headed Conclusions. In the sections which immediately follow, an attempt is made to summarize the data available for some of the more important categories of information. In each section, an indication is given of the degree of response to the corresponding questions. The degree of response, it should be noted, takes account not only of countries completing the 1953 questionnaire, but of all countries (including some non-member countries) in respect of which official data or reliable unofficial data relating to the particular category of information were available, whether or not questionnaires were completed and returned.

Forest areas

The regional distribution of the world's forests is summarized in the following table; details for more than a hundred countries and territories are presented in Appendix I: Land Categories.

Table 4. - Distribution of the world's forests

Nearly 30 percent of the earth's land surface is under forests; a further 22 percent is devoted to agriculture. The rest, or nearly half, consists of natural grasslands, brushlands and unproductive areas.

Forests cover over two-fifths of the land area in Latin America, one-third or more in the U.S.S.R. and North America, slightly less in Europe and Africa, and less than one-tenth in the Pacific area.

The forest area per inhabitant ranges from 6½ hectares in the Pacific area down to 0.3 hectares in Europe.

The fact that woodlands (if we include brushlands with the forests) cover rather more than one third of the land area of the world might lead us to suppose that they are ample in extent both to fulfill their protective role and to ensure that the world's needs of forest products are satisfied. But within each of the main regions distinguished above there are important areas severely lacking in forests; and within individual countries there are areas of scarcity amidst apparent plenty. Most of the North and Latin American countries are well endowed, Uruguay being the only notable exception. But North Africa's 8½ million hectares of forest represent only 1.5 percent of the land area and 0.19 hectares per inhabitant. In the Near East area, only 0.9 percent of the land area is forested, representing 0.12 hectares per inhabitant. And though India and Pakistan between them have 73½ million hectares of forest, 17.3 percent of the land area, this gives only 0.17 hectares per inhabitant. Were separate statistics available, central and southern European Russia and central China would yield figures showing a similar dearth of forests. Even in southern Europe, the forest area per inhabitant amounts only to 0.26 hectares.

It is common knowledge that some of these areas which today are sterile tracts of desert or near-desert were formerly well-forested, green and fertile. Reckless annihilation of the forests has led to soil degradation and sterility, in some cases in quite recent times. The 1953 inventory affords some indications of the steps being taken today to conserve existing forests and to halt and reverse the relentless march of the desert.

Fifty-five percent of the world's forests, or 2,140 million hectares, are today classified as inaccessible. Only two-thirds of the accessible forests, or 29 percent of all forests, are today in use. The immensity of the resources yet untapped may be understood if we appreciate that, leaving aside the 1,130 million hectares today exploited, there is a first reserve of 640 million hectares accessible but not as yet exploited, and a second reserve of 2,140 million hectares not yet accessible. Finally, there are many areas of non-forested land better suited to forestry than to other land uses.

This bald summing-up, however, exaggerates the world's potential, since some of the unexploited accessible forest, as well as some of the inaccessible forest, has primarily a protective role and should not be brought into the reckoning as a future source of forest products. These areas, according to the 1947 inventory, probably amount to about 1,400 million hectares. That still leaves potentially exploitable reserves of about 1,400 million hectares, considerably more than the total area of forest exploited today, though here too it must be remembered that yields might be very low, and that wood in the rough cannot economically be moved over long distances.

The accessible forests not yet exploited are found mainly in Canada, Latin America and Africa, and the following table shows the orders of magnitude involved in certain selected countries:

Table 5. - Unexploited accessible forests in certain countries

Country	Accessible forests
	today in use (in 1,000 ha.)	still unexploited (in 1,000 ha.)
Canada	66580	63590
Argentina	10000	50000
Brazil	30010	90040
Colombia	410	61590
Ecuador	500	2000
Mexico	4500	20060
Peru	5000	10000
Belgian Congo	5300	9700
Fr. Equat. Africa	12030	15020
Fr. West Africa	10500	3500

The inaccessible forests are naturally found in remote areas - in the colder zones of Alaska, Canada and the U.S.S.R., and in difficult parts of Asia and Latin America. The spreading network of communications which accompanies general economic development is rapidly enlarging the area of forest within reach of exploitation, and developments in modern logging techniques make necessary frequent reassessments of the concept of accessibility.

It has already been noted that only 29 percent of the world's forests are today being exploited. But whereas virtually all Europe's forests are in use, in Latin America less than one-tenth of the forest area is being exploited. It may seem surprising that only a third of North America's forests are being used but it must be borne in mind, as mentioned above, that protective forests account for a considerable proportion of the unexploited area.

Most regions of the world, then, have vast timber reserves which could be drawn on to satisfy the needs of the local populations. Nevertheless some of the best endowed regions still look today to Europe and North America for part of their supplies, as Table 6 shows.

Table 6. - Accessible forests and trade balance

Region	Accessible forests (in million hectares)		Net trade in forest products (average 1950-52) a (in million cubic meters roundwood equivalent)
	in use	not exploited
Europe	130	3	+ 3
U.S.S.R.	350	75	+ *
North America	220	92	+ 6
Latin America	90	253	- 2
Africa	115	167	- 2
Asia	205	54	- 2
Pacific Area	17	3	- 3

^a + net exports; - net imports.
* Negligible.

Economic growth in Europe and North America has favored intensive silviculture and the establishment of highly developed wood converting industries. In the less developed regions of the world conditions for these developments have hitherto been lacking. But cultural and economic progress is giving rise to higher standards of wood consumption at the same time as it is creating the conditions for a fuller use of indigenous forest resources.

State forests and private forests

The different forms of ownership of accessible forests in the several regions are summarized in Table 7.

Table 7. - Ownership of accessible forests

Region	Degree of response a	Forms of ownership (percentage in each category)
		State forests	Communal forests b	Owned by institutions	Private forests
Europe	100	32	13	1	54
U.S.S.R.-	100	c100	-	-	-
North America	100	49	2	*	49
Latin America	43	62	1	1	36
Africa	85	74	22	*	4
Asia	84	86	2	*	12
Pacific Area	82	76	*	-	24
TOTAL AVERAGE	93	73	5	*	22

^a Area of accessible forest for which ownership data were reported divided by total area of accessible forests reported in region, expressed as a Percentage.

^b Includes forests reserved for the benefit of native tribes.

^c Reported to include 41.2 million hectares, managed by collective farmers.

* = Negligible.

- Uil.

The response to this question was complete in the regions of the northern hemisphere, very low in Latin America and far from complete in other regions. It has to be remembered, however, that whereas in Europe, the U.S.S.R. and North America forest ownership has been progressively consolidated under the pressure of political, economic and social needs, elsewhere in the world the systematic determination of forest ownership has, for the most part, only started recently. In the less developed regions, especially in the remoter areas, considerable tracts of forest are unmapped, unsurveyed, and without established titles. Recognition of titles in the forest is a corollary of growing consciousness, public and private, of the extent and value of these resources; it is often a precursor of, and usually a prerequisite for, extended forest administration.

Nearly three quarters of the world's accessible forests are state-owned, and most of the rest are in private hands. Private forests are most important in Europe, where they account for over half the accessible forest area. In North America, too, nearly half the forests are in private hands. Only in Africa and Europe do communal forests assume considerable importance, the large figure for the former region being accounted for by the fact that forests reserved for the benefit of native tribes are included in this category.

Though any kind of forest ownership is suited to forest administration, it is clearly easier to ensure that sound principles of forestry are applied in practice in state-owned forests than in privately-owned forests. This is certainly the case where there is a multitude of private owners, each controlling tiny holdings; it is less true for large forest estates owned, for example, by industrial corporations. Some striking figures of forest distribution by size of holding are given in the following table:

Table 8. - Distribution of accessible private forests by size of holding in selected countries

Country	Percentage of total accessible private forest area in holdings of various sizes
	Less than 5 hectares	5 but less than 100 hectares	100 but less than 1,000 hectares	1,000 hectares and up
Austria a	15	51	13	21
Finland b	1	64	34	1
Ireland	25	60	15	-
Western Germany	c 42	28	15	15
French Cameroons	-	-	60	40
Peru	-	-	20	80
Turkey	1	24	46	29

^a Includes inaccessible forests: census 1935.
^b Excludes forests owned by industrial corporations.
^c Legs than 10 hectares.
- Nil.

In Western Germany, 42 percent of the private forest area consists of holdings of less than 10 hectares. In Austria, Finland and Ireland holdings of less than 100 hectares account for two-thirds or more of the private forest area. At the other extreme, 80 percent of Peru's private forests consist of holdings of 1,000 hectares or more.

The multiplicity of small private forests presents a major obstacle to enlightened forest management in many countries, an obstacle which in some cases is being surmounted by the encouragement of forest co-operatives.

Composition of the forests in use

The distribution of conifers, non-conifers and mixed woods in the world's exploited forests is shown in Table 9.

For the world as a whole just over half the forest area today exploited consists of coniferous species. The conifers, however, are unevenly distributed, more than half the stands being found in the U.S.S.R. and less than one-tenth in the Southern Hemisphere. A cool temperate climate determines the natural occurrence of most coniferous species; hence they are found in a broad belt encircling the earth below the treeless tundras of the far north. They have only a limited occurrence in the continents of the Southern Hemisphere, since these land masses taper towards the south, hardly reaching into the true temperate zones.

Table 9. - Composition of the world's forests in use

Region	Degree of response a	Area of forest in use (million hectares)					Estimated percentage of conifers c
		Total	Conifers	Non-conifers	Mixed-woods b	Open areas b
Europe	100	130	66	49	12	3	59
U.S.S.R.	100	350*	300*	50*			85*
North America	100	220*	140*	80*			66*
Latin America	94	85	8	73	1	3	9
Africa	93	107	2	104	1		2
Asia	86	177	38	101	34	4	25
Pacific Area	94	16	2	14			13
TOTAL	96	1085	556	471	48	10	53

^a Area of forests in use for which composition data were reported divided by total area of forests in use in each region, expressed as a percentage.

^b Mixedwoods and open areas are often included in the area of pure conifers and non-conifers. The total figures for pure stands are therefore over-stated and those for mixedwoods and open areas understated

^c Includes a reported allowance for conifers in mixed stands.

* Unofficial estimates.

It should be emphasized, and indeed subsequent tables will make it abundantly clear, that forest area is a very inadequate measure of forest wealth. The areas indicated in the foregoing table, both for coniferous and broadleaved species, include stands of very different densities and with very diverse rates of growth. Standing volume and growth per hectare in the northern parts of the U.S.S.R. are but a fraction of those in, for example, Chile; there are, in fact, very great contrasts even between northern and southern Sweden.

Broadleaved stands are much more evenly distributed, over a third occurring in regions of the Northern Hemisphere In Europe, North America and the U.S.S.R., they consist almost entirely of temperate hardwoods; elsewhere, tropical hardwoods dominate the scene, temperate species being found only in higher altitudes and latitudes.

The 1947 inventory indicated (subject to the statistical qualifications which have been mentioned earlier) that 36 percent of the world's productive forests consisted of conifers; for accessible productive forests alone it was 38 percent. Table 9 above, however, shows that conifers account for 53 percent of all forests today exploited. The difference between these figures reflects the fact that so far the coniferous forests have been better suited, either by quality or by location, to satisfying the demand for forest products. Hitherto broadleaved species, save for temperate hardwoods and some precious tropical species, have been mainly used as fuel and for charcoal; conifers have served a much wider range of human needs, especially for construction, transport, timber fabrication and pulp. Economic and cultural progress in the less developed regions is heightening the demand for forest products, and leading to progress in the development of their indigenous resources; in the long run this is bound to lead to an increase in the relative importance of broadleaved forests exploited.

Forest reserves, working plans and cutting practices

The conservation and rational utilization of natural resources calls for a comprehensive land use plan; in that plan the forests have an integral part, taking into account both their protective and productive functions. This is true for all countries, whether possessing abundant forests or seriously lacking in forests. In the latter case, land will be reserved for afforestation; in the former case, perhaps only part of the forests will be classed as forest reserves.

This classification into reserved and unreserved forests is indeed the first step towards rational management, since the forest administration will concentrate its efforts on the reserved stands. Table 10 illustrates the stage reached in various regions in classifying reserved stands in the accessible forests.

Table 10. - Reserved and unreserved forests

Region	Degree of response a	Area of accessible forest (in million hectares)
		Reserved	Unreserved or not yet classified
Europe	93	123	-
North America	100	312	-
Latin America	49	1	162
Africa	61	77	95
Asia	56	84	60
Pacific Area	80	8	8
TOTAL	53	605	325

^a Area of accessible forests in respect of which data concerning reservation was reported divided by total area of accessible forests in each region, expressed as a percentage.

- Nil.

Responses to this question covered 930 million hectares of accessible forest; of this area about two-thirds have so far been reserved as permanent forest. In Europe and North America, all the accessible stands are reserved. In Asia and Africa, about half the accessible stands have so far been reserved, while in Latin America progress has been negligible.

A national forest policy aims at managing the forests, whether reserved or as yet unclassified, according to the principle of maximum sustained yield. This is normally achieved by the establishment of working plans for smaller forest units, laying down management principles, allowable cut and silvicultural practice. Table 11 illustrates the progress made in various regions in establishing working plans; the last three columns afford an indication of the quality of current cutting practices.

Of the 500 or so million hectares of forests in use in respect of which this category of information was provided, less than one-third was under working plans. The proportion was over half in the Pacific Area, where the response to this question was high, and in Canada. Next comes Europe, with 42 percent, followed by Asia and Africa; for all these three regions the replies covered about three-quarters of the forests in use. There was a good response to this question from Latin America, but it indicated a negligible proportion of forests managed with working plans.

Table 11. - Management status and cutting practices in forests in use

Region	Degree of response a	Management Status			Percentage area subject to cutting practices described as
		Area of forest managed with working plans	Area of other forest in use	Area of forest with working plans as % of forest in use	Good	Fair	Poor and destructive
		(in millions hectares)			(in percent)
Europe	76	41	58	42	65	30	5
North America b	30	36	31	54	..	..	..
Latin America	94	2	83	2	10	30	60
Africa	78	11	79	13	30	30	40
Asia	72	58	89	40	30	40	30
Pacific Area	94	9	7	54	40	30	30
TOTAL	45	157	347	31	35	30	35

^a Area of forests in use for which data concerning management status were reported divided by total area of' forests in use in each region, expressed as a percentage.

^b Canada only.

.. Not available.

The following figures for certain African and Latin American countries exemplify the rudimentary stage of forest management which has so far-been attained in those regions:

Table 12. - Stage of forest management in certain countries

Country	Forest in use (in 1,000 hectares)
	Total	Managed with working plans	Others
Argentina	10000	1300	8700
Brazil	30010	400	29610
Chile	6595	-	6595
Paraguay	5020	-	5020
Peru	5000	-	5000
French Equatorial Africa	12030	1875	10155
Belgian Congo	5300	200	5100
Gold Coast	2910	105	2805

- Nil.

This state of affairs is the more to be regretted in that publicly-owned forests in Latin America and Africa make up 64 percent and 96 percent respectively of accessible forests; accordingly, it would seem easier here to bring these forests under working plans than in other regions such as Europe where the area of publicly-owned forest is relatively small and the total of privately-owned forest is often split up amongst a large number of petty owners.

Even in the areas where forests under working plans amount to almost 50 percent or more of the total forest in use, there is still much progress to be made. It would undoubtedly be too much to expect that every small woodland should be subject to a detailed management plan. All the same it would be definitely to the advantage of small owners to regulate the cut on their woodlands in some proportion to growth and to practice systematic silviculture. Even if silvicultural practices were good or average on even 50 percent of a country's forest area, the fact that the rest were not managed to take account of their potentialities in growth and new stock, could seriously jeopardize the continuity and value of any national forest policy.

Table 11 also includes data on prevalent cutting practices. ⁵ These are, essentially, "opinion" judgments submitted by national forest authorities; views of what constitutes good cutting practice vary from country to country, and regional averages have little or no meaning. The data submitted, however, are of considerable interest as indicating the views of the responding forest authorities on the present state of forest management within their own countries. Table 11 suggests that, in the view of the forest authorities themselves, only one third of the forests in use are exploited with due regard to the requirements of good silviculture, while, over another third, prevalent practice is considerably below the desired standard and could lead to the destruction of the forests. These figures, of course, are subject to reservations similar to those mentioned above in relation to working plans. The two sets of data are, in any case, interdependent. The establishment of a working plan implies the adoption of improved silvicultural practice, though of course a high standard of silvicultural treatment may precede the establishment of a working plan, as the examples in Table 13 show.

⁵ Defined as follows: Good cutting: fellings are carried out in conformity with the requirements of good silviculture; adequate planting, tending, thinnings, protection from fires and control of grazing are undertaken. Fair cutting: same criteria as good cutting, but planting, thinnings, etc. are not undertaken on an adequate scale. Poor and destructive cutting: fellings are neither carried out in conformity with the requirements of good silviculture nor is any planting, thinning or protection against grazing and fires undertaken.

Rational management, to which the silvicultural system in force is closely tied, aims at establishing in the shortest possible time stands capable of producing the maximum possible volume of roundwood on a sustained basis. In Europe, it is possible to distinguish three different forest types: high forest, coppice with standards, and coppice. Coppice, entirely composed of stool-shoots or root-suckers of broadleaved species, yields mainly fuelwood and wood for charcoal burning. Coppice with standards, mostly with hardwoods in the upper storey, yields a low percentage of industrial wood. The highest yield of industrial wood comes from the high forest, entirely composed of trees of seedling origin. To raise the yield of industrial wood, the trend in silviculture is to convert the coppice, either directly by replanting or indirectly by selective -cutting. Of the European forests in use reported on in the inventory (85 percent of the total), 86 million hectares (or 79 percent) were under high forest, 8 million hectares (or 7 percent) under coppice with standards, and 15 million hectares (or 14 percent) under coppice. The latter two systems were most extensive, and sometimes dominant, in southern Europe, as is shown in Table 14.

Table 13. - Cutting practices in selected countries

Country	Percentage of forests covered by working plans	Percentage of forests in use subject to cutting practices described as
		Good	Fair	Poor and destructive
Denmark	76	87	13	-
Western Germany	67	85	10	5
Sweden	60	90	10	-
Switzerland	71	90	10	-
Argentina	13	13	50	37
Brazil	1	10	20	70
Chile	-	5	5	90
Gold Coast	4	3	22	75
Peru	-	-	90	10
Philippines	1	-	30	70
Spain	6	15	70	15

- Nil.

Table 14. - Silvicultural systems in Southern Europe

Country	Percentage of forests in use under different silvicultural systems
	High forest	Coppice with standards	Coppice
Bulgaria	41	59
France	43	31	26
Greece	42	40	18
Italy	39	21	40
Spain	64	14	22
Yugoslavia	64	-	36

- Nil.

Growing stock in forests in use

Information reported relating to the volume of standing timber in forests in use is summarized in Table 15.

For two important regions, North America and the U.S.S.R., the standing timber data do not relate only to forests in use. On the other hand not all the forests in use are covered by the data reported for other regions; coverage in Latin America, for example, is less than one-fourth. Table 15 therefore, does not give a meaningful picture of the real distribution of growing stock, although it includes information relating to about 81 percent of the world's forests in use.

Table 15. - Growing stock in forests in use

Region	Degree of response a	Growing stock (in million cubic meters with bark)			Growing stock per hectare (in cubic meters with bark)
		Total	Conifers	Non-conifers	Total	Conifers	Non-conifers
Europe	80	7700	5000	2700	74	77	70
U.S.S.R. b	100	58700	50000	8700	93	102	64
North America c	100	23000	16500	6500	70	80	54
Latin America	23	2700	200	2500	129	272	124
Africa	69	5900	100	5800	74	41	75
Asia	68	12500	3800	8700	89	120	80
Pacific Area	95	900	200	700	56	74	53

^a Areas of forests in use in each region for which growing stock data were furnished, divided by total area of forests in use expressed as a percentage.

^b All forests.

^c All accessible productive forests for Alaska and Canada, all productive accessible and inaccessible forests for the U.S.A.

If we assume that in each region the forests reported, whether more or less extensive than the forests in use, are representative ⁶ from the point of view of growing stock per hectare in both coniferous and broadleaved forests, then it may be estimated that total growing stock in all the world's forests in use amounts to about 96,000 million cubic meters (with bark), of which 59 percent consists of coniferous species. Over all the world's exploited forests, standing timber per hectare averages 95 cubic meters for coniferous forests and 75 cubic meters for broadleaved forests, a world average for all species of 85 cubic meters per hectare. Details of these estimates are given in a table appended to this article.

⁶ i.e. where coverage was high. Where coverage was low, and the reported data clearly unrepresentative, other assumptions were made.

Though the growing stock figures in each region are not, for the reasons explained, comparable, some tentative conclusions may be drawn from the figures of growing stock per hectare. Nowhere does this exceed 100 cubic meters save in Latin America, and for this region the reported figures may well be unrepresentative. In general, the coniferous forests are denser than the broadleaved stands, and contain more timber per hectare. Africa, where conifers occupy mainly dry regions and bear little timber per hectare, presents the only exception. The high figure for the U.S.S.R., as compared with Europe and North America, derives from the fact that the forests of the Soviet Union contain a very high proportion of trees which are mature or nearing maturity.

Growing stock per hectare is a function of silvicultural treatment and age distribution, but above all of climate. In the tropical rain forests (e.g. Belgian Congo, Madagascar, French Equatorial Africa) it may reach 400 cubic meters; in temperate zones (Switzerland, Austria, Chile) 200 cubic meters is not uncommon: 50 to 60 cubic meters per hectare is typical for countries like Finland, Norway and Canada; in the savanna forests of Central Africa the figure may fall as low as 20 to 30 cubic meters.

Finally, it is perhaps worth recalling the warning given at the beginning of this article concerning standing timber data. Apart from the deficiencies in geographical coverage just referred to, there are wide differences in treatment, e.g. concerning how much of the tree is included. Even more serious is the fact that many countries include only commercial species in their estimates; this accounts for the low figures of growing stock per hectare reported by Bechuanaland (2 cubic meters), Northern Rhodesia (12), Tanganyika (14) and Sierra Leone (27). In all these cases the reported figures represent but, a fraction of the actual growing stock.

Growth and allowable cut in forests in use

Table 16 summarizes for the different regions the data reported by countries relating to gross increment.

Table 16. - Annual gross increment in forests in use

Region	Degree of response a	Growing stock (in million cubic meters with bark)			Growing stock per hectare (in cubic meters with bark)
		Total	Conifers	Non-conifers	Total	Conifers	Non-conifers
Europe	100	284	183	101	2.5	2.5	2.4
U.S.S.R. b	100	750	590	160	1.2	1.2	1.2
North America c	100	536	300	236	1.8	1.8	1.9
Latin America	20	53	5	48	3.1	6.4	2.9
Africa	20	56	4	52	2.4	2.0	2.5
Asia	46	125	42	83	1.4	1.9	1.2
Pacific Area	88	19	2	17	1.3	1.8	1.2

^a Area of forests in use for which data for increment were reported divided by total area of forests in use for the region, expressed as a percentage

^b All forests.

^c All accessible productive forests for Alaska and Canada, all commercial forests for the United States; figure for U.S.A. excludes natural losses caused by "normal" mortality.

The reported data related to about three-quarters of-the world's exploited forests. Coverage is complete for the Northern Hemisphere, adequate for Oceania, fair for Asia but so small as to render conclusions uncertain for both Africa and Latin America. Moreover, as was the case for growing stock, the figures reported for North America and the U.S.S.R. do not relate merely to the forests in use. Thus not only does Table 16 fail to reflect the real distribution of annual growth in the world's exploited forests; but any conclusions about growth per hectare must be highly tentative.

An attempt has been made to estimate, on the basis of the data available, gross increment in exploited forests for the world as a whole. This calculation, of which details are given in Appendix II, suggests that gross increment is probably around 2,300 million cubic meters, of which 1,000 million cubic meters, or 46 percent, consist of coniferous species. Growth per hectare is probably around 1.8 cubic meters for coniferous and 2.4 for broadleaved species, averaging 2.1 cubic meters for all species over the world as a whole.

Net annual growth equals gross increment less natural losses, i.e. the volume of timber rendered unusable annually by fire, insect pests, tree diseases, snow, avalanches, wind storms, etc. The report on the 1947 inventory tentatively estimated natural losses in the world's coniferous forests at about 10 percent of gross increment. The information submitted in the present inventory is summarized in Table 17.

Table 17. - Gross increment, natural losses and net growth

Region	Degree of response a	Gross increment (million m³)	Natural losses		Net growth (million m³)	Cubic meters per hectares
			Total (million m³)	As percentage of gross increment		Gross increment	Net growth
Europe	89	284	13	4.6	271	2.5	2.4
North America b	100	536	90	16.8	446	1.8	1.5
Africa	16	19	1	6.8	18	1.1	1.0
Asia	46	125	14	10.9	111	1.3	1.2
Pacific Area	88	19	13	69.6	6	1.3	0.4

^a Area of forests in use for which data for gross increment, natural losses and net growth were reported, divided by total area of forests in use for the region, expressed as a percentage.

^b See note ^c on Table 16.

The inadequate degree of response (and in certain cases the unrepresentative nature of the data reported) preclude any world estimates. In fact no estimate of natural losses makes sense unless it relates to an average over an adequate period, since several elements are "accidental" (fires, epidemics, severe gales) and can vary considerably from year to year. Thus the high figure for the Pacific region is unrepresentative since it reflects the high incidence of forests fires in the year of the Australian inventory, 1950.

The concept of natural losses as the difference between gross and net increment has an important place in theory; its definition and its measurement present serious problems. One thing, and one thing only, emerges clearly from the data reported; in Europe, where climatic conditions are favorable and where the standard of forest management is high, natural losses amount to about 5 percent of gross increment. For all other regions the state of knowledge concerning natural losses is so rudimentary, or the qualifications attached to the definition of natural losses so serious, that it would be rash to draw any conclusions.

For this reason all the estimates of net growth included in Table 17 should be treated with considerable reserve, save perhaps that for Europe. Here net growth averages 2.4 cubic meters per hectare for conifers and slightly less for broadleaved species. Net growth varies not only with climate but with the age and species composition of the forest. It may range from less than 0.5 cubic meter per hectare in extreme latitudes (Alaska) or arid areas (Rhodesia) to 5 or more cubic meters where climate is favorable.

Sustained yield is one of the aims of a national forest policy; it finds its expression in the concept of allowable cut, which may, in the short term, be higher or lower than net increment, depending on age distribution, species composition and growth. Only in a forest in equilibrium does allowable cut equal net growth. Allowable cut is a key figure for forest management and each individual working plan indicates the allowable cut for the forest which the plan covers. In the precise sense, allowable cut for a nation's forests is usually arrived at (by simple aggregation) for those forests covered by working plans; it will be recalled that only one-third of the world's exploited forests are managed in accordance with working plans. Nevertheless, each country aims at assessing the volume of roundwood which may be felled yearly in conformity with sustained yield principles. This figure, also termed "allowable cut," may be estimated by the government, by the forest authorities or by research institutes. Clearly it act only be computed if certain fundamental information relating to the nation's forests is available. The following table summarizing information reported under this heading thus essentially depicts the progress made in forest statistics and administration to date:

Table 18. - Net growth and allowable cut in forests in use

Region	Degree of response a	Total millions cubic meters		Per hectare in cubic meters
		Net growth	Allowable cut	Net growth	Allowable cut
Europe	87	269	244	2.4	2.2
Africa	8	13	9	1.4	1.0
Asia	38	74	73	1.0	1.0

^a Area of forests in use for which data for net growth and allowable cut were reported, divided by total area of forests in use for the region, expressed as a percentage.

This key figure for forest policy exists for only about 18 percent of the total area of the world's exploited forests, and only in Europe is it possible to arrive at an adequate comparison of net growth and allowable cut. The fact that the latter is but nine-tenths of the former indicates that the composition of European forests, in the view of European foresters, does not warrant fellings up to the limit of net growth. In fact with one exception allowable cut falls short of net increment in all European countries, and considerations other than those of forest conservation were decisive in the exceptional case - Yugoslavia.

In the reporting Asian countries, allowable cut is on the whole around the same figure as net growth. In the reporting African countries allowable cut is on average about two-thirds of net growth, though the proportion falls to half in the Union of South Africa, with a preponderance of young stands.

Fellings and removals

The paucity of the information available relating to net growth and allowable cut in the world's forests in use means that for only a small proportion of the world's exploited forests can these key figures be related to fellings. The response in fact covers most of Europe's, a third of Asia's, and a fraction of Africa's, forests in use. For a comparison of fellings and net growth only, the situation is only slightly better, for although this adds an adequate coverage in respect of the Pacific area, it will be recalled that the net growth figure recorded for this region is not representative.

Table 19. - Net growth, allowable cut and fellings in forests in use

Region	Degree of response a	Net growth	Allowable cut	Fellings	Degree of response b	Net growth	Fellings
		(in million cubic meters without bark)				(in million cubic meters without bark)
Europe	75	210	191	224	75	210	224
Africa	5	8	5	5	10	11	9
Asia	36	63	63	77	36	64	78
Pacific Area	..	..	..	..	92	9	15

^a,b Area of forests in use where a) net growth, allowable cut and fellings, and b) net growth and fellings, were reported, divided by total area of forests in use in each region, expressed as a percentage.

... Not available.

Table 19 shows the extent of overcutting in the forests of European reporting countries; fellings exceed net growth by 6 percent and allowable cut by 17 percent. The case of Yugoslavia has already been mentioned, but this is by no means the only European country where the figure laid down for sustained yield management is being exceeded. In other regions the exclusion of non-commercial species and the inclusion of brushlands as forest confuse the picture, but the reports of individual countries (Burma, Chile, Ethiopia, Turkey, Japan, for example) make it clear that overcutting is far from rare.

Information relating to logging and floating losses is limited and of uncertain accuracy. Table 20 summarizes the data reported for each region; it covers less than two-fifths of the world's exploited forests.

Table 20. - Fellings and removals in forests in use

Region	Degree of response a	Total feelings (in million m³)	Logging and floating losses		Removals
			Total (in million m³) b	As percentage of fellings	Total (in million m³) b	Per hectare (m³) b
Europe	75	224	18	8	206	2.2
North America	78	288	..	..	288	2.0
Latin America	55	118	13	11	105	2.1
Africa	11	22	*	1	22	1.8
Asia	50	103	1	1	102	1.2
Pacific Area	93	15	1	4	14	0.9

^a Area of forests in use where fellings and losses were reported divided by total area of forests in use in each region, expressed as a percentage.

^b Cubic meters without bark.

* Negligible.

... Not available.

The figures would suggest that for the world as a whole logging and floating losses amount to about 4 percent of fellings. This, however, is an unrealistic figure since it is hardly likely that such losses in Africa and Asia are lower than the 8 percent recorded for Europe, where the forests are served by a highly developed network of communications. No doubt inadequate felling statistics and the exclusion of non-commercial species are responsible for the low figures reported; actual losses in the Southern Hemisphere may well reach or exceed 10 percent. Individual country reports indicated losses exceeding one-fourth of total fellings in Ceylon, Chile and Madagascar, one-fifth in Paraguay and South Korea, and one-tenth in Brazil, Ecuador, France, New Zealand, Spain, Syria and Viet-Nam.

FAO collects and publishes each year figures of removals in forests in use from all its member countries and their dependencies. ⁷ These data, averaged over recent years (in most cases, 1950-52), have been supplemented by such other information as was obtainable and are presented in Table 21.

⁷ Yearbook of forest Products Statistics; the seventh issue appeared in 1953.

Table 21. - Removals in the world's forests in use, average 1950-52 (million cubic meters, without bark)

These figures exclude unrecorded removals and illicit fellings in those countries for which no official estimates have been made. Thus about 1,400 million cubic meters are removed annually from the world's exploited forests. The share of industrial wood, roughly half for the world as a whole, varies from region to region in accordance with the species distribution (a bigger proportion of conifers is used industrially) and with the wood fuel needs of the local populations. In countries well-endowed with forests, and where the population is thinly spread, most of the wood suitable only for fuel is left in the forest. In other parts of the world, where wood fuel is scarce and other fuels expensive or unobtainable, all the fuelwood is removed. Thus a high fuelwood percentage does not necessarily imply irrational exploitation.

For the world as a whole, removals average just over half a cubic meter per inhabitant annually. This again varies from region to region, and reflects, inter alia, the stage reached in the development of the wood-using industries and the scale of exports. Some of the higher figures recorded are 10 cubic meters in Finland, 6 in Canada and 3 in Norway, whilst in countries severely lacking in forests the figure falls to a very small fraction of a cubic meter.

Other roundwood supplies

The world's roundwood reserves are not limited to forest trees; they are supplemented by trees or groups of trees planted in parks and gardens, by trees planted separately, in rows or in clumps as windbreaks along rivers, canals and roads, by areas of fruit trees, poplar and other species planted on agricultural land to enhance the income obtained from the soil, by woodlands planted on irrigated land scattered throughout arid regions.

Roundwood supplies from trees outside the forest are mainly used as fuel for local consumption; sometimes they supply the woodworking industries with precious species not grown in the forest (fruit trees, for example, and especially cherry, apple and pear); occasionally they serve as an important source of constructional timber, veneer logs and pulpwood.

Statistics of trees outside the forest are almost always deficient. These trees normally belong to a multitude of small owners; they are usually outside the jurisdiction of the forest service and their felling is not controlled. Nevertheless, the data submitted by the 33 countries which were able to provide an estimate of roundwood supplies from this source suggest that the significance of this source of supply has in the past been underestimated.

In the reporting countries, about 33 million cubic meters of roundwood were derived from trees outside the forest, representing 14½ percent of all domestic roundwood supply. All but 8 percent of this wood was used as fuel, so that roundwood from this source accounted for 4½ percent and 26 percent of the total industrial wood and total fuelwood supplies respectively. These figures make it clear that trees outside the forest cannot be neglected when planning a forest policy based on a nation's total wood resources.

By way of example, relevant figures for certain European and Near Eastern countries are given in Table 22.

Table 22. - Supply of roundwood for non-forested areas

Country	Supply from non-forested areas
	Total (in thou sand cubic meters)	As percentage of total removals of
		All roundwood	Industrial wood only	Fuelwood only
France	3640	12	3	19
Great. Britain	230	13	..	..
Italy	9238	41	18	47
Jordan	2	5	40	..
Israel	1	10	17	..
Netherlands	158	20	20	20
Syria	1585	38	66	38

... Not available.

In Italy and Syria, the forests furnish only three-fifths of the indigenous roundwood supply. In both France and Great Britain trees outside the forest account for one-eighth of total native supply. It is clear that future national forest inventories, especially in countries ill-endowed with forests, will have to take into consideration the need to assess more exactly the potential supply from non-forested areas.

Conclusions

The 1953 world forest inventory shows that the world's forests are potentially capable of furnishing a plentiful flow of forest products for a world population much higher than that of today. Of 3,900 million hectares of woodlands, less than a third are today exploited. Of the immense unexploited reserve of standing timber in the world today, over 600 million hectares are accessible at the present time.

The inventory emphasises once again the contrast between the world's exploited coniferous forests, where growth and drain roughly balance, and the under-exploited broadleaved forests in use. The three predominantly coniferous regions, Europe, the U.S.S.R. and North America, account for one-third of the world population and less than two-fifths of the world's woodlands; yet between them they account for 70 percent of the removals from the world's forests.

A fundamental question is whether natural losses and fellings exceed the rate at which wood is being produced. Are the forests being overcut? Here again, the present inventory does not admit of firm and precise answers. As a very rough estimate, based on reported removals and making various assumptions concerning bark proportion, logging and floating losses, natural losses and gross increment, we can perhaps say that in the world's 600 million hectares of exploited coniferous forests, growth and drain are just about in balance - at around 1,100 million cubic meters with bark. The tentative nature of this conclusion will be apparent from earlier references to the many deficiencies in the reported data. In the 500 million hectares of exploited broadleaved forests, gross increment may be reckoned at about 1,300 million cubic meters, of which perhaps three-quarters is drained off by fellings or natural losses. This under-exploitation derives largely from the fact that many of the species growing in the tropical and sub-tropical forests are not today marketed and only a fraction of the non-commercial species is used as fuel.

Forests are renewable resources. Given skillful management, they can yield annual crops in perpetuity. On the other hand, these invaluable assets can all too easily be destroyed. And, as history has shown, reckless misuse of the forests is not simply a matter of depleting the forest capital; the consequences for the climate, the soil and the water regime can be catastrophic. Yet over vast areas-of the world forest management has not attained the stage of sustained yield. Even the basic classification of reserved forests has hardly started in some regions; the forest area covered by working plans is still relatively small, while there are very few countries indeed where the prevalent cutting practices do not leave much to be desired.

All the information sought in this second world forest inventory of FAO consisted of data which may be regarded as essential for the formulation of national forest policies. As compared with the response to the first enquiry, this inventory records encouraging, even striking, progress. Nevertheless, the material assembled does not yet enable us to build up a complete and comprehensive picture of the world's forest resources.

First because in spite of the considerable progress made in the direction of international comparability, national statistics still differ widely in scope, content and reliability. The basic distinction between accessible and inaccessible forests is neither universal nor uniform; nor is the division of accessible forests into forests in use and unexploited forests common to all countries; there are many different ways of calculating standing timber, growth and drain; recorded fellings often cover only a part of the forest crop.

Secondly, many countries do not as yet collect all the data necessary for the formulation of forest policy. In fact, the collection of many of these data, e.g. on growing stock, growth, drain and fellings, calls not only for a high degree of technical skill and the correct application of statistical methods, but also for a highly organized forest service, with arrangements for the local collection of statistics. Thus further advances depend on the wider adoption of a minimum statistical program, on progress towards agreed concepts and definitions, and on the establishment, or extension, of statistical services within the countries. Thus, while this inventory tells us a great deal, far more than has been known before, about the world's forests, it also represents a progress report which indicates the advances which have been made in recent years in forest consciousness, forest management and forest statistics.

The response to the 1953 inventory is, therefore, at once an encouragement and a challenge: an encouragement, since it demonstrates the important advances which have been made since the war; a challenge, since it emphasifies how much remains to be done if the world's forest resources are to be utilized rationally.