by A. HYNDMAN STEIN
FAO Forestry Mission, Chile
THE occurrence, extent, distribution and composition of the natural forests of Chile are influenced greatly by latitude and altitude, even more so by these factors than in other countries, owing to Chile's unique configuration. Local factors, such as soil and water conditions and aspect, affect their composition to some extent, while man must be held responsible for their present condition.
Thus, in the Northern provinces of Tarapacá, Antofagasta and Atacama - the Norte Grande - desert conditions discourage the occurrence of natural forests, and such woody vegetation as occurs is xerophilous and restricted to certain localities. On the inland pampa at about 1,000 meters in altitude, where subterranean water is available, occur patches of the deep rooted indigenous species, Prosopis tamarugo (tamarugo). Possibly there may have been more extensive natural patches of this species formerly, which disappeared gradually over the centuries by exploitation for fuel required for smelting of silver in the Inca period, and more recently by exploitation for fuel for nitrate factories. Such patches as are found now are principally the result of afforestation. The species Prosopis siliquastrum (algarrobo) introduced from Argentina, is often found growing in association with tamarugo. At elevations between 4,000 and 5,000 meters in the high Andes in this region, where short sharp showers of rain are received in the summer, occur Laretia compacta (llareta), a curious woody member of the family Umbeliferae which forms cushion-shaped masses, consisting of the tightly packed shoots of the plant, thus enabling it to withstand arid conditions. However, this species is light-demanding and favors sunny northern aspects. It is prized greatly as fuel for the population of mining centers, such as Chuquicamata, and other small towns such as Calama, as well as for the light railway from Arica to the altiplano of Bolivia.
In the province of Coquimbo and Aconcagua, and small portions of Valparaíso and Santiago provinces. - Norte Chico - the climatic conditions are more favorable for woody growth. The rainfall varies from 10 to 40 centimeters according to locality, but almost all occurs in winter, and most of the species found are xerophilous. An exception is the patch of forest at Fray Jorge in the outer slopes of the coastal range near Coquimbo, where the humidity induced by the impact of moisture-laden coastal fog against these slopes permits the growth of hygrophilous species. This region contains tracts of open woodland with a large variety of woody shrubs, which are valuable spring pastures for sheep. Towards the south of this region, Acacia cavenia (espino) occurs on level sites. In the re-entrants, carved by streams on hut/sides, especially on shady aspects, occur evergreens with leathery leaves such as Quillaja saponaria (quillay), Cryptocaria rubra (peumo), Lithraea caustica (litre), and Boldea boldus (boldo). The large demand for fuel in this region has caused the disappearance of much of the original woody growth, and the formation of plantations, mainly of eucalyptus with the assistance of irrigation. The bark of quillay is an article of commerce, and in 1954. 635 tons, worth almost one million gold pesos, were exported.
In the region comprising the southern portion of Valparaíso and Santiago provinces to the provinces of Arauco and Malleco, which have to be considered as transition provinces between central and south Chile, as portions of these provinces have affinities to one or other, rainfall also occurs mainly in winter, but increases progressively from north to south. Also the outer slopes of the coastal cordillera and the Andean slopes usually receive more rain than the central plain.
Thus Santiago has an average annual rainfall of 40 centimeters, Linares 100 centimeters, Chillán 117 centimeters, while Concepción has 150 centimeters with a better distribution, each summer month having from two to seven centimeters. These rainfall conditions are reflected by the character of the natural woodlands and forests of this region. The typical tree species of the natural vegetation of the central plain and adjoining foothills as far south as Ñuble province, about 37°S., is Acacia cavenia (espino), though years ago most woodlands of this species gave place to cultivation. The sheltered valleys of the coastal range in Valparaíso and Santiago provinces formerly contained dense stands of Chilean palm (Jubaea spectabilis), of which only two remain at Ocoa and Cocalán. The coastal range and lower Andean slopes have open woodlands of xerophilous woody shrubs, a deciduous species of Nothofagus, described by Reiche as Nothofagus obliqua var. macrocarpa (roble blanco) and leathery-leaved evergreens such as quillay, litre and boldo, as far as Colchagua province, south of which they begin to be replaced by open forests comprised mainly of deciduous species of Nothofagus, Nothofagus glauca (roble mauling or roble colorado), Nothofagus leoni (hualo) and Nothofagus alessandri.
At higher elevations in the Andes, an evergreen species, Nothofagus dombeyi (coigüe) begins to occur from Colchagua province, and a deciduous species, Nothafagus procera (raulí) from Talca province, while two other deciduous species, Nothofagus pumilio (lenga) and Nothofagus antarctica (ñirre), begin to occur at the tree limit, about 2,000 meters in this region, from Ñuble province. Similarly on the central plain in this region the deciduous species, Nothofagus obliqua (roble, roble pellín) begins to replace the Acacia cavenia formation from just north of Yungay about 37°S at first as scattered trees in fields now under cultivation, the remnants of the former forests. The forests of the Andean foothills in Ñuble, Bío-Bío and Malleco provinces, composed mainly of roble, raulí and coigüe, improve in quantity and quality as one progresses southwards, and Malleco has extensive tracts of natural forest of this type. The northern limit of Araucaria araucana (pino araucaria) is at Antuco Volcano 27° 30'S, in the Andes, but forests of this species are found also on the table-land of Nahuelbuta at 1,000 meters in the coastal cordillera of Arauco province. Libocedrus chilensis (ciprés de cordillera), the most northerly indigenous conifer, begins to occur on the Andes at high elevations up to about 1,800 meters from Colchagua province.
Roble mauling, hualo and Nothofagus alessandri do not extend southwards of Maule province, but all other species of Nothofagus which occur in this region, that is coigüe, raulí, roble, lenga and ñirre, extend far to the south, lenga and ñirre actually to Tierra del Fuego. Similarly, ciprés de cordillera and pino araucaria extend to the south of the limits of this region.
This region of Chile is well developed agriculturally, contains the three largest cities of the country, many of the industries and over 70 percent of the population. Consequently, the accessible natural forests of this region have been over-exploited, but their disappearance has been compensated, north of Talca to some extent, and south of that province, more adequately by the formation of plantations, Pinus radiata, Eucalyptus globules and Populus nigra italica. The Concepción zone, consisting of Maule, Linares, Concepción, Ñuble and Bío-Bío provinces and the transition provinces of Arauco and Malleco, have a great concentration of plantations, and contain collectively over 90 percent of the country's plantations of Pinus radiata.
The southern region of Chile, commencing from the transition provinces of Arauco and Malleco and extending to Magallanes, about 1,700 kilometers in length, has, in general, a rainy temperate climate, though as may be expected over such a great range of latitude, the rainfall and temperature present many variations. Thus, Temuco on the central plain has an average annual rainfall of 140 centimeters; Puerto Montt, 175 centimeters; Valdivia, 245 centimeters; the western slopes of the Andes at high elevations and outer islands at sea level are believed to have as much as 500 centimeters, while the trans-Andean tract in Aysen and Magallanes is notably drier with a rainfall of only 15 to 40 centimeters. This great difference in rainfall produces entirely different types of natural forest on the maritime and continental sides of the main cordillera in Aysen and Magallanes provinces, the crest of this cordillera being above the tree line, and much of it is glaciated. The temperatures in general diminish from north to south, and from sea level to the mountain heights. The intense cold of winter and the strong winds of summer on the Patagonian steppes, combined with the low rainfall, exert a great influence on the occurrence and nature of the tree growth in that locality. The tree line varies from about 1,700 meters in the north of this region to only a few hundred meters above sea level in the extreme south.
This vast region of Chile contains the major part of the natural forests and woodlands of the country, having 85 percent by area of the total area of all types of natural forest and woodland, and what is even more significant, 96 percent of the total area of commercial natural forests of Chile. It is probable that, before man arrived on the scene and influenced Nature's scheme, the whole of this region, excepting the high altitude above the tree line, the arid portions of the Patagonian steppes and occasional natural meadows, was covered with forest growth, generally dense, composed mainly of broadleaved species of types which can still be observed, as certain portions, mainly owing to their inaccessibility, remain intact. However, the view has been put forward that at the time of the Spanish Conquest much of the central plain was not densely forested, but that dense forests developed on this plain subsequently, and there is a considerable weight of evidence in support of this view. As a matter of interest it may be mentioned that fossils found in Patagonia show that many million years ago this region had forests of conifers resembling certain species of the genus Araucaria. Also the great age of Fitzroya cupressoides (alerce), found in the Lago Llanquihue -Puerto Montt tract, suggests that alerce forests have existed in that tract for thousands of years.
The Nothofagus species
A feature of the present day forests is the predominance of species of the genus Nothofagus (Fagaceae). As we have seen, certain species occur in the region of Chile further north, but it is in this region that coigüe, raulí, roble, lenga, ñirre reach their optimum and certain other species of the genus occur. It is of interest to note that the first species of this genus which became known to science, as a result of Captain Cook's voyage 1769-71, was Nothofagus antarctica, which is the poorest species of Nothofagus occurring in Chile, from the point of view of timber production. It was first known as Fagus antarctica until the genus Nothofagus was formed in the middle of the 19th century, by which time it was realized that the beeches of the southern hemisphere were distinct from those of the northern hemisphere. As well as occurring in South America, principally in Chile, species of Nothofagus are found in New Zealand, Tasmania, Australia and New Guinea. In the natural forests of this region of Chile, three evergreen and five deciduous species of Nothofagus are estimated as comprising collectively 2/3 of the forests, the remaining 1/3 consisting of a number of other hardwoods, mainly evergreen and eight species of conifers.
Mixed stands are much more plentiful than pure stands, though there are exceptions such as the extensive forests of the deciduous N. pumilio (lenga) in the trans-Andean tracts in Aysen and Magallanes, stands of the evergreen N. dombeyi (coigüe) and N. betuloides (roble de Magallanes), in the area of high rainfall and patches of conifers, pino araucaria, alerce and Pilgerodendron uviferum (ciprés de las guaitecas), on particular sites characteristic of these species. However, as the occurrence of individual species depends greatly on latitude, altitude and other factors, sites, even in the case of mixed stands, seldom contain more than ten or a dozen species, of which only three or four are dominant.
Deciduous species of Nothofagus occur mainly in the north and south of this region, that is, the drier zones of the region, the first comprising Arauco, Malleco, Cautín, Valdivia and Osorno provinces, except the tablelands and outer slopes of the coastal cordillera of these provinces, the second comprising the trans-Andean tract in Aysen and Magallanes, including Tierra del Fuego.
In the drier northern zone, the principal deciduous species, which are always the dominant species of their stands, are Nothofagus oblique (roble) and Nothofagus procera (raulí). The former favors well-drained sites on the central plain, and up to an elevation of about 800 meters generally, though the upper limit of this species varies with the aspect and stands have been observed at 1,000 meters. Raulí grows well between 600 to 1,300 meters, especially in the Andes. Llanquihue province and Valdivia province may be considered as the southern latitudinal limits of these two species respectively.
Two other deciduous species, N. pumilio (lenga) and N. antarctica (ñirre) also occur, but at higher elevations, generally from 1,300 meters to the tree line, about 1,700 meters in this zone, though ñirre in the form of low trees or scrub, is found frequently on poorly drained valley floors from 800 meters upwards. The deciduous species of this northern zone, except lenga and ñirre, which are more often found in pure stands, occur generally in association with evergreens, the principal dominant or codominant broad-leaved species being coigüe, which, however, tends to occur in pure stands, and is very plentiful, forming more than 40 percent of the forests of Valdivia province. Laurelia serrata (tepa) is the next most abundant evergreen associate, sometimes in the form of a codominant species but more often forming a definite second storey. Other evergreen associates, which usually are in the form of codominants, are Laurelia sempervivens (laurel), a mixture of this species with roble being characteristic of parts of the central plain in Osorno and Llanquihue as far south as Frutillar, Eucryphia cordifolia (ulmo), Aextoxicon punctatum (olivillo), Weinmannia trichosperma (tineo or palosanto), Persea lingue (lingue) and Drimys winter) (canelo). The principal evergreen associates which usually occur as subdominants are Myrtus luma (luma), Myrtus meld (meli), Tepualia stipularis (tepu), Myrceugenia apiculata (arrayan), Flotowia dicanthoides (trevo), Lomatia obliqua (radar), Guevina avellana (avellana), Embothrium coccineum (notro or ciruelillo) and Boldea boldus (boldo). But, as many of these species are typical of the moister sites along streams or in marshy places, where they form dense low forest, on such sites they become the dominant or codominant species.
In the drier southern zone, representing the trans-Andean tract in Aysen and Magallanes, including Tierra del Fuego, the main deciduous species are lenga and ñirre, and most of the forests of this zone consist of pure stands of lenga, generally with an undergrowth of Berberis spp. (michai or calafat). Another deciduous species of Nothofagus occurs in Tierra del Fuego, namely Nothofagus montagnei, which resembles ñirre.
The remainder of this region, that is, the mesetas and maritime slopes of the coastal cordillera in the north of the region, the central plain southwards from about 41° S. and all islands and maritime slopes of the continent south of Puerto Montt to Cape Horn, is populated by a forest, typically evergreen, and which may be regarded as a temperate zone "rain" forest, on account of the copious rainfall. Three evergreen species of Nothofagus are characteristic, namely coigüe, which occurs as far south as Aysen province, N. nitida (roble de Chiloé) which occurs from Osorno to Aysen but mainly in Chiloé, and N. betuloides (roble de Magallanes), which occurs from the meseta of the coastal cordillera in Valdivia province to the Straits of Magallanes. Other very common species of this "rain" forest are canelo and luma. All other evergreen species mentioned as associates in the deciduous forests of the northern drier zone occur also in the "rain" forest in the north of the region, but certain species disappear south of Chiloé.
Coniferous species
The natural forests of the southern region, though predominantly composed of hardwood species, are not entirely so, coniferous species forming about 7 percent.
The association, often intimate, of coniferous with broadleaved species is a characteristic feature of the natural forests of Chile, so unlike the occurrence of conifers in the northern hemisphere where they tend to form extensive pure stands or occur in mixture with other coniferous species rather than broadleaved.
Eight indigenous species of coniferous are found, namely Araucaria araucana (ping araucaria), Fitzroya cupressoides (alerce), Pilgerodendron uviferum (ciprés de las guaitecas), Libocedrus chilensis (ciprés de cordillera), Podocarpus andinus (lleuque), Podocarpus nubigenus (mañio hembra), Podocarpus salignus (mañio) and Saxegothaea conspicua (mañio macho), or nine, if the dwarf conifer Dacrydium fonckii, which occurs from the meseta of the coastal cordillera of Valdivia province southwards as far as Aysen, is included.
The first two of these species have restricted habitats. Pino araucaria is limited to the Andes between Antueo volcano (37°30' S.) and Lanin volcano (39°30' S.) at elevations from about 1,200 meters to the tree line, and as already mentioned, to the Nahuelbuta tract of the coastal cordillera, slightly north of 38° S., either forming pure stands, or occurring in mixture with coigüe and lenga, the latter only in the Andean habitat. Alerce, on the other hand, is a species of the "rain" forest. Its northern limit is the coastal cordillera of Valdivia province at elevations over 300 meters. Further south, as between Lago Llanquihue and Puerto Montt it is found on the central plain, and it continues to occur on moist sites in Llanquihue and Chiloé provinces, frequently in association with ciprés de las guaitecas. Alerce is the redwood of the natural forests of Chile, and attains great size under favorable conditions, and great age, 2,000 years or more.
Of the other conifers, ciprés de cordillera, lleuque and mañio occur mainly to the north of Osorno province, but ciprés de las guaitecas, mañio macho and mañio hembra are more typical of the heavy rainfall areas, and are found far to the south. Ciprés de cordillera frequents rocky sites. Lleuque is comparatively scarce. Mañio occurs on both cordilleras as well as on the central plain, and is generally an understorey tree below dominant deciduous or evergreen species. Ciprés de las guaitecas is dominant on moist sites as on the Isla Guaiteca, from which it derives its name. Mañio macho and mañio hembra are found generally as subdominants, though occasionally as codominants with broadleaved species.
The quality of growth in the natural forests of this region is by no means uniform. There are still some stands of raulí, coigüe, pino araucaria and alerce not yet exploited by men where large trees three meters in diameter at breast height and 40 to 50 meters in total height can be found, but such overmature trees generally have a high percentage of unsoundness. There are very extensive tracts of low forest (monte bajo), where there are few or no trees of saw timber size, and some tracts, such as the meseta of the coastal cordillera of Valdivia province, only have very stunted growth owing to the shallow soil and exposure. In general, the forests of highest quality are those of the Andean tract of Malleco, Cautín, Valdivia, Osorno and Llanquihue provinces, the quality being at its optimum in Cautín and Valdivia. The quality of the forests of the coastal cordillera of these provinces, also of the forests of Chiloé, Aysen and Magallanes, is notably lower, tending to deteriorate as the latitude or altitude increases.
A feature of the natural forests of South Chile is the dense undergrowth, sometimes consisting of the reproduction of shade-tolerant species such as tepa, luma and the three mañios, but much more frequently consisting of a profuse growth of Chusquea species (colihue and quila), which increase the silvicultural problem of regenerating these forests, especially as most of the higher value species such as raulí and roble are light-demanding. However, Chusquea gives shelter and fodder to cattle during winter when other green fodder is not available. At higher elevations in the Andes the undergrowth frequently consists of the alpine species of canelo; in the "rain" forest of Aysen fuchsia and ferns are plentiful; while in the deciduous forests of Aysen and Magallanes the most common forms of undergrowth are species of Berberis (michai or calafat).
The present extent of all types of natural forests and woodlands is estimated at 16,090,000 hectares, or 22 percent of the total surface area, 74,177,000 hectares, of the country. Of these 16,090,000 hectares, 9,465,000 hectares are not available for production, being inaccessible or only rocky non-commercial natural forest and woodlands, and only 6,626,000 hectares are accessible commercial natural forest and woodlands. The latter figure gives slightly less than one hectare of productive forest per member of the population, which is close to the world average, and is considerably more than the figure for densely populated Asian countries which is only 0.3 hectare, but less than half of the figure, 2.5 hectares, in North America.
Also, as the foregoing description of natural forests in the various regions of Chile indicates, the distribution of natural forests is most unequal, both geographically and in relation to the population. For example, the proportion of forests to the total surface area varies from far below 1 percent in the three northern provinces to over 40 percent in the southern provinces, Arauco-Malleco to Magallanes, and the quantity of forest per member of the population varies from a tiny fraction of a hectare in the northern to over 13 hectares in the southern provinces.
Chile can be divided into two broad zones from the point of view of forest sufficiency. The northern zone from Tarapacá to Talca inclusive is a deficit area. This is unfortunate, on account of the large proportion of the population in the Santiago-Valparaíso area, and the long distance from the southern natural forests which raises transportation problems and makes timber very expensive at Santiago. The southern zone from Maule-Linares to Magallanes is a surplus area, but the Concepción region is surplus only on account of the extensive plantations; the transition provinces, Arauco and Malleco, are surplus, partly on account of natural forests and partly on account of plantations, and the provinces to the south, Cautín and Magallanes, are surplus account of their natural forests.
Man's influence on the occurrence, extent and distribution of natural forests may only have supplemented in minor degree the underlying natural factors, but it certainly has been the major cause of the present condition of most of the natural forests. This influence has been particularly decisive, one might even say destructive, in the past century. Before that, the scanty population and the lack of incentive for commercial exploitation probably limited the demand on the forests to a modest local scale. With the increase in population, the need of settlers for more land for cultivation and pasture. the growth of towns, the advent of a railway line linking Santiago with the southern province as far as Puerto Montt, and the subsequent development of export, the natural forests became subject to a relentless ever-increasing pressure.
The land tenure policy, introduced by the Spanish and largely retained after independence was won by Chile, combined with the policy of giving private initiative a free hand in clearing forest land for cultivation and pasture, had the result that much forest land came to be considered the property of private individuals. North of Puerto Montt, the State-owned forest lands are limited to a few reserves, in most of which concessions for the commercial exploitation of timber were granted freely, and occupation was permitted, or took place illegally, until quite recently: 52 percent of the total area of the State forest reserves, 945,726 hectares, are estimated as being so occupied. In the southern part of Magallanes, including Tierra del Fuego, former forest land is now held on concessions or in some cases is occupied by sheep farmers, and it is only in Chiloé and Aysen provinces, also in parts of Llanquihue and Magallanes, but especially in Aysen, that extensive tracts of forest land, still owned by the State, at least nominally, remain, and these forest lands generally contain forests inferior in quality to those in private ownership further north. It is estimated that of the total area of all types of forest and woodland, including plantations, 54.5 percent are privately owned; 42.7 percent by the State and 2.8 percent are in undetermined ownership.
The private owners for the most part have been interested only in immediate maximum returns from the natural forests, and in getting them cleared as quickly as possible without heed to the future. The difficulties of exploitation, poor communications and distance from markets have encouraged selective fellings, that is felling of only the best trees of a few species of high value, frequently accompanied by the destruction of the remainder. This destruction, sometimes deliberate with the intention of clearing the land and sometimes wanton, was done through the agency of fire, a practice which has not helped to develop a public conscience on the subject of protection of the forests from fire. Extensive tracts in South Chile, where the clearing is still in progress, are encumbered by the grey specters of dead trees, stumps of exploited trees and semi-charred logs, many of which are sound internally and could be salvaged. The use of fire to effect clearing has frequently had the good effect of stimulating the regeneration of certain species, notably roble, raulí and coigüe, but where the original fire has been followed by repeated clearings and further fires, or where grazing has taken place, the young tree growth has been damaged severely or destroyed.
The selective fellings practiced have had the natural but unfortunate result of overcutting the species of high value, to mention a few, lingue, radar, ciprés de cordillera, laurel, raulí, roble, pino araucaria and alerce, in that these species have become increasingly scarce and some are threatened with extinction. For example, the production of saw timber of lingue, laurel, raulí and roble in 1945-46 was, in round figures, 850,000, 3.75 million, 5 million and 9 million pulgadas1 respectively, but in 1952-53 the production of sawn timber of these species was only 250,000, 1 million, 2.5 million and 3 million pulgadas respectively.
1 One pulgada= 10 board feet.
At present the center of natural forest exploitation is represented by Valdivia, Cautín and Malleco provinces in that order, which produce over 60 percent of the total production of sawn timber of the country. The place of forest exploitation as a source. of employment is indicated by the fact that, in 1953-54, 599 sawmills were in operation and employed about 12,000 workers.
The standing volume of the remaining productive natural forests has been estimated at 1,500 million cubic meters, and their gross annual increment at 17.5 million cubic meters. On the other hand, their annual losses, owing to natural causes such as decay, effect of wind, insects and fungi, as well as fire, generally caused by man, and exploitation have been estimated as 43 million cubic meters.
These figures indicate a very grave state of affairs, which if not corrected will lead to the exhaustion of the productive natural forests within the next 50 to 60 years.
