Radiata Pine as an Exotic

C. W. SCOTT
FAO Technical Assistance Officer

This article is a condensation of a chapter from a forthcoming FAO publication on Pinus radiata, commissioned by the Forestry and Forest Products Division. It summarizes the experience in the five countries where this species has been most extensively planted - New Zealand, Chile, Australia, Spain and the Union of South Africa. The full publication will cover the botany, ecology and growth in the native habitat; the tree as an exotic; planting, thinning and pruning techniques; natural regeneration, growth and yield; pathology and protection; harvesting methods; wood technology and utilization; and marketing and trade.

IN four countries south of the equator, New Zealand, Chile, Australia and South Africa, and in one country north of the equator, Spain, Pinus radiata has been widely used as a successful exotic since about 1923, often after much earlier planting on a small scale had shown how hardy the pine was, how fast it grew and what useful general purpose wood it produced, in the right climate on a suitable site. The total area planted with this pine in the five countries named, up to approximately 1956-57, is some 1.55 million acres (0.63 million hectares). Table 1 shows the area large planted :in each country separately for state, large companies and local bodies or private persons, where such separate data are available.

The results in each of these five countries offer valuable guidance on what to do and what not to do with this pine or any similar exotic. The information available from the five major growers is relatively extensive.

A. D. Lindsay (1937), G. B. Rawlings (1957) and climatic studies in New South Wales (Australia) (1957), make it clear that P. radiata thrives in a Mediterranean type of climate, with winter rain and summer drought and with 15 inches (380 millimeters) or more of annual rainfall, supplemented in the summer by fog, mist or other such moisture. The mean maximum temperature of the summer months should not exceed 70° F; (21° C.) midwinter frost is tolerated but frost in the growing season damages or kills the tree, according to its severity; and hail may be a limiting factor by encouraging the entry of the fungus, Diplodia, It should be remembered that, in its native California, the species grows always within some 6 miles (10 kilometers) of the sea and from sea level to only some 1,000 feet (300 meters) above that level. In New Zealand and Australia, it is successfully grown, sometimes, much further from the sea and to 2,000-4,000 feet (600-1,200 meters) above sea level.

Monterey, the home of P. radiata in California, is close to latitude 37°N., and Concepción, Chile, where the same species thrives very strikingly as an exotic, is close to latitude 37° S. The two greatest concentrations of exotic P. radiata at Rotarua, New Zealand and at Mount Burr, South Australia are both in about 38° S. latitude. In other parts of Australia, the very consider able and successful stands of the same pine in the states of Victoria and New South Wales are in latitude 34° to 37° S. but successful stands are found in New Zealand as far as 46° S., and near the north coast of Spain as far as 43° N. Moreover, recent work on natural and artificial interbreeding of P. radiata with its near relatives, P. attenuata and P. muricata, and on the two-needled P. radiata var. binata which occurs on the Mexican island of Guadalupe 500 miles (830 kilometers) south of the mainland range of the tree, in latitude 29° N., suggests that it may be possible in future to extend still further the permissible range of P. radiata as a successful exotic.

TABLE 1. - AREAS OF Pinus radiata PLANTED BY THE FIVE COUNTRIES WITH MAJOR STANDS OF THIS PINE, 1956

Country	State	Large companies	Local bodies and small private owners	Total of P. radiata	P. radiata as a % of all exotic conifers
	in thousand acres (hectares)				percent
New Zealand	202.0 (80.8)	286.0 (114.0)	85.0 (34.0)	572.0 (228.8)	60
Chile	-	-	-	494.0 (200.0)	99
Australia	217.0 (86.8)	-	89.0 (35.6)	306.0 (122.4)	76
Spain	49.0 (20.0)	-	77.0 (31.0)	126.0 (51.0 )	100
South Africa	30.0 (12.0)	-	23.0 (9.2)*	53.0 (21.2)*	8
TOTAL	-	-	-	1,551.0 (623.4)	58

* Approximate figures.

Comprehensive systems of classifying the climates of the whole world, such as that of Köppen or Thornthwaite, appear to be unsuitable as yet as a safe guide to the regions where P. radiata will thrive, other factors being favorable. From Australia comes a warning that within an area mapped as having a single class of Thornthwaite's climates there can be some districts where P. radiata will thrive and others where it will not thrive at all. Foresters are advised to study the climatic and other data of the proposed site and, if the prospects are reasonably favorable, to try out the tree on a small or moderate scale. The seed is cheap and plentiful, and results are soon evident. In particular, experience with the species in New South Wales (Australia) is valuable because the failures as well as the marked successes have been recorded candidly.

P. radiata likes 3 to 4 feet (1 to 1.2 meters) of well-drained soil and in its natural habitat is less exacting as to soil quality than Pseudotsuga menziesii or Pinus ponderosa. In Australia, however it is more exacting than Pinus pinaster (maritima). In soil moisture demands, the native P. radiata needs less moisture than Pseudotsuga menziesii but more than Pinus ponderosa.

On the much debated question of the risks involved in large areas of pure plantations, reference is invited to the balanced discussion of this general problem in the FAO publications, Forest Plantation Protection against Diseases and Insect Pests and Choice of Tree Species (Development Papers Nos. 3 and 13).

Other useful discussions of the problem, in particular that of pure P. radiata, are those of J. J. de Gryse (1955) and G. B. Rawlings (1957). All those who are familiar with the facts are agreed on the urgent need for keeping the pine to climates and sites at least reasonably favorable, and for assuring as much tending, especially suitable thinning, as is economically possible. Prudence suggests also that it is well to spread the risks, from epidemics or unforeseen changes in the type of wood wanted by consumers, by planting suitable quotas of profitable species other than P. radiata. The plans of many states and private foresters to plant great areas mainly or only with P. radiata are proof that the tree is exceptionally easy and cheap to establish and exceptionally productive. They are also a sign that it is not at all easy to find other species comparable with P. radiata in cheapness and profit. Research must continue to seek ways of reducing the risks of tree monoculture, to make it easier to vary the species or races planted, and to maintain healthy forest soils and successive crops in perpetuity.

Those who advocate uneven-aged forests of intimately mixed species must take account of the strong preference of manufacturers for considerable coupes of one species and age to simplify and concentrate extraction work and give as much uniformity as possible to the batches of material arriving at any one time at the pulp mill or sawmill. It may be necessary to compromise between the planting of different species according to the varying sites available and the economic advantages of uniformity to the manufacturer so as to secure the optimum, avoiding both unhealthy or inadequate crops and undue processing costs. For conifers such as P. radiata the best answer may be pure even-aged blocks of each species, of suitable area, with adequate variation of the species or race, by blocks, and a succession of age classes to secure continuity. From New Zealand has come the very interesting suggestion that it might be well to grow an even-aged crop of P. radiata pulpwood on a 20-year rotation below an even-aged crop of saw timber trees on a 40-year rotation as a two storied forest.

Each of the five countries with large areas of exotic P. radiata is dealt with in the order of total area of the pine. Much of the information on the three countries of the British Commonwealth (New Zealand, Australia and South Africa) comes by permission from reports prepared by them for the Seventh Commonwealth Forestry Conference of 1957, held in Australia and New Zealand. The information on all exotics from these countries is being incorporated at Oxford in a forthcoming revised edition of R. S. Troup's Exotic Forest Trees in the British Commonwealth (1932).

New Zealand

The scale and speed of exotic planting have been so great in New Zealand that there have been acknowledged mistakes, but it is interesting to find how much success has been achieved.

An arduous National Forest Survey (1946-1955) of all the indigenous forests of the country has recently been completed, in spite of the demands and problems of almost 1 million acres (400,000 hectares) of exotic conifers. It is estimated that indigenous forests once covered some 70 percent of the country and reached perhaps 45 million acres (18 million hectares), compared with the 15 million acres (6 million hectares) left in 1957 after the usual clearing for agriculture, pasture and lumber. Some of the low ground clearing was necessary; some of the high ground clearing has led to erosion; and the waste in burning high grade stands of virgin timber was great. The forests were of the mixed temperate evergreen type, with Podocarpaceae and Agathis as prominent elements, and of the southern hemisphere beech (Nothofagus) type, with considerable resemblance to the native forests of Chile.

By 1890 it was clear that the Podocarps were dwindling fast as a main source of timber for building and other purposes, and that their slow growth and lack of regeneration did not make for easy forest conservation and management for a sustained timber yield. Also by then it had been proved that exotic conifers from North America, such as Pinus radiata and Pseudotsuga menziesii, specially the former, throve exceptionally well in New Zealand and grew very fast. As a result, systematic planting by the State began about 1890 and continued on a small or moderate scale until 1923, when it suddenly increased very rapidly. Between 1923 and 1936 an exotic stand of some 600,000 acres (240,000 hectares) was planted within about 12 years, at an average rate of 50,000 acres (20,000 hectares) per year, roughly half by the State and half by private interests. P. radiata formed about 40 percent of the state plantation and 85 to 90 percent of the private woods. Together with the planting before 1923 and since 1936, the grand total of exotic conifers in 1957 was some 950,000 acres (380,000 hectares).

The exotic planting boom of 1923-36 led to serious mistakes and financial losses. Private investors suffered, in particular; so much so that an official enquiry was held in 1934 which led to improvement in the constitution of afforestation organizations. It is wrong to attribute those losses to faults in the chief species concerned, P. radiata. The losses were due to mishandling. Subsequent successes have proved what an excellent tree is this pine when well handled, and how productive it is of good lumber and pulp if so handled. The New Zealand Forest Service considers among the major mistakes that were made in planting exotics were unsuitable sites, inferior seed and planting techniques, lack of tending (weeding, thinning), too wide spacing, inadequate fire protection, a bad age-class distribution, and, in some cases, poor location in relation to markets. This is a formidable list on which it is easy to be wise after the results are apparent. The important point is to learn from the record for current planting programs and for the future, and to recognize how much, nevertheless, has been achieved with Pinus radiata.

This Californian exotic, of no economic account in its natural range, has in fact filled a great gap in New Zealand's timber requirements. It has provided the basis for a large lumber and pulp industry, and substantial exports. Up to 1930, 90 percent of New Zealand's timber needs were met from her native forests, which were disappearing under the load. By 1956, nearly half the total annual cut of trees was being met from the exotic plantations, and P. radiata formed 95 percent of the exotics cut. Nearly half the building timber used in the country is now from home-grown exotics and all the pulp and paper produced is from P. radiata. In recent years, some 35 million board feet (82,600 cubic meters) of lumber from the exotics have been exported annually. Finally it should be remembered that, in 1957, little of the exotic stand was as yet over 40 years old. The New Zealand Forest Service feels that there is no reason now to malign the product of the untended and frequently ill-sited forests established 25 to 30 years ago. It is better than anyone had any right to expect, and from the range of exotic conifers established in New Zealand one would have difficulty in naming a timber superior to P. radiata for troth general and special utility.

Climate

The climate of most of New Zealand is of maritime type with an annual rainfall usually between 25 and 80 inches (625 and 2,000 millimeters), except for certain mountainous zones which are much wetter and two drier areas of the South Island (central Otago and the Canterbury plains). The rain tends to be evenly distributed throughout the year, but in the North Island there is a slightly lower fall in summer, a feature which when pronounced appears to be important for the health of P. radiata in other countries. Atmospheric humidity is usually high in the central area of the North Island where much P. radiata has been planted (Rotorua-Kaingaroa), and the climate of that area is described as superhumid. Temperatures are favorable to tree growth for much of the year, especially in the North Island, so that exotic forest trees may have a very long growing season. Unseasonable frosts do occur, however, which cause some damage to exotics and restrict their safe range to some extent. On the whole, the climate of those parts of New Zealand where there is most P. radiata is extremely favorable for rapid growth, though it is not of the Mediterranean type in which the pine thrives in its native home and in the Concepción zone of Chile.

G. B. Rawlings (1957) has warned of the dangers to the tree if summers are too warm and wet. He regards the climate of New Zealand north of latitude 39° S., including the great Kaingaroa and other plantings of P. radiata, amounting to some 400,000 acres (160,000 hectares) or more, as approaching the humid-temperate type, rather than the west-maritime type south of 39° S. Others may not agree with his climate classification, but there is no doubt of the danger to P. radiata if there is too much damp heat in summer.

Soils and land available for planting

The greatest area of P. radiata is on the podzolized pumice soils formed in the center of the North Island from rhyolitic ash showers. They are sandy but hold moisture fairly well. Such soils occupied much of the Kaingaroa plains and were easy to plant. They were largely devoid of big trees and carried only tussock grass (Poa caespitosa) or bracken (Pteridium esculentum), a thin growth of manuka (Leptospermum scoparium) or low growth of monoao (Dracophyllum subulatum). Some 600,000 acres (240,000 hectares) of exotic conifers have been planted in this area, of which about two thirds are P. radiata. At the time of the great tree planting boom, in 1923- 1936, these pumice soils were believed to be unfit for agriculture or grazing; but since then it has been discovered that if their lack of a trace element, cobalt, is corrected, most of them are excellent for farming.

In the extreme north of North Island the soils are less favorable, including heavy podzolized soils of low fertility, in some cases developed under burnt kauri (Agathis) forest. In the South Island the soils east of the main mountain chain include loess mixed with shingle and clay on the low ground and unstable mountain soils on the higher ground. The latter pose urgent problems of conservation and the prevention of erosion in which exotic trees may help.

Area planted and future planting

New Zealand has the largest total area of P. radiata in the world. 572,000 acres (231,000 hectares). This P. radiata is approximately two thirds of the total stand of exotic conifers of all kinds. The privately, owned plantations consist of P. radiata to the extent of 85 percent or more, but in the state plantations the proportion is only some 40 percent, giving a better spread of risk and a better insurance against epidemic. Of the state plantations of P. radiata some 65 percent are in the 1921-1930 age class. A very large proportion of the company-owned P. radiata was planted in 192336. The present state planting program is for some 3,000 to 4,000 acres (1,200 to 1,600 hectares) per year of P. radiata but plans are being drawn up for a much larger program in which radiata will be included at least in proportion to its share of percent planting (40 to 50 percent).

Sites used

The pine has been found to tolerate a wide range of soils from sands to clays, including coastal sand dunes. It seems to grow best on deep, freely drained, sandy loams of moderate fertility, capable of supporting moderate to vigorous bracken fern (Pteridium). It does not thrive on wet sites or low fertility podzolized clays, where it is prone to die-back, poor crowns and needle fusion. It is drought resistant but young trees are sensitive to frost. On shallow soils, especially with a layer of pan or consolidation, it is subject to wind throw.

Recent work suggests that the order of nutrient requirements in soils for exotic pines in New Zealand is as follows:

Least exacting	- P. pinaster (maritima)
Rather more exacting	- P. elliottii and P. taeda
More exacting	- P. radiata and P. patula

Results and potentialities

The broad results from P. radiata in New Zealand indicate that, in spite of mistakes and in some cases mishandling, this exotic has succeeded recently in meeting about half the total annual cut of home grown timber, or in other words reducing by half the consumption for lumber of the disappearing native trees, such as Podocarps. It has also provided the sole raw material for an already large pulp and paper production for home needs and export, with good prospects, and an appreciable quota of sawn lumber for export. The successes achieved are the more remarkable because the P. radiata crops concerned are only 40 years old or less. The annual yield of P. radiata is put at 53 million cubic feet (1.6 million cubic meters) of saw-logs, 0.34 million cubic feet (9,629 cubic meters) of peeler logs for veneers, and 25 million cubic feet (708,000 cubic meters) of pulpwood; and the annual sawmill output of radiata lumber at 290 million board feet (684,400 cubic meters).

The yield on an average site in New Zealand is estimated at 5,240 cubic feet (148 cubic meters) at 20 years, 9,860 cubic feet (279 cubic meters) at 30 years, and 12,260 cubic feet (347 cubic meters) at 40 years, in all cases measured inside the bark to a minimum 6 inches (15 centimeters) top diameter.

The potentialities of P. radiata in New Zealand are very great, especially as chief substitute for the stands of native trees which are vanishing under heavy consumption. The native species apparently cannot supply the lumber needed for the home demand on a sustained basis at an economic cost, however useful and important they may well be as protection forests against erosion and for water conservation. Further, this chief exotic pine P. radiata is a first class producer of pulp and paper for home use and export; and with proper handling it is a potential source of excellent cheap export lumber, when thinning, pruning, and certainly the use of stock of superior parentage, with lighter branches and fewer large knots, have raised the average grade of the lumber produced. At present there is too much rough lumber of the box-making grades and not enough fit for export as house building lumber.

The whole future of P. radiata and all other exotics depends on so handling them that they remain healthy and free from disastrous epidemics or soil deterioration. The progress in this respect in agriculture encourages the hope of similar success in forestry.

Chile

The history of exotics in Chile, specially that of P. radiata (in that country always called pino insigne), has much in common with the history of exotics in New Zealand. One difference is that the half million acres (200,000 hectares) of pino insigne in Chile were, in 1958, roughly 15 to 20 years younger, on the average, than the 600,000 acres (240,000 hectares) of the same species in New Zealand. Another difference is that the Concepción zone of Chile, where most of the P. radiata has been planted, has a truly Mediterranean type of climate, with a dry summer. The Chilean stands are, therefore, specially healthy and vigorous, even more so than in New Zealand. However, Chile has great need of vigilance against epidemics because P. radiata forms practically 100 percent of her main stands of exotic conifers, and 92 percent of all her plantations in the main pino insigne zone.

The native forests of Chile are dominated by the southern beeches (Nothofagus) and Laurelia serrata (tepa), with some indigenous conifers related to those of New Zealand, such as Araucaria and sundry Podocarps. These forests are disappearing rapidly, especially in the more accessible areas, under fire and axe, not only from land suited to permanent agriculture and grazing but also, unfortunately, from much land which would be best used for permanent forest. In this situation, as in New Zealand, the exotics, specially pino insigne, have come to the rescue, with great effect in the supply of urgently needed cheap lumber and pulpwood for home needs and for export. The exotics, however, are not planted in the higher mountains where conservation of the native forests to avoid erosion and floods is urgent.

Pino insigne was introduced to Chile in 1885 by Sr. Arturo Junge. Large-scale planting began in a number of places about 1935, averaging perhaps 20,000 to 25,000 acres (8,000 to 10,000 hectares) per year, and increased to a peak of 40,000 acres (16,000 hectares) a year in 1947-49. The figures are only approximate because much of the planting has been by small private landowners and others for whom accurate details are not recorded. Over 80 percent of all the P. radiata in Chile is concentrated in the central part, in 7 of her 26 provinces, called the Concepción zone. Fortunately, it has the best climate, perhaps close to the optimum available in the world, for this pine. Of the pine, 85 percent is privately owned, and only 15 percent is owned by the State or semi-state agencies. About 70 percent of the pine was under 15 years old in 1968, compared with New Zealand's 65 percent of 30 years old or less in the same year.

The State has encouraged tree planting by exempting plantations from taxation for their first 30 years, by distributing plants, and by other measures. However, the prime motives in the pine planting have been the enterprise of private persons and companies, aiming at profitable supplies of trees for pulp and lumber. It is to be hoped that these legitimate aims will not be frustrated by lack of capital and skill for building and operating the necessary pulp, paper and saw mills, or by lack of the essential road, rail and harbor facilites, and marketing organization, to handle the fast mounting production of the plantations.

The magnitude of the production already achieved shows how much native forest the exotic pine is already saving, although most of that pine is only 15 years old or less. The current production of pino insigne lumber is estimated at about 50 to 60 million board feet (120,000 to 140,000 cubic meters), of which some 10 to 30 percent has been or is being exported, depending on the foreign demand. Two pulp or paper mills, using at least a proportion of pino insigne, have been in operation for some years, two new ones have been built, and four more are projected. By 1960-61 there may be an export of 100,000 tons of pulp, wholly from pino insigne.

Finally, it is to be noted that much of the pine is on poor land, unsuitable for permanent agriculture and subject to erosion if not protected by forest or other cover. Possibly modern methods may make some of this type of land suitable for carefully controlled pasture; but in the 3.75 million acres (1.5 million hectares) in the Concepción zone which are estimated to be unsuitable for agriculture and suitable for pine there appears to be ample room for both pasture developments and pine planting, to the full extent justified by home and export markets.

Climate

As already said, the important zone for pino insigne is that of the seven provinces around Concepción, from 35°15' S. to 38°30' S. where over 80 percent of the pine grows. This zone has a typical Mediterranean climate, like that of the home of P. radiata in California, with relatively dry summers and rain mainly in the winter. It is highly favorable for the health and rapid growth of the pine. The annual rainfall in the plantation areas ranges from about 40 to 52 inches (1,000 to 1,300 millimeters) in much of the zone, with some parts receiving only 28 inches (700 millimeters) and others possibly up to 64 inches (1,600 millimeters) where rather higher ground has been planted. Neither winds nor frost are troublesome, and there is no serious snow or hail damage.

G. B. Rawlings (1957), on his visit to Chile, noted signs of less favorable growth in the minor pine areas planted north of the Concepción zone, in drier conditions, and found clear signs of trouble from leaf cast and wind and snow damage in plantations south of the Concepción zone, where there is more summer rain, a much heavier annual rainfall, up to 120 inches (3,000 millimeters), and more wind and snow.

Soil and land available for planting

The point made by A. D. Lindsay (1937) and others that P. radiata thrives best, in its own home and elsewhere, with 3 to 4 feet (1 to 1.2 meters) depth of well-drained soil is confirmed by the behavior of the tree in Chile. In such classic P. radiata centers as Lota, near Concepción, the height at a given age and rate of growth are clearly proportional to the depth of soil available. Where the soil is shallow and lies over quartz-bearing rocks, the annual growth in height may be only 20 inches (50 centimeters) or less, compared with much faster growth on deeper and less acid soils.

An experienced forester at Lota estimates that in the provinces of Concepción and Arauco roughly 50 percent of the planted soils are less than 20 inches (50 centimeters) deep, 40 percent are between 20 and 40 inches (50 and 100 centimeters) deep, and only 10 percent are over 40 inches (1 meter) deep. It is clear, too, from personal visits to extensive plantations in the Laja and Itata drainages, east of Concepción, that where the soil is very shallow and rock or a hard pan approaches the surface the growth of the pine is poor or even stunted. A surprisingly high percentage of low quality class plantations appears in the 1953-54 sampling enumerations of all the P. radiata plantations in the Concepción zone. It is likely that one factor in this result is the siting of too many plantations on poorer and shallower soils, where growth and production are far below the high levels reached on better soils.

As already mentioned, there are estimated to be 3.75 million acres (1.5 million hectares), of land in the Concepción zone which are unsuitable for agriculture and available for tree planting or pasture development. There is, therefore, ample room for expansion, without using very inferior sites associated with very shallow or otherwise unfavorable soils.

The estimated average yield in Chile is little below the average in New Zealand.

TABLE 2 - EXOTIC CONIFER PLANTATIONS IN AUSTRALIA TO JUNE 1957, WITH SPECIAL REFERENCE TO Pinus radiata (Hall - 1951)

State	Pinus radiata		Total	% Pinus radiata of all exotic conifers	Future planting of all conifers
	State	Private			Total target	Annual quota
	in 1,000s of acres (hectares)			Percent	in 1,000s of acres (hectares)
South Australia	97 (39)	38 (15)	135 (55)	95	200 (80)	3 to 4 (1.2 to 1.6)
Victoria	33 (13)	46 (19)	79 (32 )	88	200 (80)	1 (0.4)
New South Wales	63 (21)	1 (0.4)	54 (22)	70	200 (80)	6 (2.0)
Australian Capital Territory	17 (7)	-	17 (7)	89	40 (16)	1 (0.4)
Tasmania	11 (4)	4 (2)	15 (6 )	100	50 (20)	1.2 (0.5)
Western Australia	5 (2)	-	5 (2)	22	100 (40)	2 (0.8)
Queensland	1 (0.4)	-	1 (0.4)	3	200 (80)	6 (2.0)
TOTALS	217 (88)	89 (36)	306 (122)	76	990 (400)	18.2 to 19.2 (7.3 to 7.7)

All figures are approximate, rounded and adjusted to agree as nearly as possible with exact totals.

Sites used

The main effort has been on the coastal Cordillera and the plain between that range and the Andes, in the Concepción zone, as already described. A wide variety of sites has been used, from highly favorable ones with deep soil, especially on low hills near the coast, to generally poorer sites further inland, on more level ground. In these latter sites, in some cases but by no means all, the soil may be too shallow or otherwise unfavorable for high quality growth; but even on these poorer sites, excluding the worst, the production is still high and attractive, especially for pulpwood if within economic reach of a mill.

Results and potentialities

Much that has been said already in connection with New Zealand applies to Chile. The main stands of the exotic pino insigne are still very young, mostly 16 years old or less. Already they are helping to ease the burden on the overworked native forests by meeting a substantial share of the home lumber consumption and providing some lumber for export. The exotic stands are helping also to reduce erosion and conserve water in the coastal Cordillera and the plains. They are not planted in the Andes.

The main pulp and paper era in Chile is just beginning, is dependent wholly on pino insigne and has excellent prospects. The volume potential of Chile's half million acres (200,000 hectares), of P. radiata is formidably large. If it is to be used to advantage to all concerned, including the large numbers of small private forest owners, there is urgent need to press on with the building of pulp, paper and saw mills, roads, harbors, and all the other facilities needed to manufacture good produce and sell it wherever markets can be found and held by satisfying the consumers.

The pino insigne stands in the main planting zone of the country are at present extremely healthy and free of pests. It is vital to take all proper economic precautions to keep them so. Their potentialities depend on a healthy soil and freedom from disease.

Australia

Australia includes six states and the Australian Capital Territory. Each of these seven units has a separate forest department and all seven are planting exotic conifers, including P. radiata. In the space available it is not easy to give even in outline an adequate account of this.

G. J. Rodger and N. Hall (1951) have shown that Australia's native conifers are only some 5 percent by volume of her total indigenous timber resources; that conifer or softwood lumber formed half the annual consumption, prior to 1939, involving heavy imports. A large planting program of native and exotic conifers was therefore adopted. In the 30 years, 1919-49, it was carried out on a substantial scale, so that by 1949, the total of planted conifers was about 300,000 acres (120,000 hectares), 87 percent state- and 13 percent privately-owned. This total included much planted native hoop pine, Araucaria cunninghamii, as well as exotic pines; but by 1951 the output of the exotics exceeded that of the native species, and the chief exotic was P. radiata, especially in the Capital Territory and all the states except West Australia and Queensland. In the two last-named, the poor soil available or the humid summers dictated mainly other pines, such as P. pinaster (maritima) and P. elliottii.

Further; in 1949, a new program was adopted to plant in all one million acres (400,000 hectares), of conifers, a total likely to be reached in some 35 years, at the annual rates for the various states, allowing for the 300,000 acres (120,000 hectares), already planted. Table 2 shows the total and annual conifer planting targets named in 1949, the total area of P. radiata in the Australian Capital Territory and in each State at June 1957, and the percentage of radiata in each case in relation to all exotic conifers.

Climate

The parts of Australia with enough rain to support native forest or exotic trees are relatively limited and therefore important. In the extreme southeast of South Australia and in the extreme southwest of Western Australia there are zones with a Mediterranean climate, adequate winter rainfall and dry summers, which suit P. radiata well. The largest area of this pine is in the Mediterranean zone of South Australia, where good advantage has been taken of the favorable climate and suitable soil. In West Australia, the areas of soil fit for P. radiata are much more limited, but such as are available are being planted.

Victoria, New South Wales, the Australian Capital Territory and Tasmania offer climatic zones in which P. radiata thrives. It has been tried in New South Wales on a considerable scale in four very different climatic zones. It thrives only in the one zone of the four which has good rainfall mainly occurring in winter, and summer drought. All P. radiata planting is now confined to that zone, to such areas as Tumut-Batlow, about 60 miles (100 kilometers) WSW of Canberra, and Jenolan-Oberon, about 80 miles (135 kilometers) west of Sydney. Plantings of P. radiata in the summer rainfall zone at Armidale, in the coastal uniform rainfall belt at Tuncurry, and in the hot dry inland zone at Forbes have not been successful enough to be continued.

It has to be remembered that in South Australia and Western Australia and parts of Tasmania most of the planting is at low altitudes, e.g., below 1,000 feet (300 meters) above sea level. In the other states, it goes up to 3,000 feet (1,000 meters) or more. Victoria records that her P. radiata shows maximum growth with an annual rainfall of 35 inches (875 millimeters) or more, satisfactory growth at 26 to 35 inches (650 to 875 millimeters) and slow growth if the rainfall is under 26 inches (650 millimeters) a year.

Queensland has little available land with a suitable climate for P. radiata but is interesting because of its very active and successful planting of native hoop pine (Araucaria cunninghamii), and slash pine (P. elliottii) from the southeast of the United States of America, in its summer rainfall zone. It has one center in the extreme southeast of the State (Passchendaele, near Stanthorpe) where P. radiata appears able to grow reasonably well and avoid fungal attack. The rainfall there, 34 inches (850 millimeters) a year, is semiuniform but rather less in summer than winter, and the height is 3,000 feet (1,000 meters) above sea level. The latitude is 28°30' S.

Soils and land available

In the two states, South Australia and Western Australia, with considerable areas which have a Mediterranean climate much of the sandy soil, near the coast is considered almost marginal for the growth of P. radiata. In Western Australia similar land is considered to be too poor for that species, especially if the P₂O₅ content in the surface and subsurface soil is below 250 parts per million.

The Forest Service of Western Australia (1957) emphasizes that the P₂O₅ content is to be regarded only as an index, not necessarily a direct factor; and that cultivation of the soil may make it fit to grow P. radiata without any increase of the P₂O₅ as shown by analysis. Also in South Australia it has been shown that applications of commercial superphosphate may make otherwise unsuitable land fit for P. radiata. In both Western Australia and South Australia a lack of zinc in the soil is corrected by spraying the foliage of the young pines with a 2.5 percent aqueous solution of Zn SO₄, with excellent results. However, it is well to remember the salutary warning of the late N. W. Jolly (1950) that the pine soils of South Australia are not fertile but frequently almost marginal. Special care is needed, therefore, with fast growing pines on a relatively short rotation, that the rotation is not made too short for the sustained fertility of the soil. If it is economically possible to apply superphosphates as in agriculture, clearly this would affect the choice of a suitable rotation for maximum profit and sustained yield.

The demand for softwood lumber is so keen in South Australia and the success of P. radiata there has been so marked that recently somewhat better land has been provided, where forestry offers at least as good a return as agriculture. In Western Australia, the coastal sands have proved much more suitable for P. pinaster (maritima) than for P. radiata, and the latter is now planted and thrives mainly on the red-brown sandy loams derived from basic igneous rocks (dolerite) on the Darling Range and plateau, up to 900 feet (300 meters), above sea level. P. radiata does not thrive on the laterite or on the lighter colored soils derived from more acid rocks, both of which occur also in the Darling country.

Experience with P. radiata in the other states and the Australian Capital Territory shows that depth of suitable soil is an important factor, that basaltic soils give superior growth, and in New South Wales that the soils derived from sandstones are to be avoided, if possible. Victoria finds that sandy loams are satisfactory provided that a pervious clay layer occurs at 3 to 6 feet (1 to 1.5 meters) below the surface, but that very deep porous soils, such as sand of 10 feet (3 meters) or more in depth, are quite unsuitable in the climate concerned. The relatively large planting targets for P. radiata in the Australian Capital Territory and all the states other than Western Australia and Queensland, where soil or climate severely restricts its use, show that these territories all have adequate land for planting and great faith in the species.

Areas planted and future planting

Australia has planted some 305,000 acres (122,000 hectares) of P. radiata, to 1957, and the species forms about 76 percent of all its exotic conifers. Future planting of exotic and native conifers is planned to bring the present total of some 400,000 acres (160,000 hectares) (all species) to one million acres (400,000 hectares) in about 30 years time, at some 20,000 acres (8,000 hectares) a year. As already explained, P. radiata is to be the chief exotic conifer in all states except the two where soil or climate limit its use. This emphasis on P. radiata is striking evidence of its unique attractions in Australia for cheap production of much-needed lumber and pulp, and a challenge to the skill of the foresters responsible for the hygiene of the plantations and their soil.

Sites used

In South Australia, the limiting factors are stated to be exposure and summer soil moisture. Bracken (Pteridium) is a useful indicator of soil drainage and aeration but for P. radiata the bracken may indicate a favorable site on heavy clay land but not on deep sand, where the soil may be too poor for the pine. In the main planting area, in the extreme southeast of the State, much of the P. radiata is within a few hundred feet of sea level. In Western Australia, only sites with the soil character and minimum content of P₂O₅, already described, are favored, at heights up to 900 feet (300 meters) above sea level. In Victoria, as elsewhere, wet sites and too dry sites are found unsuitable, and planting is from sea level to 3,300 feet (1,000 meters). In New South Wales, the suitable height limits in the climate concerned are from 1,800 to 4,300 feet (600-1,400 meters) above sea level, with snow causing damage at the higher levels. Sites with soils derived from sandstone are avoided. At Canberra, the planting is from 1,500 to 3,500 feet (500-1,100 meters) above sea level, and the best growth is on deep red loams with 25 inches (625 millimeters) or more of annual rainfall. In Tasmania, sites are from sea level to 2,500 feet (800 meters) above it, with the best results where rainfall is about 50 inches (1,250 millimeters) a year if there is no snow damage. Queensland confines P. radiata to one planting center and to soils of 2 or more feet deep.

Results and potentialities

Australia stands at present only third in the magnitude of area planted with P. radiata but has attained a notable standard of tending and management. South Australia has 135,000 acres (54,000 hectares) of this pine, of which over 80 percent of the stands fit for thinning are under regular thinning schedules, at least in the 70 percent or more of state-owned plantations. Also in some 80 years of planting in South Australia at first on a small or moderate scale, the tree has remained free from serious pests; and difficulties due to poor soils have been overcome by research in this State and in Western Australia.

It has been shown by B. H. Bednall (1957) that, in the 15 years from 1938 to 1953, home-grown lumber production, mainly of P. radiata, has risen in South Australia from 14 to 62 million board feet (33,000 to 146,300 cubic meters) a year, with a corresponding rise of 19 to 48 in the percentage of total lumber consumption supplied from home-grown trees, excluding railway sleepers (ties). Not only box and case lumber has been made from P. radiata but also excellent flooring for houses, and many other types of lumber. These supplies have proved invaluable when imported supplies were cut off. Similar satisfactory results are believed to have been secured in the other territories of Australia, in relation to the extent and age of their plantations; and wherever the species has been used for pulp and paper it has proved most satisfactory, as in New Zealand.

The potentialities are clear from the target total of 1 million acres (400,000 hectares) of planted conifers, with P. radiata as the chief species, and the high yields normal when the stands are healthy and well handled. As in New Zealand and Chile, the great volume of production in sight depends on keeping the trees and soil healthy, a task in which Australian research is as outstanding as it is in the parallel task of the efficient manufacture and use of the trees for lumber, pulp and paper treated poles, posts and sleepers (ties) plywood, fibre-board and particle board.

Spain

Spain is sparsely wooded, having less than 10 percent of her total area under well-stocked forest. In spite of the dry climate of much of the country, an active policy of afforestation has produced between 1940 and 1956 nearly 2.5 million acres (1 million hectares) of new forest. A summary of the situation, especially the afforestation results and plans, is available in Unasylva, Volume 12, Number 1, in an article titled "The Spanish Afforestation Program " (1958). The target is 12.5 million acres (5 million hectares), without encroaching on the present agricultural land area but using much mountainous grazing land. At present, there is extensive grazing in the forests and on the potential forest land of the country, so much so that the income from this grazing is over half the income from timber on the same land. However, it is hoped to improve the grazing on one third of the land concerned to such an extent that it will carry as much livestock as the whole area has been carrying, even if the other two thirds are used for forest.

Of the 2.5 million acres (1 million hectares) planted in 1940-56 about 95 percent has been done by the State on public land, and 5 percent by private owners. It is estimated that up to 22 percent of the whole 2.5 million acres (1 million hectares) has been planted with faster growing trees, native or exotic, such as a special race of P. pinaster (maritima) from Galicia in northwest Spain, Eucalyptus spp., and Pinus radiata. The other and slower species used have been mainly native pines such as P. pinea, P. halepensis, P. nigra, P. sylvestris, P. uncinata and P. canariensis, and poplar, the last restricted by its need for favorable soils and moisture.

The two outstanding exotics used in Spain are Eucalyptus spp. and Pinus radiata. Of the former the area planted is some 420,000 acres (170,000 hectares), which is more than half the total area of Eucalyptus in the Mediterranean region of Europe. Of the latter, P. radiata, 126,000 acres (51,000 hectares) has been planted, 39 percent by the State and 61 percent by private owners, all in north and northwest Spain, within some 100 miles (160 kilometers) of the Bay of Biscay or Atlantic. The main use of P. radiata is for paper-pulp and pit-props (in mines), on a short rotation of some 16 to 30 years, depending on the fertility of the site. Its production per acre per year is about six times that of the common native conifers and makes it a very attractive investment. There is, or was, a famous specimen tree in a park at Lequeitio, some 25 miles west of San Sebastian, which was 68 years old in 1928 and measured then 3 feet 9 inches ( 1.14 meters) in diameter, showing how the species thrives in sheltered sites on the north coast of Spain.

Climate

P. radiata thrives in the climate typical of the northern coastal zone of Spain. The drier and hotter climate typical of all other parts of Spain is favorable for Eucalyptus but not for P. radiata.

Soils and land available

P. radiata thrives in north and northwest Spain on deep, well-drained soils of high moisture retention, including siliceous clays and acid soils. The depth, the slope and the physical structure of the soil are considered to be prime factors in the moisture retention which is essential for the good growth of the pine in this zone. Large areas are reported to be available for P. radiata along the north coast, sufficient to grow pulpwood for all the country's present and future needs of chemical and mechanical pulp.

Areas planted and future planting

The total area planted with P. radiata is given in 1958 as 126,000 acres (51,000 hectares), all in the provinces of La Coruna, Lugo, Orense, Pontevedra, Santander, Guipuzcoa, Vizcaya and Alava, that is to say, between the frontier with France at the west end of the Pyrenees and the frontier with Portugal, south of Vigo: 61 percent of these plantations are privately owned and 39 percent are state owned or managed. The exact age distribution is not known, but it is understood that there are few large stands over 20 years old. The rotation in most cases is 20 years or less. Future planting depends much on the private landowners concerned and may average, perhaps, 3,750 to 5,000 acres (1,500 to 2,000 hectares) a year.

Sites used

The species does best in valleys, hollows and wherever sheltered from wind, with enough moisture and depth of soil. It grows poorly on exposed ridges with shallow soil and is there much more prone to fungal and insect attack. The yield tables show clearly the great effect of site quality on the growth, an effect which almost doubles the rotation necessary, even for pulpwood, from 16 to 30 years. It is found inadvisable to plant at more than 1,600 feet (500 meters) above sea level, owing to the usually poorer soil and risk of wind and snow damage.

Results and potentialities

As in the three other countries already considered, the results from P. radiata in Spain are highly satisfactory and encouraging wherever the climate and sites are favorable and the plantations have been well tended. Spanish foresters consider maintenance of an adequate density of the crop is most important, with light or moderate thinnings every three years, to avoid overcrowding, and well-controlled low pruning of the type known in the United Kingdom as brashing.

The average quality class is III, with a mean annual increment of some 172 cubic feet (true) per acre (12 cubic meters per hectare). This contrasts with average figures of about 14 to 29 cubic feet (true) per acre (2 cubic meters per hectare) per year from the common native conifers in much of Spain. Echeverria (1942, 1943, 1956) of the Instituto Forestal de Investigaciones y Experiencias, Madrid, gives full details on the yield of P. radiata in northern Spain from a large series of sample plots observed over 13 or more years in four provinces. These bulletins cover also initial spacing and thinning to different intensities, and the characteristics of the wood for pulp and paper. Martinez (1942) gives the chief fungi to which the tree is susceptible on unfavorable sites.

Most of the stands are worked on a rotation of about 20 years, with 90 percent of their produce going to the paper mills and the other 10 percent to boxes. The produce of the few stands worked on a longer rotation than 20 years is estimated as going 55 percent to pulp and paper, 25 percent to pit-props for the mines, 10 percent for shuttering for concrete, and 10 percent for other sawn lumber.

The potentialities of P. radiata in north coastal Spain are very good, provided the trees and soil are kept healthy. As already mentioned there is said to be an area suitable for planting which could supply all of Spain's present and future needs for pulpwood.

South Africa

The Union of South Africa occupies 472,000 square miles (1,222,480 square kilometers) and has less than 1 percent under indigenous forest, excluding savannas. It is not surprising, therefore, that exotic trees have been planted on a very great scale, approaching 2 million acres (800,000 hectares), about one quarter by the State and three quarters by private enterprise. This total includes roughly 750,000 acres (300,000 hectares) of Australian tan wattles (Acacia mollissima and decurrens), grown primarily for the tannin in their bark, 700,000 acres (280,000 hectares) of conifers, mainly pines other than P. radiata, and 440,000 acres (176,000 hectares) of Eucalyptus. The last of the above figures relates to 1953 and the other figures to 1955-67.

R. J. Poynton (1957) gives full information on the present position of these exotics, including P. radiata. He mentions that the average annual increment in a typical indigenous high forest is only 35 cubic feet per acre (2.5 cubic meters per hectare) against mean annual increments of 250 to 400 cubic feet (18 to 29 cubic meters per hectare) (true) per acre in plantations of the chief exotic pine (P. patula) and the limited but appreciable areas of P. radiata, He also quotes impressive figures for 1953-54 of the total money yield from the indigenous and exotic forests, respectively. These were SA£43,000 ($120,400) from the former, and SA£4,700,000 ($13,160,000) from the exotic plantations, exclusive of SA£6 to SA£7 million ($16.8 to $19.6 million) for the bark from the Acacias, for tannin, additional to the timber, fuel and pulp revenue.

Poynton has this to say of P. radiata in South Africa: " The potentialities of this species are severely limited by its susceptibility to damage by hail and subsequent infection by Diplodia pinea and by its intolerance of infertile and poorly-drained soils. As a result, future plantings will be confined to selected sites in the western and south-eastern Cape Province. It is, however, quite the most desirable species on suitable sites in these areas, both from the point of view of rapid growth and of timber quality, and will therefore be used wherever conditions permit. Even on marginal sites it is often planted in preference to other species on the principle that the yield from a somewhat indifferent stand of P. radiata is likely to be better than that which could be obtained from a more thrifty stand of another species ".

P. radiata was introduced to South Africa about 1883 or earlier, at roughly the time of its introduction to Chile. The less favorable climate of South Africa, from the point of view of this particular pine, has been the chief cause of its limited use there and its replacement by the Mexican P. patula and other pines as the major species in the South African conifer plantations.

A special feature of the history of exotic conifers in South Africa has been the very outstanding work on the silviculture and utilization of these exotics, including P. radiata, by the Department of Forestry. Classic research was done and successful original techniques were developed in spacing thinning and pruning by I. J. Graib (1939, 1947), and others, and in wood technology and utilization by J. M. Turnbull (1937, 1947), M. H. Scott and R. P. Stephens (1947, 1953) and others.

Climate

The climate of South Africa has been well studied and analyzed from the point of view of exotic forest trees by South African foresters. Their system was first published by R. S. Troup (1932). A system of 15 zones is based on the amount and distribution of the rainfall, and the average temperature.

Métro (1955) summarizes and illustrates Troup's system, and shows that the eucalypts are confined in South Africa mainly to 8 of the 15 climatic zones. Pinus radiata is planted successfully in only 5 of the 15 zones, namely where the annual rainfall is over 25 inches (100 millimeters) and is either mainly winter rain or more uniformly distributed throughout the year, and the mean annual temperature is 55° to 64° F. (13° to 18° C.) to a much smaller extent where the annual rainfall is from 18 to 25 inches (450 to 625 millimeters), is mainly winter rain or uniformly distributed, and the average temperature is as before; and to a small extent precariously where the annual rainfall is 33 to 75 inches (825 to 1,875 millimeters), is mainly in summer, and the average annual temperature is 55° to 62°F. (13° to 17° C.).

The key to much of the climatic restriction of P. radiata in South Africa appears to be the bad effects of a warm humid summer, with hail damage allowing a fungus, Diplodia pinea, to thrive in the damp heat and enter the damaged pines, with severe or fatal injury to the trees. But, even in the absence of hail, an excess of damp summer heat has a very adverse effect on this pine, in South Africa as in all other parts of the world. In other words, the less the departure is from a Mediterranean climate, with a dry summer, the better, especially if hail or much warmth accompanies the summer rain. Poynton (1957) mentions that P. radiata is found hardy to frost, moderately resistant to snow, and able to withstand drought to about the same extent as P. pinaster (maritime). The zones where P. radiata thrives or grows tolerably well are on the mountains within 100 miles (167 kilometers) of the sea, roughly only in the extreme south and west of South Africa.

Soils and land available

The pine is regarded in South Africa as rather exacting as to soil, needing a moderately fertile, deep and well-drained soil for its best development, and doing poorly on acid, peaty or badly drained sites. On poor sandy soils, with little humus, such as on the upper slopes of mountains, P. pinaster grows better than P. radiata. In the uniform rainfall zone P. radiata specially needs good drainage; for there, on stiff clay soils or where there is a layer of impervious clay near the surface, the species is severely attacked by Diplodia pinea, and is stunted or not vigorous

Areas planted and future planting

The total area of P. radiata in the State plantations at March 1955 was 30,000 acres (12,000 hectares), of which much had been planted in 1920-25 and 1940-55, after a setback in 1926-1939, due to planting in unsuitable climatic zones and attacks by Diplodia pinea. As it became known how such failures could be avoided, the rate of planting rose again. Future planting is likely to be on a moderate scale wherever it is possible in the limited zones and sites well suited to the species.

Sites used

Cool moist sites are favored, and southerly and easterly aspects, observing that in the southern hemisphere southerly sites are cooler and moister than northerly sites. Sites exposed to sea breezes are tolerated well by P. radiata.

Results and potentialities

It is clear that in the limited parts of South Africa where suitable climatic and soil conditions for P. radiata occur the pine is an outstanding success. In such conditions, it is considered the most desirable softwood, both for quantity and quality. The fact that South Africa has a much lower percentage of P. radiata (8 percent) in her large total of exotic conifers than have New Zealand (60 percent), Chile and Spain (99 to 100 percent) and Australia (76 percent) in their totals, is due partly to restrictions imposed on South Africa by climate and soil, and partly to a wise policy of deliberate variation of the species planted, in order to spread the risks from epidemics. The good results obtained owe much to good tending and utilization, the fruits of far-seeing research, carried through and applied on a large scale. In South Africa, the need to study markets and the consumers' wants have been kept well in mind by the silviculturists and others responsible for growing the trees. At the same time, the health of the trees and soils has been studied to good effect. The potentialities of the species in South Africa may be rated as excellent within the limited areas suitable and available for it.

References

BEDNALL, B. H. Exotic Forest Trees in South Australia. S.A. For. Dept. Bull 8. Adelaide. 1957. 48 pp.

BOYCE, J. S. Forest Plantation Protection against Diseases and Insect Pests. See Food and Agriculture Organization of the United Nations, 1958b.

CHAMPION, Sir. H., and BRASNETT, N. V. Choice of Tree Species. See Food and Agriculture Organization of the United Nations, 1958b.

CRAIB, I. J. Thinning, Pruning and Management Studies on South African Exotic Conifers. S.A. Dept. Agr. and For. Sci. Bull 196. Pretoria. 1939. 179 pp.

CRAIB, I. J. Silviculture of Exotic Conifers in South Africa. Paper, Brit. Comm. For. Conf., (Pietermaritzburg) 1947. 36 pp.

DE GRYSE, J. J. Forest Pathology in New Zealand. N.Z. For. Serv. Bull 11. Wellington. 1955. 62 pp.

ECHEVERRIA, I. Ensayo de tablas de producción del P. insignis en el norte de España. Inst. For. Inv. y Exp. Año XIII: 22. Madrid. 1942.

ECHEVERRIA, I. Tratamiento del P. insignis. Inst. For. Inv. y Exp. Año XIV: 26. Madrid. 1943. 153 pp.

ECHEVERRIA, I. P. insignis en el norte de España y aplicación a la elaboración de pastas de celulosa. Inst. For. Inv. y Exp. Año XXVII: 75. Madrid. 1956. 54 pp.

FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS. Forest Plantation Protection against Diseases and Insect Pests. by J. S. Boyce. For. and For. Prod. Devl. Paper No. 3. Rome. 1954. 41 pp.

FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS. Eucalypts for Planting, by A. Métro. For. and For. Prod. Study No. 11. Rome 1955. 403 pp.

FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS. The Spanish Afforestation Program. Unasylva 12:1 :3-8. 1958.

FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS. Choice of Tree Species, by Sir Harry Champion and N. V. Brasnett. For. and For. Prod. Devl. Paper No. 13. Rome, 1958. 307 pp.

HAIG, I. T., et al. Forest Resources of Chile. USDA and CORFO. Santiago. 1946. 256 pp.

HALL, N. Establishment of Coniferous Plantations in Australia. Australian Jnl. Sci. 13:7. 1951.

JOLLY, N. W. Thinning of P. radiata Plantations. S. Australian For. Dept. Bull 4. Adelaide. 1950. 27 pp.

LINDSAY, A. D. Monterey Pine in its Native Habitat. Comm. For. Burl Bull 10. Canberra. 1937. 57 pp.

MARTINEZ, B. J. Las micosis del P. insignis en Guipuzcoa. Inst. For. Inv. y Exp. Año XII: 23. Madrid. 1942. 72 pp.

MÉTRO, A. Eucalypts for Planting. See Food and Agriculture Organization of the United Nations, 1955.

NEW SOUTH WALES. Principal Exotic Forest Trees in New South Wales. Paper, Brit. Comm. For. Conf. Wellington. 1957. 13 pp.

POYNTON, R. J. Notes on Exotic Forest Trees in South Africa. Brit. Comm. For. Conf. Wellington (Pretoria). 1957. 135 pp.

RAWLINGS, G. B. Pathology of P. radiata as an Exotic. Paper, Brit. Comm. For. Conf. Wellington. 1957. 16 pp.

SCOTT, M. H., and STEPHENS, R. P. Quality of Mature P. insignis Timber in South Africa. Paper Brit. Comm. For. Conf. Great Britain. (Pietermaritzburg.) 1947. 23 pp.

SCOTT, M. H. Utilization Notes on South African Timbers. S.A. Dept. For. Bull 36. Pretoria. 1953. 95 pp.

TROUP, R. S. Exotic Forest Trees in the British Empire. Oxford. 1932. 259 pp.

TURNBULL, J. M. Variations in Strength of Pine Timbers. South African Jnl. Sci. XXXIII. 653-682. 1937.

TURNBULL, J. M. Some Factors affecting Wood Density in Pine Stems. Paper. Brit. Comm. For. Conf. Great Britain. (Pietermaritzburg.) 1947. 22 pp.

WESTERN AUSTRALIA. Exotic Conifers in Western Australia. Paper. Brit. Comm. For. Conf. Wellington (Perth). 1957. 22 pp.