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20 LIFE-ZONES IN RELATION TO AGRICULTURE

The following statement gives the exports of Canadian farm produce for 1905 in all cases in which the totals exceed one million dollars:

Cheese $20,300,500 Wheat flour $5,877,607

Wheat 12,386,743 Canned meats 3,538,976

Bacon 12,194,458 Apples 2,627,467

Cattle 11,338,431 Hay 1,261,210

Butter 5,930,379

Government assistance.

Agriculture in Canada is well protected and assisted by the various governments. The federal government has a minister of agriculture, who presides over a department with many branches. Under his direction are five experimental farms: Central Experimental Farm at Ottawa; the Maritime Farm at Nappan, N. S.; the Manitoba Farm at Brandon; the Northwest Territory Farm at Indian Head; and the British Columbia Farm at Agassiz. The various branches of the department—Dairying, Live-Stock, Fruit, Poultry, Pure Seeds, and Markets—are concerned mainly with the questions of transportation and marketing.

Education is a function of provincial government. Prince Edward Island provides agricultural education and directs experimenting through the professor of agriculture of Prince of Wales College. Nova Scotia has recently opened an agricultural college at Truro in close cooperation with the Provincial Normal College. New Brunswick maintains a dairy school at Sussex. These three maritime provinces enjoy in common the advantages of the Dominion Experimental Farm at Nappan, Nova Scotia, the New Brunswick Dairy School at Sussex, and the agricultural college at Truro, where live-stock has become the most important feature.

Quebec has a dairy school at St. Hyacinthe, and gives grants to several agricultural schools that are conducted by religious orders. There are ten experimental fruit stations. The southwestern part of Quebec (that is, the English-speaking part) and the eastern part of Ontario will, in the near future, be benefited by the magnificent agricultural college now in formation on the western end of the Island of Montreal (St. Anne de Bellevue), erected and endowed through the liberality of Sir William Macdonald. The extent of this new institution may be understood when it is stated that it will be endowed by several millions of dollars.

Ontario has the most extensive system of government organizations. There is an agricultural college at Guelph, with its well-equipped allied Macdonald Institute for young women. There are three dairy schools,— at Guelph, Kingston and Strathroy. There are twelve experimental fruit stations. There are provincial organizations of all the different branches of agriculture. The Department of Agriculture at Toronto publishes the following reports in addition to bulletins and special reports: Ontario Agricultural College, Experimental Union, Dairy associations, Fruit-growers, Fruit Experiment Stations, Farmers' Institutes, Women's Institutes, Entomological Society, Live-stock associations, Bee-Keepers, agricultural societies, agricultural statistics.

Manitoba conducts a dairy school and has an agricultural college near Winnipeg. Classes were first organized November 7, 1906.

British Columbia has for some years maintained vigorous dairy and fruit-growers' branches, and exercises a close supervision over horticultural imports and exports.

The dominion and provincial departments combined expend in all about one and a half million dollars every year for the benefit of the agriculture of Canada.

LIFE-ZONES IN RELATION TO AGRICULTURE

By T. D. A. COCKERELL

Every one is aware that the same animals and plants are not found in all localities, and that all regions are not suited for the same crops. The presence of any particular kind of animal or plant in any particular place is due to or permitted by several different factors. In the first place, if it did not originate there, it must have had some means of traveling from the place where it did originate, and sufficient time must have elapsed for the journey. In the second place, if it is able to maintain itself in its present habitat, the surroundings must be sufficiently favorable, or it must be sufficiently well adapted to them.

In a broad way, these factors may be said to be chiefly historical and climatic. The agriculturist is concerned with the latter rather than with the former. The southern extremity of Florida has a tropical climate, but it has not such a characteristically tropical fauna and flora as the island of Cuba. From the standpoint of the naturalist, it is to be classed with the adjacent and contiguous land to the north, rather than with the West Indies. Nevertheless, such West Indian types as have reached it do well there, and man is able to raise such crops as the climate allows, without being in the least disturbed by the fact that the sea has been a barrier to the larger part of the native West Indian fauna and flora. In other words, the agriculturist is concerned with what now is, rather than with what has been, and with existing conditions of soil and climate, not with "natural barriers," which are no barriers to him.

In the Rocky mountains, there are numerous kinds of oaks, which abound in New Mexico, and grow north to central Colorado, where they abruptly stop. From the altitudes at which they are found in New Mexico and southern Colorado, there appears to be no climatic reason why they should not range much farther north. It appears probable that they were driven south during the glacial period and have

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Fit. H. Main Life-zones of the United States and adjacent Canada. —1. Boreal; 2. Transition; 3, Upper and Middle Austral: 4. Lower Austral: 5, Gulf strip of Lower Austral; 6, Tropical. The dotted parts of the Austral zones east of the great plains indicate the extent of the humid divisions of these zones, known respectively as the Alleghanian, Carolinian and Austroriparian faunas. The undotted parts of the same zones are known as the Transition, Upper Sonoran and Lower Sonoran (adapted, with modifications, from 0. Hart Merriam).

not yet recovered the lost territory, their fruit (the acorn) being heavy and not readily carried great distances, especially in the absence of rivers flowing north and south. This is very interesting to the naturalist, but such phenomena do not affect the agriculturist, who is able to take his seeds or plants wherever they will grow.

The present and past existence of "natural barriers" may even be favorable to man's operations. Thus the curious Australian tree, Casuarina, is grown from seed in the West Indies, and is practically free from insect enemies, because the numerous kinds which infest it where it is at home have never been able to cross the Pacific Ocean, or otherwise reach this side of the world. The same is true of the Eucalyptus trees in California.

In defining zoological and botanical regions, naturalists have taken the combined results of all factors, as exhibited in the existing faunas and floras, and, in consequence of this, the regions have not been found altogether applicable to agriculture. For example, the north of Africa is, zoologically and botanically, strikingly different from southern Arizona. Nevertheless, the investigations of the Department of Agriculture have shown that it presents great climatic similarity to the Salt river valley and adjacent country, and the date-palm, native in the one, has been successfully introduced into the other. This introduction will be followed by others, until the agricultural and horticultural products of the United States include all the valuable ones at present existing in climatically similar areas of the Old World.

Dr. C. H. Merriam, of the Department of Agriculture, having in view the economic side of the question, undertook, a number of years ago, to define the great Life-zones that cross the United States, as the result of climatic conditions. In this he was so successful that, in its main outlines, his work is everywhere accepted, and is used to throw light on very numerous and varied problems. It was found that there are two great areas, occupied by the boreal or northern, and the austral or southern types, respectively. There is also an intermediate territory, in which they mingle, and where they seem to struggle together for dominance. The spread of the boreal types southward is evidently prevented to a considerable extent by the competition of the austral ones, and vice versa; but more important factors seem to be those of temperature and moisture, exactly those that are so important in agriculture.

Life is continually adjusting itself to the physical environment. The processes of nature constitute, as it were, a great experiment, lasting for an indefinite period. Hence the plants and animals of any locality, to the eye of the discriminating observer, afford an accurate criterion of the climatic conditions, and consequently a reliable indication of agricultural possibilities. It is natural to ask, why attack the subject in such a roundabout way? Why not treat the records of the Weather Bureau as certain and satisfactory indications of climate, and leave the indigenous plants and animals out of account? The answer is, that the fauna and flora exhibit the work of nature's weather bureau, which has been in operation for centuries, instead of a few years; and further, that plants and animals may be found nearly everywhere,whereas weather stations are few and far between. Moreover, instrumental weather records do not give a complete account of climate, for some of the features of climate are quite unmeasurable and unrecordable in figures. It would be foolish for either the naturalist or the agriculturist to ignore the work of the meteorologist; but this work can be usefully supplemented, especially in mountainous regions, by observation of the native products. Correlations between plants or animals and climate, once recorded, can be used to determine the details of the climate of broken-up and varied regions where complete weather observations would be totally impossible.

In 1894, Dr. Merriam formulated a law, that the northward distribution of animals and plants in the northern hemisphere is determined by the sum of the effective temperatures (or the total quantity of heat) during the season of growth and reproduction. It is not sufficient that the organism should live: it must reach maturity and reproduce. Thus, for example, Indian corn is readily grown in England, but it is rarely able to mature, and there is no likelihood of its being a profitable crop in that country. This maturity depends on the long continuance of a suitable amount of heat, just as a man's maturity results, not from his last meal alone, but from a sufficient succession of them. Roughly, the "biological isotherms" have been mapped by adding together the numbers represented by the temperatures of the days concerned, until in each case the proper total was obtained. Commenting on this method, Professor C. H. T. Townsend (1895) observed that another factor must be considered, namely, the lowest temperatures during the winter season. Some organisms are not affected by low temperatures at this time, but others are; the coconut-palm, for example, cannot endure frost, while the date-palm can doubtless endure as much as anywhere goes with sufficiently high summer temperatures.

Professor Townsend further observed, however, that it is an error to base the conclusions as to distribution wholly on the temperature of the air, as shown by the ordinary thermometer. Different amounts of moisture, as well as the prevalence of winds, greatly affect the "sensible temperature," because of their influence on evaporation. If one pours a little alcohol or ether on the hand, the place at once feels cold, because the evaporating liquid takes up the heat. In the same way, the transpiration which all animals and plants show, giving off moisture into the air, must greatly affect their powers of resistance to extremes of temperature. It is related that on one occasion some persons walked into a large brick oven, with food cooking all around them, and escaped unscathed, to the wonder of onlookers. The explanation was that their rapid and profuse perspiration saved them. But since the rapidity of evaporation depends not merely on the temperature, but also on the amount of moisture already in the air, it is evident that high temperatures will be more oppressive to man and animals in damp climates than in dry ones. This is actually the case, and white men walk about without fatigue or danger in the arid southwest, in temperatures which would produce heat apoplexy in the moist tropics. The effect of wind is also important, and in the arid regions it frequently produces so much transpiration in cultivated plants that desiccation results, and hence windbreaks become of great value. The relation between the "actual" and "sensible" temperatures has been well described by Mr. Willis L. Moore, in a paper entitled "Some Climatic Features of the Arid Regions," published in 1896 by the United States "Weather Bureau. In this work it is shown that the "sensible" temperature, obtained by the wet-bulb thermometer, may be many degrees below the air temperature, this difference in the arid regions during the summer months often amounting to 20° or 30° Fahr.

It is also evident that the relation between organisms and temperature is far from being a simple one. We are net to assume, because two plants grow on the same isotherm, and mature at the same time, that they are equally affected by the available heat. The amount of leaf-surface exposed, the

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Fig. 15. Vegetation in the boreal zone, as it approaches the arctic sub-zone.—The tundra, Copper river valley, Alaska.

rapidity of transpiration, the situations occupied, and other factors are influential, and the general result must be explained in partly physical and partly physiological terms. The situation occupied is often so influential that, if one is ignorant of it, one may reach the most erroneous conclusions. Thus at Pecos, New Mexico, within an area of less than a square mile, without more than a hundred feet difference in altitude, the writer found plants characteristic of the arid austral zone, and others usually looked for in the boreal zones of the mountains. The former were growing on the rocky hillside, the latter under the shade of a dense grove of cottonwoods close by the Pecos river. Studying the matter on the spot, it seemed simple enough; but if the distribution records had been found plotted on a map, the most curious conclusions might have been reached. Similarly, at Minnehaha Falls on Pike's Peak, Colorado, the two sides of the deep canon have quite different floras. The north side, exposed to the sun, has such plants as are found in the transition zone, while the south side, cold and damp, has a boreal flora. Just such conditions as these can be taken advantage of in agriculture, and it is no doubt an important part of the wisdom of farming, to choose suitable slopes and provide shade when necessary. So true is this in the arid west that, within the same immediate vicinity, one farm may be worth twice as much as another, at least for certain purposes. In Wet Mountain valley, Colorado, there is a small area, near a hill, where the currents of air meet in such a way that hail falls there more frequently than elsewhere, and this particular place may be white after a storm, in strong contrast with the rest of the valley. A more important kind of local influence is observed in the valleys of New Mexico and Arizona. The cold air, being heavier than that which is warm, flows like a stream of water to the bottom of the valley, and consequently the lower altitudes are actually colder than the higher ones. In Salt river valley, Arizona, for example, oranges are much less likely to be injured by cold at the sides of the valley than in its middle; and in the Mesilla valley a very moderate elevation may make the difference between a killing frost and a comparatively slight one. In the latter valley, if irrigation could be carried to a higher level, it is probable that the injury from spring frosts would be much reduced. These local phenomena seem to contradict the general rule that higher altitudes are colder, and yet they are real enough, and may not be ignored without loss.

In order accurately to map the life-zones all over the country, an immense amount of work would be necessary. The maps we possess at present are only approximately correct. This is true not only of the general maps, which treat the matter in the broadest way, but also of the more special ones, intended for particular purposes. Thus, for instance, a bulletin of the Division of Chemistry, Department of Agriculture (1899), contains a large map, showing the probable areas suited to beet-culture, between the isotherms of 69° and 71°. This map is based on the records of the Weather Bureau, and was supplied for the particular purpose in mind. The writer has had occasion to examine somewhat critically the New Mexico part. When this is compared with the larger detailed maps issued by the Weather Bureau, it is seen to be rough and general and not reliable for practical purposes. As a matter of fact, it does not indicate the actual areas suited to the beet, as proved by numerous experiments in growing this plant. Again, when we come to examine minutely even the large and detailed temperature maps, we find that they are based on the records of a few stations, which do not at all represent the various conditions existing in a mountainous country. This is not said in criticism of the Weather Bureau, or of any other bureau or of any person, but only to show the inadequacy of our knowledge; for to obtain really complete meteorological and other statistics would require an expenditure of money which it is not likely that Congress would ever sanction. Using the data obtained here and there, the Weather Bureau has to fall back on the work of the Topographical Survey, and assume that its contour lines fairly correspond in local areas with isotherms. But again, the work of the Topographical Survey, in many parts of the west, has had to be done with quite inadequate means, and therefore is frequently inexact as to details. So, taking one thing with another, it is quite impossible to furnish accurate detailed life-zone maps at present, except in a few regions which have been carefully gone over. The work of the Biological Survey, which, as explained above, is so necessary for the correction and amplification of data obtained in other ways, should be greatly extended. Its scope should include the details of the distribution of plants, both native and cultivated, and the Weather Bureau should be able so to cooperate as to bring out the necessary facts. In all these matters, an excellent beginning has been made, but it must be recognized that much more is to be done, and that it is useless to expect satisfactory results without the expenditure of much time and money; and the means will not be forthcoming until public sentiment rises to meet the needs.

The accompanying map, adapted from that of Dr. Merriam, indicates the life-zones according to present information, without any attempt, however, to go into great local detail. The zones may be

further described as follows:

(A) Boreal.

The boreal zone may be divided into three sub-zones:

(a) Arctic-alpine zone.—In the arctic regions, beyond the limit of trees, and in our high mountains, above timber-line. The arctic and the alpine parts of it are not identical in their climatic features, the continuous light in summer of the far north being in strong contrast with the regular day and night of the mountain peaks that arise out of the temperate regions. In accordance with this, Gaston Bonnier has observed that arctic and alpine plants assumed to be of the same species differ essentially in structure from one another; and in recent years Rydberg, Wight and others have discriminated as new species plants of the higher Rockies, which were supposed to be identical with those of the extreme north. The Arctic-alpine zone is, of course, not adapted for agricultural purposes.

(b) Hudsonian zone.—So called from its prevalence in the vicinity of Hudson's Bay. It is the zone of "black timber" in the Rocky mountains, the great trans-continental zone of spruces and firs, occurring in comparatively small isolated areas in the eastern states, but in the west more extensive and important. It is not an agricultural zone in the ordinary sense, but, when we regard timber as a crop, it assumes a

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Fig. 16. Vegetation in northern Alberta, illustrating the Hudsonian sub-zone.

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