December 22, 1897.] 



Garden and Forest. 



507 



dry grass cuttings or pine needles. One such thorough water- 

 ing is quite sufficient to carry a tree in good condition through 

 any ordinary season of drought. 



Now, near the end of the seventh year of my experiment, I 

 can look back and, through the many mistakes that have be- 

 come evident, see how various things should have been 

 done at the start. Most of them can be remedied, some of them 

 cannot. Much work remains to be done in the way of trans- 

 planting, for at first, according to the custom of most amateurs, 

 trees were planted much too near together and without due 

 reference to their artistic arrangement. One tree intercepts 

 what without it would be a beautiful vista ; another is already 

 bending away from the larger growth on one side, and certain 

 shrubs whose mature stature had been underestimated, 

 have quite outgrown the limits assigned to them. At the end of 

 the last transplanting season I was congratulating myself that 

 the hard work was practically done, and I had now before me 

 only the pleasure ot watching the progress of my plants ; but 

 one summer's growth has quite dispelled this illusion, and 

 the approaching autumn will be scarcely less notable than pre- 

 ceding ones in the amount of digging and changing things 

 about. This would be most discouraging were it not also 

 evident that my ideal, while by no means yet attained, is (bar- 

 ring limitations which preclude the possibility of actual attain- 

 ment) each year less remote. 



Brookland, District of Columbia. Robert hulgway. 



Recent Publications. 



The Geographical Distribution of Forest Trees in Canada. 

 By Dr. Robert Bell. 



This is a paper read a few months ago before the Scottish 

 Geographical Society, and now issued in separate form 

 from the Scottish Geographical Magazine of June, 1897. Dr. 

 Bell has had exceptional opportunities for studying the 

 northern distribution of the Canadian trees, as for forty 

 years he has been engaged every year in exploring, in 

 connection with the Canadian Geological Survey, the 

 extreme northern regions of the continent east of the Rocky 

 Mountains. In 1873 Dr. Bell prepared a map showing the 

 northern limits of the principal trees in the four original 

 provinces of the Dominion, and in 1879 a reduction of this 

 sheet was published in the Report of the Montreal Horti- 

 cultural Society and Fruit-growers' Association ; and in the 

 Report of the Canadian Geological Survey of 1882 he 

 joined to another map a paper containing the latest in- 

 formation upon the northern range of thirty of the principal 

 forest-trees which grow in Canada east of the Rocky Moun- 

 tains. The present paper, which is accompanied by a map 

 on which the northern distribution of these thirty trees is 

 marked, must be considered a supplement to Dr. Bell's 

 earlier papers, and contains the results of his own observa- 

 tions and those of other travelers and explorers in the far 

 north during the last seventeen years, and these probably 

 in the case of several of the species, at least, must be con- 

 sidered final ; although such a comparatively small part of 

 the interior of Labrador has yet been explored, that some 

 changes in the limit-lines now laid down by Dr. Bell 

 for that part of the country will doubtless be needed. 



Dr. Bell has had so much experience and has studied so 

 carefully the distribution of Canadian trees and the causes 

 which control their different ranges that his conclusions are 

 extremely interesting and valuable. He finds, for example, 

 that " in approaching their northern limits some kinds of 

 trees become gradually smaller and smaller, and are finally 

 reduced to mere bushes before they disappear altogether, 

 while others terminate abruptly or without any apparent 

 diminution in the average size of the individual trunks. 

 The latter habit is commoner in the southern than in the 

 northern species, and it appears to prevail more in the 

 eastern than in the western parts of Canada." He finds, 

 too, that " it is probable that those trees which bear large 

 numbers of seeds capable of being carried for some dis- 

 tance by the wind, such as the conifers and the Poplars, 

 have now reached the extreme northern limits of their 

 growth, but some other species may be continuing to ex- 

 tend their borders. Indeed, the general tendency appears 

 to be to advance still farther north, as if many kinds of our 



trees had not yet had sufficient time to occupy all the ter- 

 ritory congenial to their existence." In support of this 

 theory Dr. Bell cites successful experiments which have 

 been made in growing the Black Walnut in the neighbor- 

 hood of Quebec, although the nearest place where this tree 

 grows naturally is 500 miles farther to the south-west, 

 showing that the range of this tree is capable of being 

 extended over a much greater area than it yet occupies 

 naturally. On Pelee Island, in Lake Erie, the most south- 

 ern point in Canada, is the only place in the Dominion 

 where the Honey Locust and the Kentucky Coffee-tree are 

 known to grow naturally, although the former flourishes 

 wherever it has been planted through the Ontario peninsula 

 and down the St. Lawrence nearly to Montreal, and the 

 Kentucky Coffee-tree grows to a large size in Ottawa. The 

 Negundo, which has not extended its natural range east of 

 the western end of Lake Superior, grows as well in Mon- 

 treal, 900 miles further east, as it does in Manitoba, and 

 the Black Ash is perfectly hardy on James Bay, 100 miles 

 to the north of its natural range. 



This ability of various trees to grow far from their exist- 

 ing homes is not attributed by Dr. Bell to any change of 

 climate since they attained their present range, as there is 

 no meteorological proof of such improvement, but because 

 sufficient time has not elapsed to permit the " fullest possi- 

 ble territorial expansion of all the species. When frost 

 alone operates to check the northward extension of a tree, 

 there would appear to be no reason why such a species 

 should not grow as far in that direction as it can ripen its 

 seeds, even once in a number of years. When early frost 

 happened to coincide with good seed years many seasons 

 might intervene between crops of ripe seeds, and the natu- 

 ral progress of northward extension would be very slow. 

 The Red Oak, which requires two seasons to ripen its fruit, 

 would suffer a double disadvantage." Dr. Bell notices that 

 the Beech, Elm and Black Ash seldom bear any fruit to- 

 ward the northern limits of their range. 



It is interesting to read that Dr. Bell considers " the 

 greater dryness of the region between Red River and the 

 Rocky Mountains is one of the principal causes of its 

 treeless and partially treeless condition. The former 

 country is called plain and the latter prairie. The other 

 principal cause is the extremes of heat and cold. Some 

 persons have jumped to the conclusion that the plains and 

 prairies have resulted from repeated fires burning off pre- 

 existing forests in modern times. If this were the case the 

 tree-lines in their general westward course would all end 

 abruptly at the edge of the burnt space, and some traces of 

 the various species would still be found in the prairie 

 region. But, instead of this, on approaching the prairie 

 country they all curve gradually to the southward in a 

 concentric fashion, so that what was the northern limit of 

 each successive species now becomes in turn its western 

 boundary. But if other evidence be required it may be 

 found in the prairie flora, the absence of hollows with hil- 

 locks accompanying them, left by the bodily upturning of 

 the roots of trees with a large quantity of earth attached, 

 which are always to be found where forests have grown ; 

 the comparative scarcity of water courses, and the preva- 

 lence of regular rings of boulders around the edges of the 

 nearly circular ponds which have resulted from the action 

 of ice in a treeless region." 



While it is probable that the treeless condition of the 

 northern extension of the prairie region and of the plains 

 as distinguished from the prairies, is due to insufficient mois- 

 ture and to cold, it is evident that the absence of trees from 

 the comparatively well-watered prairie regions of the 

 United States can be largely ascribed to fires, which if they 

 did not originally destroy the forest covering, have certainly 

 prevented a growth of trees, because when the annual burn- 

 ing over of the prairies stopped with the settlement of the 

 country by the whites, trees soon covered or attempted to 

 cover'the surface of the ground wherever there was suffi- 

 cient moisture for tree-growth. 



Unfortunately space will not permit us to make longer 



