CANADIAN FORESTRY ASSOCIATION. 57 



The reason for this is not entirely explained so far, but perhaps it may be ac- 

 counted for by the fact that the land of North America extends much nearer to the 

 polar regions than does the land of Europe, and the forests of ancient time ranged 

 extremely far north. During the glacial period the forests were compelled to move 

 south. 



The creeping back of the trees towards the north is the result of the disappearance 

 of the ice-sheet. I have devoted a great deal of study to the geographical distribution 

 of forest trees, and have come to the conclusion that only a certain proportion of those 

 trees have yet got entirely back or reached the most northern limits possible. Some 

 of them have done so, their seeds being carried by the wind, such as the poplars and 

 birches. It is possible that these have reached their northern limits. As we know, when 

 their seeds are ripe, being attached to a large mass of down, they are carried hundreds 

 of miles ; therefore, a single tree may seed an area equal to a whole county and plant the 

 tree as far north as it is possible for it to grow. And those trees which are not provided 

 with a good means of transport would travel northward somewhat more slowly, in accord- 

 ance with the difficulties they encounter. Some coniferous trees have very large wings 

 compared with the weight of the seed ; others have very small ones, and those with the 

 best wings fly the farthest. Other seeds have no means for transportation. Take, for in- 

 stance, the nut-bearing trees, such as the walnut and oak; their means of spreading 1 

 are exceedingly limited. The greater number of the seeds would have to remain im- 

 mediately under the tree that produces them, or they might be blown a little way by 

 the wind, but it would only be a very short distance, not more than the diameter of 

 the top of the tree, that is, the spread of the branches, or they might be carried a little 

 distance by squirrels or other animals which would take them for food. If an unfor- 

 tunate squirrel were to make caches here and there, and then was killed by a hawk, for 

 instance, his store of nuts would remain in the ground and some of them would germ- 

 inate and you would have young trees a little distance away from the parent. 



Amongst the proofs that some trees have not yet reached their passible limits, I 

 might say that where the seeds of trees, or small trees themselves, have been carried 

 a long distance north, they are found to grow about as well as at the place from which 

 they were taken. Sir Henri Joly de Lotbiniere has proved, for instance, that the black 

 walnut will grow at Quebec, five hundred miles beyond its nearest home in Canada. 

 The same experiment has been tried in many other instances; for example, in the 

 county of Peterboro, around Ottawa and in the county of Lanark. This is a very large 

 jump, several hundred miles at once, and it goes to show that trees may be suddenly 

 moved and become acclimatized to the new conditions, and that the change is not 

 necessarily fatal to them. 



A great many other trees have been brought a long way north, and have been 

 found to grow just about as well as at the parent home. At Ottawa city they plantod 

 numerous kinds of shade trees taken from Kochester, some of which were not indi- 

 genous to the Ottawa valley and yet they have grown just about as well as where they 

 pome from. The city council of Ottawa made a contract for these trees and it was 

 stipulated that they should be brought from Rochester. The result has been very satis- 

 factory. I need not enlarge on this point, if you will accept what I say in regard to the 

 examples I have seen in a great many instances. It is a fact that trees will bear trans- 



