296 SCOTTISH GEOGRAPHICAL MAGAZINE. 



growth, they develop tall trunks with the branches high up. In one 

 hundred years the poplars are dying and falling down, and the canoe 

 birch has attained maturity and soon after shows signs of old age. 

 Meantime the older conifers have overtopped the other trees and given 

 a new character to the general appearance of the forest. The younger 

 conifers of various ages, which have been springing up from seed every 

 year, take possession of the ground left by the decay of the first 

 occupants, and in about one hundred and fifty years the forest has again 

 become almost entirely coniferous, and is ready to be destroyed once more 

 by fire. Such is the rotation of crops of trees which is perpetually 

 going on in these regions. Perhaps one-third of the whole area consists 

 of " second growths " of less than fifty years, one-third of trees from 

 fifty to one hundred years old, while the remaining third may be one 

 hundred years and upwards. 



THE BANKSIAN PINE IN RELATION TO FIRE. 



Fire appears to be a necessity in the propagation of the Banksian pine. 

 Its knotty cones are not deciduous, but stick to the tree as long as it 

 lasts, the older crops becoming covered with lichens and showing great 

 age. If the tree dies or falls over and decays, the cones lie about 

 unopened. But when the standing trees are scorched by a forest fire, 

 the cones immediately open, and the seeds become scattered far and wide 

 by the wind. Forest fires have probably occurred every year since trees 

 of the present species existed on the continent, and an interesting 

 question arises as to how the Banksian pine acquired this curious 

 habit. Charred wood occurs under great depths of Pleistocene deposits 

 near Toronto, while there is no evidence of the advent of man in Canada 

 until a very recent period. 



