DECEMBER. 357 



of them of good size, I have seen none of those giants which 

 one would look for in a primeval forest. 



F. I have made the same reflection ; I have read of 

 very enormous trees occasionally occurring in the woods of 

 Upper Canada, but in this province, certainly, they do not 

 generally surpass mediocrity. The largest boles with us 

 appear to be those of elm, birch, and hemlock, none of which 

 I have seen that would measure more than five feet in dia- 

 meter, at about a yard from the ground. I have heard of 

 large logs of white pine, but the trees of this valuable species 

 have been all cut away in this neighbourhood. Possibly, in 

 other parts of the province, the timber may grow to a larger 

 size, but I have never heard such a fact hinted. 



C. What is the cause of the coarse furrows and corruga- 

 tions of the bark in many trees ? 



F. Let us examine the structure of a tree : here is a 

 recently-cut maple log, which will serve our purpose. We 

 perceive several manifest divisions, the exterior of which is 

 the bark ; this, however, is not homogeneous in its texture ; 

 the outer part is called the rind or epidermis ; in some, as 

 the birch and beech, this is thin ; in others, as the maple, 

 elm, and basswood, it is thick, dry, and rough ; in others, as 

 the ash and spruce, it is scaly. The inner part is the liber,, 

 or true bark ; and is the seat of life in the tree, the origin of 

 the new buds ; in some trees it resembles the rind in appear- 

 ance, as in the maple, but in others is widely different, and 

 may be separated, as in the elm and birch. It appears that 

 the bark does not increase so rapidly as the wood of the tree, 

 the increasing diameter of which forces and tears apart the 

 rind, causing these furrows ; which process is well exem- 

 plified in the stringy rind of the cedar, which is torn into 

 lozenge-shaped divisions, like the meshes of a net. In many 

 trees the outer layers of the rind are being continually thrown 

 off by exposure to the weather, and their place as constantly 



