6o TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



Canada are built of coniferous wood, most of our paper comes 

 from the same source, and, in all but the most densely 

 populated regions, most of the domestic fuel. ^ 



From the relative abundance and number of species it is evident 

 that the average conifer species is represented by a much larger 

 number of trees than the average hardwood. It happens that 

 most of our conifers form pure stands of greater or less extent, 

 in some part of their ranges at least, so that there are about as 

 many types of coniferous forest as there are species of conifers. 

 All but a few of the rarer or less important types will be 

 described below, beginning with the northernmost, which are 

 mainly confined to the glaciated region, and ending with those 

 confined to the coastal plain, and one whose range extends south- 

 ward into the tropics. The treatment of each type will include 

 geographical distribution, correlations with soil, water, climate, 

 fire,- etc., and notes on the economic aspects of the trees 

 themselves and the regions in which they grow. 



The Forest Types in Detail. 



The Boreal or Spruce Type. — The northernmost type of 

 forest, which covers almost the whole of eastern North America, 

 from the Arctic tundra down to latitude 45°, with many more or 

 less isolated areas farther south, especially in the mountains, is 

 mainly composed of Jack pine {Finus Banksiana), tamarack 

 {Larix laricina), two or three species of spruce {Ficea), balsam 

 fir {Abies balsamea), and arbor-vitse or northern white cedar 

 {Thuja occidentalis). In places some one of these may cover 

 considerable areas exclusively (this is especially true of the 

 pine), but usually two or three of them are mixed together. 



^ A map between pages 4S8 and 489 of I lie ninth volume of the Tenth Census 

 shows the distribution of coal and wood fuel in the United States three 

 decades ago. 



■' Forest fires have generally been looked upon as regrettable accidents, and 

 much more thought has been given to devising means to prevent them than 

 to studying their geographical distribution and historical frequency. But those 

 that start from natural causes seem to be just as much a part of Nature's pro- 

 gramme as rain, snow and wind (which, like fire, may do both good and harm at 

 the same time), and to be suljject to more or less definite laws Their frequency, 

 extent and effects vary greatly in different parts of the country and in different 

 types of forests, as will be shown l^elow, and nearly every species of conifer 

 seems to have become accustomed or adjusted to a certain amount of fire, as 

 to other environmental factors. 



