Page:Popular Science Monthly Volume 85.djvu/342

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IN eastern North America about thirty species of coniferous trees make up at least two thirds of the existing forest, while the remainder comprises something like 250 hardwood or broad-leaved species. About 70 per cent, of the lumber sawed in the eastern United States at the present time is of conifers or softwoods, and if the statistics for eastern Canada and for fuel, pulp-wood, cross-ties, poles, etc., were included the preponderance of softwood in the area under consideration would be still more evident. Most of the houses in the United States and 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.[1]

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 parts 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 southward into the tropics. The treatment of each type will include geographical distribution, correlations with soil, water, climate, fire,[2] etc., and notes on the economic aspects of the trees themselves and the regions in which they grow.

  1. A map between pages 488 and 489 of the 9th volume of the Tenth Census shows the distribution of coal and wood fuel in the United States three decades ago.
  2. 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 program as rain, snow and wind (which like fire may do both good and harm at the same time), and to be subject 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 below, and nearly every species of conifer seems to have become accustomed or adjusted to a certain amount of fire, as to other environmental factors.