206 ESS A YS. 



ransres. Through most of California these two Pacific forests 

 are separate ; in the northern part of that State they join, 

 and form one rich woodland belt, skirting the Pacific, backed 

 by the Cascade Mountains, and extending through British 

 Columbia into our Alaskan territory. 



So we have two forest regions in North America, — an At- 

 lantic and a Pacific. They may take these names, for they 

 are dependent upon the oceans which they respectively bor- 

 der. Also we have an intermediate isolated region or isolated 

 lines of forest, flanked on both sides by bare and arid plains, 

 — plains which on the eastern side may partly be called 

 prairies, on the western, deserts. 



This mid-region mountain forest is intersected by a trans- 

 verse belt of arid and alkaline plateau, or eastward of grassy 

 plain — a hundred miles wide from north to south, — through 

 which passes the Union Pacific Railroad. This divides the 

 Eocky Mountain forest into a southern and a northern por- 

 tion. The southern is completely isolated. The northern, in 

 a cooler and less arid region, is larger, broader, more dif- 

 fused. Trending westward, on and beyond the northern 

 boundary of the United States, it approaches, and here and 

 there unites with, the Pacific forest. Eastward, in northern 

 British territory, it makes a narrow junction with northwest- 

 ward prolongations of the broad Atlantic forest. 



So much for these forests as a whole, their position, their 

 limits. Before we glance at their distinguishing features and 

 component trees, I should here answer the question, why 

 they occupy the positions they do i — why so curtailed and 

 separated at the south, so much more diffused at the north, 

 but still so strongly divided into eastern and western. Yet I 

 must not consume time with the rudiments of physical geog- 

 raphy and meteorology. It goes without saying that trees 

 are nourished by moisture. They starve with dryness and 

 they starve with cold. A tree is a sensitive thing. With its 

 great spread of foliage, its vast amount of surface which it 

 cannot diminish or change, except by losing that whereby it 

 lives, it is completely and helplessly exposed to every atmos- 

 pheric change ; or at least its resources for adaptation are 



