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NATURALIST'S GUIDE TO THE AMERICAS 



it is easily divisible into a few general 

 regions in which biological conditions 

 are broadly similar. At least four 

 primary divisions are necessary: (1) the 

 humid and relatively warm southeastern 

 or Sitkan region; (2) the intermediate 

 glacial region lying next to the coast 

 just northwestward; (3) the wooded 

 plateau and mountains of the interior, 

 and (4) the treeless coast of the Arctic 

 and Bering Sea. 



II. REGIONAL ACCOUNTS 



1. Southeastern region 



A. Topography. This is the so-called 

 panhandle of Alaska extending from the 

 British Columbian boundary to the 

 vicinity of Lynn Canal and including 

 a narrow strip of wholly mountainous 

 coast and numerous adjacent islands, 

 some of considerable size and also moun- 

 tainous. The mainland is only 20 mi. 

 in average width and is much dissected 

 by long fjords bounded on either side by 

 mountains rising sheer from the water. 

 These fjords and smaller channels are 

 very deep and usually navigable for large 

 vessels. The mountains rise to heights 

 from 5000 to 8000 ft .with timberlines from 

 2000 to 3000 ft., the higher elevations 

 mostly to the northward. One large navi- 

 gable river, the Stikine, breaks through 

 the mountain wall. In the northern part 

 of the region, another river of consider- 

 able size is the Taku, but although other 

 streams are numerous, they are all of 

 small size. At the head of some of the 

 inlets and on the higher slopes are gla- 

 ciers of some size, although small as 

 compared to those found farther north. 

 The evergreen forests, snow-crowned 

 mountains and narrow waterways com- 

 bine to make the region exceedingly 

 picturesque. The islands of the Alex- 

 ander Archipelago lie close to the main- 

 land and are similar to it in character, 

 but the relief is generally lower and in 

 many cases the mountains are fully 

 timbered. Some of the islands are 

 quite large, Prince of Wales, the largest, 

 being about 140 mi. long and 40 mi. wide. 



B. Climate. The climate of south- 



eastern Alaska is relatively mild and, 

 in general, is similar to that of the Puget 

 Sound region. In ordinary winters but 

 little snow falls, and severe cold is 

 almost unknown. At Sitka, the mean 

 for February, the coldest month, is 33° 

 and for August, the warmest, it is 57.2°. 

 The region is subject to much rain and 

 cloudy weather. At Sitka and Juneau, 

 the annual precipitation is about 90 in. 

 and at stations farther southeast, annual 

 rainfall may be as much as 130 in. The 

 greatest fall is during the months from 

 September to January and the pleasant- 

 est months as well as the warmest are 

 May, June and July. The rains are 

 usually of the soft gentle variety but 

 often continuous for many days and 

 nights at a time. 



C. Original biota. Vegetation: Al- 

 though the region has been inhabited for 

 many years and has been exploited to 

 some extent, its general biological condi- 

 tions are not greatly changed. The 

 forests are so vast that the consumption 

 of lumber for local purposes has had 

 little effect and no great amount of 

 exporting has yet taken place. This is 

 partly due to the bringing of over 1000 

 sq. mi. under federal control in the 

 Tongass National Forest. The entire 

 region below an altitude of 2000 ft. is 

 heavily grown with coniferous forest. 

 This consists of the giant cedar (Thuja), 

 which is generally distributed; the yel- 

 low cedar (Chamaecyparis) , mostly scat- 

 tered except in a few fine stands; the 

 Sitka Spruce (Picea sitchensis), com- 

 mon throughout; the western hemlock 

 (Tsuga heterophylla) , very abundant; 

 the yew (Taxus vrevifolia), locally abun- 

 dant; and the mountain hemlock [Tsuga 

 mertensiana) , scarce and local. The 

 important timber tree, the Douglas 

 Spruce [Pseudotsuga), does not occur, 

 its northern limit being reached in 

 British Columbia. Underbrush and her- 

 baceous plants are everywhere very 

 luxuriant. The principal shrubs are 

 Ahnis, Ribes, Vaccinium, Viburnum, 

 Menziezia, Gaultheria, and Echinopanax. 

 At higher elevations on the mountains 

 is an alpine flora. 



