Sixteen possible climatic zones from hot and arid to cold and 

 wet are listed in the table below. 





HOT 



Prec 

 ARID 



pitation Effectiveness Index 

 DRY MOIST 



Class 



WET 



SSs 



Hot-arid 

 1 



Hot-dry 

 3 



Hot-moist 

 6 



Hot-wet 

 10 



Temperatu 

 Effectivene 

 Index Cla 



WARM 

 COOL 



Warm-arid 



2 

 Cool-arid 



4 



Warm-dry 



5 

 Cool-dry 



8 



Warm-moist 



9 



Cool-moist 



12 



Warm-wet 



13 

 Cool-wet 



15 





COLD 



Cold-arid 



7 



Cold-dry 

 11 



Cold-moist 

 14 



Cold-wet 

 16 



Twelve zones are distinguished in mainland Alaska. As would 

 be expected, the cold-wet areas are along the south and southwest 

 coast and correspond to the coastal forests. Southeastern Alaska is 

 in the cold-wet zone also. The cold-moist and cold-dry areas are 

 along the west and north coasts, and the hot-arid and hot-dry areas 

 are in the eastern interior basins, primarily along the Tanana and 

 Yukon Rivers and the Copper River Basin. 



22. Vegetation of Alaska. A colored vegetation map was 

 first prepared by Lloyd A. Spetzman (1963) , of the U.S. Geological 

 Survey, and published by the U.S. Army Office, Chief of Engineers 

 (printed by Army Map Service), scale 1:2,500,000. This map 

 was modified by the senior author and published in "Alaska Trees 

 and Shrubs" (Viereck and Little 1972), scale 1:5,000,000. It has 

 been further adapted for publication in this Atlas, scale 1:10,000,- 

 000. Also, treeless bogs and shrub thickets have been combined 

 under other types and not shown separately. 



Six vegetation types are distinguished, 3 of forests and shown 

 also in "Forests of Alaska" (General Map 23) and 3 of tundra 

 or treeless, as follows: 



1. Sitka spruce— hemlock forests. Tall, dense coastal forests of 

 Sitka spruce, western hemlock, locally with other conifers, and 

 black cottonwood, often interspersed with open treeless bogs. 



2. Closed spruce-hardwood forests. Tall to moderately tall closed 

 forests of white and black spruce, paper birch, aspen, and balsam 

 poplar; on moderate to well-drained sites. 



3. Open, low-growing spruce forests and treeless bogs. Primarily 

 of black spruce but often interspersed with white spruce, paper 

 birch, tamarack, and willows, locally interspersed with treeless 

 bogs; on poorly drained sites usually underlain by permafrost. 



4. Moist tundra. Tundra meadows dominated by sedges, espe- 

 cially in tussocks. Also extensive areas of willow and alder thickets 

 along streams and on protected slopes. 



5. Wet tundra. Wet coastal tundra and marsh, predominantly 

 sedges and grasses. Also extensive shrub thickets along streams. 



6. Alpine tundra, ice and snow. Predominantly barren, alpine 

 tundra dominated by white mountain-avens, low heath shrubs, 

 prostrate willows, and dwarf herbs. Also extensive shrub thickets 

 of resin birch, alder, and willows at lower elevations. 



The second and third forest types in the interior together form 

 the northern coniferous forest or taiga. 



23. Forests of Alaska. The U.S. Forest Service has published 

 maps of the forests. Taylor (1929) prepared a map of forest 

 regions of Alaska in color in "Pocket Guide to Alaska Trees," 

 scale 1:5,000,000, which in a later edition was reduced to scale 

 1:12,500,000. A revision in color appeared in "Alaska's Forest 

 Resource" (Hutchison 1967), scale 1:5,500,000. 



The map in this Atlas is slightly revised and adapted also from 

 that of "Vegetation of Alaska" (General Map 22) . However, forests 

 are shown more clearly, because nonforested areas are unmapped. 

 The following types are distinguished: 



1. Sitka spruce— hemlock forests (coastal). Tall, dense coastal 

 forests of western hemlock, Sitka spruce, locally with other conifers, 

 and black cottonwood, often interspersed with open treeless bogs. 

 These fast-growing forests are found along the Pacific coast from 

 the extreme southeast to the west side of Cook Inlet and Afognak 

 and Kodiak Islands. Commercial and of high economic importance. 



2. Spruce-hardwood forests (interior). Tall to moderately tall 

 closed forests (well stocked) of white and black spruce, paper 

 birch, aspen, and balsam poplar; on moderate to well-drained 

 sites. Commercial and capable of supporting a forest industry. 



3. Open, low-growing spruce forests (interior). Primarily of 

 black spruce but often interspersed with white spruce, paper 

 birch, tamarack, and willows, locally interspersed with treeless 

 bogs; on poorly drained sites usually underlain by permafrost. 

 Open forests of slow growth (poor to medium stocked), generally 

 classed as noncommercial at present. 



4. Nonforest or treeless. Shrub thickets (willow, alder) along 

 streams, bogs, tundra (moist, wet, and alpine), and ice and snow. 



The two forest types of the interior together form the northern 

 coniferous forest or taiga. 



SPECIES MAPS AND RANGES 



The natural distribution of each species within Alaska is shown 

 on a map (Species Maps 1—82) and is stated below in words 

 concisely for reference. A paragraph summarizes the range some- 

 what like a legend, because a map without accompanying text is 

 incomplete. The descriptions have been revised slightly from those 

 in "Alaska Trees and Shrubs" to agree with the new, larger maps. 



Place names along the corners and borders of the range within 

 Alaska are mentioned. General distribution beyond the State has 

 been added, as in the earlier handbook. Most place names cited 

 may be found on the two base maps of North America and Alaska 

 (General Maps 1 and 2). The larger areas under management 

 by the Federal Government where each species is known were 

 listed in that handbook because of special interest to residents and 

 visitors. These names of National Forests, National Parks, Wildlife 

 Refuges, etc., have not been repeated here. 



Numbers, common names, and scientific names of the 82 species 

 of Alaska trees and common shrubs in the paragraphs of ranges 

 below correspond to the species maps and the list of Species Maps 

 under Contents (page iii). Botanical descriptions and drawings of 

 each species, and also keys for identification, may be found in 

 "Alaska Trees and Shrubs." 



Size and general distribution are summarized by letters for 

 reference, as in that handbook. Trees and shrubs are distinguished 

 as follows: LT, large tree, more than 70 ft. (21 m.) high; MT, 

 medium tree, 30-70 ft. (9-21 m.) high; ST, small tree, 12-30 ft. 

 (4-9 m.) high; LS, large shrub, 6-20 ft. (2-6 m.) high; MS, 

 medium shrub, 2-6 ft. (0.6-2 m.) high; SS, small or low shrub, 

 0-2 ft. (0-0.6 m.) high; and PS, prostrate or creeping shrub. 

 General distribution is given as I, interior, and C, coastal, with 

 small letter where restricted. The 10 tree species producing nearly 

 all the commercial timber are indicated by an asterisk (*). 



8 



