EXPLANATION OF THE MAPS 



"Volume 2, Alaska Trees and Shrubs" contains maps of 82 

 species of native woody plants, 32 of trees, 6 of shrubs rarely- 

 reaching tree size, and 44 more of common shrubs. The shrub 

 species mapped, about one-half of the total, include the more com- 

 mon or widely distributed, those of large size, and those of 

 economic importance. 



The species and species maps are arranged by plant families 

 and are numbered for convenient reference. Within large families 

 the order is alphabetical by scientific names. For each species the 

 preferred common name and the accepted scientific name are the 

 same as in "Alaska Trees and Shrubs." Other names in use may 

 be found in that handbook. 



Distribution of each species in Alaska is shown in brown on a 

 black-and-white base map. Alaska Map A of the United States 

 Geological Survey (1947, reprinted 1971) was adapted for this 

 purpose. That widely used map is about 16V£ by 23!/2 inches, 

 scale 1:5,000,000, too large for a book. 



Atlas Volume 2 has page dimensions of approximately 914 by 

 11% inches, somewhat less than Volume 1, 121/2 by 14 inches. 

 The smaller size has advantages, including lower printing costs 

 and retail price, compactness, and convenience. Thus, the maps 

 of Alaska have been reduced to one-half or about 8 by 11 inches, 

 scale 1:10,000,000. It was necessary to trim the right margin 

 slightly, because of page dimensions. General Map 2 is Alaska 

 Map A reduced without other changes to one-half, black-and-white, 

 scale about 158 miles to 1 inch (100 km. to 1 cm.). 



All species maps in this volume have the same size and scale, 

 1:10,000,000. The entire State is displayed, even though the 

 distribution may be restricted. Thus, the ranges of different species 

 may be compared readily with one another and with the general 

 maps. Also, the base maps of contiguous United States for the 

 200 tree species in Volume 1 have the identical scale. Therefore, 

 distances and areas in Alaska and the lower 48 States can be 

 compared visually and directly. Then, beside the smaller States, 

 the vast expanse of Alaska becomes better understood. 



The black-and-white base for the species maps has been simpli- 

 fied by the elimination from Alaska Map A of place names, towns, 

 and railroads, which may be found on General Map 2. Highways 

 have been brought up-to-date through extended lines. To aid 

 orientation there have been added 20 small dots (or rings) at 

 cities, towns, and key points scattered over the State. These dots, 

 roughly from north to south and west to east, are located as fol- 

 lows: Barrow, Prudhoe Bay, Kotzebue, Nome, Bettles, Fort Yukon, 

 Fairbanks, McGrath, Bethel, Dillingham, Kodiak, Anchorage, 

 Seward, Valdez, Yakutat, Skagway, Juneau, Sitka, Wrangell, and 

 Ketchikan. 



The natural distribution or range of a tree or shrub species, as 

 mapped in this Atlas, is the geographical area where the species, 

 including all varieties, is native or wild. Varieties have not been 

 mapped separately, and hybrids are omitted. Mapping is as of 

 the present time, exclusive of changes caused directly or indirectly 

 by European inhabitants. In Alaska the changes in range limits 

 following European settlement are believed to be negligible or 

 recognizable. 



Natural distribution or range of each species is printed clearly 

 in brown on the black-and-white base map of Alaska. Borders 

 of range are shown by lines, except where ocean or lake shores 

 form natural boundaries. The area occupied is filled in b\ dots 



(stippling). Broken lines along the limits of several ndi- 



cate uncertainty of the exact position. 



Within the range limit-, locality r< 1 orda are shown also 

 These dots are based mainly upon published r including 



floras and lists, herbarium specimens, and unpublished sigh - 

 ords by the authors, other observers, and reviewers. Diameter of the 

 dots is almost 3/16 inch (4 mm.), approximately 25 mile- 

 kin. 1. The large size needed for visibility on a map thus compen- 

 sates for minor errors in location and plotting. 



Outlying stations or outliers are shown likewise by dots or, if 

 larger, also by lines. However, the smallest areas, such as a grove 

 with only a few trees, must be enlarged to a dot of similar 

 A circle or open dot indicates a remote locality whose record is 

 subject to verification. 



Presence or absence is shown, but not abundance or density. Any 

 large areas within the main range where a species is known to be 

 absent, for example, high mountains above the timberline and 

 with caps of ice and snow, are marked by lines or holes unshaded 

 within. Commercial range is not indicated for obvious reasons. 

 Such information becomes out-of-date following cutting of virgin 

 forests, abnormal losses by fire, insects, and disease, and changing 

 demands, practices, and standards in utilization. Altitudinal limits, 

 which vary in different latitudes, are not outlined in detail within 

 mountainous areas. 



Thus, the species maps summarize distribution both by dots 

 and by lines and indicate the reliability of the limits drawn, also 

 gaps in the record and where more information is needed. The 

 dots are so numerous that more precise range borders can be 

 indicated than on earlier maps. Botanical exploration in the State 

 has become detailed. Consequently, absence of records of large or 

 conspicuous woody-plant species in certain geographical areas 

 may be significant. 



The species maps do not indicate forest types, forest cover types. 

 or vegetation types, which are the subject of General Maps 22 and 

 23. However, many woody-plant species are characteristic of and 

 largely within certain broad forest or vegetation types. 



These maps do not show where a species grows outside the 

 natural range after having been introduced directly or indirectly 

 by the human species, whether planted, escaped, adventh 

 naturalized. Becords of planted or introduced trees and shrubs 

 outside the continuous natural ranges have not knowingly been 

 plotted. Localities of trees and shrubs planted for forestry, shade, 

 or other uses and of escapes from cultivation purposely have been 

 omitted. Nevertheless, in the future, maps adding forest planta- 

 tions or other introductions beyond the original occurrence may 

 merit compilation. 



Introduced species of trees and shrubs, which are relatively un- 

 common in Alaska, have been excluded. Only one tree species is 

 classed as naturalized, thai is. introduced outside the natural range 

 and thoroughly established and reproducing as though native. 

 European mountain-ash. Sorbus aucuparia I... has escaped from 

 cultivation locally in southeastern \laska. 



Distribution of the tree and shrub species in this volume is 

 not mapped outside of Uaska. However, similar maps of the 

 same species elsewhere are available in other publications or are 

 in preparation. As previously, noted. Volume 1 contains small - 

 maps of North America of Maska's 1 1 species of conifers and 5 

 important hardwoods, including ranges across Canada. The re- 

 maining native tree species ranging south to the contiguous 

 United States will be treated likewise in the forthcoming volume 

 on minor western hardwoods. 



