Seven tree species are widespread in the interior or northern 

 coniferous forests from Alaska across Canada to Labrador, New- 

 foundland, and the northeastern contiguous United States: tama- 

 rack {Larix laricina) , white spruce {Picea glauca) , black spruce 

 (Picea mariana) , paper birch {Betula papyrifera) , balsam poplar 

 (Populus balsamifera) , quaking aspen {Populus tremuloides) , 

 and Bebb willow (Salix bebbiana) . 



A few species of low shrubs are almost everywhere or cosmo- 

 politan having ranges nearly throughout the. interior and south- 

 east except on areas covered by perpetual ice and snow. Examples 

 are crowberry (Empetrum nigrum), bog blueberry (Vaccinium 

 uliginosum) , mountain-cranberry (Vaccinium vitis-idaea) , and 

 netleaf willow (Salix reticulata). 



Many species of Alaska's arctic shrubs are widely distributed 

 in far northern regions around the globe, or circumpolar, across 

 Canada, Europe, and Asia to Siberia. Others extend just to 

 northern Europe or to Siberia. Some, known as arctic-alpine 

 species, occur southward above the timberline in the alpine zone 

 of the Rocky Mountains and high peaks of New England. 



As shown on the maps, a few tree species are rare and local 

 at their northern limits in southeastern Alaska. However, all 

 extend southeast into some of the lower 48 States and are not 

 endangered. Examples are Pacific yew (Taxus brevifolia) , Pacific 

 silver fir (Abies amabilis) , subalpine fir (Abies lasiocarpa) , and 

 Hooker willow (Salix hookeriana) . 



APPLICATIONS OF THE MAPS 



Several applications of these maps of Alaska trees and common 

 shrubs may be mentioned, though most uses are obvious and 

 have been noted in Volume 1. First, the maps show where each 

 species grows wild and can be found for study for any purposes. 

 Also, where plantations or plants from locally collected seed should 

 be successful. 



It is hoped that the maps will be useful in land-use planning 

 in the 49th State. Some native species may be plant indicators 

 whose presence may indicate or show certain combinations or 

 tolerances of climate or soil conditions, or the suitability for 

 agricultural crops or other uses. Maps have economic values, 

 suggesting possible sources of wood and other products in addi- 

 tion to the detailed information on timber volumes provided by 

 forest surveys. 



The maps may arouse interest in their improvement and encour- 

 age further botanical exploration in Alaska to fill the gaps in 

 records. To specialists, the maps may reveal errors and suggest 

 corrections, also likely localities where further field work is 

 needed for revision and where range extensions and State records 

 may be sought. The natural ranges are preserved for the historical 

 record, before the forests and other vegetation types are destroyed 

 or changed, for example, by plantations and settlements. 



The general maps and the species maps together summarize 

 graphically the average and extreme conditions of the environ- 

 ment (temperature, precipitation, latitude, altitude, etc.) of each 

 species. They provide the basis for correlation studies of distri- 



bution of a species and the environment, including limiting fac- 

 tors. Also, there may be indicated local climates to which 

 geographical or local races may be adapted. 



In the collection of seed, maps can be useful. They show where 

 seed can be collected from wild plants and suggest the possible 

 occurrence of geographic races and seed sources, especially in 

 far northern regions. Examples are tree improvement programs 

 and testing or introduction beyond the native range, such as in 

 foreign countries with similar climates. 



Maps can be helpful in identifying wild trees and shrubs, 

 indicating the presence or absence of a species in a particular 

 area. Finally, the maps serve as background material for such 

 studies as classification, evolution, paleobotany, and genetics. 



There is still much to be learned about tree and shrub distribu- 

 tion in Alaska. The earlier request for additional data, particularly 

 regarding the ranges of trees and shrubs, is repeated here. This 

 information can be sent to the Institute of Northern Forestry, 

 USDA Forest Service, Fairbanks, Alaska 99701. 



ACKNOWLEDGMENTS 



Credit is due many persons for assistance in the preparatior 

 of this Alaska volume of the Atlas. Professor Eric Hulten, Natur- 

 historiska Riksmuseum, Stockholm, Sweden, the foremost author- 

 ity on Alaska plants, prepared and published the detailed species 

 distribution maps which served as the beginning of the larger 

 ones appearing here. 



George W. Argus, National Museum of Canada, Ottawa, Ontario, 

 published similar species maps of the genus Salix, willow, in 

 Alaska and assisted in identifying collections. Thanks are due 

 the University of Alaska Herbarium, Fairbanks, for the privilege 

 of compiling distribution records from the large plant collections. 



Many reviewers have helped greatly in the revision of the 

 species maps, especially in making available their unpublished 

 records. Foresters of the Forest Service at Juneau, Anchorage, 

 and elsewhere have aided from their store of field experience. 

 Among these, Arland S. Harris, research forester, has contributed 

 much information on tree ranges in southeast Alaska. 



Other reviewers of the preliminary maps meriting special 

 mention for their significant contributions include: John Dennis, 

 research biologist, National Park Service, Anchorage, Alaska; 

 Dennis R. Jaques, Concord, California; Herbert Melchoir, research 

 associate, Cooperative Park Studies Unit, University of Alaska, 

 Fairbanks; Charles Racine, assistant professor, Department of 

 Botany North Carolina State University, Raleigh, North Carolina; 

 Kurt Rein, forester, Joint State-Federal Land Use Planning Com- 

 mission, Resource Team, Anchorage; Stanwyn G. Shetler, curator, 

 Department of Botany, U.S. National Museum of Natural History, 

 Washington, D.C.; Lloyd A. Spetzman, botanist, Agricultural 

 Research Service, U.S. Department of Agriculture, Beltsville, 

 Maryland; Gregory P. Streveler, research biologist, Glacier Bay 

 National Monument, National Park Service, Juneau; Stanley L. 

 Welsh, professor of botany, Brigham Young University, Provo, 

 Utah; and Steven B. Young, director, The Center for Northern 

 Studies, Wolcott, Vermont. 



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