222 



3^ 



Wildlife and 



Old-Growth Forests 



in Southeastern 



Alaska 



John W. Schoen 



Matthew D. Kirchhoff 



Alaska Dcpt. of Fish and Game 



P.O. Box 20 



Douglas, Alaska 99824 



Jeffrey H. Hughes 



Alaska DepL of Fish and Game 



333 Raspberry Road 



Anchorage, Alaska 99518 



ABSTRACT: The archipelago and coastal mainland that comprise soulhcaslcm 

 Alaska include millions of heclares of old-growth forest, most of which is administered 

 by the U.S. Forest Service. This old-growth forest includes a mosaic of different stand 

 types that vary in form, function, and value to different species of wildlife. Certain types 

 of old growth, particularly low elevation, high-volume stands (productive sites with 

 large trees), arc rare in the national forest and are heavily used by numerous wildlife 

 species including the Sitka black-tailed deer {Odocoileus hemionus silkensis), brown 

 bear (JUrsus arcios), and bald eagle (Haliaeelus leucocephalus). Scheduled clearcul 

 logging of old-growth limber on ihe Tongass National Forest will not affect a large 

 percentage of the land area but will have significant and long-lasting effects on our 

 inventory of certain old-growth types and their associated wildlife species. Old growth 

 should be recognized as a diverse and complex mosaic of forest types. Maintenance of 

 adequate populations of many wildlife species in southeastern Alaska will require 

 maintaining the natural diversity of forest types that comprise the old-growth 

 ecosystem. 



INTRODUCTION 



Southeastern Alaska is characterized by 

 rugged mountains, rain-shrouded forests, 

 and thousands of kilometers of marine 

 shoreline. At nearly 7 million ha, the 

 Tongass National Forest is the largest 

 national forest in the United States and 

 encompasses more than 90 percent of the 

 land base of southeastern Alaska. The 

 Tongass is located along a narrow coastal 

 band from Dixon Entrance north to 

 Yakutat Bay and includes the islands of 

 the Alexander Archipelago (Figure I). 



Although old growth is rare throughout 

 most of North America today (Thomas et 

 al. in press), old-growth rain forest is a 

 predominant feature of southeastern 

 Ala.ska. These forests provide valuable 

 resources (e.g., salmon, timber, and 

 wildlife) upon which many residents 

 depend for their livelihoods. Old growth 

 also provides important habitat for a 

 variety of wildlife and fish species, as 

 well as abundant recreational 

 opportunities for local residents and 

 increasing numbers of tourists. 



FOREST ECOLOGY 



What is an old-growth forest? In 

 southeastern Alaska, old-growth forests, 

 primarily western hemlock-Sitka spruce 

 (Tsuga heterophylla-Picea sitchensis), 

 have developed over centuries in the 

 absence of widespread, catastrophic 

 disturbances (e.g., wildfires). These 



forests (Figure 2) are dynamic, steady- 

 stale forests (Bormann and Likens 1979) 

 where the death of old trees is balanced 

 by the growth of new trees. Seedlings, 

 saplings, and pole-sized trees grow in the 

 scattered openings that are created as 

 large old trees die and fall to the forest 

 floor. Trees of all ages occur in such 

 stands, and the ages of dominant trees 

 typically exceed 3(X) years. In some 

 stands the oldest trees are more than 800 

 years old, 3 m in diameter, and 60 m in 

 height 



Old-growth forests have broken, 

 multilayered canopies through which 

 sunlight penetrates to the forest fioor. 

 The forest floor of an old-growth stand is 

 carpeted by an abundance of ferns, 

 mosses, herbs, and shrubs (Alaback 

 1982). Lichens and fungi add to the 

 ecological diversity found in old-growth 

 forests as do standing snags and decaying 

 logs, both on the ground and in streams. 

 Old growth is structurally complex and 

 provides unique habitat for many species 

 of plants and animals (Franklin et al. 

 1981, Schoen et al. 1981, Meehan et al. 

 1984, Sigman 1985, Thomas et al. in 

 press). 



When old growth is clearcut, the 

 ecological relationships on the site 

 change dramatically. Following 

 clearcutting in southeastern Alaska, 

 herbs and shrubs grow abundantly and 

 spruce and hemlock seedlings become 

 established. After fifteen years saplings 



138 Natural Areas Journal 



Volume 8 (3), 1988 



