FIG 23-5 Gallery pattern of a bark beetle in lodgepole pine: 

 (a) nuptial chamber, (b) egg gallery, (c) egg niche (Reid 

 1955). 



northern states during the last 75 years and caused 

 considerable defoliation and destruction of tamarack 

 (Coppel and Leius 1955). The spruce budworm (a 

 lepidopteran larva) feeding on the leaves has killed 

 balsam fir and spruce trees on vast areas at repeated 

 intervals in the past: 1807-18. 1870-80, 1904-14 

 (Swaine and Craighead 1924). and again in the 

 1940's Several kinds of bark beetles, wood borers, 

 and long-horned beetles are also destructive forest 



insects. , ,■ i r 



Beetles, ants, aphids, jumping plant lice, leaf- 



FIG. 23-6 Seasonal history of a baric beetle (Reld 1955). 



, OVER 



V^SnG MAV JUNE JULY _^U^ JEPIJ^^!!^^:^ 



hoppers, and spiders, and invertebrates— notably 

 snails, annelids, and millipedes— are not numerous 

 over most of the biome (Rasmussen 1941, Hay ward 

 1945. Blake 1945). Most ground invertebrates have 

 higher population densities in the serai aspen and 

 birch stages than in the coniferous climax (Hofif 

 1957). Reptiles are few. only the garter snake ex- 

 tends very far north. The northern wood frog, leop- 

 ard frog, and mink frog are widely dispersed in 

 suitable habitats throughout the boreal biociation. 

 Because of its greater humidity and more equable 

 temperatures, invertebrates and cold-blooded verte- 

 brates are generally more numerous in the Coast for- 

 est than elsewhere through the biome. 



HUMAN RELATIONS 



Only the lower, warmer portions of the 

 coniferous forest biome are permanently inhabited in 

 large numbers by white man throughout the year. 

 Logging for pulpwood and lumber is an important 

 occupation. Over the more rugged northern portions 

 of the coniferous forest, the population is scattered 

 and in North America, there are more Indians than 

 whites, at the present time. The Indians engage in 

 hunting and fur-trapping for support. Larger settle- 

 ments of white men occur where minerals may be 

 mined or oil obtained. These regions, as well as the 

 higher conifer-clad mountains, are resorted to for 

 fishing and other recreational activities during the 

 warm summer months. 



WOODLAND BIOME 



In contrast to forest, woodland is an open 

 stand of trees with an intervening good growth of 

 grasses or shrubs. The trees are usually short, 6 to 15 

 m high (20 to 50 ft) , but may have a dense crown. In 

 favorable local habitats, the trees form a closed 

 canopy, but in arid situations they are scattered 

 The trees vary widely in leaf structure, but nearly all 

 species are evergreen and tolerant of low moisture. 

 In North America, woodland of different types ex- 

 tends from Washington and Wyoming well down 

 into Mexico. A similar type of broad-leaved ever- 

 green sclerophyllous woodland, together with chapar- 

 ral, occurs around the Mediterranean Sea in Eurasia 

 and Africa. 



CLIMATE 



In Utah, precipitation in this biome ranges 

 from 4 to 6 cm (10 to 15 in.) per year, and mean 

 monthly temperatures from — 5°C to 21 C {li to 

 69°F) (Woodbury 1947). Precipitation is often 



310 Geographic distribution of communities 



