TY?E OF FOREST AFFECTS I'/ILDLlFE 



Compared xdth other parts of a dense forest, the floor is pre.c- 

 ticolly devoid of animal life. Few animals can utilize it for a per- 

 manent home. Food is scarce, and shelter is scant. On sach a forest 

 the only forms present in any ahundance are those capable of arboreal 

 life. Chickadees ( Penthestes ) , nuthatches (Sitta) , pine squirrels 

 ( Tamiasciurus) , gray squirrels (Sciurus) , and a few chipmunks ( Eutamias ) 

 frequent the treetops. The more-open forests, as those of the pondcrosa 

 pine ( Pinus pondcrosa ) of the West, arc more hospitable to wildlife. Ex- 

 cept in dense reproduction thickets, the trees are so spaced that some 

 light reaches the forest floor. Grasses and herbaceous vegetation thrive 

 in proportion to the openness of the canopy. Here small rodents exist 

 in somewhat greater abundance, and birds and the larger mammals, includ- 

 ing the fur bearers and deer, in notably larger numbers. The sugar pine- 

 fir type of the Sierra Nevadas seems intermediate in v/ildlife carrying 

 capacity. In this kind of forest in California, sugar pine (Pinus 

 lambertiana ) is not reproducing on many largo areas. Instead, white 

 fir ( Abies concolor ) and incense cedar ( Libocedrgs decurrens) predom- 

 inate in the reproduction. 



On any forest, disturbances of catastrophic proportions, as burn- 

 ing or cutting, caase abrupt chan.ges in the biotic community. This was 

 observed in California forests, Follovring logging on the sugar pine-fir 

 type, the ground cover increased rapidly. Herbaceous species, as grasses, 

 shrubs, and especially bur-clover ( Chamaebatia foliolosa ) , grew abundant- 

 ly, the bur-clover forming a tenacious mat on the ground. The habitat 

 v/as vastly improved for small rodents and mice (Pcromyscus sp, and Microtus 

 mordax) , and chipmunks increased from 10 to 50 fold. 



As such an area grows up to broxifse species, deer ( Odocoilous 

 hcmionus ) find it suitable for summer pasture. Ifinter range of doer in 

 this area is more of a restrictive factor than summei* range, and manage- 

 ment that produces additional summer range should also provide the sup- 

 plementary winter range that will inevitably be needed. In a few years, 

 many of the cut -over areas support a large population of Beechey ground 

 squirrels ( Citellus beechoyi boechoyi ) . The statement is often made 

 that this species is extending its range to higher elevations. In tho 

 Stanislaus National Forest, Calif., these squirrels did increase on 

 cut -over areas, either by migration to a habitat made suitable for oc- 

 cupancy by the cu.tting, or ''oy the breeding of relict populations. In 

 either event, the result was a noticeable increase in this highly adapt- 

 able rodent. Because the Beechey groujid squirrel is food for certain 

 predators, its increase may be followed ''oy enlargement of the population 

 of the carnivores, especially when other habitat factors are favorable. 



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