TOPOGRAPHY AND LIFE ZONES OF OREGON [ 39 ] 



that scatter islands of yellow pine all through the lodgepole. Such 

 anomalies as these confuse the beginner's efforts to understand life zones 

 and make for the serious student a fascinating puzzle to fit together. 

 Incidentally, studies of these unusual distributions often throw much 

 light on the factors affecting distribution of species. 



Red elder (Sambucus callicarpa), mountain-ash (Pyrus sitchensis), service- 

 berry {Amelanchier), mountain maple {Acer douglastt), and balsam poplar 

 (Populus balsamifera) are commonly found in the zone. Among the char- 

 acteristic herbaceous species of plants are beargrass (Xerophyllum fenax), 

 Oregon box (Pachistima myrsinites), several low blueberries (Vaccinmm), 

 the dainty twinflower (JLinnaea borealis), a low-growing manzanita (Arcto- 

 staphylos nevadensis), several species of Arnica, and Clintonia uniflora. 



Mule deer (Odocoileus), snowshoe hares (Lepus) t conies (Ochotona), flying 

 squirrels (Glaucomys}, martens (^Martes), shrews (^Sorex), chipmunks (Euta- 

 mias), pine squirrels (Sciurus), and many forms of mice are peculiar to 

 this zone or have their greatest abundance here. 



Among the most noticeable and characteristic breeding birds are the 

 Harlequin Duck, Barrow's Golden-eye, Richardson's and Gray Ruffed 

 Grouse, Williamson's, Red-naped, and Red-breasted Sapsuckers, Arctic 

 and Alaska Three-toed Woodpeckers, Olive-sided Flycatchers, Rocky 

 Mountain and Gray Jays, Cassin's Finch, White-crowned Sparrows, Jun- 

 cos, Water Ouzel, Crossbills, and Evening Grosbeaks. 



HUDSONIAN ZONE 



THE HUDSONIAN is the timber-line zone surrounding the highest peaks in 

 the State. In many ways it is poorly defined, and most of the species 

 found in it overlap into the zones above and below. In reality it is an 

 enchanted land where one may wander through clumps of grotesque 

 misshapen trees and meadows bedecked with flowers of all the hues of 

 the rainbow. The altitudinal range of the zone itself, which is generally 

 1,000 feet, or less, and does not exceed 1,500 feet, may occur anywhere 

 between 6,000 and 9,000 feet, depending on slope and exposure. For 

 example, on Mount Hood, at the northern end of the Cascades, timber 

 line is at approximately 6,000 feet on the northern slope and 7,000 on 

 the southern slope, whereas on Mount McLoughlin (Mount Pitt), at the 

 southern end of the Range, it is at 7,000 feet or more. In the Wallowas, 

 timber line is at approximately 8,000 feet on cold exposures and 9,000 feet 

 on warmer exposures, whereas in the Steens Mountains, the correspond- 

 ing figures are approximately 500 feet higher. There are no great areas 

 of Hudsonian Zone anywhere in the State. The area about the bases of 

 the Three Sisters and Broken Top forms the largest continuous mass in 

 the Cascades. In the higher parts of the Wallowas there is also con- 



