CONIFERS OF THE ROCKY MOUNTAIN REGION. 5 



The tree grows on shallow, moist soils of nearly every consistency, 

 from stiff clay to coarse sand, but thrives on moderately retentive 

 loams, especially those with rich leaf mold. The occurrence of 

 tamarack in saturated soil seems to indicate not so much a special 

 requirement as it does ability to exist where other species more 

 tolerant of shade can not grow. Tamarack does not grow well, 

 however, where its roots are constantly submerged, particularly 

 during the summer season. It occurs in open scattering stands 

 mixed with black spruce, black cottonwood, alder, and willows, or 

 sometimes forms rather dense, pure growths of limited extent. 

 Even in the closest stands, however, the crown cover is never very 

 dense, for it requires a great deal of light throughout life, at no time 

 enduring heavy shade. 



Larix laricina produces seed abundantly about every 2 to 4 years, 

 some seed being borne annually. Trees begin to bear cones at an age 

 of from 10 to 20 years, seed production increasing rapidly thereafter up 

 to an age of about 100 years, after which it decreases in amount and 

 regularity. The seed has only a moderately high rate of germination 

 and fairly persistent vitality. Conditions favorable to germination 

 of the seed and early growth of the seedlings are fresh organic 

 or mineral soil, with a sparse protecting cover of grass or herbs. 

 Seedlings require this slight protection at first; afterwards in full light 

 they grow fairly rapidly in height, so that they persist in mixture 

 with more tolerant but slower growing species of the same age. 



LONGEVITY. 



The largest trees are from 150 to 180 years old; those from 10 to 

 12 inches through are from 60 to 75 years old. 



WESTERN LARCH. 



Larix occidentalis Nuttall. 



COMMON NAME AND EARLY HISTORY. 



Western larch is known to lumbermen and settlers in its range 

 only as " larch," a name which is applied more or less also to other 

 native species of Larix. The common name western larch, a literal 

 translation of the technical name, is suggested in order to avoid 

 confusion. 



The first discovery of Larix occidentalis was made in 1806 by 

 by Lewis and Clark, 12 whose narrative tells of finding a "larch tree," 

 now believed to be the western larch, on the upper Clearwater River 

 in western Montana. It is evident that the Scotch explorer David 

 Douglas 13 was the next one to observe this tree, on the Columbia 



12 History of the Expedition under command of Lewis and Clark (ed Coues), III, 1043, 1066, 1806. 

 is Companion Botanical Magazine II, 109, 1836. 



