REFORESTATION IN NORTHERN IDAHO 39 



fir, tamarack, Douglas fir and cedar, the thick-barked tamarack 

 suffered least and often only the trees of this species less than 6 

 to 8 inches in diameter were killed. This gave rise to what are 

 apparently nearly pure forests of tamarack; but in most all 

 cases sufficient seed trees of the other species were left to insure 

 re-seeding; and at present a new generation of white fir and 

 tamarack are especially prominent (fig. 6) . In some of the more 

 accessible canons, lumbering has been carried on and in some 

 places the operations of the lumberman have been followed 

 by ground fires, some of which must have occurred not more 

 than 5 years prior to the time when the authors made their 

 observations. 



On these most recent burns the predominating plants were 

 Epilobium angustifolium, and Carduus breweri and occasional 

 specimens of Erigeron acris. These three species along with 

 other annuals and biennials and some young willows afforded 

 conditions suitable to the early growth of the scattered seedlings 

 of Larix, Pseudotsuga and Pinus ponderosa, which had already 

 established themselves. On those slopes formerly occupied by 

 a mixed forest of larch, Douglas fir, white fir, spruce, and white 

 cedar, it was interesting to note that in the older burns these same 

 species had succeeded in reestablishing themselves. Cutting off 

 a large number of the trees of each species at the surface of the 

 ground and counting the annual rings, it was found that the 

 most xerophytic species, i.e., Douglas fir, yellow pine, and larch, 

 were the oldest, and therefore, the first to establish themselves. 

 It is also a matter of interest to note that a period of 2 or more 

 years must elapse before any but a limited number of even the 

 hardiest of these trees can launch into permanency. Naturally, 

 those slopes and situations affording the greatest degree of 

 protection from evaporation and excessive heat and light produce 

 a more abundant stand of those annuals and biennials which pre- 

 pare the way for the coniferous forest of later years. And 

 observation has shown that the preparation of exposed slopes for 

 coniferous seedlings is considerably delayed because of the lim- 

 ited number of individual herbaceous plants produced in any 

 season and the consequent slow accumulation of humus. 



