58 BOTANICAL SURVEY OF THE C<EUR D'ALENE MOUNTAINS. 



contrary, the trees of the lowlands thriving only in drier air and soil 

 would not extend far upward, and, in point of tact, we find that the 

 upper limits of the coniferous zones arc far better defined than the 

 lower. 



The Coenr d'Alenes possess no proper foothill region, unless the 

 small area to the east of the north end of Lake Coeur d'Alene can be 

 so called. If there were a central ridge whose slopes were continuous 

 with a lower or plains region, the diversity of climatic conditions now 

 experienced would not be met with inside the Coeur d'Alene triangle, 

 and the forest zones would be far more readily defined. 



I will now pass to the question of the limits of the forest zones and 

 the features which give the distinguishing character to each. 



ZONE OV YELLOW PINK. 



There is first the Lower, or Zone of Yellow Pine. This is at the 

 present time by far the most important from a lumberman's point of 

 view, as, owing to its accessibility, it supplies the larger portion of the 

 logs sawed into lumber. The principal upper and lower limits of its 

 vertical range are between G50 and 850 meters (2,100 and 2,800 feet). 

 It is marked by its open character. The trees stand far apart and there 

 is but a sparse undergrowth, generally made up of species of Opulaster 

 and Rosa, Holodiscw discolor, Ceanothw sanguineus, and an occasional 

 Philadelphus lewisii. The ground is covered with a fair, sometimes a 

 very luxuriant, growth of grass, principally species of Festuca and Poa, 

 with occasionally an area of sedge— Carex geyeri. There is not much 

 fallen timber. Where the growth is pure the forest is park like and 

 has a clean and open appearance. 



Usually, however, the growth is mixed, and here and there among the 

 yellow pines are more or less extensive groves of Douglas spruce, white 

 fir, and the lowlands form of the black pine. In low or moist places 

 will be found the tamarack. The Douglas spruce sometimes replaces 

 the yellow pine to the extent of 75 to 80 per cent, and the black pine 

 occasionally crowds it out altogether. In such cases the forest growth 

 is dense. A heavy stand of these species is a sort of transition ground 

 to the next section. The undergrowth will be the same as that of the 

 typical yellow-pine forest, but in addition there will bo a multitude of 

 young trees of the white fir, so crowded that the larger number will 

 never develop beyond mere shrubs. 



The number of trees to the acre varies so greatly that it is almost 

 impossible to give, even approximately, an accurate estimate. T should 

 consider that in a yellow-pine forest untouched by the ax, 20 to ,"50 

 trees of Finns ponderosa or of Pscudotsuga, 70 cm. (28 inches) and 

 upward in diameter, would be a fair average. Where the timber is 

 mixed the diameters of the trees will average much less and the num- 

 ber is greatly increased. Thus in a black-pine grove an estimate of 

 1,000 to 1,200 to the acre, 15 cm. (0 inches) and upward in diameter, 



