552 Part IV. Chapter 3. 
at an elevation between 11,000 and 12,000 feet. In the Vellowstone National 
Park timber line is at 9,600 feet elevation. on the peaks and somewhat higher 
on the table-lands. In Colorado timber line as on Pikes Peak js at 11,500 feet 
and the altitudes of the belts mentioned for the Coeur d’Alene Mountains are 
much higher for the same belts in Colorado farther south. This fact should be 
born in mind, as it explains the apparent discrepancy in the member of feet 
given for the altitudinal distribution of each species. 
The forest on many ranges of the northern Park Mountains exhibit three 
distinct types, viz: (1) the belt of Pinus Ponderosa'), (2) the belt of Pinus mon- 
tcola, (3) the belt of Adies subalpina (= A. lasiocarpa°’). The Pinus pon- 
derosa-belt does not extend above 2,900 feet although on warm southern 
exposures it may go as high as 4,700 feet. It consists of Pinus ponderosa 
(10 per cent.), Pseudotsuga Douglasii (70 per cent.), Adies grandis (15 per 
cent.), Larir occidentalis, Pinus Murrayana. The altitudinal limit of Pinus 
ponderosa as a timber tree is 3,500 feet above sea-level, while Pseudotsuga 
readily ascends to 4,500 feet on the slopes facing the south west and east. 
Larix occidentalis is a bench-land tree associated with Pinus ponderosa in 
such places. In the Bitterroot Mountains, Pinus ponderosa forms a belt reach- 
ing to 5,800 feet; in the canyons it extends from two to three miles above 
their outlet. On the east side of Bitterroot Valley, it fringes the tributary 
canyons sometimes with a pure growth 3). 
In the neighborhood of Pikes Peak, Colorado, Pinus ponderosa is the most 
abundant and widely distributed tree and is found from the lowest altitude 
(under 6,000 feet) up to above 10,000 feet where it is supplanted by the other 
species. In some places, it forms a true forest, but as a rule Psendotsuga 
Douglasii is more or less plentifully associated with it and occasionally it 
occurs mixed with Pinus Murrayana. On south slopes, rocky ledges 8,000 feet \ 
to timber line 11,00 feet, Pinus arıstata, Pinus edulis, Picea Engelmamiı, 
Picea Parryana = P. Pungens, etc. On the higher it is not so localized as 
in the lower slopes where it predominates on slopes facing the south, while 
Pseudotsuga is more plentiful on those facing the north. This is a marked 
feature in most of the canyons and gulches which extend in an easterly and 
westerly direction. 
e =“ 
u Ali; > hc + An a aan En a 1 > ah TE nt 
Ende dr a " 
REN RE ON 
Bang a 1 Szene Zar Enkel age na aaa 
ERS N 
a A A LA DZ 
Pinus ponderosa is abundant at 8,000 feet in southwestern Colorado. Ac- 
cording to BRANDEGEE Pinus Rexilis, an uncommon tree here, grows with it 
at an altitude of 8,500 feet as do also Abdies grandis, A. Menziesii, Piwea 
Engelmanni, Pseudotsuga. 
I) In this belt always Pinus ponderosa, var. seopulorum (Editor.). “ 
2) See also LEIBERG, JOHN B.: General Report on a botanical Survey of the Coeur d’ Alene 
Mountains in Idaho during the Summer of 1895. Contributions U. $. National Herbarium V? 
ı—85. 1897. 
3) PAmmEL, L.H.: Notes on the Flora, especially the forest Flora of the Bitterroot Mountains. 
Iowa Academy of Sciences 1904: 87—100 with 6 plates, 
