52 UNIVERSITY OF COLORADO STUDIES 
Picea engelmanni (Parry) Engelm. ENGELMANN SPRUCE 
A handsome conical tree frequently forming pure forests at about 10,000 to 11,000 ft. 
Common everywhere in the higher altitudes throughout the county. It forms most of 
the “wind timber” at timber line. Used for timber and railroad ties. The lumber is 
known locally as “white spruce.”’ 
Altitude: 8,500 to 11,500 ft. Collections: Eldora, Silver Lake. 
Pseudotsuga mucronata (Raf.) Sudw. DoucLas SPRUCE 
A handsome broad-based conical tree of moist gulches and north slopes. It has a 
less compact and more feathery appearance than the true spruces. The wood is valuable 
scopulorum 
Sargent 
angustifolia 
scopulorum 
fontinalis 
Rubus 
deliciosus 
Alnus tenuifolia 
tremuloides 
mucronata 
involucrata 
murrayana 
Picea parrayana 
fruticosa 
Pinus flexilis 
Abies lasiocarpa 
= 
= 
5 
2 
2 
> 
= 
wv 
2 
= 
a 
Acer negundo 
Crataegus spp 
Sabina 
Populus 
Populus 
Pinus 
Betula 
Populus 
Juniperus 
Paeudotsuga 
Distegia 
Dasiphora 
Vaccinium 
CHART ILLUSTRATING ALTITUDINAL DISTRIBUTION 
The figures at the left indicate altitude above sea level expressed in feet. The lowest 
point in Boulder County is about 4,900 ft. Probably most of the species which are indica- 
ted as extending down to 5,000 ft. really reach to the lowest point in the county. The 
species selected for the chart are those most easily recognized without attention to minute 
characters. 
for lumber and when used locally is known as “red spruce.” Young trees are cut for 
decoration at Christmas time. 
Altitude 6,000 to 10,000 ft. Collections: South Boulder Canyon; Gregory Canyon; 
Sugarloaf Mountain; Eldora. 
Abies lasiocarpa (Hook.) Nutt. BatsAm Fir 
Usually a small tree, but sometimes 3 to 4 dm. in diameter. In the lower parts of 
