35^ Forestry Quarterly. 



a thickness of from 1.5 to 2 inches. Contrary to the usual 

 opinion, the low, dense crown of the seedling growth is not par- 

 ticularly inflammable, and, especially in the heavy clump growth, 

 serves as a protection against fire rather than as a means of in- 

 creasing the liability to injury from this source. 



Local Occurrence. This species does not occur in pure stands 

 over extensive areas', although at higher elevations, on sites where 

 moisture conditions are favorable, it sometimes forms a full 

 stand over areas several acres in extent. One such stand, in Sec- 

 tion 16, Twp. 35 S., Range 6 East, at an elevation of about 6000 

 to 6400 feet, consists of a fairly dense, thrifty growth of mer- 

 chantable White fir. There is very little reproduction under the 

 stand and the forest floor is quite clean- Practically all of the 

 suppressed class is dead. This tract has a slope toward the east 

 of 10% to 25%. The soil is a rocky loam and has about 1/2 

 inch of humus. Another tract, in which the site conditions are 

 similar, is located in Section 20, Twp. 32 S., Range 6 East. The 

 stand in this case is just above the pole stage. The forest floor 

 is fairly clean, there is no reproduction, and most of the sup- 

 pressed trees are dead. Such areas as those just mentioned are 

 not numerous and it is probable that the conditions found in 

 these two are characteristic. 



As already stated, the usual manner of occurrence, especially 

 at the lower altitudes is in pure clumps in mixture with the Yellow 

 pine stand. These clumps vary from a few square feet to sev- 

 eral rods in extent. A clump usually starts in some protected 

 spot, or on a decayed log where surface moisture conditions are 

 good, and the dense cover, by reducing the rate of evaporation 

 serves to extend the favorable moisture conditions around the 

 border of the clump. This margin is gradually taken possession 

 of by more seedlings and the group thus increases in size. As a 

 group continues to spread, the edges come into competition with 

 Yellow pine and the area growth is checked. During this period 

 of development the older trees at the center of the group are 

 being differentiated into crown classes and a few dominant trees 

 finally secure control. These, of course, continue to develop at 

 the expense of the smaller trees, gradually shading them out, 

 until in the final stage the original clump is represented by two or 

 three or perhaps a half dozen merchantable trees that have sur- 



