590 JOURNAL OF FORESTRY 



many plants, particularly grasses, which are always present as a dis- 

 tinct layer society. These quickly form an almost impenetrable sod, so 

 that seed of pine not only finds cover with great difficulty, but is sub- 

 jected to the keenest competition for moisture in a situation which is, at 

 best, semi-arid. I will not attempt to trace in detail the struggle which 

 ensues. Suffice it to say that lack of moisture, early frosts, and lack 

 of winter snow, when the denudation has gone to any great extent, 

 retard the return of the climax formation for many years. It is there- 

 fore of the utmost importance to forestry that cutting in this formation 

 should be very conservative, and that even grass fires should be ex- 

 cluded with all vigilance. In some localities white fir (A. concolor) 

 appears as subdominant (society) in this formation. This is rarely, 

 however, of any great significance. Since it is favored by shade and 

 by the moisture of stream banks, it is probable that it can be completely 

 excluded from the reproduction by the kind of cutting which is most 

 favorable to yellow pine. 



When we turn to the Douglas fir formation we have a much more 

 complex problem. First, let me state that this forest, being fairly 

 dense and yet rarely too moist to permit the spread of fire, has been 

 most deplorably ravaged. The Douglas fir forests now remaining in 

 Colorado and Wyoming probably cover no more than 5 per cent of 

 the area which they once occupied. In Wyoming and in Colorado as 

 far south as the Pikes Peak region in the east and the Gunnison-Rio 

 Grande Divide in the west, the Douglas fir formation has been so com- 

 pletely invaded by lodgepole pine that there is little possibility of a 

 natural return to the climax formation within the next 500 years. In 

 many cases one may travel for miles through this forest without seeing 

 a vestige of the Douglas fir. Here, of course, succession must be re- 

 tarded by the lack of material for migration. Again, an occasional 

 large and thrifty seed-tree of Douglas fir will be found in the lodge- 

 pole forest, but its progeny are absolutely nonexistent. An explanation 

 of this failure to reproduce is one of the most important questions 

 facing us. For the most part, Douglas fir has been relegated to dry, 

 rocky areas in which a fire could not spread and from which, it is 

 readily seen, the fir can spread only very slowly. 



It is thus plainly evident that the treatment of the lodgepole sub- 

 climax forest is a distinct problem in itself. Some of us believe that 

 the climax formation would be so much more valuable to forestry as to 

 justify its artificial restoration, and investigations are now being made 

 along this line. 



