Figure 3. — Dense stand of 

 advanced reproduction of 

 Rocky Mountain Douglas - 

 fir under a well-stocked 

 overs tory of mature 

 ponderosa pine on a risk 

 rating plot in the Piquett 

 Creek Experimental Area, 

 Bitterroot National 

 Forest, Montana. 



The serai nature of ponderosa pine in most of the plot stands is only partially 

 indicated by these nonpine tree species in the overstory. More conclusive evidence of 

 ponderosa pine's serality in the plot stands is the intrusion in recent years of increas- 

 ing amounts of nonpine reproduction in the understory stands of the plots. Dense 

 stands of Rocky Mountain Douglas-fir, in particular, now occupy the ground under the 

 pine canopy on parts of some plots (fig. 3). Stimulated by effective control of wild- 

 fires and by growing conditions that have favored nonpine species during the past three 

 decades, resultant nonpine reproduction is preventing or crowding that of ponderosa 

 pine in many of the plot stands. 



Observations disclosed that the pine understory on most of the plots was so sparse 

 that its maturation will produce timber yields far short of those expected from ponderosa 

 pine site indexes 70, 80, or 90 that the plots represent (Meyer 1938). 



The mean stocking density for all species ranged for each plot stand from 14.7 to 

 44.9 trees per acre (12,920 to 25,730 gross board feet per acre). The mean stocking 

 density for ponderosa pine alone ranged for each plot stand from 14.7 to 37.3 trees 

 per acre (9,990 to 25,200 gross board feet per acre) (fig. 4). The stocking densities 

 for pine and nonpine species are shown for each of the 35 plots in tables 1 and 2. 



9 



