fire chronology starting in the early 1600's (except 

 plot F-2) was developed for each plot by correlating 

 dates obtained from individual trees. 



The six dry site stands occurred at relatively high 

 elevations on moderately steep (45 to 55 percent) 

 south-facing slopes on the Bitterroot and Lolo National 

 Forests (fig. 1). These represent the Pinus ponderosa 

 phase of the Pseudotsuga menziesiilCalamagrostis 

 ruhescens habitat type (h.t.) (Pfister and others 1977), 

 a common dry site-type for serai ponderosa pine. 



The three Bitterroot National Forest plots are lo- 

 cated within about 0.3 mile of each other on a broad 

 slope directly north of Fales Flat Campground, south- 

 west of Darby, MT, (fig. 1). This site lies at 5,400 to 

 5,900 ft elevation and is near the chmatic (cold) Hmits 

 of the ponderosa pine type, where pine/Douglas-fir 

 gives way above to pure Douglas-fir. We located the 

 plots within the large patches where ponderosa pine 

 was a major component of the overstory. Analysis of 

 multiple fire scar sequences (Amo and Sneck 1977) 



50 miles 



Figure 1 — General location of the old growth ponderosa pine/fir study plots. 



2 



