Overall, these data indicated that, in unburned timbered 

 habitats, the trend during the last 20 years has been toward 

 increasing overhead canopy, with a decline in coverage by 

 snowberry, currant, gooseberry, and probably rose. Shrub 

 species showing an increase, or at least no significant 

 decrease, included fragrant sumac, rubber rabbitbrush, and 

 green rabbitbrush. 



Eichorn and Watts (1984) reported that burning of mature 

 stands in the Douglas fir-juniper type on this area increased 

 canopy coverage of snowberry, rose, and chokecherry. They 

 also noted a similar increase in shrubs on burned pine-juniper 

 types, though the ultimate increase and canopy coverage was 

 less than occurred on the Douglas fir- juniper type. 



As part of a study of the ecology of fragrant sumac in 

 Montana, Martin (1972) established 5 point-center-quarter 

 transect plots on the study area, each of which included 20 

 tagged fragrant sumac plants . These plants and transects were 

 first measured in 1971 and subsequently remeasured in 1982 

 and 1986 (Table 3.11). None of the 100 fragrant sumac plants, 

 tagged in 1971, were dead in either 1982 or 1986. Plant 

 diameter, area, volume, corrected plant area, and corrected 

 plant volume were all significantly greater in 1982 and 1986 

 than in 1971. The percent crown dead remained the same in 

 1982 as 1971, but there was significantly less percent crown 

 dead in 1986 than in 1971 or 1982. Height was significantly 

 lower in 1986 than 1982. Despite considerable girdling by 

 microtine rodents in winter 1978-79, all fragrant sumac plants 

 present in 1971 continued to live, and in aggregate, increased 

 in area and volume. 



Although, as noted above, all 100 fragrant sumac plants 

 tagged in 1971 were still alive in 1986, point-centered- 

 quarter measurements for 1972 and 1982 (Table 3.12) indicated 

 a relative decline in the number, density, and frequency of 

 plants. That resulted because the point-centered-quarter data 

 gives relative values, not absolute values. The 2 sets of 

 data (Tables 3.11 and 3.12) indicated that, although numbers 

 of fragrant sumac and rubber rabbitbrush plants probably were 

 similar in 1972 and 1982, the numbers of other shrubs, 

 especially snowberry, had increased. Four of 5 of these sites 

 had been burned more than 25 years previously and, as 

 predicted by Eichorn and Watts (1984), some overstory 

 sensitive shrubs may have continued to increase following 

 initial measurements in 1972. 



Collectively, the measurements indicated that increasing 

 or at least stable shrub populations occurred on most 

 transects despite 1 to 2 "irruptions" of the mule deer 

 population over the intervening years, consistently heavy use 

 of rubber rabbitbrush plants by deer, and at least occasional 



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