the bankfull width of the channel. The wood count was adjusted to stem density/ 1000'. 

 We also counted all functional instream wood associated with the pools and recorded 

 their function (e.g. vertical scour). Methods for measuring woody debris included 

 counting and recording the number of woody stems in one of four diameter categories (4 - 

 12"; 1'- 2'; 2' - 2.5' and > 2.5'), and one of three length sub-categories (5' - 16'; 16' - 

 <50'; and > 50'). Diameters were measured at breast height (DBH). Root wads with 

 stem lengths of < 5' were recorded under the respective diameter category based on the 

 diameter of the root mass. Diameters and lengths of partially covered wood in logjams 

 were estimated. To simplify analysis, LWD was summarized by the overall total number 

 of stems/reach, mean number of stems/ 1000' per reach and by the four major diameter 

 categories, regardless of length. To test the relationship of LWD density among reaches, 

 we used a Kruskal-Wallis One Way Analysis of Variance (ANOVA), with differences 

 considered significant at < 0.05. 



Results 



Summary geomorphic measurements show a wide range of variability between 

 reaches (Table 4). LWD stem densities were significantly different among the three 

 reaches (ANOVA, 2df, P < 0.001), with a 89 % decrease from a mean of 122.6 

 stems/1000' in the upper reaches to 12.9 stems/ 1000' in the lower reach. The highest 

 concentrations of LWD were found in logjams between river mile 91 and 102 in the 

 upper reach (Figure 43, Table 6). 



Table 4. Summary of geomorphic features of three reaches of the upper Blackfoot River 



Geomorphic variable 



U pper 



middle 



lower 



Table 5. Summary of habitat measurements for three reaches of the upper Blackfoot River. 



58 



