Table 1 . -- Distribution and description of sample plots 



Age of Slope 

 Number of stands Average ( Range] 



U J.U L o 











lyi • J 







0. 

 



A c r* 1" c 

 r\.j UfcJ L- L o 



12 



Cathedral Peak 



















(Coeur d'Alene 



N 



F 



) 



40 



44 



(20-80) 



NW,N,NE,E 



6 



Brett Creek 



















(Coeur d'Alene 



N 



F 



} 



29 



42 



(25-55) 



N, NE 



3 



Miscellaneous 



















(Coeur d'Alene 



N 



F 



) 



23-46 



12 



(7-25) 



NE, SW 



3 



Miscellaneous 



















(Kaniksu N.F.) 









30-33 



20 



(16-26) 



NE 



Height, diameter, crown class, and distance from the road edge were recorded for 

 all trees larger than 2.5 inches d.b.h. Height increment (for the first 5 years above 

 breast height) was measured on all dominant and codominant trees to assess road effects 

 on height during early stand development. /" 



Scatter diagrams were prepared for each plot relating tree diameter and height to 

 distance from the road. The diagrams were used to evaluate stocking uniformity and to 

 estimate how far the road effects extended into the stand. Analysis of variance, with 

 individual degree-of -freedom tests, was used to test the hypothesis that roads had no 

 effect on growth of adjacent trees. 



RESULTS 



The Cathedral Peak plantation plots were selected for detailed analyses of road 

 effects because they had uniform stocking, were all of the same age, and there was a 

 well-located road through an area large enough for several replications on varying 

 aspects and topography. Applicability of data from Brett Creek and elsewhere was 

 diminished by variation in stocking due to heavy blister rust mortality, nonutilization 

 of roadside space, inadequate area to obtain suitable replications within each planta- 

 tion, and different ages of the plantations. The results reported below are therefore 

 based primarily on these 12 Cathedral Peak plots; the information from the other 12 

 plots is used only to supplement the Cathedral Peak analysis. 



For the Cathedral Peak plots, scatter diagrams revealed an obvious roadside effect 

 on height and diameter of trees in the plots below the road; this effect appeared to 

 extend an average of 24 feet into the stand. No roadside effects were observed in the 

 plots above the road. 



Heights and diameters of dominant and codominant trees were adjusted to remove 

 between-plot site variation and were pooled within six 11-foot zones as shown in 

 figure 2. The average height of border trees in the plots below the road was 113 

 percent of that within the stand, or approximately 7 feet greater. The average 

 diameter of border trees in plots below the road was 131 percent of that within the 

 stand, or approximately 2.5 inches greater. In neither case were effects evident 

 above the road. (Distance from road edge did not appear to influence early height 

 increment for the 5 years above breast height on any of the 12 plots.) 



3 



