June 14,1924 
Factors Affecting Reproduction after Logging 
1153 
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Fig. 2.—Some earlier results of germination and survival on different surfaces, by species. The three 
horizontal bars opposite each species indicate (1) germination, per cent of seed sown; (2) survival, 
spring of 1915, per cent of germination; (3) average height in inches, fall of 1917 
Some of the earlier results are shown in figures 1 and 2. 
Satisfactory germination of these species took place both on the bare, loose 
mineral soil and on the ashes, and the survival on both was good. The duff 
surfaces show poor results for all three species and more distinctly so here than 
in the 1918 series. 
Even in the absence of exact measurements of moisture content and surface 
temperature, one would surmise that the great fluctuations in moisture taking 
place on duff surfaces would be a disadvantage to seed germination. It is of 
interest to record a few of the more outstanding and characteristic results of a 
great many tests of duff moisture contents and fluctuations made at the Priest 
River Forest Experiment Station by H. T. Gisborne and the author, dating 
back to 1913. 
