Bul. 1200, U. S. Dept. of Agriculture. 
Fic. 1.—A group of ninety-one 2-year-old Douglas fir seedlings that grew from a store of seeds 
presumably buried by rodents. 
Fia.2.—Cross section of typical forest floorin Douglas firtype. The following percentages 
of forest tree seeds were contained in each layer: (A) 80 to 85 per cent. of hemlock seed; 80 
to 85 per cent of cedar seed; 40 to 50 per cent of Douglas fir seed. (B) 10 to 15 per cent of 
hemlock seed; 10 to 15 per cent ofcedar seed; 35 to 40 per cent of Douglas firseed. (C)0to 
5 per cent ofhemlock seed; 0 to 5 percent ofcedar seed; 5 to 15 per cent of Douglas fir seed. 
The rule shown is divided into inches, with the top level with the surface. The kinds 
and amounts of seed in the layers of vegetable matter and soil explain how fire may 
change the proportion and kinds oftrees by burning to different depths. (See Hof- 
mann, J. V., Young Growth and How It Originates. West Coast Lumberman, Vol. 39, 
No. 463, Jan. 15, 1921.) 
