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Journal of Agricultural Research 
Vol. XXVIII, No. 12 
4. The average annual rate at which the pine stands became infected con¬ 
stantly increased over a period of 16 years and in 1916 the rate of infection was 
20 times the rate in 1901. 
5. The infection percentages in pine stands varied according to the diameter 
classes of the trees, being highest among the larger size classes. 
6. The infection percentages in pine stands varied according to the degree 
of pine stocking, being highest in understocked stands. 
7. The infection percentages in pine stands varied according to crown classes, 
being highest among dominant trees. 
8. Destruction of all Ribes prevented the occurrence of new pine infections 
and permitted the area to be naturally restocked with disease-free seedlings. 
