BOARD OF HORTICULTURE 



179 



grows mueh niore extensively in tlie "West as a wliole, and its lumher has even 

 a greater eomparative value. The approximate number of feet of this species in 

 Oregon is reekoned at 825,000 million witli an estimated value of $2,887,500. 

 White pines are fast growin trees, and if the young trees are allowed to 

 develop the annual growth will remain a large asset to the State. The introduction 

 of White Pine Blister Rust would c-ertainly mean that mach of this young timlier 

 would never develop. Young white pine Stands are readily killed out by this 

 disease. Mature trees are greatly weakened. Init in most cases may still be cut for 

 timber. Constant loss of young growth would leave Ihese great tracts with no 

 future as white pine forests, after the mature Stands had been cut. 



Figure 3. Underside of black currant leaf, shov/ing brown-hair or autumn stage 

 of disease. (Loaned by the courtesy of the Bureau of Plant Industry, U. S. Department 

 of Agriculture. ) 



Wild currants and gooseberries are abundant in Oregon, 30 species being 

 known to occur within the State. They are plentiful throughout the raountainous 

 regions, where the white pines are found, and would allow the disease to flourish 

 there, if once introduced. They are also found in sufficient numbers in eastern 

 Oregon to carry the disease to these pines, from any neighboriug region. 



Blister Rust Work in Oregon 



During the past three years the Bureau of Plant Industry of the United States 

 Department of Agriculture has worked to keep the western white pine forests 

 free from tlie White Pine Blister Rust. A campaign has been conducted in all 



