6 BULLETIN 838, U. S. DEPARTMENT OF AGRICULTURE. 



for its full length. Young hedges but 3 or 4 years old have been 

 found infested and some of the trees dead even before the hedge 

 has become of any particular use or ornament. 



Windbreaks with an opening here and there, caused by the death 

 of a tree or group of trees, are not nearly as efficient as they would 

 be otherwise. 



In the drier regions of the State the injury is more apparent than 

 in the fog belt, where the tree seems to be much more thrifty. In 

 the former regions the cypress is not a long-lived tree, and when in- 

 fested death is hastened considerably. 



Trees occasionally are found that are heavily infested, yet quite 

 normal in appearance. It is believed that such trees have only re- 

 cently been infested, and will eventually show the effects of this slow- 

 working insect. 



In some localities in central California there is hardly a respect- 

 able row of trees or hedge left to greet the eye. At Los Gatos many 

 trees have died and very few remain which are not now infested. 

 About San Jose, Livermore, Benicia, etc., there are also heavy in- 

 festations. 



INJURY IN THE SELBY SMOKE ZONE. 



The " Selby smoke zone " is an area extending for nearly 10 miles 

 along the Carquinez Strait, between San Pablo and Suisun Bays. 

 The Selby smelter is located on the south side and at the west end of 

 this strait. The prevailing winds are from the west and southwest, 

 thus blowing the smelter smoke across the strait onto the territory 

 between Vallejo and Benicia. 



In this area there has been considerable complaint of damage 

 done to different trees and plants by this smoke. Many of the Mon- 

 terey cypresses in this territory are dead or dying. Examination of 

 these trees and plants by specialists of the Selby Smelter Commis- 

 sion has proved that insects and fungi are responsible for part, at 

 least, of the damage. 



The writer has examined Monterey cypresses in certain parts of the 

 smoke zone and has found the scale insect abundant. In the Benicia 

 Cemetery, practically 100 per cent of the trees were found infested 

 and a large percentage were dead or dying. According to Prof. 

 Doane, this cemetery, although infested in 1913, contained but few 

 dying trees. Probably at that time the infestation was rather re- 

 cent, but has gained headway since. 



In the writer's judgment, the cypress bark scale is the main factor 

 causing the unsightly and dying condition of these trees. One need 

 only see the condition of the cypresses in the Livermore and Santa 

 Clara Valleys to reach this conclusion. 



