1122 



AMERICAN FORESTRY 



WHITE PINE THREATENED 



FOUR recent serious outbreaks of the white pine 

 blister rust on currant bushes in Massachusetts 

 and New York have called attention sharply to 

 the alarming character of this disease and the economic 

 loss which it threatens in the northeastern and western 

 United States unless it can be brought under control 

 within the next two years. This disease has been known 

 for some years, having been introduced at many points on 

 white pine nursery stock imported mainly from Germany. 

 The disease first established itself at Geneva, N. Y., in 

 1906. In 1909 extensive importations of diseased white 

 pine nursery stock were located and destroyed in New 

 York and other eastern states and warnings issued broad- 

 cast against further importation of white pine from 

 Europe. In spite of these warnings importation con- 

 tinued even from the particular nursery in Germany 

 which was definitely known to be the main source of 

 disease, until finally in 1912 all such importation was 

 stopped by Federal law. Whether this law was passed 

 too late remains to be seen, as it depends on whether the 

 disease already established in the United States can be 

 stamped out. 



The white pine blister rust affects the eastern white 

 pine, the western white pine, the sugar pine and, indeed, 

 all of the so-called five-leaf pines, producing cankers on 

 the stems and branches, killing young trees and maiming 

 and disfiguring old ones. It also produces a leaf disease 

 of currant and gooseberry bushes. The fungus causing 

 the disease must live for a part of its life on pine trees 

 and part of its life on currants and gooseberries. The 

 disease cannot spread from one pine tree to another, but 

 must pass first to currant bushes and then back to pine. 



In Europe the disease has made the culture of Ameri- 

 can white pine impracticable in England, Denmark, and 

 Holland, and has seriously handicapped its cultivation in 

 Germany. Since the trees which it attacks include three 

 of the most important timber trees of the United States, 

 the loss which this disease will produce if unchecked is 

 uncalculable. Fortunately, the disease is not now known 

 tc be present west of Buffalo, N. Y., but its ultimate 

 spread to the vast forests of the Rocky Mountains and 

 the Pacific Coast is certain if it is not checked in the 

 eastern states. The disease now occurs in three locali- 

 ties in New Hampshire, two in Vermont, two in Connecti- 

 cut, five in New York, one in Pennsylvania, and three in 

 Ontario, Canada. At one point in Ontario, two in New 

 York, two in New Hampshire and two in Massachusetts, 

 the disease is present on currants in sufficient quantity to 

 be serious. 



The disease is controllable at this stage by the destruc- 

 tion of the diseased white pines or the complete destruc- 

 tion of all currant and gooseberry bushes in the vicinity. 

 Whether or not this simple action can be accomplished 

 depends upon the legal authority possessed by the various 



state horticultural inspectors concerned. If the inspector 

 is not armed with authority to destroy either currant 

 bushes or the few diseased white pines with or without 

 the consent of the owner, all efforts at control will be 

 unavailing, as a single person, by permitting diseased 

 pines or currants to remain on his place can nullify the 

 work of an entire well-disposed community. The imme- 

 diate issue, then, is whether the several states will see 

 that their inspectors have sufficient authority or whether 

 still another imported disease shall be added to the already 

 long list of undesirable fungus and insect immigrants, 

 and the white pines of the United States be reduced from 

 their present high standing to that of inferior trees. 



PINON TREE SPLITS LARGE ROCK 



THE great rock-splitting force of a growing tree 

 is shown in the photograph of a pifion tree in the 

 Mesa Verde National Park, of the State of Colo- 

 rado, at the head of Prater Canyon. The tree is dead 



ROCK SPLIT BY A TREE 



The force of a growing tree is illustrated by this picture of a pifton tree. 

 The rock is deeply imbedded in the earth, yet it was split by the 

 growing tree. 



now, but this is due to old age, not to any squeezing of 

 the stone. The tree made a full and healthy growth, bear- 

 ing doubtless many bushels of pifion nuts, and gradually 

 widening the crack in the rock as its trunk required 

 more and more space. The power exerted by the tree 

 is all the more remarkable as it is evident that the sand- 

 stone boulder is embedded in the earth to a considerable 

 depth. 



