1904 FORESTRY AND IRRIGATION 347 



published Professional Paper No. 22, been culled or cut from 148,845 acres, 



which bears the title ' ' Forest Condi- The timber cut on these tracts has been 



tions in the San Francisco Mountains converted into tie, stull, or round mining 



Forest Reserve, Arizona." This paper timber and saw-logs, 



embodies the results of investigations Grazing, especially sheep herding, 



made during 1901 and 1902 by John B. is ruinous to the seedling growth of 



Leiberg, Theodore F. Rixon, and Arthur a young forest. Sheep are especially 



Dodwell, and is prefaced by an intro- fond of the young aspen, which spring 



duction written by F. G. Plummer, up as the first restockage on the non- 



which is particularly interesting. forested park lands at the base and on 



The San Francisco Mountains Forest the slopes of San Francisco Mountains. 



Reserve comprises portions of the broad It was found that the destruction of 



summit and slopes of an elevated tract seedlings on any particular tract of land 



of land in north- central Arizona, which ranged from 50 per cent to total after 



includes the southern part of the Colo- a single passage over such ground by 



rado Plateau. The northern part of the 2,000 head of sheep, 



area is dotted by several hundred vol- Fires have been of frequent occur- 



canic cones and the southern part is rence in all portions of the reserve, 



gashed by numerous deep canyons. The The badly burned areas, on which the 



altitude of the region ranges from 3,500 destruction has been 60 per cent or 



feet at Oak Creek, in its southwestern more, aggregate 6,790 acres. The ori- 



portion, to 12,794 feet at the summit of gin of fires in recent years may, in part, 



San Francisco Peak. be ascribed to the carelessness of sheep 



Among the coniferous trees in the re- herders, in part, to sparks from engines 



serve the western yellow pine constitutes on the Atchison, Topeka, and Santa 



over 99 per cent of the total forest. The Fe Railroad, but by far the largest num- 



aspen takes first rank among the broad- ber of fires are due to lightning, and 



leafed species, but has a close competitor this cause has, of course, always oper- 



in the oak. The chief lumber tree at ated. Sections exist on which 50 per 



present is the western yellow pine, which cent of the mature western yellow pine 



is extensively cut and furnishes all of has been either wholly or in part killed 



the mill timber sawed, used in, and ex- by lightning strokes, 



ported from the region. Its average Among other interesting questions 



total height is 85 feet, with about 10 feet considered in this paper are the low re- 



of clear trunk. The diameter averages productive ratioof the yellowpine, thein- 



18 inches, which corresponds to an age fluence of the forest on run-off, the graz- 



of 1 80 years. In the 812,500 acres of ing value of the reserve, and the effects 



forest area examined, 2, 743,558, ooofeet, of sheep herding on the forest floor. 



B. M., of standing timber were found, The bulk of the paper is devoted to de- 



which gives an average of only 3,377 tailed descriptions of the areas, by range 



feet, B. M. , per acre. It is evident that and township, that make up the reserve, 



the western yellow-pine stands, even . 

 where entirely untouched by the ax, do 



not carry an everage crop of more than Hydrology Mr. N. H. Darton, geol- 



40 per cent of the timber they are ca- in Western ogist in charge of the 



pable of producing. This condition is States. western section of hy- 



chiefly attributable to the numerous drology. United States 



fires which have swept over the region Geological Survey, left for the field 



within the last two hundred years, de- June 20, to spend five months in super- 



.stroying seedling and sapling growth. vising the work of assistants in various 



The chief agencies through which the portions of the West. He will make 



forests in the reserve suffer destruction an examination of the western slope of 



are cutting, grazing, and fire. Logging the Bighorn Mountains, and will spend 



operations have been carried on in most several weeks in the region lying north 



of the central forested areas that are of the Black Hills in order to obtain 



tributary to railroads. The forest has material required to complete a report 



