384 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



tlucccl. Tlic classes of trees which produce the most vigorous seed- 

 Ungs and the transmission of defects in seed-bearing trees to the 

 seedlings form a second group of valuable studies. Tentative results 

 obtained at the Coconino Experiment Station indicate that jellow- 

 pine trees under 250 years of age produce seed of 8 per cent liigher 

 fertility than that from trees of a greater age; and that trees afl'ected 

 by mistletoe or infested with bark beetles produce seed of a much 

 lower germination per cent than healthy trees. Records have been 

 established at this station of about 100 trees in various stages of 

 decadence to determine how long they will continue to bear seed. 



Studies in natural reforestation have been begun on a number of 

 National Forests, the primary object being to determine methods of 

 cutting and brush disposal in timber sales which will secure the best 

 reproduction of desirable species. These experiments include Douglas- 

 fir stands in the Cascade Mountains, lodgepole-pine and Engelmann- 

 spruce stands in the Rocky Mountains, and yellow-pine stands in 

 Arizona. On the Coconino Forest, experiments begun in 1908 to 

 determine the effect of scattering brush upon reproduction indicate 

 that while brush protects young seedlings against drought and frost 

 it is not sufficient to carry them through protracted periods of rigorous 

 climatic conditions. The presence of scattered brush was found det- 

 rimental in keeping seeds from reaching the mineral soil 'and shading 

 the young plants excessively at certain periods. 



Observations on the effects of different methods of brush disposal 

 on the Minidoka, Sawtooth, Cache, and Targhee Forests, in both old 

 and recent cuttings, indicate that lopping and scattering will apply 

 to nearly all types in Utah, Nevada, and northern Arizona. This 

 method increases the fire danger and will not be advisable near settle- 

 ments and lines of travel. 



Studies of the effects of grazing upon natural reproduction were 

 conducted in Arizona, with a view to devising a system of range con- 

 trol wliich would minimize such injury without requiring the total 

 exclusion of stock from the range. Serious damage was found to 

 have occurred to seedlings under 4 feet in height, during the dry 

 season, on areas containing poor forage, or which had been overgrazed, 

 or where there is little or no underbrush. It was found that sheep 

 do tvncG as much damage as cattle. The revegetation of overgrazed 

 areas, reductions in the amount of stock in some cases, pro'sdsions 

 for better distribution of stock by regulation of watering places, and 

 the exclusion of sheep from cut-over areas on which reproduction 

 is deficient until the seedlings reach a sufficient height are among 

 the measures to be tested for lessening this injury. 



Experiments were also conducted to determine the practicabihty 

 of opening dense stands of chaparral in northern California by regu- 

 lated goat grazing, in order to make possible the extension of forest 

 growth into the enormous brush fields of that locality. Definite 

 results have not yet been reached. 



Aside from investigations related to reforestation, the work of the 

 year included experimental studies of forest influences, the climatic 

 requirements of forest types, growth and yield studies, sample plot 

 studies, and insect and fungus investigations. 



That the forest exercises a decided moderating influence upon tem- 

 perature extremes, wind motion, and evaporation was shown by 

 experimental observations wliich have been conducted at the Fort 



