FOREST RERVICB. 385 



Valley Experiment Station since January 1, 1908. These conclu- 

 sions, which are based upon a comparison of records in a large open 

 park and within a virgin forest, may be used to good advantage in 

 selecting the most favorable sites for reforestation. 



One of the conclusions drawn from the observations is that the 

 presence of a forest cover retards the melting of snow in the spring. 

 Both this question and the influence of the forest upon the accumu- 

 lation of snow will be studied further through a special investigation 

 in the 3^ellow-pine type of Arizona and the Douglas-fir and Engelmann- 

 spruce types of Colorado. 



At the VVagon Wheel Gap Station records of great interest are being 

 obtained from the principal experiment, wliich is to determine the 

 effects of forest upon streamfiow. The entire purpose of tho study 

 during the first two or three years is to determine the character of 

 the two streams which are to be measured. The forest cover on the 

 two watersheds is practically the same. The results so far obtained 

 indicate that the influence upon streamfiow must be about the same 

 in both cases, and, consequently, a comparison of these streams after 

 the denudation of one watershed will be a very fair test of the influence 

 of the forest cover upon the relative height of the flood stage and low- 

 water stage, the amount of erosion, and the rate of melting of the 

 snow. 



In August, 1909, the town of Ephraim, on the Manti Forest, Utah, 

 experienced a disastrous flood from Ephraim Canyon, which was 

 attributed in part to the overgrazed conditions on the watershed. 

 An examination made in the spring of 1910 clearly demonstrated 

 that the severity of the flood was a direct result of deterioration of 

 forest, brush, and grass cover due to prolonged overgrazing. The 

 canyon was therefore closed to grazing as an immediate protective 

 measure, and it is planned to restore the forest cover on Ephraim 

 Canyon by sowing and planting. 



The climatic requirements of forest types has been studied at the 

 Fremont Experiment Station since January 1, 1910, through experi- 

 mental observations. The first step is to obtain a complete meteoro- 

 logical record as a basis for determining what climatic conditions are 

 most important in limiting the natural range of the yellow pine, 

 Douglas fir, and Engelmann spruce. The first year's study shows 

 that soil moisture and soil temperature are the controlling factors 

 in determining the existence of the three different types, and gives 

 knowledge as to what climatic conditions each of the three species 

 must have in order to succeed. 



ReHable growth and jaeld data for different species and types are 

 necessary to properly handle timber sales as well as for forest man- 

 agement. They are also essential for determining damages caused 

 by fires, trespass, etc. During the year there were secured a large 

 number of volume tables on the Custer and volume and yield tables 

 on the Deerlodge and Kaniksu Forests for lodgepole pine, western 

 yellow pine, and Douglas fir. Considerable progress has been made 

 on growth studies for yellow pine, sugar pine, and incense cedar on 

 the Stanislaus -National Forest. 



Sample plots have been established on a number of large timber- 

 sale areas in important forest types. On each plot of 6 or more acres 

 every tree is carefully measured and recorded. Similar measure- 



23165°— AGB 1911 25 



