RESEARCH METHODS IN STUDY OF FOREST ENVIRONMENT. 63 



Where density is estimated, the depth and density are entered 

 when the report is received, and the water equivalent may be com- 

 puted at any time. Where density apparatus is used, it is necessary 

 to compute the density and apply this figure to the depth reading at 

 the scale, which may be somewhat different from the depth noted 

 on the tube. 



It is self-evident that, while the progress of snow accumulation 

 throughout the winter is interesting, the most important data are 

 those which show the maximum accumulation just prior to the 

 beginning of rapid spring melting. 



Tabulation. 



The form for " Daily and Hourly Precipitation " may serve as a 

 monthly summary both for daily observations and for notations from 

 hourly records where these are obtained. The following should be 

 tabulated from daily observation : 



Total precipitation in inches of rain or melted snow. 



Urwnelted snow, as measured in the gauge, in snow bins (84), or 

 on the ground. Precise measurements of the snowfall appear to be 

 useless to the ecologist. 



Depth of snow on the ground at time of observation. 



X umber of storms of rain, sleet, or snow which, by the weight of 

 accumulated water or because of accompanying wind, do mechanical 

 damage to trees. 



The following data are merely intended to depict the character 

 of storms, and should be obtained from the hourly automatic records 

 for a few stations typical of the different regions and altitudes : 



Number of hours having measurable precipitation. 

 Number of hours having 0.05 to 0.10 inches precipitation. 

 Number of hours having 0.10 to 0.20 inches precipitation. 

 Number of hours having 0.20 to 0.50 inches precipitation. 

 Number of hours having more than 0.50 inches precipitation. 



Tlio "Summary" form will serve as an annual summary for pre- 

 cipitation data of both classes and will include all of the data given 

 i- the monthly sums or means on the several "Daily and Hourly Pre- 

 cipitation" forms. As usual, sums and means should be computed 

 for the growing season as well as for the whole year. 



I.N'S'I klMI.VI S AM) Al'i'KOXIMATE PSIOES. 



Rain and snow gauges : 



Rain and -now gauge, 8-inch Weather Bureau pattern $5.00 



Supports, box, for rain and snow- gauge L.50 



Measuring sticks, ram gauge, cedar, \o. L2236 . 1.5 



Rain gauge, tipping-bucket, with supports and measur- 

 ing tube T.").'i<) 



