RESEARCH METHODS IX 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. 
Unmelted 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. 
Xnm~ber 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. 
The " Summary " form will serve as an annual summary for pre- 
cipitation data of both classes and will include all of the data given 
as 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. 
Instruments and Approximate Prices. 
Rain and snow gauges : 
Rain and snow gauge, 8-inch Weather Bureau pattern.- $5.00 
Supports, box, for rain and snow gauge 1.50 
Measuring sticks, rain gauge, cedar, No. 12236 . 15 
Rain gauge, tipping-bucket, with supports and measur- 
ing tube 75.00 
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