(339) 



rain gauge near Saltonstall ridge, the records of which were 

 kindly supplied by Mr. Leonard M. Tarr of the Weather Bureau. 

 For Ithaca, Mr. W. M. Wilson kindly furnished us with records 

 for a station two miles east of Ithaca, and therefore rather near 

 to the Cornell stations. These gauges nearer our stations gave 

 slightly higher readings than the ones of the Weather Bureau in 

 the towns of Ithaca and New Haven. 



The amounts of precipitation in the open have been inserted in 

 Table I, and from them the amounts under the forest subtracted. 

 The differences represent the net interception by the forest 

 canopy for the particular spots where the rain gauges were 

 placed. The weekly records, which are not reproduced in this 

 report, show that some of the readings under the forest were 

 actually higher than in the open. This happened with 19 of the 

 readings at the New York stations, where we fortunately have 

 daily as well as weekly records. It also occurred occasionally at 

 New Haven. These higher readings under the forest must 

 have been due for the most part to dripping from the ends of the 

 branches which may have been more pronounced under some con- 

 ditions than under others. 



Except at the New York stations, the net interception was 

 considerable, running from 31 per cent at the Ithaca hemlock to 

 48 per cent, for the New Haven ridge top, or from nearly a third 

 to nearly a half. At New Haven the north slope interception is 

 decreased by two periods during which the gauge at this station 

 showed considerably more than in the open. If the excess for the 

 north slope station in these periods were eliminated, the intercep- 

 tion would be 47 per cent, or practically the same as the ridge top. 

 At New York, even if we eliminated the amounts in excess of the 

 open readings, the interception would still be small, only 13 per 

 cent, for hemlock, 11 per cent, for the transition and 6 per cent, 

 for the hardwoods. Just why interception at the New York 

 stations is so much less than at the others is not clear, unless the 

 gauges at all three of these stations were nearer the edge of the 

 crowns than at the five other stations. This hardly seems 

 probable. It may be that the character of the precipitation, in 

 particular the prevalence of short heavy showers near New York, 

 has something to do with the lower interception here. 



