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the hemlock grove on the grounds of the New York Botanical 

 Garden, in addition to which stations were established in an 

 adjoining mature hardwood forest, in the transition between 

 hemlock and hardwoods and in the open. With the cooperation 

 of Yale University, Cornell University, and the State College of 

 Forestry at Syracuse, two stations were established near New 

 Haven representing favorable and unfavorable hemlock sites, 

 two at Ithaca representing a hemlock and a hardwood type, and 

 one at Cranberry Lake in the Adirondack Mountains under a 

 group of hemlock in the northern hardwood and spruce forest. 



At each station weekly readings were taken during the summer 

 of 1923, covering evaporation (with Livingston atmometers), 

 solar radiation (black and white atmometers), precipitation, and 

 maximum and minimum temperature of the air and of the soil at 

 6 and at 18 inches depth. 



The evaporation under hemlock was higher than that under 

 hardwoods, 12.2 c.c. per day as against 8.9 c.c. 



The evaporation under the five hemlock stations was very 

 similar. It was, in c.c. per day. New York, 12.2; New Haven 

 ridge top 12,0, New Haven north slope 10.3, Ithaca 11.8, and 

 Cranberry Lake 7.5 



The difference in evaporation between extreme hemlock sites 

 near New Haven was less than the difference between hemlock 

 and hardwoods at New York; only 1.7 c.c. as against 3.3 c.c. 

 Hemlock forests 300 miles apart have a closer resemblance with 

 respect to evaporation than hemlock and hardwoods 300 yards 

 apart. 



The rate of evaporation under hemlock is intermediate between 

 that found for spruce, 7.0, and for white pine, 17.4, on Mt. 

 Desert Island, Maine, during approximately the same period. 



The air temperature under hemlock had a higher maximum and 

 mean, but a slightly lower minimum than under the hardwoods. 



The soil temperature under hemlock at both 6 and 18 inches is 

 colder than under hardwoods. 



The extreme range of temperature between the north and 

 south limits of hemlock included in this study is small: 12° F. for 

 the mean air temperature, 10° for the mean soil temperature at 

 6 inches, and 11° for the same at 18 inches. 



The stations probably include the coldest growing season condi- 

 tions at which the hemlock type can occur naturally. The 



