(33o) 



at three other stations for comparison. The first station was 

 placed in the open about 300 yards west of the hemlock grove, 

 and about 100 yards north of the Museum building. The aim 

 was to measure the conditions themselves, uninfluenced by the 

 forest. This gives a basis or starting point from which we can 

 tell how the forest has changed conditions. It also represents 

 the environmental factors which the forest must encounter in 

 becoming established. 



The second station was in the hemlock grove proper. In 

 order to have it as fairly representative as possible, and avoid 

 local variations due to slopes which cut off the wind and so forth, 

 it was placed approximately on top of the ridge with exposure on 

 all sides, but completely surrounded by hemlock. There is a 

 small proportion of oak scattered through the hemlock forest, 

 and the station happened to be near a white oak. This probably 

 does not appreciably affect the results. There was no under- 

 growth, and the forest floor was the usual mat of hemlock 

 needles with a sprinkling of oak leaves. There was no young 

 growth of hemlock. 



The third station was on the transition line between the 

 hemlock and hardwood types. It was on a gentle slope about 

 200 yards south of the hemlock station. On one side the forest 

 was predominantly hemlock. The instruments were placed 

 under a mixture of hemlock and beech. There was very little 

 undergrowth, and the forest floor was covered with a thin layer 

 of hemlock needles and beech leaves. 



The fourth station was under a typical hardwood forest about 

 150 yards south of the transition station, on the east side of a low 

 gently sloping ridge. The instruments were beneath the outer 

 crown of a large white oak about 30 inches in diameter at ^]/^ feet 

 above the ground. There was an undcrstory of dogwood and 

 witch hazel, with a considerable amount of herbaceous under- 

 growth on the leaf-covered forest floor. There was also a small 

 amount of oak reproduction. The contrast between this light- 

 green deciduous forest with its variety of different species, and 

 the rather sombre pure hemlock such a short distance away was 

 indeed striking. 



The hemlock forest on the IJotaiiical Garden grounds is 

 mature, well over 100 years old. While it may be second growth 

 following a former stand which was cut or burned many 



