Figure 1. — Cedar-hemlock eco- 

 system surrounds lysimeter 

 station 42. 



In this study, six lysimeter stations are grouped in pairs as follows: station 39 

 adjacent to station 40 and station 45 adjacent to station 42, both pairs situated on the 

 north aspect; and station 49 adjacent to station 47 on the south aspect. A distance no 

 greater than 300 feet separates the stations in each pair. The three pairs were placed 

 into operation in 1967, 1968, and 1969 in the order mentioned. In relation to forest 

 cover, station 39 is located in the northeast quadrant of a small, manmade clearing; 

 stations 45 and 49 are situated midway across long, 50-foot-wide clearcut strips. These 

 stations represent the situation termed "small opening." The "forest condition" includes 

 stations 40, 42, and 47 positioned well into the undisturbed forest. These stations 

 lie within the drip zone of a major tree species but away from the annular zone of the 

 tree bole. Other descriptive details of each lysimeter station appear in table 1. 



Weather stations provide precipitation and temperature data to complement the 

 lysimeter information. Each weather station is mounted on an elevated platform (fig. 4), 

 situated near the lysimeter. In the forest, the weather station is located underneath a 

 tree with a canopy configuration similar to that over the lysimeter; in the small open- 

 ing, the station is nearly the same distance from the bordering trees as is the lysimeter. 



The precipitation instruments are incapable of separating rain from snow; therefore, 

 observed rainfall (in the small opening) is determined indirectly by comparing the catch 

 of precipitation with ambient air temperature recorded in a standard (ventilated) shelter. 

 It is assumed that rain occurs if the temperature is greater than 33° F. There are 

 exceptions when snow falls during a storm, although the temperature indicates rain or 

 vice versa. 



Figure 2. — Typical lysimeter pan 

 with rod- frame J sliding collar^ 

 and polyethylene bag attached. 

 Inclination of collar is par- 

 allel to angle of ground 

 surface . 



