STUDIES IN TOLERANCE OF NEW ENGLAND FOREST TREES 9 



TABLE IV MINIMUM LIGHT REQUIREMENTS FOR SOME NATIVE TREES AND SHRUBS 



(WIESNER) 



Additional data taken from Wiesner's work appears below. 



TABLE V AVERAGE MINIMUM LIGHT INTENSITY REQUIRED 



(WIESNER) 



These figures represent the averages of many readings. In several 

 cases such large variations in light intensities were found that more 

 than one so-called minimum is given ; for example, Acer saccharinum, 

 not given in the table, has values of 0.200 and 0.143. Similar variations 

 are given for Larix decidua. This tree has a so-called minimum of 

 0.166, 0.250 and 0.200. For Picea excelsa the following values are 

 given: 0.011, 0.016, 0.025, 0.05, and 0.125. In the last case cited the 

 great range in light required from 0.011 to 0.125 would seem to indi- 

 cate that possibly the method used was not entirely trustworthy. 



