Table 1. — Shoot growth of eastern white pine during the growing season 



preceding artificial defoliation and during the growing season 



_ 



following defoliation^ 

 (In centimeters) 







Time of treatment 







Treatment 



: July 1960 



: September 1960 : 

 : Before : After : 



April 



1961 





: Before : After 



Before 



: After 



Complete defoliation 



Removal of current (1960) 

 needles only 



Removal of all but current 

 needles 



15.8 



14.1 



14.6 



u 



0.0 



6.4 



19.6 



12.2 



14.4 



14. 



3/ 



5.5 



7.8 



21.6 



2 / 

 16.2 :=^0.0 



16.2 £^4.8 



16.4 



21.1 



No defoliation 



15.9 



22.1 



15.1 



22.: 



17.2 



23.5 



!_/ Evidence indicates that annual growth in white pine is completed by 

 July (McGregor, W. H. D., and Kramer, P. J. Seasonal trends in rates of 

 photosynthesis and respiration of loblolly pine and white pine seedlings. 

 Amer. Jour. Bot . 50: 760-765. 1963). Measurements of shoot growth for each 

 year were thus comparable even though time of treatment differed. 



2/ No surviving pines. 



sy Two surviving pines . 



aJ One surviving pine. 



Table 2. — Height of eastern white pine before artificial defoliation 

 and at the end of the first growing season after defoliation ]J 



(In centimeters) 





Time of treatment 



Treatment 



July 



1960 : September 1960 : 



April 



1961 





Before 



: After : Before : After : 



Before 



After 



Complete defoliation 



81.0 



Removal of current (1960) 



needles only 73.6 



Removal of all but current 



needles 86.6 



No defoliation 



81.2 



60.0 



79.0 



128.8 

 126.8 



41.0 £50.5 



67.0 77.6 



72.4 111.4 



76.6 120.8 



78.6 



0.0 



68.0 1^75.0 



77.0 96.0 



85.6 133.1 



\J Growth in height in 1960 is included in "before" figures; that in 

 1961 in "after" figures. "Before" figures are comparable to each other as 

 are "after" figures (see footnote 1, table 1). 



"ij No surviving pines. 



3/ Two surviving pines. 



'\J One surviving pine. 



-4- 



