effects of individual fumigants to warrant a preference for any of the methyl bromide- 

 based formulations. The effects of Vapam were measured only on western white pine and 

 are inconclusive. None of the fumigants caused any significant changes in the measured 

 characteristics of ponderosa pine at Coeur d'Alene. Douglas-fir had the largest 

 proportion of significant increases of seedling size, followed by spruce, western white 

 pine, and ponderosa pine. 



Most of the estimates of the effect of fumigation on seedling size are probably 

 conservative since the higher densities, typical of most fumigated seedbeds, tended 

 to independently reduce most seedling size characteristics. The growth of western 

 white pine seedlings at Savenac in thinned and unthinned beds demonstrates these 

 relationships (table 5). Although fumigation generally resulted in larger stock at 

 both high and low densities, the high-density seedlings grown in fumigated soil were 



Table S.--Size aharaoteristias of 2-0 western white pine seedlings grown at tow 

 (55/sq.ft. ) and high (15S/sq. ft. ) seedbed densities in fumigated and 

 wnfwnigated soil 



Characteristic 



Seedbed 

 density 



Fumigated^ 



Unfumigated 



1 



Top height (cm.) 



Stem diameter (mm.) 



Root-area index (units) 



Top dry weight (g.) 



Root dry weight (g.) 



Shoot/root ratio 

 (dry weight basis) 



Low 



High 



Low 



High 



Low 



High 



Low 



High 



Low 



High 



Low 



High 



6.0 

 7.1' 

 2.4 

 1.9-' 



7.1 



** 



3.5' 



0.93 



* * 



0.45' 



0.35 



* * 



0.17- 



2.08 

 * 



2.66' 



* * 



* * 

 ** 



** 

 * * 



* * 



* * 



4.9 



* * 



5.0 



.2.2 

 * * 



1.7 



.5.5 

 ** 



3.2 



,0.50 

 ** 



0.31 



,0.28 



* * 



0.15 



.1.82 

 * 



2.06 



■"■Asterisks between any horizontal or vertical pair of the four means given for 

 each characteristic indicate a significant difference at the 95% (*) or 99% (**) 

 probability level. Dashed lines (--) indicate no significance. Symbols within the 

 diagonal lines mean that the test applies only to the means connected by the diagonal 

 line . 



15 



