that individual trees of various ages 

 are attacked rather than entire stands. 

 For example, extended drought dur- 

 ing the Summer of 1953 may have 

 damaged pine rootlets on individual 

 trees in relatively unfavorable sites. 



During the rainy period in the 

 Spring of 1954, even damaged roots 

 could have furnished enough water 

 temporarily to the tree crown if the 

 rainy period had not been followed 

 suddenly by hot dry days. Then 

 the poor balance between the injured 

 or restricted roots and the lush 

 foliage could not maintain the water 

 necessary for the extensive needle 

 growth during a hot dry period. Ac- 

 cordingly, typical pines affected would 

 be individual trees of a group grow- 

 ing on cleared land with no pine 

 needle mulch, where drought effects 

 or injury to roots might be severe. 



Trees commonly affected are pines 

 in stands opened recently or pines 

 in fields and pastures rather than 

 trees in areas of typical pine forest 

 stands. 



Fertilizer May Help 



Fertilizer applied while trees are 

 dormant may help develop feeding 

 rootlets. The mulch of fallen pine 

 needles may be retained as a pro- 

 tection against further damage to the 

 development of feeding rootlets near 

 the surface of the soil. 



Watering ornamental pines, es- 

 pecially during hot dry weather in 

 early summer, may aid unaffected 

 trees, but watering is not a cure for 

 damage already done. 



Except in small trees, pruning is 

 of limited value because ornamental 

 pines are distorted when the upper- 

 most branches are removed. 



Hasty Action Not Advised 



If the record of similar previous 

 years is borne out, many trees will re- 

 cover slowly or even completely with- 

 out treatment in a year or several 



The lines across the needles Indicate the 

 distance from needle tip affected by redden- 

 ing. Pholo by Robert L. Coffin 



years. Comparatively few trees with 

 extensive root injury or relatively 

 unfavorable sites may show needle 

 blight in successive years and fail to 

 produce normal growth. In any 

 event, hasty action in removing 

 affected trees is not advisable since 

 it is not evident that the trouble is 

 contagious. 



Research Opportunity 



Obviously, the development of 

 needle blight of white pine is at 

 best imperfectly understood. More 

 recently, studies to determine the 

 possible relationship of fungus in- 

 fection of pine roots failed to give 

 positive results. So, once again 

 the familiar theme — a problem that 

 looks so easy to solve on the surface 

 may actually be rather involved. 

 Perhaps there is no single explana- 

 tion. And maybe some of the 

 answers suggested may fit some of 

 the conditions observed. At any 

 rate, after 50 years, outbreaks of 

 needle blight of eastern white pine 

 still occur with irregularity but 

 annoying frequency in the list of 

 partlv unresolved experiences of 

 forest pathologists. 



