1 .9622 

 I2R312 



JAMES C. SPACE 



UNITED STATES DEPARTMENT OF AGRICULTURE 

 FOREST SERVICE 



mtMOWTAlN FOREST & RAHE EXPERIMENT STATION 



O C D E N 



UTAH 



No. 87 



DAMAGE TO PONDEROSA PINE PLANTATIONS 



James D. Curtis and Marvin W. Foil ask/ 

 Division of Forest Management Research 



■ 



March 1962 



Three types of damage to trees in three different plantations of 

 ponderosa pine occurred recently in southern Idaho. One was due to disease, 

 one to rabbits, and one to insects. All these plantations were established 

 on granitic soil, typical of the sites on which ponderosa pine grows in this 

 part of its range. 



The first injury occurred to 10 trees in a 1-acre plantation on a timber 

 sale area on the Payette National Forest. About a year after the trees were 

 planted, dead cambium appeared at the ground level. Fruiting bodies found on 

 the stems suggest that a pathogen could be the primary cause. Though the in- 

 jury was slight in extent, it killed the seedlings that were infected. One 

 stem contained a specimen of a Hylurgops adult, which is considered commonly 

 to be a secondary insect. 



The damage caused by rabbits (feces near stems suggest snowshoe hares) 

 occurred in early July in a 40-acre experimental planting on the Boise Basin 

 Experimental Forest. Each of four 10-acre blocks had been sprayed twice by 

 helicopter with different dosages of herbicide to minimize plant competition 

 prior to planting. The animals removed the terminal buds of many hundreds of 

 the 2+1 ponderosa pine seedlings that had been planted by machine in furrows 

 in the spring of the same year. Heaviest damage occurred on the only plot 

 that had been sprayed to kill both the herbaceous and the woody vegetation. 

 It is interesting that invariably only the terminal bud was removed. Multiple 

 stems will result from this feeding, an unseasonal activity for these mammals. 



1/ The authors are research foresters, stationed at Boise, Idaho. 



