UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 799 



Contribation from the Bnrean of Plant Industry 

 WM. A. TAYLOR, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



November 10, 1919 



A STUDY OF THE ROTS OF WESTERN WHITE PINE. 



By James R. Weib, Forest Pathologist, and Ernest E. Hubert, Scientific As- 

 sistant, Office of Investigations in Forest Pathology, Bureau of Plant 

 Industry, Missoula, Mont. 



CONTENTS. 



Page. 



Losses due to fungi 



Local pathology of western white pine- 

 Field studies of the rots in western 



white pine 



Relation between rot and various fac- 

 tors _ 



Age 



Size 



Pag». 



Relation between rot and various fac- 

 tors — Continued. 



Infection age 11 



Injuries , 13 



Sporophores 15 



Discussion of results 19 



Methods of control 22 



Summary 23 



LOSSES DUE TO FUNGL 



The estimated stand of western white pine {Pinus monticola) in 

 British Columbia, Oregon, "Washington, Idaho, and Montana is about 

 23,685 million feet B. M., valued at approximately $102,875,000. 

 The average loss due to the activities of fungi in western white pine 

 for the entire white-pine belt, based on data from logging operations 

 in northern Idaho, is 1,658 million feet B. M.^ This figure, 

 on a basis of the above given valuation, shows a loss of $7,201,250 

 from this cause alone. These figures, taken as an average condition 

 throughout the merchantable range of the species, indicate the loss 

 from decay to be enormous. The limited area occupied by 

 merchantable white pine, the adaptability of its wood to a wide 

 range of uses, and the ease with which it is worked so establish its 

 value as a timber tree that it becomes imperative to investigate any 

 cause of financial loss in the species, the amount of this loss, the 



1 Based on the recorded data, which give 6.9 as the average rot percentage for the 

 entire area upon which the data were collected. The actual loss due to rot would no 

 doubt be greater if figured on a basis of cull percentage or actual volume discarded, 

 according to scalers' practice. 



, 128265° — 19— Bull. 799 1 



