JAMES C. SPACE 



1 9622 

 I2R312 



UNITED STATES DEPARTMENT OF AGRICULTURE 



immmAifi 



FOREST SERVICE 



FOmr & RAUE EXPERmm STATIO!^ 



O C D E N 



UTAH 



No. 84 



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rn 



C"3 



Kay 1961 



CAN PONDEROSA PINE IN BRUSHFIELDS BE SPRAYED AFTER PLANTING? 



James D. Curt i si'' 

 Division of Forest Management Research 



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When brushfields are to be regenerated by planting, several options of 

 site treatment are available. One of these is to plant without any site prep- 

 aration and later spray the brush with suitable herbicides to eliminate the 

 competition. To test this procedure, four 0.1-acre plots were laid out on a 

 severe west exposure at Town Creek, Boise National Forest, in central Idaho 

 in late July 1957. The area had been planted with 2+0 ponderosa pine in 1954 

 by the dug hole method. 



One of the plots was chosen randomly as a check, and the other three were 

 sprayed by hand nozzle and portable pump with 2,4,5-T in the proportion of 1 

 gallon to 200 gallons of water — The seasonal growth of both pine and brush 

 was complete at the time although the Ceanothus had finished its growth first. 

 The spraying was done in 95° F. weather and though particular care was taken 

 not to spray the tender pine leaders and laterals, they probably received 

 spray from drift. 



The trees were staked for later identification and examined each year to 

 record the mortality and growth since spraying. The results of these examina- 

 tions are shown below. 



If the lethal effects of spraying are considered to last no more than 2 

 years or so, only Plot 4 appears to have suffered any appreciable mortality 

 from this cause; later mortality may be due to competition. There is little 

 to choose in periodic growth between the plots except that Plot 4 produced 

 least. Trees on the check plot average some 0.35 foot higher than trees on 

 the treated plots. 



1/ Forester, Intermountain Forest and Range Experiment Station, U.S. 

 Forest Service, Ogden, Utah. 



2/ Chemicals for these trials were supplied through the courtesy of The 

 Dow Chemical Company. 



