INFLUENCE OF THE PERIOD OF TRANSPLANTING 

 WESTERN WHITE PINE SEEDLINGS UPON THEIR 

 BEHAVIOR IN NURSERY AND PLANTATION 



By E. C. Rogers 



Forest Examiner, Forest Service, United States Department of Agriculture 



At forest nurseries in the northern part of the United States the work 

 is customarily crowded into three or four weeks in spring immediately 

 following the time when the soil can first be worked. Preferably, the 

 stock is lifted, packed, shipped early, and spring sowing and transplanting 

 are all usually crowded into this period. At the Savenac Nursery, Haugan, 

 Mont., this spring congestion has been keenly felt; and the experiments 

 outlined below have had for an object the determination of the safe 

 limits of the transplanting season. The results may or may not apply 

 beyond the local conditions prevailing in the region of western Montana 

 and northern Idaho. 



FALL TRANSPLANTING 



Work was commenced upon this problem at the Savenac Nursery in the 

 fall of 1913. By the use of the Mast trencher method, 600 i-year-old 

 seedlings of western white pine {Pinus monticola Dougl.) were transplanted 

 on each of the four following dates: August 15, September i, September 

 15, and October 10. In May, 19 14, these plants were examined and the 

 overwinter losses were recorded. Loss by frost heaving, as indicated 

 in the figures, includes not only plants completely thrown out but also 

 those lying prostrate on the ground, even though they were quite firmly 

 attached and still alive, because in that condition they would never 

 recover sufficiently to be fit to plant. A few individuals showed the 

 symptoms of winterkilling. These were about evenly distributed among 

 the four units, in no case amounting to i per cent of the total. Figure 

 I shows the loss by frost heaving. From one- third to one-half of the 

 plants were heaved out during the cold nights of late October, before 

 the coming of snovv^, and during the clear weather of late March and 

 early April after the snow left. The loss was greatest in the October 10 

 unit. This may be explained by supposing that, because of the warmer 

 soil temperature the individuals transplanted earlier had had time to 

 make sufficient root growth to render them more resistant to the frost 

 lifting, but that those transplanted latest were virtually heeled in. 

 However, precise evidence on this point is lacking. 



As it had been suggested that possibly in the Mast V-shaped trench 

 a pocket of loose soil was formed around the lower roots and that this 



Journal of Agricultural Research, Vol. XXII, No. i 



Washington, D. C. Oct. i, 1921 



z p Key No. F-6 



