Current Literature 525 



Studies in Tolera.nce of Nezv England Forest Trees. By G. P. 



Burns and F. P. Hooper. Bulletins 178 and 181. Vermont 



Agricultural Experiment Station. Burlington. 1914. Pp. 127- 

 144; 235-262. 



The investigations described in the above bulletins v^^ere made 

 mostly upon the behavior of White pine seedlings under various 

 controlled and instrumentally recorded conditions in the Vermont 

 State Nursery at Burlington. The first bulletin has the sub-title 

 of Development of White pine seedlings in nursery beds, and the 

 second bulletin, Relation of shade to evaporation and transpira- 

 tion in nursery beds. 



The loss of seedlings by the damping off disease has been thor- 

 oughly checked by applying to the soil previous to planting 36 

 gallons of one per cent formaldehyde solution per 32 square feet 

 or 26 gallons of water and 4^ fluid ounces of commercial sul- 

 phuric acid for each 24 square feet. The two fungicides seem 

 equally efficacious. Experiments on the influence of depth of 

 planting upon germination showed that germination under one- 

 half inch of sand was almost sixteen times as great as under 

 barely covered condition and more than twice as great as under 

 one-fourth inch cover. The limiting factor seems to be the water 

 content of the soil, for in case of the shallow planting where the 

 surface layer of the soil was given sufficient moisture to prevent 

 drying out, the number germinating was practically the same as 

 in beds with deeper planting. Shading by retarding evaporation 

 had the effect of overcoming the disadvantages of shallow 

 planting. 



Beds were prepared under full lath-shade, one-half lath-shade 

 and no shade, and it was found that full shading did not increase 

 the number of seedlings produced, although it gave a somewhat 

 more even stand, but it did delay the germination about two 

 weeks. The light intensity values in the no-shade beds were 

 sometimes thirty times greater than in the full lath-shade beds, 

 and it was only in the no-shade beds that the temperature values 

 reached the optimum for germination. This was in the month of 

 May. The conditions of these two factors explain the delayed 

 germination in the shaded beds. Three months after planting 

 the seedlings without lath-shade were in much more vigorous 

 condition than the shaded seedlings in respect to length and nam- 



