MORTALITY O]' WHlTE-PINE AND RlCD-PINIv PLANTATION'S 317 



fall ; also that the better the grade of stock the greater is the height 

 growth and root development. 



Mortality 



Counts for the mortality during the first season of plantations of 

 graded nursery stock were made weekly at the experimental plots of 

 the grades of white pine and red pine described previously. 



While growth measurements were made only on 50 per cent of the 

 trees, the mortality counts included every tree. These were made on 

 the same dates that the measurements were taken. 



Table 5 shows by weeks the loss in each grade of each species, the 

 total number dead, and the per cent living. 



Results here are of exactly the same nature as with the height growth, 

 the better the grade of stock planted the more satisfactory are the re- 

 sults. The absence of mortality in grades A and B and the mortality 

 of less than 2 per cent with grade C of the four-year white pines 

 show how successful planting can be carried on during a favorable 

 growing season if careful treatment is given the stock. In contrast the 

 high mortality — 46 per cent — of the three-year white pines shows what 

 may be expected from stock which is not well cared for at all stages of 

 nursery practice. The death of many of these trees is directly traceable 

 to the delay in transplanting in 1914 and in the treatment incident to 

 planting in 191 5. 



Grade A of the red pines was unusually thrifty and the low mor- 

 tality is not unexpected. Grade B shows that, as with white pine, the 

 better the grade of stock the lower the mortality. With justice to this 

 grade, it should be said that the ground cover was more dense and 

 troublesome on this than on any other plot and has probably as nuich 

 effect as the grading on mortality. Even with this, however, the ex- 

 periment shows that during the first season plantations of red-pine 

 and white-pine stock of higher grades will be less affected by mortality 

 than will those of lower grades of the same stock. 



Mortality counts were also made biweekl)^ on plantations of red 

 pines and white pines located about four miles north of Ithaca. The 

 soil is a dark Dunkirk clay loam, almost free from stones and easily 

 worked. The land planted is almost flat and well drained. Thirty-six 

 thousand trees were set out, there being an equal number of red pines 

 and white pines in mixture. A layer of sod covered the fields ( tiiis was 

 formerly pasture and hay land). 



Temperature and precipitation records can be ascertained from the 

 graphs shown iireviously. 



