508 Forestry Quarterly 



see an old spruce thus surrounded by a close thicket of descendants. 

 And when to the superiority of spruce within the protection forest 

 as compared with pine, we consider the greater tolerance of the 

 former, which enables it to migrate upward under cover of birch 

 or any other tree, and that it by virtue of tolerance finds room for 

 five within a space required by one pine, increasing in a geometric 

 ratio as compared with pine, we will have to acknowledge that a 

 future predominance of spruce on the upper slopes and at timber- 

 line may have its benefits. 



Spruce together with birch will bring the timberline higher. 

 These two species will at least stay the receding tendency of pine. 

 But where pine occurs alone the timberline will continue to recede. 



J. A. L. 



Tidskrift for Skogsbruk, January, 1913. 



A. H. Graves reports the appearance in 

 Root the nursery of the Yale Forest School, during 



Rot the spring and simimer of 1914, of a serious 



of root rot. About 20 per cent of a bed of 



Seedlings one-year-old Red pines (Pinus resinosa) 



were destroyed while 5 per cent of a bed of 

 one-year-old White pines (P. strobus), several thousand two-year- 

 old Red pines, as well as a few seedlings of one-year-old hemlock 

 {Tsuga canadensis) succumbed. 



The disease first became noticeable through a dark red or 

 reddish-brown discoloration of the tips of the leaves. By slow 

 degrees this color was extended and subsequently became brown or 

 yellow brown. Diseased seedlings were examined and showed a 

 root system entirely dead. 



Repeated efforts were made to isolate a fungus without success, 

 but a study of the soil beds showed that the soil was stiff and 

 clayey. This, together with the fact that the disease caused most 

 destruction early in the season and disappeared when dried condi- 

 tions prevailed, has led to the conclusion that it is due to the lack 

 of oxygen in a soil which is saturated with water. 



Phytopathology, April, 1915, pp. 213-7. 



