PINES 



195 



ible 2. The table shows that P. proved attractive to 



5S in the field, as well as ir. the laboratory; also that in the field 

 it uas mildly attractive to hares. 



Vole gnawing damage is one of the greatest problems in plantations 

 of forest trees in Hokkaido, Japan. IVhen the population level of the 

 vole is low, s escapes gnawing damage, but when the level is 



high, : . Ls severely gnawed. Therefore, control of voles must 



be obtained if P. and many other introductions are to become 



important to forestry in Japan. 



Table 2. Vole- and hare-gnawing of various tree species in the 

 field, after Takahashi and Iwamoto (1963) 



SPJ 



Percentage of trees gnawed 

 By voles By hares 



L. 39 



P. c L. 98 



isis 0. $ S. var. hoveana Ueki 11 



L. Isptolspis Gord. 89 



el Ini (Kupr.) Litvin 



--st. 



-c (Sieb. & Zucc.) Carr. 2 



Regel 41 



B. platyphylla Skat. var. japonica 



(Miq.) Hara 3 



7 

 6 

 3 

 5 

 

 

 



15 



NEEDLE RUST SUSCEPTIBILITY AMDNG hHITE PINES 



Inoculation experiments using 8 species of white pines and inocula- 

 ting with sporidia of 5 Coleosporiian needle-rust species were made from 

 1959 to 1968 (Saho, 1968 and 1969). Results given in Table 3 show that 



■ila is quite resistant to all these species of needle rusts and 

 that ?. pentaphylla is resistant to 4 of the 5 rust species. On the 

 contrary, ?. koraiensis is highly susceptible to all 5 rusts, and 

 montiaola is moderately to highly susceptible to 4 of the 5 rusts. 





