WHITE PINES OF JAPAN 



Haruyoshi Saho 



Laboratory of Forest Botany 3 University of Tokyo , 

 Bunkyo-ku 3 Tokyo 3 Japan 



ABSTRACT 



Five white pines native to Japan, plus several introduced white 

 pines, are considered. Native Pinus pentaphylla from cool, 

 rocky sites of northern Japan, and P. himekomatsu from similar, 

 mountainous sites to the south, both exhibit slower growth but 

 higher needle-rust and rodent-damage resistance than introduced 

 P. strobus. The often dwarf and very slow-growing P. pumila 

 occupies mountain-top sites throughout northern and central 

 Japan, and is quite resistant to needle rusts. P. koraiensis 3 

 limited almost entirely to the central mountains of Honshu, 

 exhibits growth slightly better than P. pentaphylla, but still 

 well below that of P. strobus. It is highly susceptible to 

 needle rusts. P. strobus is the preferred white pine introduc- 

 tion, but under high vole populations control of these rodents 

 is required if it is to escape severe gnawing damage. Only 

 limited information is now available on P. montioola 3 P. griffithii, 

 P. albioaulis 3 P. flexilis 3 and P. lambertiana. A brief discus- 

 sion of the controversy concerning the division of the species 

 P. parviflora into northern (P. pentaphylla') and southern (P. 

 himekomatsu) taxons is given. Also, some evidence for and 

 against the presence of Cronartium ribioola on Ribes spp. and 

 on native and introduced white pines in Japan is presented. 



INTRODUCTION 



Japan has a relatively rich white pine flora including 5 native 

 species or major varieties (Fig. 1). In order of decreasing importance 

 these are Pinus pentaphylla Mayr, Pinus himekomatsu Miyabe and Kudo, 

 Pinus pumila Regel, Pinus koraiensis Sieb . £ Zucc, and a variety (v. 

 amamiana Hatusima) of Pinus armandii Franch. The latter variety is 

 restricted to 2 islands south of Kyushu, and will not be considered 

 further in this paper. 



Similarly, Japan's introduced white pine flora is quite rich--and in 

 the case of one species {Pinus strobus L.) of high potential value. 

 Besides that species introductions include Pinus albioaulis Engelm. , 

 Pinus flexilis James, Pinus griffithii McClell. (syn. Pinus walliohiana 

 A.B. Jacks.), Pinus montieola Dougl., and Pinus lambertiana Dougl . P. 

 strobus has given good results in Japanese plantations, even though it 

 suffers heavy needle-rust {Coleosporium spp.) infection and may be 

 severely damaged by voles or hares. 



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