38. 富士高地産カラマツの樹型変異と北海道における次代の生育(会員研究発表講演)

抄録

Seed lots were gathered from the trees with different forms of prostrate and erect types growing at various elevations of Mt. Fuji around its forest and timber lines and those with cones of non-recurvate scales like Korean larch. And the seedlings from them were investigated at the Tokyo University Forest in Hokkaido, in order to ascertain whether such tree forms are genotypic or phenotypic, and to examine the taxonomic entity of the individuals with such particular cones. Through observations and measurements of them at the nurse, stage and during the period. of about 10 years after planting out in experimental fields, the following facts became clear. (i) All progenies of mother trees of prostrate type compared quite well with those of erect type in their trunk form and vigorous growth, and did not include any single seedling of prostrate form. Moreover, there was not found any obvious correlation between the forms of mother trees and various characters of their progenies such as growth vigour, formation of lateral branchlets, time of terminal bud formation and that of autumnal colouring of needles. Therefore it is doubtless that this difference of tree forms is merely phenotypic. (ii) However, the progenies of the trees growing at high elevations more than 2300-2400m are to some extent different from those at lower elevations or those of artificial plantations at Yamabe in their formation of lateral branclaets (less), time of terminal bud formation and of autumnal colouring of needles (earlier for some days), and growth at the stage of 3-year-old. seedlings (worse). (iii) Generally speaking, the provenances in the district of Mt. Fuji are conspicuous among all those those put to the provenance test by their habit of spreading primary branches or limbs in the shape of obVious storeys like kurile larch. (IV) The progenies of trees with Korean larch-type cones were not distinguishable from those of ordinary type in the characters discussed in the preceding paragraphs. Therefore it is quite reasonable to consider that these trees are still within the range of morphological variation of Japanese larch with only small deviations from the typical. According to several reports as to provenance tests of Japanese larch, both in this and foreign countries, this species shows constant variation among provenances of geographical difference in frost-(and pest-) hardiness, flower-setting, some morphological characters, and others, but does not in the growth of progenies. The result of the present study suggests the same inclination as to the sources of altitudinal difference.