The investigation for the conservation of the Fagus crenata forest in southern limit of distribution area

分布区南缘水青冈林保护调查

• 批准号: 10660151
• 负责人: ISHII Hiroshi
• 金额: $ 1.47万
• 依托单位: KAGOSHIMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10660151/
• 关键词: Fagus crenata; Southern limit of distribution; Regeneration; 南限地

The structure of beech (Fagus crenata) stands and the regeneration regimes of beech were investigated at the ridge in Mt. Takakuma, which is the southern limit of beech distribution.(1) The height of beech in Takakuma is suppressed compared with the radial growh or the horizontal extension of the crown when the beech was taller than the shrub layer. Poor dominance of canopy tree species may be an indirect reason for such a change in the trade-off relationship between vertical and horizontal growth. However, although the height of beech in Takakuma was suppressed, death of beeches or obvious declines of radial growth were not observed.(2) The density of the basal area and beech trees in Takakuma was as low as that of other Pacific Ocean type beech forests. The proportion of small trees with <10cm in Dbh to canopy trees with >20cm in Dbh was lower in 0.5. Furthermore, there were no saplings less than 2m in height even though Sasa was absent, although the gap ratio exceeded 50% in Mt. Takakuma.(3) The nut production vas large in 1998, however there were remarkably few viable nuts because the proportion of empty nuts was nearly 80%. Although the mortality of nuts in winter season was low, there were no current seedlings whether Sasa was removed or not in the autumn of the mast year.(4) The beech in Takakuma did not regenerate successfully, and other canopy tree species or the community of shrubs with Sasa may replace the beech stands.

对山毛榉分布南端高熊山山脊处的山毛榉（Fagus crenata）林分结构和再生状况进行了研究。（1）与径向生长相比，高熊山的山毛榉高度受到抑制。或当山毛榉高于灌木层时树冠的水平延伸。冠层树种优势度较差可能是导致垂直与水平生长权衡关系发生变化的间接原因。然而，尽管高熊山毛榉的高度受到抑制，但并未观察到山毛榉的死亡或径向生长的明显下降。（2）高熊山毛榉的断面积和树木密度与其他太平洋型山毛榉一样低森林。胸径<10cm的小乔木与胸径>20cm的冠层乔木的比例较低，为0.5。另外，高熊山虽然没有笹，但间隙比例超过50％，没有高度低于2m的树苗。(3) 1998年坚果产量很大，但能成活的坚果却很少，因为比例太低。空坚果率接近80%。尽管冬季坚果死亡率较低，但在丰年秋季无论是否除去笹笠，都没有现苗。(4)高熊山毛榉没有成功再生，其他冠层树种或群落莎莎灌木可能会取代山毛榉林。