Journal of Phytogeography and Taxonomy 53 : , 2005 The Society for the Study of Phytogeography and Taxonomy Hideyuki Ida : Why do

Size: px

Start display at page:

Download "Journal of Phytogeography and Taxonomy 53 : , 2005 The Society for the Study of Phytogeography and Taxonomy Hideyuki Ida : Why do"

かずしすわ
5 years ago
Views:

1 Journal of Phytogeography and Taxonomy 53 : , 2005 The Society for the Study of Phytogeography and Taxonomy Hideyuki Ida : Why does beech dominate in forests receiving heavy snows? : A discussion from the viewpoint of leaf phenology Institute of Nature Education in Shiga Heights, Faculty of Education, Shinshu University, Shigakogen, Nagano , Japan Abstract The leaf phenology for a tree community was investigated in a beech Fagus crenata forest characterized by heavy winter snows in central Japan. A tree community of seventeen species dbh 5 cm ; 202 trunks total in a 0.5 ha stand was observed at an interval of 1 4 weeks during the growing seasons of 1999 thaw period was early May ; early year and 2003 thaw period was late May ; average year. As for an understory community height < 10 m, in the early year, beech flushed two weeks later than other species e.g. Acer nipponicum, Acer japonicum and Cornus controversa after the thaw. However, beech completed flush very quickly and was able to compete with the other species effectively. In the average year, beech and other species flushed at the same time with beech reaching full flush earliest. Therefore, beech is able to dominate over other woody species in forests characterized by heavy winter snows for two reasons : 1 young beech flush speed ; 2 delayed flush period of other species remaining in snow pack. Key words : beech forest, flush period, leaf phenology, regeneration, snow pack. Sasaki Fagus crenata Blume Fig Shimano and Masuzawa 1995 ; Maruta et al ; Homma 1997 Shimano and Masuzawa 1998 Takatsuki

植物地理分類研究第 53 巻第 2 号 2005 年 12 月 Fig. 1. A beech Fagus crenata forest characterized by heavy winter snows in central Japan Mt. Nabekura, Nagano Prefecture.

2 植物地理分類研究第 53 巻第 2 号 2005 年 12 月 Fig. 1. A beech Fagus crenata forest characterized by heavy winter snows in central Japan Mt. Nabekura, Nagano Prefecture. 雪地のブナ林では高木層の開葉が低木層のそれを待たずに始まるがこれは寡雪地の夏緑林でのパターンと正反対である丸山 1979 加藤他 1999 さらに丸山 1979 は豪雪地で積雪の影響を直接受ける低木層のうちブナの生育期間が最も長いことを述べている本間 2002 によると積雪の影響を直接受ける下層では開葉の早いブナ低木に比べ他の樹種は年間獲得光量を約 20 ロスするというつまり物質生産面からみればブナ個体群の同化生産期間が群集内で相対的に長いということは林分を優占する上でも有利な条件であるといえるだろうそこで筆者はブナ林群集の葉群フェノロジーに着目しブナが豪雪地で優占林分を形成する要因について検証した具体的には豪雪地のブナ林において融雪期の遅速が樹木群集の葉群フェノロジーにどのような影響をおよぼすかについて調べた調査地と調査方法調査地は長野県木島平村カヤの平にあるブナ成熟林標高 1,500 m で最大積雪深は 3 m を超える豪雪地である年の冬期では最大積雪深 340 cm であったこの林分はブナが胸高断面積合計換算で約 90 を占める典型的な日本海型ブナ林である葉群フェノロジーの観察は 1999 年と 2003 年の両年春から秋にかけ 0.5 ha の方形区内の樹木胸高直径 5 cm 以上全 17 樹種計 202 本について約 1 4 週間間隔で行ったなお融雪時期完全に雪がなくなった時期は 1999 年が例年よりも早く 5 月上旬で 2003 年が例年並みの 5 月下旬であったフェノロジーの進行段階は 1 冬芽 2 開芽 3 葉身展開 4 開葉完了 5 紅葉黄葉 6 落葉の 6 区分とし段階 2 から 6 についてはそれぞれ樹冠の 0 以上 25 以下 26 以上 50 以下 51 以上 75 以下 76 以上 100 以下の 4 段階のうちどれに達しているかを記載した階層間の比較では便宜上上層木樹高 10 m 以上と下層木樹高 10 m 未満に分けたブナ以外の主要な樹種幹本数 n 10 はトチノキ Aesculus turbinata テツカエデ Acer nipponicum ハウチワカエデ Acer japonicum ミズキ Cornus 140

3 December 2005 J. Phytogeogr. Taxon. Vol. 53. No. 2 controversa Fig Fig Fig. 2. Schema of the leaf flush pattern of a tree community in 1999 thaw period was early May and 2003 thaw period was late May in the study stand at Kayanodaira Beech Forest in Nagano Prefecture, central Japan. 141

4 m Fig Shimano Homma, K Effects of snow pressure on growth form and life history of tree species in Japanese beech forest. J. Veg. Sci. 8 : p : p : : Maruta,E.,Kamitani,T.,Okabe,M.andIde,Y Desiccation-tolerance of Fagus crenata Blume seeds from localities of different snowfallregimeincentraljapan.j.jpn.for.soc. 2 :

5 December 2005 J. Phytogeogr. Taxon. Vol. 53. No : Sasaki, Y Versuch zur systematischen und geographischen Gliederung der japanischen Buchenwaldgesellschaften. Vegetatio 20 : : Shimano, K Regeneration dynamics, causal factors, and characteristics of Pacific Ocean-type beech Fagus crenata forests in Japan. Folia Geobotanica 37 : Shimano, K. and Masuzawa, T Comparison of preservation of Fagus crenata Blume under different snow condition. J. Jpn. For. Soc. 77 : Shimano, K. & Masuzawa, T Effects of snow accumulation on survival of beech Fagus crenata seed. Plant Ecol. 134 : Takatsuki, S Foot morphology and distribution of Sika deer in relation to snow depth in Japan. Ecol. Res. 7 : Received October 5, 2005 ; accepted December 1,

橡 PDF

橡 PDF ( ) * Regeneration of many tree species by soil scarification under canopies -Relation between canopy openness and species richness- Hajime SATO ( )20 20 40 PAR30 0.5 1 (2) 1970 1993 1997 1996 1982 Hokkaido