Vegetation Science 31 : 179-192, 2014 179 1 2 1 2 Forest floor conditions causing regional differences in the habitat of forb species in Japanese beech forest, eastern Japan Akira HIRUMA 1 and Tukasa HUKUSIMA 2 1 Nagano Environmental Conservation Research Institute 2 The Open University of Japan In cool temperate forest zones in eastern Japan, certain forb species like Cimicifuga simplex in light - snow regions grow on slopes of beech forests, while in heavy - snow regions its habitat is rather limited to valleys adjacent to beech forests. This research study reveals reasons for this difference in forb species habitats. As key factors, the study focuses on differences in the lighting environment during the leafing season as well as the state of tree leaf litter sedimentation on the forest floors in both light - snow and heavy - snow environments. Regardless of the amount of snow, the volume of tree leaf litter sedimentation on the forest floor was large on slopes of beech forest and small in valleys. In heavy - snow beech forests, the number of layers of litter sedimentation as well as the density of litter compaction within a certain thickness of sedimentation were larger compared to light - snow regions. In terms of the lighting environment during the summer season, no difference was observed on slopes of beech forest between light - snow and heavy - snow environments. However, over the spring season in light - snow regions, the lighting environment of the forest floors was good during the leafing seasons, because foliation begins with the herbaceous layer and leaf expansion of canopy trees comes later. On the other hand, in heavy - snow regions, the lighting environment of the herbaceous layer was poor during the leafing season, since foliation starts from canopy trees as snow covering the floor remains longer. In valleys, foliation of herbaceous layer preceded that of shrubs even in heavy - snow regions. This phenomenon was attributed to the fact that lingering snow in the valley floor covers the shrubs alongside the valley, which in turn delays foliation of the shrubs. Two factors are considered reasons restraining the growth of forb species in beech forests in heavy - snow regions: 1 the large number of layers and the high density of litter sedimentation at the forest floor constrict the establishment and germination of forb species, and 2 the poor lighting environment from spring to early summer which are supposed to be productive seasons is due to lingering snow that makes the crown canopy of beech forests foliate before forb species. However, the study found that forb species are able to grow in valleys in heavy - snow regions, because the volume of litter sedimentation is small and herbaceous layer begins and completes foliation before shrubs do. key words: herbaceous layer, leaf phenology, light condition, litter, snow accumulation 1981; 1986 1987; 1987; 1998 1974 1987 1995 381-0075 2054-120E - mail: kanotume11@gmail.com The Society of Vegetation Science : 2011 11 25 : 2014 9 11
180 Vegetation Science Vol. 31, No. 2, 2014 Sasamorpho - Fagion crenetae Miyawaki, Ohba et Murase 1964 Saso - Fagion crenatae Miyawaki, Ohba et Murase 1964 2004 2004 Cydes & Grime 1981; 1987, 1996 Uemura 1994; Shimano 2000 2004 2004 Corno - Fagetum crenatae Miyawaki, Ohba et Murase 1964 cacalietosum yatabei Hukusima et al. 2001 Saso kurilensis - Fagetum crenatae Suz. - Tok. 1949 sasetosum tsukubensis Hukusima et al. 2001 2 4 1 1. 2. 3. typicum Hukusima et al. 1984 4. 4 WI45-85 C 2004 1964 4-400 m 2 2004 1992 1992
181 1. m 2004 : ; : Cydes & Grime 1981; 1987, 1996 % 1 cm 2 1 3 % 30% 70% 3 1 0 0 0 30% 3 2 0 0 6 9 50 cm Nikon COOLPIX995 Nikon Fisheye Converter FC - E8 1 HemiView Ver. 2.1 Delta - TGlobal site factor GSF: 1. 19 18 4 38 30-16 18 2 44 42 2
182 Vegetation Science Vol. 31, No. 2, 2014 1 50 cm Uemura 1994; Shimano 2000 3 1 2002 4 6 2 2002 5 6 2003 5 2003 5 1997 2003 2004 4 Kruskal - Wallis Tukey - Kramer B, C, D 2 90% 26% 33% 2 43% 58% 42%, 39% 14%, 17% 10%, 13%5%, 0% 2 3 3 - C, D 4 4 - C, D
183 2. % 73 64 76 68 19 49 18 62 0 0 5 1 26 10 33 10 100 100 93 99 74 90 67 90 19 16 21 16 43 14 58 18 11 13 10 10 29 16 17 9 7 9 0 4 0 7 8 5 42 36 39 40 14 36 17 30 21 27 31 28 14 27 0 38 0 0 9 0 0 2 0 5 0 0 0 0 5 2 6 2 60 44 58 41 79 37 72 47 30 52 13 46 11 47 17 29 0 0 4 3 0 0 6 3 10 5 13 7 5 10 0 11 0 0 1 3 0 2 0 2 0 0 0 0 0 0 0 2 2. P<0.01 5 2 Kruskal - Wallis P=0.411 4 - A, B
184 Vegetation Science Vol. 31, No. 2, 2014 3. 4. P<0.01
185 5. GSF 6. 2003 5 12 6 1.5-2 m 1. Heady 1956; Monk & Gabrielson 1985; Facelli & Pickett 1991a, b Cydes & Grime 1981; 1987, 1996 1996 4
186 Vegetation Science Vol. 31, No. 2, 2014 2004 2. GSF 2 1978; 1979; Hukusima 1988; 2002 1978 10 15-20 1 m 1 1.5 1979 Uemura 1994 1 2 Uemura 1994 50% 1996; 2005 2004
187 2 2004 40-60 7 6 1954; 1969; 1975; 1978; 1980; 1983; 1987; 1989; 1999; 1999a, b
188 Vegetation Science Vol. 31, No. 2, 2014 7. 1. 2004 2. 3. 4.
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190 Vegetation Science Vol. 31, No. 2, 2014 2004 : 1 10% +: 1 10% : 16 20 11 6 18 10 4 7 4 6 3 5 14 6 5 30 A: Polygonatum lasianthum + + Smilacina japonica + + + + Disporum smilacinum + + + Paris tetraphylla + + + + + Panax japonicus + + + + + Tripterospermum japonicum + + + B: Laportea bulbifera + + Cimicifuga simplex + + + Trillium smallii Trillium tschonoskii + + Plectranthus kameba + + Salvia nipponica Leucosceptrum japonicum + + + Dioscorea septemloba + + + Viola vaginata + Aruncus dioicus var. tenuifolius + Galium japonicum + + + C: Ainsliaea acerifolia var. subapoda + + + Astilbe thunbergii + + + Solidago virga - aurea var. asiatica + + + D: Cacalia hastata var. farfaraefolia + + Veratrum maackii var. japonicum Maianthemum dilatatum + Adenophora remotiflora + + Rodgersia podophylla + + Phryma leptostachya var. asiatica + + + + + Carpesium triste + + + + Synurus pungens + +
191 Cimicifuga acerina + Filipendula multijuga + + + Cacalia yatabei + Clematis japonica Viola eizanensis + Potentilla yokusaiana Aconitum japonicum var. montanum + + Aster ageratoides var. harae f.leucanthus + + + + + + Pseudostellaria palibiniana + Arisaema japonicum + + Meehania urticifolia + Chelonopsis moschata Eupatorium chinense var. simplicifolium + Polygonatum falcatum + + Aconitum pterocaule + Caulophyllum robustum + + Galium paradoxum + Peracarpa carnosa var. circaeoides + + Spuriopimpinella calycina + + Epipactis papillosa + + Aegopodium alpestre Viola kusanoana + Cacalia adenostyloides Veronicastrum sibiricum Paris verticillata + + Pyrola secunda Waldsteinia ternata + + Oreorchis patens Streptopus streptopoides var. japonicus Cirsium nipponicum Anemone debilis Rubus pseudo - japonicus Pyrola incarnata Ligularia dentata + + Thalictrum tuberiferum + + Viola selkirkii Aquilegia buergeriana Asarum sieboldii + + + Cacalia farfaraefolia + + Clintonia udensis E: Shortia uniflora + Smilax nipponica + + + Goodyera foliosa + + Mitchella undulata + + + + Polygonum cuspidatum + + + Heloniopsis orientalis
192 Vegetation Science Vol. 31, No. 2, 2014 16 20 11 6 18 10 4 7 4 6 3 5 14 6 5 30 F: Cacalia tebakoensis Anemonopsis macrophylla Cirsium effusum + Viola bissetii Saussurea sinuatoides + Pedicularis gloriosa Viola shikokiana + + Plectranthus umbrosus + Saussurea nipponica var. sendaica G: Asarum megacalyx