Natural and semi-naturalvegetation in Japan M. Numata A. Miyawaki and D. Itow Contents I. Introduction 436 II. and in Plant life its environment Japan 437 III. Outline of natural and semi-natural vegetation 442 1. Evergreen broad-leaved forest region 442 i.i Natural vegetation 442 Natural forests of coastal i.l.i areas 442 1.1.1.1 Quercus phillyraeoides scrubs 442 1.1.1.2 Forests of Machilus and of sieboldii thunbergii Castanopsis (Shiia) .... 443 Forests 1.1.2 of inland areas 444 1.1.2.1 Evergreen oak forests 444 Forests 1.1.2.2 of Tsuga sieboldii and of Abies firma 445 1.1.3 Volcanic vegetation 445 sand 1.1.4 Coastal vegetation 447 1.1.$ Salt marshes 449 1.1.6 Riverside vegetation 449 lake 1.1.7 Pond and vegetation 451 1.1.8 Ryukyu Islands 451 1.1.9 Ogasawara (Bonin) and Volcano Islands 452 1.2 Semi-natural vegetation 452 1.2.1 Secondary forests 452 C. 1.2.1.1 Coppices of Castanopsis cuspidata and sieboldii 452 1.2.1.2 Pinus densiflora forests 453 1.2.1.3 Mixed forests of Quercus serrata and Q. acutissima 454 1.2.1.4 Bamboo forests 454 1.2.2 Grasslands 454 2. Summergreen broad-leaved forest region 454 2.1 Natural vegetation 455 Beech 2.1.1 forests 455 forests 2.1.2 Pterocarya rhoifolia 457 daviniana-Fraxinus 2.1.3 Ulmus mandshurica forests 459 Volcanic 2.1.4 vegetation 459 2.1.5 Coastal vegetation 461 2.1.5.1 Sand dunes and sand bars 461 2.1.5.2 Salt marshes 461 2.1.6 Moorland vegetation 464 2.2 Semi-natural vegetation 465 2.2.1 Secondary forests 465 2.2.1.1 Pinus densiflora forests 465 2.2.1.2 Quercus mongolica var. grosseserrata-Castanea crenata forests 465 2.2.2 Grasslands 465 Contribution from No. *) JIBP-CT 34 supported by the special research project 'Studies on the dynamic status of the biosphere' sponsored by the Ministery of Education. 2 ) Department of Biology, Chiba University, Yayoi-cho, Chiba, Japan. 3) Faculty of Education, Yokohama Nat. University, Shimizugaoka, Minami-ku, Yokohama, Japan. 4 ) Faculty of Liberal Arts, Nagasaki University, Bunkyo-cho, Nagasaki, Japan. 12 436 BLUMEA VOL. XX, No. 2, 1972 3. Subalpine and subarctic coniferous forests region 467 in 3.1 Abies mariesii-A. veitchii forest Honshu 467 3.2 Mixed forests of Thuja standishii and Tsuga diversifolia 468 Larix 3.3 leptolepis forests 469 3.4 Thickets of Quercus mongolien var. undulatifolia 469 ermanii 3.5 Betula thickets 469 Picea forests in Hokkaido 3.6 jezoensis-Abies sachalinensis 471 Picea 3.7 glehnii forests 471 3.8 Tall herb communities 471 4. Alpine region 472 of Pinus 4.1 Thickets pumila1 472 4.2 Snow-patch vegetation 473 heathlands 4.3 Wind-blown 473 4.4 Alpine desert vegetation 474 IV. Epilogue 474 Literature cited 475 I. Introduction Studies on the composition of the forests and other vegetation of Japan were initiated by J. Tanaka (1887) in the Meiji Era. According to his introduction his field survey in and resulted into classification of started 1879 a vegetation zones (forest zones), mainly based dominant later of the lowland, on physiognomy and species. In years some other Honda also major proposals of the vegetation zonation were made. (1900) distinguished based his and it with the first altitudinal zones, on survey on dominance, provided vege- tation map. Nakano (1942—1943) stressed the physiognomy combined with species and succession but did not Kira described composition, sociology, produce a map. (1949) the of the climax and forest zones Japan stressing concept correlating ecology mostly he with with temperature; added a map. Miyawaki (1967) wrote a large book (provided the in a map) on vegetation of Japan which the climax concept played an important role, did the Suzuki who tried actual as it in study by (1966a) partly to integrate vegetation with climax to the he also coloured types, paying great attention sociological aspect; gave a in of communitiesand map. Miyoshi (1903) introduced Japan the study plant some years later (1907) the study of ecology, and these two disciplines have been pursued by the his Yoshii research schools of pupils, Nakano at Tokyo University, at TohokuUniversity, etc. A large number ofpapers have resulted in these two fields ofvegetation study, mainly published in the Botanical Magazine, Tokyo (Botanical Society of Japan, 1887—), Japanese of Journal ofBotany (Japan Science Council, 1922—), Journal Japanese Botany (Tsumura Acta Geobotanica Laboratory, 1926—), Phytotaxonomica et (Kyoto University, 1932—), Bulletinof the ofPlant Ecological Review (Tohoku University, 1935—), Japanese Society & Ecol. Ecology (Tokyo University, 1941 —1943), Physiology and Ecology (Physiol. Pub- lish. Ass., Kyoto, 1947—), Hikobia (Hiroshima University, 1950—), Bulletin of the Society Hokuriku of of Plant Ecology (Tohoku University, 1951 —1954), Journal Botany or Jour- nalof of Geobotany (Kanazawa University, 1952—), Japanese Journal Ecology (Ecological Society of Japan, 1954—), etc. Besides the these of have contributed papers in journals, science reports universities to the development of ecological studies in Japan. A historic review of plant ecology in Japan and basic concepts, principles, and methodologies of ecology was given by Numata revised edition and brief ofthe literature concerned (1953, 1967) a very bibliography was published in ‘Ecology’ (Numata, 1958). The ofthis is to describe briefly the purpose paper entirepicture of Japanese vegetation M. Numata et ah: Natural and semi-natural vegetation in Japan 437 with reference the studies. Such overall has been to more important recent aspect strongly and first author requested by many foreign botanists, ecologists, geographers, and the realized the of concise of when he keenly desirability a summary Japanese vegetation gave brief lecture the of of a at Department Geography, University Kansas (Prof. A. W. Kiichler) and the Department of Botany, University of Illinois (Prof. L. C. Bliss) during his the recommendation of Prof. van stay in 1967. Moreover, Dr. C. G. G. J. Steenis the nth Pacific Science in has whom we met at Congress in Tokyo 1966 led to the com- of this The pletion paper. first author, attending an IBP-CT Meeting at Monks Wood, to discuss the check sheet for reserved submitted England 1965, areas, (with Itow) a paper 'Outline of and environment of this vegetation natural Japan'. From working paper the critical has emanated. present compilation II. PLANT LIFE AND ITS ENVIRONMENT IN JAPAN The climate of is in wide it is arctic subarctic in Japan temperate a sense, though or northern Japan and highlands, particularly in winter, and subtropical in southwestern The Japan, particularly in summer. four major islands of Japan proper, Hokkaido, Honshu, 0 Shikoku, and Kyushu are located between 30° and 45 NL, the Ryukyu and Bonin Islands extending further south almost to the Tropic of Cancer. Thus, the Japanese realm chain of islands of latitude. is a long ranging over c. 22° rather cold like the Even in Tokyo at 36° NL it is in winter, andhot in tropicsin summer. In summer the lowlands in southwestern Japan are hotter than those in Taiwan, and in the Tohoku winter District at about 40° NL is colder than northern Europe at 6o° NL (Ministry Agr. For., 1961). The distinction of the four in the seasons is, general, very clear, though periods of and autumn rather shorter in the northern Weather and climate spring are part. are variable and differ locally. Japan as a whole is under the influence of a monsoon climate. wind of The southeast monsoon in summer brings a large amount rain on the Pacific side, and the northwest monsoon wind in winter brings a large amount ofsnow on the Japan Sea side and in Hokkaido (Nemoto et al., 1959). There two of thePacific and the because are mainly types climate, type Japan Sea type, of influences of and the backbone mountain the above-mentioned monsoon ranges the four islands. These climatic from the running through major types appear clearly climate diagrams (Fig. 1). The often from the Lowland mountainous topography begins sea coast. plains are few and very valleys are deeply dissected. Pavers are mostly short and swift and even the river in the Shinano is is longest Japan, River, only 369 km. Of the Japanese land 77 % between and m 18 between and and 0 700 altitude, % is 700 1300 m, 5 % is highlands is over 1300 m. The inclination of slopes rather steep, being over 30° in 24 % of the 0 0 in and less than in The is land, 30°—15 31 %, 15 45 %. geomorphology very compli- cated. As characteristics of the the principal Japanese climate, annual mean temperature is from o° C (central Hokkaido) to 18° C (southern Kyushu), the annual precipitation is 600 mm at the minimum(northeastern Hokkaido) and about 4,000 mm at the maximum (Odaigahara in Kinki District in southern Honshu and Yaku Island south offKyushu). The annual which a average precipitation in Japan proper is 1,600 mm is high figure with other of the world latitudes and of compared parts at comparable testimony an oceanic climate. The frostless in the lowlands is from in northeastern Hokkaido to period 125 days 275 BLUMEA VOL. No. 438 XX, 2, 1972 Sea Fig. 1. Paired climate diagrams of the Japan type (left) and the Pacific type (right), both lowland stations. The is Sea U-shaped curve of the precipitation distribution characteristic to the Japan type and the reversed is that of the Pacific Scales for and U-shaped curve type. temperature precipitation are on The minimum left and right hand respectively. black bar indicates the months with mean temperature below O° C, and the batched bar indicates the months with the absolute minimum temperature below Mean O° C.