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IBSS FEB RAS
|Current state of knowledge in phytosociology of spruce forests
Yezo spruce, Picea jezoensis, occurs in the montane submaritime and maritime areas of northeastern Asia between the latitudes 35 N and 56 N. The range of the Yezo spruce forests includes the northern part of the Sikhote-Alin mountain range, the western coast of the Sea of Okhotsk, Mt. Chanbai, Shantar Islands, Sakhalin Island, the southern Kurils (Iturup and Kunashir Islands) and Hokkaido. In addition, disjunct localities are found in the middle part of Honshu Island (Picea jezoensis var. hondoensis) (Numata et al. 1972), in central Kamchatka (Man'ko & Voroshilov 1978), in Korea (Song 1991, 1992), and in northeastern China on the mountain range Dunlin (Wang 1961). Within this range, Yezo spruce forests can be considered the zonal vegetation type in the lower part of the Amur River basin (the Sea of Okhotsk coast), on Sakhalin Island, in the southern Kurils (Iturup Island) (Kolesnikov 1961) and on Hokkaido (Kojima 1979, 1983). Here, Yezo spruce forms stands in a broad belt at elevations ranging from sea level to the alpine timberline, or, in northern temperate and boreal zones, up to the altitudinal belt of Betula ermanii forests. Spruce forests occupy almost the whole range of habitats in this belt, avoiding only mires, rock outcrops and areas around solfataras, the jets of hot water with sulphur dioxide and hydrogen sulphide in the regions of volcanic activity (Rozenberg 1959, Man'ko 1967, Nakamura 1988).
Yezo spruce forests occur in different proportions with other forest types across their range. Two species of fir, namely Abies nephrolepis in the mainland and A. sachalinensis in the island part of the area, are important co-dominants in the main part of the species' range. In the southern part of its range, Picea jezoensis grows together with Abies koreana and Thuja koraiensis in Korea (Song 1991) and with Abies veitchii and A. mariesii on Honshu (Miyawaki 1985).In the northern portion of its range, however, including Kamchatka, the northernmost parts of the Schmidt peninsula (Sakhalin) and the Maya River basin in the mainland, Yezo spruce forms pure stands without fir. Elsewhere in its range, other conifers may occur admixed with Yezo spruce stands. In the southern portion of the range of Yezo spruce, Picea koraiensis forms pure stands usually in the river valleys or on the low or middle parts of gentle slopes (Kurentsova 1960, 1968). On these sites it can also occur in a mixture with Yezo spruce. Picea obovata and P. jezoensis occur together in the Okhotsk part of the range of Picea jezoensis, although across all the range Picea obovata can occasionally form pure stands, mainly in river valleys. Picea glehnii occurs in southern Sakhalin (Tatewaki 1958, Tolmachov 1959), the southern Kurils (Vorob'ev 1963, Ishizuka 1974), on Hokkaido (Numata et al. 1972) and in northern Honshu on Mt. Hayachine (Ishizuka 1961). In contrast to P. jezoensis, its optimum lies in waterlogged sites with a water table above or at ground level during the growing season. These species therefore tend to form mixed stands only where their ecological ranges overlap in slope-mire ecotones (Man'ko 1987).
The ecology and distribution of Picea jezoensis in the Russian Far East were thoroughly studied by Tolmachov (1954, 1955), Rozenberg (1959), and Man'ko (1961, 1965, 1967, 1974, 1980, 1987). It is commonly accepted that fir-spruce forests represent the climax vegetation of the boreal zone in its southern and middle subzones in the submaritime and maritime sectors (Kolesnikov 1961, Hamet-Ahti et al. 1974, Grishin 1995). Spruce forests as a zonal vegetation type are characteristic for the western coast of the Sea of Okhotsk, going west into the continent on a distance about 1500 km, and for central Kamchatka, where they form so-called conifer island. The first area was named by Kolesnikov (1961) the Western Okhotsk Area of dark conifer forests and the second area we call the Eastern Okhotsk Area of dark conifer forests.
Phytosociological studies of Yezo spruce forests have been scattered up until now. An extensive phytosociological study of the spruce forests on Hokkaido was undertaken by Nakamura (1988). Two associations belonging to the alliance Piceion jezoensis Suzuki-Tokio ex Jinno et Suzuki 1973 (Abieti-Piceetalia Miyawaki et al. 1968, Vaccinio-Piceetea Br.-Bl. in Br.-Bl. et al. 1939) were delineated (Nakamura 1988). That phytosociological study covered only the easternmost, island part of the range of Yezo spruce. The subalpine conifer forests of Korea were extensively studied by Song (1991), who delineated the associations Taxo-Pinetum pumilae Song et Nakanishi 1985, Thujo-Abietetum nephrolepidis Song 1991 and Abieti koreanae-Piceetum jezoensis Song 1991 within the alliance Abieti nephrolepidis-Piceion jezoensis Song 1991, and the associations Saso-Abietetum koreanae Song et Nakanishi 1985 and Betulo saitoanae-Abietetum koreanae (Song et Nakanishi 1985) Song 1991 within the alliance Abietion koreanae Song 1991. For the spruce forests of northeastern Asia Song (1992) proposed the new order Abieti nephrolepidis-Piceetalia jezoensis Song 1992 instead of Abieti veitchii-Piceetalia jezoensis hondoensis Miyawaki et al. 1968, accepted by Nakamura (1988) for Hokkaido. The last order, in Song's opinion, "fits only for subalpine coniferous forests because they are not compared with the continental syntaxa" (Song 1992: 182).
Several phytosociological studies of the Picea jezoensis forests have been performed in the major part of their range, on the territory of Russia. However, up until now, no syntaxonomical conclusions have been published in the international literature. A study of Yezo spruce forests on the westernmost edge of their range, in the Tukuringra-Dzhagdy Mountains, was undertaken by Petelin (1990), who distinguished five associations on the basis of 46 releves and proposed the alliance Betulo lanatae-Piceion ajanensis for the continental part of the range of Picea jezoensis. Data from the remaining majority of the range of Picea jezoensis forests have existed in various sources but have never been analyzed using the Braun-Blanquet approach. The present study includes all phytosociological data available from the entire range of Picea jezoensis forests and aims at producing a single, unifying phytosociological classification of these forests in the Far East.
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© Pavel Krestov 2002-2004
© IBSS FEB RAS 2002-2004