Map of vegetation during the last glacial maximum in Japan

A vegetation map reconstructed for the Japanese Archipelago (based upon pollen data from 28 sites and plant macrofossil data from 33 sites) at the time of last glacial maximum shows that coniferous forests covered extensive areas of the land. Boreal conifer forests (dominated by the Picea jezoensis complex, P. glehnii, Abies sachalinensis, A. mariesii, Tsuga diversifolia, and Pinus with Larix gmelinii, though the latter species was confined only to the northern part of northeastern Honshu and Hokkaido) occupied the modern cool-temperature deciduous broadleaf and mid-temperate conifer forest zones, and temperate coniferous forests (mainly Picea maximowiczii, P. polita, P. bicolor, P. koyamai, Abies firma, A. homolepis, Tsuga sieboldii, and Pinus), the present warm-temperate evergreen (laurilignosa) forest zone. Small populations of various broadleaf forest species were scattered in the full-glacial temperate conifer forest mainly along the coastal belt, and the true laurilignosa forest was limited in distribution, occurring only in the paleo-Yaku Peninsula.     

Variation of Cl and SO3 Contents of Microphenocrystic Apatite in Intermediate to Silicic Igneous Rocks of Cenozoic Japanese Island Arcs: Implications for Porphyry Cu Metallogenesis in the Western Pacific Island Arcs

Abstract. Determinations of SO₃ and Cl contents of igneous accessory apatite were carried out on Late Cenozoic intermediate to silicic intrusive and volcanic rocks in the Japanese island arcs of the western Pacific rim including the southwestern Kuril arc (eastern Hokkaido), Northeast Japan arc (southwestern Hokkaido through northeastern Honshu to central Honshu), Izu‐Bonin arc, Kyushu‐Palau ridge, Southwest Japan arc (northern Kyushu) and northern Ryukyu arc (southern Kyushu). These were compared to those from the Western Luzon arc, Philippines, to better understand the metallogenesis of porphyry Cu deposits in the western Pacific island arcs. In addition, SO₃ and Cl contents of accessory apatite in the Cretaceous magnetite‐series granitic rocks in the Kitakami belt (northeastern Honshu) and the Miocene ilmenite‐series granitic rocks in the Outer Zone of Southwest Japan (southern Kyushu) were also examined. Microphenocrystic apatites in shallow intrusions associated with porphyry Cu deposits in the Western Luzon arc contain >0.1 wt% S as SO₃. Such high SO₃ contents of microphenocrystic apatite are a common characteristic of hydrous mag‐matism in the Western Luzon arc, from 15 Ma old tonalitic plutonic rocks of the Luzon Central Cordillera to present‐day volcanism at Mount Pinatubo. The accessory apatite in intrusive rocks associated with porphyry Cu deposits, especially those at the Santo Tomas II deposit, show significantly high Cl contents (>2 wt%). The SO₃ contents of microphenocrystic apatite in most of the hydrous silicic rocks along the volcanic front, in andesites related to native sulfur deposits, and in Miocene and younger shallow granitic intrusions in northeastern Honshu, are generally <0.1 wt%. On the other hand, the SO₃ contents of apatite in such rocks from eastern Hokkaido, southwestern Hokkaido, Izu, northern Kyushu and southern Kyushu are similar to those from the Western Luzon arc. The SO₃ contents of accessory apatite in the Cretaceous magnetite‐series granitic rocks in the Kitakami belt are variable, whereas those of the Miocene ilmenite‐series granitic rocks in southern Kyushu are extremely low. The Cl contents of accessory apatite in some rocks of the Northeast Japan arc, Izu‐Bonin arc and Southwest Japan arc are significantly high. In terms of the Cl and SO₃ contents of microphenocrystic apatite, Cenozoic Japanese arc magmatism show similarities with arc magmatism associated elsewhere with porphyry Cu mineralization, except for the most of northeastern Honshu of the Northeast Japan arc. Apatite commonly occurs as inclusions in other phenocrystic phases. Thus the variation in SO₃ contents of apatite is a feature of early stage magmatic differentiation. The SO₃ contents of microphenocrystic apatite are considered to reflect the redox state of the magma source region or fluids encountered during magma generation.     

Sulfur Isotope Study on Hg and Sb Deposits in Japan

Abstract. Sulfur isotope ratios of cinnabar from Hg deposits and stibnite, jamesonite and berthierite from Sb deposits in Japan are examined in order to understand metallogeneses of Hg and Sb deposits in Japanese island arcs. The studied Hg and Sb deposits include the Hg deposit at Yamato‐suigin (Honshu) and the Sb deposit at Ichinokawa (Shikoku) in the Southwest Japan arc. In addition, Hg deposits including Itomuka and Ryushoden in central Hokkaido and Hg and Sb mineralizations in Northeast Japan arc are examined. The δ³⁴S values of cinnabar from the Hidaka‐Kitami district, central Hokkaido, including the Itomuka and Ryushoden deposits range widely, from ‐10 to +16 %o, the highest values encountered at the Samani deposit. The δ³⁴S values of cinnabar from other areas in Japan range from ‐12 to +5 %o, having δ³⁴S values higher than +2 %o from southwestern Hokkaido (Meiji deposit), Shikoku (Suii deposit) and Kyushu (Hasami and Yamagano deposits). On the other hand, the δ³⁴S values of stibnite from all areas in Japan range from ‐14 to +5 %o, having positive δ³⁴S values higher than +2 %o up to +5 %o from southwestern Hokkaido (Yakumo, Toyotomi and Teine deposits) and eastern‐central Honshu (Hachiman and Daikoku deposits). The variation in δ³⁴S values of Hg and Sb deposits may reflect the variation in δ³⁴S values of country rocks or variation in mixing ratio of sulfur extracted from the country rocks, sulfur derived from seawater sulfate, and sulfur derived from magmatic emanations. The relatively high δ³⁴S values of cinnabar and stibnite higher than +2 %o from southwestern Hokkaido, eastern‐central Honshu and Kyushu are probably caused by contribution of volcanic emanation from arc magmas having positive σδ³⁴S values, whereas the positive δ³⁴S values of cinnabar higher than +2 %o from Suii deposit in Shikoku may be attributed to structurally substituted sulfate in limestone country rocks and/or sulfur derived from seawater sulfate. However, the wide range of the δ³⁴S values of cinnabar from the Hidaka‐Kitami district, central Hokkaido, is difficult to explain at this moment. Other relatively low, negative δ³⁴S values of cinnabar and stibnite, berthierite from other areas in Japan may be attributed to 1) incorporation of isotopically light sedimentary sulfur or sulfur derived from ilmenite‐series silicic magma, or 2) less contribution of volcanic emanation from arc magmas having positive σδ³⁴S values.     

HAUTERIVIAN AND BARREMIAN IN THE FAR EAST

Valanginian marine sediments are widespread in the eastern margin of Asia from China northward over the Sikhote-Alin region, as far west as the Amur river, and as far north as the Amgun river. This was an interior type sea with abundant islands and a boreal fauna. It is surmised that Kamchatka, Sakhalin, Hokkaido, and the other Japanese islands were not invaded by the sea. A paralic coal basin is known on southwestern Honshu. Post-Valanginian folding and erosion preceded a Barremian-Albian marine transgression over the same general area. In these younger Cretaceous rocks southern faunas appear and the boreal fauna is present north of 45° latitude. Aucella and Aucellina species are important elements of the faunas. This review of faunas and correlations, including western North America, suggests that Hauterivian folding was a major event in North Pacific tectonic history. -- C. G. Tillman.     

Climate and vegetation in Hokkaido, northern Japan, since the LGM: Pollen records from core GH02-1030 off Tokachi in the northwestern Pacific

Vegetation and climate since the LGM in eastern Hokkaido were investigated based on a pollen record from marine core GH02-1030 from off Tokachi in the northwestern Pacific. We also examined pollen spectra in surface samples from Sakhalin to compare and understand the climatic conditions of Hokkaido during the last glacial period. Vegetation in the Tokachi region in the LGM (22–17 ka) was an open boreal forest dominated by Picea and Larix. During the last deglaciation (17–10 ka), vegetation was characterized by abundant Betula. In the Kenbuchi Basin, central Hokkaido, a remarkable increase of Larix and Pinus occurred in the LGM and the last deglaciation, which was assigned as the “Kenbuchi Stadial.” Comparison of climatic data between the core GH02-1030 and that of Kenbuchi Basin demonstrates that variations in temperature and precipitation were larger in inland Hokkaido than in the maritime area of the Pacific coast. During the LGM in the Tokachi region, the August mean temperature was about 5 °C lower, and annual precipitation was about 40% lower than today. In the Kenbuchi Basin, central Hokkaido, the August mean temperature was about 8 °C lower, and annual precipitation was half that of today. During the last deglaciation, August mean temperatures were about 3 °C lower, and annual precipitation was about 30% lower than today in the Tokachi region. In the Kenbuchi Basin, August mean temperatures were about 5–8 °C lower, and annual precipitation was about 40–60% lower than today. Cold ocean water and a strengthened summer monsoon after 15 ka may have resulted in the formation of advection fogs, reduced summer temperatures, and a decrease in the seasonal temperature difference in the Tokachi district, which established favorable maritime conditions for Betula forests.     

Pollen and radiolarian records from deep-sea core RC14-103: Climatic reconstructions of northeast Japan and Northwest Pacific for the last 90,000 years

Using modern pollen and radiolarian distributions in sediments from the northwest Pacific and seas adjacent to Japan to interpret floral and faunal changes in core RC14-103 (44°02′N, 152°56′E), we recognize two major responses of the biota of eastern Hokkaido and the northwest Pacific to climatic changes since the last interglaciation. Relatively stable glacial environments (～80,000–20,000 yr B.P.) were basically cold and wet (<4°C and ～1000 mm mean annual temperature and precipitation, respectively) with boreal conijers and tundra/park-tundra on Hokkaido, and cool (<16°C) summer and cold (<1.0°C) winter surface temperatures offshore. Contrasting nonglacial environments (～10,000–4000 yr B.P.) were warm and humid (>8°C and >1200 mm mean annual temperature and precipitation, respectively), supporting climax broadleaf deciduous forest with Quercus and Ulmus/Zelkova, with surface waters in the northwest Pacific characterized by warm (>1.5°C) winter and cold (10.4°–14.3°C) summer temperatures. Climatic evidence from RC14-103 shows a high degree of local and regional variation within the context of global climatic change. Correlative ocean and land records provide the detailed input necessary to assess local/regional responses to variations in other key elements (i.e., solar radiation, monsoonal variations) of the northeast Asian climate system.     

Altitudinal and latitudinal migration of Cryptomeria japonica for the past 20,000 years in Japan

Biostatistical analysis of modern pollen assemblages in 152 Japanese surface samples shows that Cryptomeria japonica can normally grow in areas with a mean January temperature of approximately −7° to 7°C, a mean August temperature of 19° to 27°C, and an effective precipitation (total precipitation during the growing season) of over 1000 mm. The full-glacial distribution of the species on both the Sea of Japan and the Pacific coasts (35–36°N lat) indicates that in these areas the maximum possible reduction of temperature was 8.7–10.2°C in January and 6.0–7.3°C in August, and that the effective precipitation was low, being 1000–1350 mm, or 40–55% below the modern level, provided that the species has not changed its physiological characteristics. Populations of C. japonica expanded northward and upslope from their full-glacial areas of distribution immediately after late-glacial climatic amelioration. This expansion appears to have been regulated mainly by the availability of effective precipitation which became high in northeastern Honshu about 4000 yr ago. After about 2500 yr B.P., C. japonica was planted extensively by humans in moist, temperate climatic regions (excluding Hokkaido), and now has its widest distribution since at least the last full-glacial interval.     

Double seismic zone beneath the middle of Hokkaido, Japan, in the southwestern side of the Kurile Arc

The vertical section of microearthquakes, determined accurately by using the Hokkaido University network, shows two dipping zones (the double seismic zone) 25–30 km apart in the depth range of 80–150 km beneath the middle of Hokkaido in the southwestern side of the Kurile arc. Hypocentral distribution of large earthquakes (m_b > 4) based on the ISC (International Seismological Centre) bulletin also shows the double seismic zone beneath the same region. The hypocentral distribution indicates that the frequency of events occurring in the lower zone is four times greater than that in the upper zone. The difference in seismic activity between the two zones beneath Hokkaido is in contrast with the region beneath northeastern Honshu in the northeastern Japan arc.Composite focal mechanisms of microearthquakes and individual mechanisms of large events mainly characterize the down-dip extension for the lower zone as is observed beneath northeastern Honshu. For the upper zone, however, the stress field is rather complex and not necessarily similar to that beneath northeastern Honshu. This may be considered to indicate the influence of slab contortion or transformation in the Hokkaido corner between the Kurile and the northeastern Japan arcs.     

从泥河湾层花粉分析谈南沟冷期等问题

第四纪下限问题是地学的一个重要课题,故历来为人们所重视。分布在大同、阳原等盆地的泥河湾层,沉积厚,又有玄武岩穿插其间,剖面出露和接触关系清楚,含有丰富的动、植物化石,并有人类化石与石器,是罕见的第四纪典型剖面。近年来,我们对该区泥河湾层进行了花粉分析,现就其古植被、古气候和地层等方面的问题作一初步讨论。     

Shifting zonal patterns of the southern boreal forest in eastern Canada associated with changing fire regime during the Holocene

This research aims at uncovering the stand-scale Holocene fire history of balsam fir forest stands from two bioclimatic zones of the boreal forest and assessing the existence of a sub-continental shift in past fire activity that could have triggered a change in the Holocene zonal pattern. In eastern Canada, the extant closed-crown boreal forest corresponds to two ecological regions separated along 49°N, the northern black spruce zone and the southern balsam fir zone. We sampled balsam fir stands from the southern fir zone (n = 7) and among the northernmost patches of fir forest located far beyond the fir zone boundary, into the spruce zone (n = 6). Macrofossil analysis of charcoal in mineral soils was used to reconstruct both the stand-scale and regional Holocene fire histories. Data were interpreted in the context of published palaeoecological evidence. Stands of the balsam fir zone were submitted to recurrent fire disturbances between c. 9000 and 5000 cal. yr B.P. Local fire histories suggested that four sites within the fir zone escaped fire during the Holocene. Such fire protected sites allowed the continuous maintenance of the balsam fir forest in the southern boreal landscape. Stands of the spruce zone have been affected by recurrent fires from 5000 cal. yr B.P. to present. Local fire histories indicated that no site escaped fire in this zone. Published palaeoecological data suggested that balsam fir migrated to its current northern limit sometime between 7300 and 6200 cal. yr B.P. A change of the fire regime 5000 years ago caused the regional decline of an historical northern balsam fir forest and its replacement by black spruce forest. The consequence was a sub-continental reshuffling of the fir and spruce zones within the closed-crown boreal forest. The macrofossil analysis of charcoal in mineral soils was instrumental to the reconstruction of stand-scale Holocene fire history at sites where no other in situ fire proxies were available.     

LATE CENOZOIC GOLD VEINS AND VOLCANIC COLLAPSE TECTONICS IN THE ISLAND ARC JUNCTIONS OF THE JAPANESE ISLANDS

0 Introduction The Japanese Islands consist of five volcanic arcs (Fig.1).The North-East and SouthWest Japan arcs together form the Honshu arc,to which the Kurile arc joins at Hokkaido,whereas the Izu-Mariana arc joins at Izu-Fossa Magna,and the Ryukyu arc joins at Kyushu.These regions where volcanic arcs converge,are termed "island arc junctions".     

Spatial pattern of Abies and Picea surface pollen distribution along the elevation gradient in the Qinghai–Tibetan Plateau and Xinjiang, China

In this study we examine the relationships between Abies and Picea abundance in surface pollen and sub-alpine coniferous forest (SCF) distribution, elevation and climate in the Qinghai–Tibetan Plateau using a large modern pollen data set consisting of 857 samples. Results indicate that Abies and Picea pollen are abundant in the southern and eastern Qinghai–Tibetan Plateau, where SCF dominates the landscape. Pollen percentages of both Abies and Picea show a unimodal pattern with changes in elevation and climate, and their optima occur at elevations from 2500 to 4000 m a.s.l., mean annual temperature from −1 to 10 °C and mean annual precipitation from 450 to 850 mm. The optimal elevation of Abies and Picea pollen distribution decreases with latitude from c . 4000 m in the south (21–32°N) to c . 2500 m in the north (43–49°N). The spatial pattern of Abies and Picea pollen abundance is highly correlated with the modern distribution of these taxa, which is largely controlled by elevation and climate. These relationships could provide a practical reference for interpretation of fossil pollen data in terms of climate and elevation in the Qinghai–Tibetan Plateau.     

华北区第四纪植被演替与气候变化

文中华北区是指燕山、辽南一线以南、吕梁山以东、渭河谷地与准阳丘陵以北地区。该区属暖温带,即蒙古和东北寒温带、温带区域与华中和华东亚热带区域之间的过渡地带,故第四纪冰期、间冰期气候的变化,对本区的影响表现得很强烈,它引起第四纪植被的明显演替,是我国第四纪植被变化较大的两个区域之一(另一为青藏区)。     

The tunica hills,Louisiana-Mississippi: Late glacial locality for spruce and deciduous forest species

Reinvestigation of Quaternary sediments in West Feliciana Parish, southeastern Louisiana, and adjacent Wilkinson County, southwestern Mississippi, has resulted in revision of previous terrace stratigraphy of this portion of the Gulf Coastal Plain. Plant-macrofossil and pollen assemblages incorporated in fluviatile terrace deposits in the study area are reexamined in light of the current stratigraphic understanding. Macrofossils identified as white spruce (Picea glauca), tamarack (Larix laricina), and northern white cedar (Thuja occidentalis), recovered from these terrace deposits along with fossil remains of distinctly southern plant species, were initially interpreted as the result of dynamic intermixing of aggressive boreal species within a southern forest during the early Wisconsin (Brown, 1938). Failure to distinguish chronologically separate fossiliferous deposits resulted in the conceptual “mixing” of northern and southern plant species which came from two distinct fluviatile terrace sequences. Terrace 2 is now believed to be a fluviatile and coastwise depositional terrace of Sangamon Interglacial age; deposits of terrace 2 contain a distinctly warm-temperate plant assemblage. Fluviatile terrace 1 dates from 12,740 ± 300 to 3457 ± 366 BP and is now considered to be related to late glacial and Holocene aggradation and lateral migration of the Mississippi River (the local base level for streams in the study area); basal portions of terrace 1 contain fossils of white spruce, tamarack, and many plant species today characteristic of the cool-temperate Mixed Mesophytic Forest Association. Terrace 1 fossil deposits occur in fluviatile terraces along tributary streams of the Mississippi River at elevations 15 to 30 m above the maximum recorded historic flood stage of the Mississippi River. The plant macrofossils represent remains of species that grew at or very near the site of deposition; they were not “rafted in” by floodwaters of the Mississippi River. We present quantitative data for plant macrofossils and pollen that support our hypothesis that at least local cooling along the Blufflands of Mississippi and Louisiana promoted southward migrations of mixed mesophytic forest species and certain boreal species along this major pathway during late Wisconsin continental glaciation.     

Paleoenvironmental changes at the northern limit of the subantarctic Nothofagus forest,lat 37°S,Argentina

Paleoenvironmental changes dating back to before 10,000 yr B.P. at the northernmost occurrences of Nothofagus forests in Argentina at about latitude 37°S permit the reconstruction of past changes in the intensity of the winter rains, related to the southern westerlies that appear to determine the forest boundary. The paleoenvironmental interpretation is based on changes in the proportions of different Nothofagus species and changes in the ratio betwen forest and steppe taxa. The relatively most diverse and dense Nothofagus forest developed only during the last 4500 yr, prior to human impact during the last 300 yr. Before the middle Holocene, climatic conditions must have been different from the modern ones, with less overall precipitation judging from the overall lower amount of tree pollen and the reduction to primarily Nothfagus pumilio. An interval dated to older than 10,000 yr B.P. is characterized by co-occurrence of Prumnopitys andina, Nothofagus pumilio, and shrub-steppe taxa. Prumnopitys andina is known today only from scattered upper montane forest sites in Chile between 36° and 43°S lat and its ecological requirements are essentially unknown. The taxa combination, however, suggests that late-glacial climate must have been drier, and probably cooler than today. This implies that the winter rains and, consequently, the seasonal shift of the westerly circulation was reduced during the late Pleistocene and did not reach modern levels before 8500 yr B.P.     

Coniferization of the mixed‐wood boreal forests under warm climate

Mixed‐wood boreal forests are characterized by a heterogeneous landscape dominated by coniferous or deciduous species depending on stand moisture and fire activity. Our study highlights the long‐term drivers of these differences between landscapes across mixed‐wood boreal forests to improve simulated vegetation dynamics under predicted climate changes. We investigate the effects of main climate trends and wildfire activities on the vegetation dynamics of two areas characterized by different stand moisture regimes during the last 9000 years. We performed paleofire and pollen analyses in the mixed‐wood boreal forest of north‐western Ontario, derived from lacustrine sediment deposits, to reconstruct historical vegetation dynamics, which encompassed both the Holocene climatic optimum (ca. 8000–4000 a bp ) and the Neoglacial period (ca. 4000 a bp ). The past warm and dry period (Holocene climatic optimum) promoted higher fire activity that resulted in an increase in coniferous species abundance in the xeric area. The predicted warmer climate and an increase in drought events should lead to a coniferization of the xeric areas affected by high fire activity while the mesic areas may retain a higher broadleaf abundance, as these areas are not prone to an increase in fire activity. Copyright © 2019 John Wiley & Sons, Ltd.     

Total and pyrogenic carbon stocks in black spruce forest floors from eastern Canada

Pyrogenic carbon (PyC), a by-product of recurrent boreal wildfires, is an important component of the global soil C pool, although precise assessment of boreal PyC stock is scarce. The overall objective of this study was to estimate total C stock and PyC stock in forest floors of Eastern Canada boreal forests. We also investigated the environmental conditions controlling the stocks and characterized the composition of the forest floor layers. Forest floor samples were collected from mesic black spruce sites recently affected by fire (3–5 yr) and analyzed using elemental analysis and solid state ¹³C nuclear magnetic resonance (NMR) spectroscopy. PyC content was further estimated using a molecular mixing model. Total C stock in forest floors averaged 5.7 ± 2.9 kg C/m² and PyC stock 0.6 ± 0.3 kg C/m². Total stock varied with position in the landscape, with a greater accumulation of organic material on northern aspects and lower slope positions. In addition, total stock was significantly higher in spruce-dominated forest floors than stands where jack pine was present. The PyC stock was significantly related to the atomic H/C ratio (R² 0.84) of the different organic layers. ¹³C NMR spectroscopy revealed a large increase in aromatic carbon in the deepest forest floor layer (humified H horizon) at the organic-mineral soil interface. The majority of the PyC stock was located in this horizon and had been formed during past high severity fires rather than during the most recent fire event.     

Late-glacial vegetation and climate at the Manis Mastodon site,Olympic Peninsula,Washington

As the late Wisconsin Cordilleran Ice Sheet retreated, sediment accumulated in shallow depressions at the Manis Mastodon Archaeological site on the Olympic Peninsula, near Sequim, Washington. Pollen, plant macrofossils, and bones of mastodon, caribou, and bison occur within the lower 47 cm of these deposits. The fossil pollen and seed assemblages indicate persistence for 1000 yr (11,000–12,000 yr B.P.) of an herb-and-shrub-dominated landscape at a time when forest species appear elsewhere in Washington and in adjacent British Columbia.At present, Sequim is near the northern coastal limits of both Cactaceae and Ceratophyllum. Mean annual precipitation is 42.7 cm and summer temperatures average 15°–16°C in July. The absence of coniferous trees and the presence of cactus and Ceratophyllum in late-glacial sediments are explained by a regional climate that was drier and at least as warm as today. These conditions persisted in the rain shadow of the Olympic Mountains until at least 11,000 yr B.P.     

Late-glacial and postglacial vegetational history of the Berkshires, western Massachusetts

A pollen analytical investigation of the sediments of Berry Pond, Berkshire County, Massachusetts, has demonstrated a sequence of pollen assemblage zones similar to those detected elsewhere in New England. From about 13,000 to 12,000 yr B.P. the vegetation of the region was treeless, probably tundra. By 11,500 yr tundra had been replaced by open boreal forest. Closed boreal forest became dominant by 10,500 yr. Boreal forests were replaced by mixed coniferous and deciduous forests with much white pine about 9600 yr ago. A “northern hardwoods” complex with much hemlock, beech, and sugar maple succeeded the mixed forests 8600 yr ago. Hemlock declined very rapidly approximately 4800 yr ago and was replaced by birch, oak, beech, ash, and red maple. This decline may have been biologically rather than climatically induced. There is a slight maximum of pine (much of it pitch pine) from 4100 to 2600 yr ago, perhaps indicative of warmer and/or drier conditions. There were slight changes in the forests about 1600 yr ago as chestnut immigrated and spruce and larch increased slightly. European land clearance and subsequent land abandonment are detectable in the uppermost levels.     

A lateglacial climatic reversion in hokkaido, Northeast Asia, inferred from the Larix pollen record

At present, Larix gmelini is a main component of taiga developed in north Sakhalin, northeast China and east Siberia. During the interval from ∼11.8 to 12.4 ka BP, pollen assemblages from north Hokkaido, Japan, are dominated by Larix. Pollen assemblages of this Lateglacial climatic reversal, known as the “Kenbuchi Stadial”, are similar to pollen assemblages from the Last Glacial Maximum in north Hokkaido. Vegetation of Hokkaido inferred from these pollen assemblages — open taiga composed of Larix gmelini, Pinus pumila and Picea jezoensis and/or Picea glehnii — may have been like that of north Sakhalin today. Comparison of these fossil pollen assemblages from Hokkaido with pollen assemblages from modern surface samples in Sakhalin suggests that ∼ 11.8 to 12.4 ka BP, temperatures relative to today were at least 9°C lower in January and 7°C lower in August, and that annual precipitation was at least 735 mm lower than present.