A Late Weichselian and early Flandrian pollen diagram from Østervatnet, Varanger peninsula, NE Norway

A relative and absolute (pollen concentration) diagram is presented from Østervatnet, southern Varanger peninsula, north of the Main sub-stage (Tromsø-Lyngen) moraines. The pollen assemblage zones are correlated biostratigraphically with chronozones from Bølling to Middle Flandrian. Sediment analyses (loss on ignition and particle size) and implied sedimentation rates support this chronology. The three 14 C-dates are considered too old by 1000–2000 years because of hard water error. Redeposited Tertiary palynomorphs were encountered in the lower, mineral sediments; their source is unknown. Pollen spectra and pollen deposition rates indicate tundra throughout the Late Weichselian, with Artemisia -grass steppe predominant during Older and Younger Dryas. Rapid vegetational changes began at around 10,000 B.P., followed by successive immigration and establishment of tree birch (with accompanying floristic change) and Juniperus. Ericales were conspicuously unimportant and the pollen diagram records a herb flora rich in basiphilous species     

Late quaternary vegetational change in the Kotzebue sound area, northwestern Alaska

Two sediment cores from Kaiyak and Squirrel lakes in northwestern Alaska yielded pollen records that date to ca. 39,000 and 27,000 yr B.P., respectively. Between 39,000 and 14,000 yr B.P., the vegetation around these lakes was dominated by Gramineae and Cyperaceae with some Salix and possibly Betula nana/glandulosa forming a local, shrub component of the vegetation. Betula pollen percentages increased about 14,000 yr B.P., indicating the presence of a birchdominated shrub tundra. Alnus pollen appeared at both sites between 9000 and 8000yr B.P., and Picea pollen (mostly P. mariana) arrived at Squirrel Lake about 5000 yr B.P. The current foresttundra mosaic around Squirrel Lake was established at this time, whereas shrub tundra existed near Kaiyak Lake throughout the Holocene. When compared to other pollen records from north-western North America, these cores (1) represent a meadow component of lowland. Beringian tundra between 39,000 and 14,000 yr B.P., (2) demonstrate an early Holocene arrival of Alnus in northwestern Alaska that predates most other Alnus horizons in northern Alaska or northwestern Canada, and (3) show an east-to-west migration of Picea across northern Alaska from 9000 to 5000 yr B.P.     

A pollen record from the Agassiz Ice Cap, northern Ellesmere Island, Canada

A continuous pollen record from the last glacial period to 100 B.P. was obtained from an ice core drilled in 1977 near the top of the Agassiz Ice Cap. Pollen concentrations are low ( c . 15–173 grains/100 I) through-out the core and exotic pollen grains (from distant sources) dominate over regional pollen grains (from Ellesmere Island). The very low concentrations during the Wisconsinan glacial period and the early Holocene are attributed to the increased distance of potential sources as most of northern North America was ice-covered or supported tundra vegetation. An increase of exotic grains (mainly birch and alder) at c . 7,600 B.P. corresponds to the period of alder migration into the Low Arctic regions. The subsequent fluctuations of exotic pollen, especially the increase at c . 3,100 B.P., are unexplained at present. Regional pollen concentrations start to increase at c . 6,100 B.P. and a maximum concentration is reached at c . 3,100 B.P. The pollen record suggests that plant migration into northern Ellesmere was limited until 6,100 B.P., then increased gradually and continued to do so for about 1,000 years after the climate had started to deteriorate at about 4,000 B.P.     

Multivariate statistical estimates of Holocene vegetation and climate change,forest-tundra transition zone,NWT, Canada

Newly derived fossil pollen data were obtained from four sites along a transect from the boreal forest limit into tundra in the eastern Northwest Territories. Multivariate statistical analyses were employed to interpret the pollen assemblages. Transfer functions were constructed between the pollen data and climatic data, and paleoclimatic estimates were derived. The objective nature of the reconstructions provides an independent verification of the general outlines of the chronology of tree-line movements during the mid- and late-Holocene as established in previous paleosol and pollen studies. Boreal forest extended to approximately 62°N, associated with mean July temperatures 1 to 3°C above modern means, from at least 5500 to 3700 yr B.P. Although a major episode of southward displacement of tree line at about 3700 yr B.P. is recorded, later events are not clearly represented. Considerations of the statistics, the time scales, and the nature of the pollen rain suggest only conservative interpretations of the results are possible. It is suggested that the pollen sites may have been sensitive recorders of regional vegetation change only when they were near the ecotone, corresponding to a climatic threshold.     

Holocene climate and landscape evolution East of the Pechora Delta, East-European Russian Arctic

This study presents a multiproxy record of Holocene environmental change in the region East of the Pechora Delta. A peat plateau profile (Ortino II) is analyzed for plant macrofossils, sediment type, loss on ignition, and radiocarbon dating. A paleosol profile (Ortino III) is described and radiocarbon dated. A previously published peat plateau profile (Ortino I) was analyzed for pollen and conifer stomata, loss on ignition, and radiocarbon dating. The interpretation of the latter site is reassessed in view of new evidence. Spruce immigrated to the study area at about 8900 ¹⁴C yr B.P. Peatland development started at approximately the same time. During the Early Holocene Hypsithermal taiga forests occupied most of the present East-European tundra and peatlands were permafrost free. Cooling started after 5000 ¹⁴C yr B.P., resulting in a retreat of forests and permafrost aggradation. Remaining forests disappeared from the study area around 3000 ¹⁴C yr B.P., coinciding with more permafrost aggradation. The retreat of forests resulted in landscape instability and the redistribution of sand by eolian activity. The displacement of the Arctic forest line and permafrost zones indicates a warming of at least 2–3°C in mean July and annual temperatures during the Early Holocene. At least two cooling periods can be recognized for the second half of the Holocene, starting at about 4800 and 3000 ¹⁴C yr B.P.     

The contemporary distribution of pollen in eastern North America: A comparison with the vegetation

By mapping and summarizing 478 pollen counts from surface samples at 406 locations in eastern North America, this study documents the relationships between the distributions of pollen and vegetation on a continental scale. The most common pollen types in this region are pine, birch, oak, and spruce. Maps showing isopercentage contours or isopolls for 13 important pollen types reflect the general N-S zonation of the vegetation. The maps and tabulations of average pollen spectra for the six major vegetational regions indicate high values for the following pollen types in each region: (1) tundra-nonarboreal birch, sedge, and alder; (2) forest/tundra-spruce, nonarboreal birch and alder; (3) boreal forest-spruce, jack pine (type), and arboreal birch with fir in the southeastern part; (4) conifer/hardwood forest-white pine, arboreal birch, and hemlock with beech, maple, and oak in the southern part; (5) deciduous forest-oak, pine, hickory, and elm, with beech and maple in the northern part, and highest values of oak and hickory west of the Appalachian crest; and (6) southeastern forest-pine, oak, hickory, tupelo, and Myricaceae. In some cases, less abundant pollen types are diagnostic for the region, e.g., bald cypress in the southeast. In the conifer-hardwood region and southward, pollen of weeds associated with deforestation and agriculture is abundant. The maps also show that much of southeastern U.S. and the area just to the east of Hudson Bay are in need of additional sampling. At 51 of the sites, absolute pollen frequencies (APF; grains/ml lake sediment) were obtained. These confirm the major conclusions from the percentage data, but differences are evident, e.g., the percentages of alder pollen peak in the tundra whereas alder APFs peak in the boreal forest, and spruce percentages peak in the forest-tundra whereas spruce APFs peak in the boreal forest. Because the APF data reflect the patterns of absolute abundance of individual taxa in the vegetation as well as the overall forest densities, future counts of modern pollen should include APF determinations. The effects of sedimentation processes on APF quantities indicate that APF samples should be obtained from moderate size lakes of similar morphology and hydrology and that, in each lake, several samples from the profundal zone should be pooled to create a sample representative of that lake.     

Paleoecology of late-glacial peats from the bering land bridge, Chukchi Sea shelf region, northwestern Alaska

Insect fossils and pollen from late Pleistocene nonmarine peat layers were recovered from cores from the shelf region of the Chukchi Sea at depths of about 50 m below sea level. The peats date to 11,300−11,000 yr B.P. and provide a limiting age for the regional Pleistocene-Holocene marine transgression. The insect fossils are indicative of arctic coastal habitats like those of the Mackenzie Delta region (mean July TEMPERATURES = 10.6–14°C) suggesting that 11,000 yr ago the exposed Chukchi Sea shelf had a climate substantially warmer than modern coastal regions of the Alaskan north slope. The pollen spectra are consistent with the age assignment to the Birch Interval (14,000–9000 yr B.P.). The data suggest a meadow-like graminoid tundra with birch shrubs and some willow shrubs growing in sheltered areas.     

Late Wisconsin vegetational and climatic history at Kylen Lake, northeastern Minnesota

Kylen Lake, located within the Toimi drumlin field, is critically positioned in relation to Late Wisconsin glacial advances, for it lies between the areas covered by the Superior and St. Louis glacial lobes between 12,000 and 16,000 yr B.P. The pollen and plant-macrofossil record suggests the presence of open species-rich “tundra barrens” from 13,600 to 15,850 yr B.P. Small changes in percentages of Artemisia pollen between 14,300 and 13,600 yr B.P. appear to be artifacts of pollen-percentage data. Shrub-tundra with dwarf birch, willow, and Rhododendron lapponicum developed between 13,600 and 12,000 yr B.P. Black and white spruce and tamarack then expanded to form a vegetation not dissimilar to that of the modern forest-tundra ecotone of northern Canada. At 10,700 B.P. spruce and jack pine increased to form a mosaic dominated by jack pine and white spruce on dry sites and black spruce, tamarack, and deciduous trees such as elm and ash on moist fertile sites. At 9250 yr B.P. red pine and paper birch became dominant to form a vegetation that may have resembled the dry northern forests of Wisconsin today. The diagram terminates at 8410 ± 85 yr B.P. Climatic interpretation of this vegetational succession suggests a progressive increase in temperature since 14,300 yr B.P. This unidirectional trend in climate contrasts with the glacial history of the area. Hypotheses are presented to explain this lack of correspondence between pollen stratigraphy and glacial history. The preferred hypothesis is that the ice-margin fluctuations were controlled primarily by changes in winter snow accumulation in the source area of the glacier, whereas the vegetation and hence the pollen stratigraphy were controlled by climatic changes in front of the ice margin.     

Postglacial climate and vegetation history, north-central Kola Peninsula, Russia: pollen and diatom records from Lake Yarnyshnoe-3

A sediment core from Lake Yarnyshnoe-3 (69°04'N; 36°04'E), an emerged coastal lake from the tundra of the north-central Kola Peninsula, has been analyzed for fossil pollen and diatoms. The pollen record shows the Younger Dryas event marked by increasing Artemisia coupled with decreases in Poaceae, Cyperaceae and Salix at c. 10 700 to 10 000 BP. This core provides the first well-defined palynological record of the Younger Dryas event on the Kola Peninsula. Stomates from Pinus were recovered from the core interval between 8000 and 6000 BP. The stomates, coupled with elevated values of pine pollen, indicate that Pinus sylvestris grew near the arctic coastline of the central Kola Peninsula in the middle Holocene. However, the small number of stomates suggests that pines were not plentiful. The diatom record from the core reflects basin isolation from the sea and indicates additional limnological changes during the climate transition between c. 5000 and 4000 BP. The broadly similar climate and vegetation history on the north-central Kola Peninsula and in Fennoscandia demonstrates the propagation of late glacial and Holocene climate events from the North Atlantic region into the Eurasian Arctic.     

Holocene pollen stratigraphy and bog development in the western part of the Kola Peninsula, Russia

Pollen and macrofossil investigations and radiocarbon datings were carried out at a bog in the Khibiny mountains and the northernmost bog in European Russia on the Rybachiy Peninsula (69°98'N) on the western part of the Kola Peninsula. Peat accumulation on the Kola Peninsula started at c . 8500–7500 BP. Pinus sylvestris reached its present northern limit on the peninsula by 7000 BP, while 6000–5000/4500 BP was a time of maximal progress of birch forest tundra up to the Barents Sea shoreline. Alnus ineana grew up to the Rybachiy Peninsula c . 40 km north of its present-day northern limit. By c , 5500/5300 BP Picen ohovata had immigrated to the Khibiny mountains. After 5000/4500 BP the forested area had retreated in the northern part of the Kola Peninsula and the tundra belt bordering the Barents Sea shore was formed. By 3500 BP spruce had reached its modern northern limit.     

Pollen analysis of a late pliocene and early pleistocene section from the Gubik Formation of Arctic Alaska

A 14-m-thick section of marine and nonmarine sediments of the Gubik Formation of northern Alaska, exposed in bluffs near Ocean Point on the Colville River, has been studied by means of pollen analysis. Pollen from the marine sediments, of probable late Pliocene age, records a boreal forest of spruce and birch with minor amounts of alder in the adjacent terrestrial vegetation. Pine and perhaps true fir were probably at or near their northern limit here, but hemlocks and hardwoods were absent. The suggested environment for the Arctic Slope during the time represented by the marine sediments is similar to that of present-day Anchorage. Pollen floras from the overlying fluvial strata, of early or middle Pleistocene age, record predominantly herbaceous taxa indicating tundra conditions probably more severe than those of the present day. These deposits were most likely contemporaneous with glacial conditions in the Brooks Range to the south. Pollen of woody taxa (spruce, alder, birch, heaths) is rare through most of the section, although birch and alder percentages similar to those found in modern river sediments indicate an interstadial or interglacial warming in midsection. Inland climates during glacial episodes may have been similar to those of the present Arctic coast.     

Late Weichselian and early Flandrian vegetational history of Varanger peninsula, northeast Norway

Relative a absolute (pollen concentration) diagrams are presented from Bergebyvatnet, Holmfjellvatnet and Stjernevatnet on Varanger peninsula. All three sites are outside the younger Dryas (Main substage) moraines and the pollen assemblage zones are correlated biostratigraphically with chronozones from Allerød to Middle Flandrian. Radiocarbon dates from Bergebyvatnet appear to have been affected by hard water error, but dates from the other two sites agree will with the inferred chronostratigraphy. Pollen diagrams from Varanger peninsula suggest broadly similar vegetational histories, the longest record beign that from Østcrvatnet (H. C. Prentice 1981, Boreas , Vol. 10, pp. 53–70). Open tundra-like conditions prevailed throughout the Late Weichselian, with Salix dominance interrupted by unstable vegetation with abundant Artemisia during the Older and Younger Dryas zones. Major vegetational and floristic changes began just before 10,000 B.P., the rapid scquence from herb pollen flora was rich and varied, including a mixture of floristic clements similar to that found during the Late Weichselian in southern Scandinavia. Basiphilous herbs were particularly abundant at Østervatnet and Bergebyvtnet. Betula nand and species of Ericales became locallydominant just before the full establishment of B. pubescens , which rapidly spread beyond its present limit. Later immigrants included Alnus incana; Juniperus communis ; and Pinus sylvestris , which reached the south western part.     

Vegetation dynamics during the Younger Dryas-Holocene transition in the extreme northern taiga zone, northeastern European Russia

Vegetation dynamics during the Younger Dryas-Holocene transition in the extreme northern taiga zone of the Usa basin, northeastern European Russia, were reconstructed using plant macrofossil and pollen evidence from a sediment core from Lake Llet-Ti. The pollen stratigraphy during the Younger Dryas (about 12 500-11 500 cal. yr BP) is characterized by pollen types indicative of treeless arctic vegetation, whereas the macrofossil evidence shows the occurrence of scattered spruce and birch trees around the lake. The Younger Dryas-early Holocene transition is characterized by a rapid increase in vegetation density, including an increase in the birch population, followed by the expansion of the spruce population at about 10 000 cal. yr BP. Dense spruce-birch forest dominated until 5000 cal. yr BP. Our results contribute to the debate about the Lateglacial environments in northern Russia, and illustrate the importance of plant macrofossil records in Lateglacial vegetation reconstructions.     

Late Quaternary vegetation and climate history of the central Bering land bridge from St. Michael Island, western Alaska

Pollen analysis of a sediment core from Zagoskin Lake on St. Michael Island, northeast Bering Sea, provides a history of vegetation and climate for the central Bering land bridge and adjacent western Alaska for the past ≥30,000 ¹⁴C yr B.P. During the late middle Wisconsin interstadial (≥30,000-26,000 ¹⁴C yr B.P.) vegetation was dominated by graminoid-herb tundra with willows (Salix) and minor dwarf birch (Betula nana) and Ericales. During the late Wisconsin glacial interval (26,000-15,000 ¹⁴C yr B.P.) vegetation was graminoid-herb tundra with willows, but with fewer dwarf birch and Ericales, and more herb types associated with dry habitats and disturbed soils. Grasses (Poaceae) dominated during the peak of this glacial interval. Graminoid-herb tundra suggests that central Beringia had a cold, arid climate from ≥30,000 to 15,000 ¹⁴C yr B.P. Between 15,000 and 13,000 ¹⁴C yr B.P., birch shrub-Ericales-sedge-moss tundra began to spread rapidly across the land bridge and Alaska. This major vegetation change suggests moister, warmer summer climates and deeper winter snows. A brief invasion of Populus (poplar, aspen) occurred ca.11,000-9500 ¹⁴C yr B.P., overlapping with the Younger Dryas interval of dry, cooler(?) climate. During the latest Wisconsin to middle Holocene the Bering land bridge was flooded by rising seas. Alder shrubs (Alnus crispa) colonized the St. Michael Island area ca. 8000 ¹⁴C yr B.P. Boreal forests dominated by spruce (Picea) spread from interior Alaska into the eastern Norton Sound area in middle Holocene time, but have not spread as far west as St. Michael Island.     

Late quaternary pollen records from the Kobuk and Noatak river drainages, northwestern Alaska

Pollen diagrams from Joe and Niliq Lakes date to ca. 28,000 and 14,000 yr B.P., respectively. Mesic shurb tundra grew near Joe Lake ca. 28,000 to 26,000 yr B.P. with local Populus populations prior to ca. 27,000 yr B.P. Shrub communities decreased as climate changed with the onset of Itkillik II glaciation (25,000 to 11,500 yr B.P.), and graminoid-dominated tundra characterized vegetation ca. 18,500 to 13,500 yr B.P. Herb tundra was replaced by shrub Betula tundra near both sites ca. 13,500 yr B.P. with local expansion of Populus ca. 11,000 to 10,000 yr B.P. and Alnus ca. 9000 yr B.P. Mixed Picea glauca/P. mariana woodland was established near Joe Lake ca. 6000 yr B.P. These pollen records when combined with others from northern Alaska and northwestern Canada indicate (1) mesic tundra was more common in northwestern Alaska than in northeastern Alaska or northwestern Canada during the Duvanny Yar glacial interval (25,000 to 14,000 yr B.P.); (2) with deglaciation, shrub Betula expanded rapidly in northwestern Alaska but slowly in areas farther east; (3) an early postglacial thermal maximum occurred in northwestern Alaska but had only limited effect on vegetation; and (4) pollen patterns in northern Alaska and northwestern Canada suggest regional differences in late Quaternary climates.     

A 23,000-yr pollen record from Lake Euramoo, Wet Tropics of NE Queensland, Australia

A new extended pollen and charcoal record is presented from Lake Euramoo, Wet Tropics World Heritage rainforest of northeast Queensland, Australia. The 8.4-m sediment core taken from the center of Lake Euramoo incorporates a complete record of vegetation change and fire history spanning the period from 23,000 cal yr B.P. to present. The pollen record is divided into five significant zones; 23,000–16,800 cal yr B.P., dry sclerophyll woodland; 16,800–8600 cal yr B.P., wet sclerophyll woodland with marginal rainforest in protected pockets; 8600–5000 cal yr B.P., warm temperate rainforest; 5000–70 cal yr B.P., dry subtropical rainforest; 70 cal yr B.P.–AD 1999, degraded dry subtropical rainforest with increasing influence of invasive species and fire.The process of rainforest development appears to be at least partly controlled by orbital forcing (precession), though more local environmental variables and human activity are also significant factors. This new record provides the opportunity to explore the relationship between fire, drought and rainforest dynamics in a significant World Heritage rainforest region.     

Southern Westerlies during the last glacial maximum

Vegetation and climate over approximately the past 13,000 yr are reconstructed from fossil pollen in a 9.4-m mire section at Caleta Róbalo on Beagle Channel, Isla Navarino (54°56′S, 67°38′W), southern Tierra del Fuego. Fifty surface samples reflecting modern pollen dispersal serve to interpret the record. Chronologically controlled by nine radiocarbon dates, fossil pollen assemblages are: Empetrum-Gramineae-Gunnera-Tubuliflorae (zone 3b, 13,000–11,850 yr B.P.), Gramineae-Empetrum-assorted minor taxa (zone 3a, 11,850-10,000 yr B.P.), Nothofagus-Gramineae-Tubuliflorae-Polypodiaceae (zone 2, 10,000–5000 yr B.P.), Nothofagus-Empetrum (zone 1b, 5000-3000 yr B.P.), and Empetrum-Nothofagus (zone 1a, 3000-0 yr B.P.). Assemblages show tundra under a cold, dry climate (zone 3), followed by open woodland (zone 2), as conditions became warmer and less dry, and later, with greater humidity and lower temperatures, by closed forest and the spread of mires (zone 1). Comparisons drawn with records from Antarctica, New Zealand, Tasmania, and the subantarctic islands demonstrate broadly uniform conditions in the circumpolar Southern Hemisphere. The influences of continental and maritime antarctic air masses were apparently considerable in Tierra del Fuego during cold late-glacial time, whereas Holocene climate was largely regulated by interplay between maritime polar and maritime tropical air.     

Holocene insect fossils from two sites at Ennadai Lake, Keewatin, Northwest Territories, Canada

Ennadai Lake, in the forest-tundra ecotonal region of Keewatin, Northwest Territories, Canada, has been the subject of several paleoecological investigations (palynology, plant macrofossils, fossil soils). This study concerns Holocene insect fossils at Ennadai, a new approach in a region shown to be sensitive to climatic change. The Ennadai I site yielded 53 taxa, representing 13 families of Coleoptera and 7 families of other insects and arachnids, including abundant ants. These fossils range in age from about 6300 to 630 yr B.P. The Ennadai II site produced fossils of 58 taxa, including 13 beetle families and 15 families of other arthropods, ranging in age from 4700 to 870 yr B.P. The insect evidence suggests the presence of trees in the Ennadai region from 6000 to 2200 yr B.P. A conifer pollen decline from 4800 to 4500 yr B.P. at Ennadai has previously been interpreted as an opening up or retreat of forest in response to climatic cooling, but the insect fossils reveal the continued presence of trees during this interval. Both insect assemblages suggest trends of forest retreat and tundra expansion between about 2200 and 1500 yr B.P., presumably due to climatic cooling, with a return of woodland by about 1000 yr B.P.     

Holocene climate of New England

Stratigraphic studies of pollen and macrofossils from six sites at different elevations in the White Mountains of New Hampshire demonstrate changes in the distributions of four coniferous tree species during the Holocene. Two species presently confined to low elevations extended farther up the mountain slopes during the early Holocene: white pine grew 350 m above its present limit beginning 9000 yr B.P., while hemlock grew 300–400 m above its present limit soon after the species immigrated to the region 7000 yr. B.P. Hemlock disappeared from the highest sites about 5000 yr B.P., but both species persisted at sites 50–350 m above their present limits until the Little Ice Age began a few centuries ago. The history of the two main high-elevation conifers is more difficult to interpret. Spruce and fir first occur near their present upper limits 9000 or 10,000 yr B.P. Fir persisted in abundance at elevations similar to those where it occurs today throughout the Holocene, while spruce became infrequent at all elevations from the beginning of the Holocene until 2000 yr B.P. These facts suggest a more complex series of changes than a mere upward shift of the modern environmental gradient. Nevertheless, we conclude that the minimum climatic change which would explain the upward extensions of hemlock and white pine is a rise in temperature, perhaps as much as 2°C. The interval of maximum warmth started 9000 yr B.P. and lasted at least until 5000 yr B.P., correlative with the Prairie Period in Minnesota.     

Charcoal analysis for paleoenvironmental interpretation: A chemical assay

Pollen and charcoal analysis of radiocarbon-dated sediment cores from Duck Pond in the Cape Cod National Seashore provide a continuous 12,000-yr vegetation and climate history of outer Cape Cod. A Picea-Hudsonia parkland and then a Picea-Pinus banksiana-Alnus crispa boreal forest association grew near the site between 12,000 and 10,000 yr B.P. This vegetation was replaced by a northern conifer forest of Pinus strobus-P. banksiana, and, subsequently, by a more mesophytic forest (Pinus strobus, Tsuga, Quercus, Fagus, Acer, Ulmus, Fraxinus, Ostrya) as the climate became warmer and wetter by 9500 yr B.P. By 9000 yr B.P. a Pinus rigida-Quercus association dominated the landscape. High charcoal frequencies from this and subsequent levels suggest that the pine barrens association developed during a warmer and drier climate that lasted from 9000 to about 5000 yr B.P. Increased percentages of Pinus strobus pollen indicate a return to moister and cooler conditions by about 3500 yr B.P. A doubled sedimentation rate, increased charcoal, and increased herb pollen suggest land disturbance near the pond before European settlement. These results suggest a rapid warming in the northeast in the early Holocene and support a hypothesis of a rapid sea level rise at that time. Comparison of the pollen results from Duck Pond with those from Rogers Lake, Connecticut, illustrates the importance of edaphic factors in determining the disturbance frequency and vegetation history of an area.