Tilia Pollen Research Articles

A reflection of modern vegetation of the Zhizhgin Island (White Sea) in pollen spectra of lake sediments

The first data on the composition of pollen spectra of subrecent lake sediments were obtained from surface samples of Lake Vodonosnoye and Lake Chernyaevskoye sediments on Zhizhgin Island, which is located in the southern part of the White Sea. Currently, woody vegetation on the island grows in small areas and consists mainly of shrubby birch and willow and oppressed pine. The pollen spectra generally reflect the modern vegetation of the island. The pollen spectra include pollen of tree species and grasses, which occupy large areas of open meadows and wetlands. Picea and Pinus pollen found in significant quantities is partly introduced. Abies and Tilia pollen are also likely introduced. The results of pollen analysis of surface samples will be used for pollen analysis of sediment sequences of the investigated lakes, which will allow for correct interpretation of the data obtained and a more correct reconstruction of the island’s vegetation in the past.

Lime tree honey resources in Eurasia

The genus Tilia, commonly known as linden, basswood (North America) or lime tree (Eurasia), was investigated as a resource for honey. This article describes the results of melissopalynological analysis of the role of lime tree (Tilia spp.) in honey from Eurasia. From a review of published palynological characteristics and using independently discovered data from lime tree honey in Europe and Asia, five resource zones were identified where lime tree honey is produced. The lowest levels of Tilia pollen grains (0–44%) are typical for samples of lime honey from western and southern Europe (henceforth resource zone 1, RZ 1). In central European countries (RZ 2), honey with similar characteristics was reported (10–41% of Tilia pollen). The content of Tilia pollen grains in monofloral linden honeys from RZ 3, which includes the territory of south-eastern Europe, the south of central and eastern Europe, and the southern part of European Russia, was higher than in the previous zones (25–88%). Even higher rates (30–99%) were typical for linden honey samples extracted from the north of eastern Europe and European Russia (RZ 4). The regions in the Russian Far East (Primorye Krai) and the northeast China have been allocated to RZ 5. Here, we noted lime honey samples had the highest proportion of Tilia pollen (50–99%). An analysis of the features of the pollen spectra of all Eurasian linden honeys allowed the zones to be combined and be identified into two major groups: southern and northern.

Characterisation of Tilia pollen seasons in 2018–2019

Literature reports suggest that Tilia pollen exhibits low or moderate allergenicity. The aim of the study was to compare the pollen seasons of this taxon in seven Polish cities in 2018 and 2019. The aerobiological research stations were located in Bialystok, Cracow, Lublin, Piotrkow Trybu-nalski, Sosnowiec, Szczecin, and Warsaw. Aerosol samples were collected with the volumetric method using Burkard or Lanzoni pollen samplers. The length of the pollen season was determined using the 95% method. The earliest onset of the Tilia pollen season was noted in Cracow in both years of the study. In 2018, it began already in May. The highest concentrations of lime pollen grains were recorded in Lublin, whereas the lowest values were reported from Bialystok and Cracow. The maximum daily Tilia pollen concentration was recorded in most of the measurement sites between June 6th and June 11th in 2018 and between June 16th and June 24th in 2019. The annual pollen grain sum in both study years was the highest in Lublin (971, 844), whereas the lowest values were noted in Bialystok (85, 102) and Cracow (111, 75). The concentrations of Tilia pollen in Lublin in 2018 and 2019 were several times higher than the mean values recorded in this city in 2001–2017. The allergen index calculated for Tilia trees growing in the centre of Lublin indicates a moderate allergenic threat posed by the pollen of this taxon to the residents of the city.

Allergenic pollen concentrations in the air of urban parks in relation to their vegetation

In the face of the intensifying process of urbanization and the increased incidence of pollen allergies among urban residents, there is still a need to continuously monitor the airborne concentration of allergenic plant pollen. Urban green spaces (UGS) are a desirable element of the urban fabric and necessary for the proper functioning of cities, but they are a rich source of allergenic pollen that may pose a certain risk to people visiting them. The main aim of this study was to analyse the airborne allergenic pollen content in parks of different types relative to a reference point located on the roof of a building. Moreover, this study investigated the relationship between tree canopy volume and the number of recorded airborne pollen grains (SPIn- Seasonal Pollen Integral), and these parameters were compared with the potential impact of vegetation in the parks studied through the Index of Urban Green Zones Allergenicity (IUGZA). Aerobiological monitoring was carried out in Rzeszów, SE Poland in 2016. A volumetric Hirst-type device was used. The pollen seasons of many taxa largely overlapped at each site where the monitoring was carried out, but the concentration values clearly differed. Tree pollen concentration values were not dependent on total canopy volume, and the greatest disproportions were found for Acer, Betula, Quercus, and Tilia pollen. This may be due to the fact that a solitary tree produces more pollen than a tree growing near others of the same species. The downtown park, surrounded by densely built-up areas, exhibited the highest allergenic potential, and the concentration of pollen, in particular tree pollen, was highest there. It is undesirable to plant hedges of allergenic plants, as they are a rich local source of pollen. Aerobiological monitoring carried out in urban parks provides information about the real threat of allergenic pollen to park visitors.

Response of Tilia sp. L. to climate warming in urban conditions – Phenological and aerobiological studies

Lindens belong to valued trees that are frequently planted in urban green areas. Nevertheless, during their flowering they can pose a risk to sensitive people in cities due to their allergenic pollen. This paper presents the results of a 3-year phenological study (2016–2018) and an 18-year aerobiological study (2001–2018) conducted in Lublin (Poland). The flowering phenology data for the following five species: T. americana, T. cordata, T. × euchlora, T. platyphyllos, and T. tomentosa, were compared with the data regarding Tilia pollen seasons. It was shown that the largest amounts of airborne Tilia pollen grains occur during the full flowering period of T. cordata and that the flowering sequence of the linden species studied is constant during the growing season: T. platyphyllos, T. americana, T. cordata, T. × euchlora, and T. tomentosa. We found pollen seasons to start earlier by 14 days and to be extended by 15 days. Throughout the study period, the annual Tilia pollen sum did not change significantly. However, in 2018 in which there was a significant increase in temperature above the average for the previous 17 years, flowering and pollen release distinctly accelerated, and the annual pollen sum increased more than three times compared to the average for the previous 17 years.In central-eastern Poland, the risk of pollen allergy due to the presence of Tilia pollen occurs in May, June, and July. We recorded the highest linden pollen concentrations in June. Due to the acceleration of flowering and pollen release in linden trees as a result of global warming, the incidence of pollen allergy in central Europe can be expected to become more intense already in the second half of May. Therefore, linden plantings in new urban green areas should be planned to be established at some distance from residential estates.

Posterholt, a Late Pleistocene – Holocene record of the vegetation history in and around the valley of the Vlootbeek, a tributary of the river Meuse (southeastern Netherlands)

AbstractThe infill of an abandoned branch of the small river Vlootbeek, a tributary of the Meuse, revealed a record of the vegetation history from the Allerød to the Middle Ages, albeit with at least two hiatuses in its upper reach. Striking observations are the continuous presence ofPinusin a period long after this tree was absent elsewhere in the Dutch landscape, and the high percentages ofTiliapollen in the mid-Holocene. The former is explained by the sandy–gravelly subsoil in the valley of the Vlootbeek. The latter is ascribed to the short distance between the coring location and the plateau on whichTiliamust have been the dominant tree. Anthropogenic influence is apparent from the Early Neolithic Linearbandkeramik farmers onwards.

The Tilia decline: vegetation change in lowland Britain during the mid and late Holocene

Pollen data indicate Tilia was an important component of the primary woodland cover of many lowland areas in northern and central Europe. High values recorded in mid-Holocene pollen diagrams are generally followed by well-defined declines. In this study the palynological, spatial and temporal trends associated with declines in Tilia pollen at sites from lowland Britain are assessed to evaluate the nature and relative importance of the processes responsible. Processes primarily related to the depositional environment (paludification, marine inundation, breaks in sedimentation) and percentage representation of pollen data play the dominant role in 44% of the 164 declines included in the study. Anthropogenic activity can account for the remainder. Tilia rarely recovers from low values after anthropogenic declines, suggesting such declines have the potential to elucidate patterns in the destruction of primary woodland across lowland Britain. Other than declines associated with the mid-Holocene Ulmus decline event, few anthropogenic Tilia declines have been reliably dated prior to c. 5000 cal. BP. Tilia largely disappeared from areas with calcareous and loamy soils as a result of clearance activity in the period 5000–3000 cal. BP (Late Neolithic to Late Bronze Age). Between 3000 and 2500 cal. BP few declines are recorded suggesting a link between clearance activity and climate change. Later declines are concentrated on the sandier lithologies and often associated with heathland formation. The scarcity of declines after 2000 cal. BP is likely to be related to the exhaustion of primary woodland.

Litorina Sea shore displacement and pollen analytical indications of forest succession during the Mid-Holocene in Gästrikland, east central Sweden

This paper deals with the mid-Holocene shore level history and vegetation development in Gästrikland, east-central Sweden. This is investigated using sediment and microfossil records and 14C datings. The time span covered is c. 8000–5000 cal yr BP. Vegetation history during this time includes an increase in Tilia pollen 6500–6300 cal yr BP and a decrease in Ulmus and Corylus c. 5500 cal yr BP. The former change coincides with a sharp drop in relative sea level (RSL) of some 5 m; this RSL drop can be correlated to the regression from the L3 transgression of the Litorina Sea, identified in other areas around the Baltic Sea. The possible connections between RSL and climate (in particular changes on a maritime-continental continuum), as indicated by new pollen data and other records, are investigated. The new material shows, in comparison to other pollen records from southern and central Scandinavia, unusually high percentages of Tilia, Ulmus and Corylus pollen, but less Quercus. The change in pollen spectra around 5500 cal yr BP can be correlated to the northern European “elm decline”. A regional cooling is recorded in widespread data for this time, but observations suggest that other factors must be considered here, including disease and change in the physical landscape due to the ongoing land uplift.

Integrated varve and pollen-based temperature reconstruction from Finland: evidence for Holocene seasonal temperature patterns at high latitudes

A detailed understanding of decadal to millennial-scale climate changes requires seasonal-scale (summer-winter) reconstructions of past precipitation and temperature fluctuations. Comparing seasonally resolved varve records with pollen-based sum of growing degree-days (GDD) reconstructions from Lake Nautajärvi, we examined the intra-annual nature of climate variability in central southern Finland during the Holocene. The organic varve record and the GDD reconstruction show roughly comparable trends supporting the interpretation that both proxies predominantly reflect summer temperatures in the study area. The records suggest low but rising early-Holocene (9500 to 8500 cal. yr BP) summer temperatures. The Holocene Thermal Maximum (HTM) in the GDD record dates to about 7500 to 4500 cal. yr BP, but the organic varve record along with reconstructed changes in vegetation composition, notably a peak of Tilia pollen percentages, indicate that during the HTM there was a trend towards a more continental climate with maximum mid-summer temperatures reached at 6500 to 4500 cal. yr BP. Both records reflect the start of the post-HTM cooling at about 4500 cal. yr BP, simultaneously with an increase of the amount of catchment erosion and mineral matter influx into the lake, suggesting gradually colder and/or longer winters with high net accumulation of snow. The organic varve record and the GDD record start to diverge at 2000 cal. yr BP, possibly owing to the human influence on catchment processes. The reconstructed mid-Holocene summer temperature peak deviates from the regional climate model outputs, which suggest highest summer temperatures during the early Holocene.

The first find in southern Georgia of fossil honey from the Bronze Age, based on palynological data

The results of a palynological analysis of the organic content of earthenware pots from the Kodiani burial mound (27th–25th centuries b.c.) are reported. The character of the palynological spectrum differs significantly from that of a buried soil within the same burial mound. In the samples taken from the pots, pollen concentration is very high, pollen grains are perfectly preserved and an abundance of pollen from insect-pollinated plants is recorded. It is well known that these features are peculiar to honey palynospectra. In all three pots the pollen of Rosaceae, a family of plants that produce good honey, is dominant. However, the second, third and fourth most dominant pollen types in all three samples are different. For example, Tilia pollen is the second dominant in only one pot. In the second pot, Apiaceae and Poaceae are predominant, and in the third pot, Poaceae, both wild and cultural, is the second dominant. It is clear that the different pots contained different types of honey. The variety of honey types indicates highly developed bee-keeping in the Early Bronze Age. In the same regions of Georgia, agriculture was also highly developed. Wheat cultivation was very important. According to the palynospectra, the landscape and climate of this period were probably quite different to those of today.

Pollen, Pollenkitt, and Orbicules inCraigia bronniiFlower Buds (Tilioideae, Malvaceae) from the Miocene of Hambach, Germany

Well‐preserved polliniferous flower buds from the Upper Miocene Inden Beds (Hambach lignite, Lower Rhenish Basin, Germany) were studied by scanning electron and transmission electron microscopy techniques. The Craigia bronnii flower buds are in many respects very similar to those of extant Tilioideae (Malvaceae). The in situ pollen strongly resembles fossil Craigia and recent Tilia pollen, respectively. Especially features of the endexine and the foot layer in the apertural areas and the idiomatic reticulum, including the peculiar mode of branching columellae, are highly similar. Amorphous, highly electron‐dense substances (pollenkitt) and orbicules, which are both likewise highly similar to those of recent Tilia, are present between and on the pollen grains of the flower buds. There is evidence from staining and sectioning behavior of this amorphous substance that it in fact represents pollenkitt.

Fruits and seeds of Craigia bronnii (Malvaceae – Tilioideae) and associated flower buds from the late Miocene Inden Formation, Lower Rhine Basin, Germany

Abundant, well-preserved fruits of Craigia bronnii (Unger) Z. Kvaček, Bůžek et Manchester in various ontogenic stages have been found together with associated dispersed seeds and flower buds from a fossiliferous layer of late Miocene age within the Inden Formation in the Hambach open-cast lignite mine near Düren, the Lower Rhine Basin. Detailed morphological, anatomical features, along with characteristics of the in situ pollen provide new information on this arboreal element, which was widely distributed in the European Tertiary. The flower buds, previously described as Tilia gieskei Pingen et Gregor, are similar both to Tilia and Craigia, which are closely related extant genera. We interpret them to belong to the same species as the fossil fruits because of co-occurrence, and shared type of pubescence. The pollen is tricolporate with microreticulate, heterobrochate sculpture, thin endexine, and a thick footlayer. We caution that it could be difficult to distinguish Craigia and Tilia pollen without the combination of LM and SEM features and it is likely that many reports of Tilia, and Tilia-like pollen from the Tertiary of Europe may actually correspond to Craigia. Although the fruit morphology of these fossils conforms precisely to that of extant Craigia, this fossil plant differs in some respects (pollen sculpture, position of hilum) from the extant Craigia yunnanensis W.W. Smith et W.E. Evans, a relict of southern China. The associations of taxa, in which C. bronnii often occurs, including Taxodiaceae and hygrophilic broad-leaved deciduous trees and herbs, support the interpretation that it thrived in wetland habitats such as the Inden vegetation. Elsewhere in the European Tertiary, it entered also into the non-swampy parts of mesophytic forests. Hence its ecological tolerance may have been wider than that of its extant relatives.

Paludification and pollen representation: the influence of wetland size on Tilia representation in pollen diagrams

The representation of taxa with poorly dispersed pollen grains in pollen diagrams is strongly influenced by basin size. Waterlogging and peat formation (paludification) can, by leading to an expansion in wetland area, produce changes in the representation of dry-land taxa. This phenomenon appears to be responsible for reductions in Tilia pollen at a number of sites across lowland England, reductions which formerly may have been wrongly attributed to anthropogenic activity. Distinguishing between these processes can be problematic as both are likely to produce increases in herb pollen.

Flandrian vegetational history of sout‐heastern England. Stratigraphy of the Brede valley and pollen data from Brede Bridge

summaryThe results of palaeoecological analyses and lithostratigraphic investigations are used to reconstruct the Flandrian evolution of a valley in the East Sussex Weald, the Brede. Particular emphasis is placed upon mid‐Flandrian vegetational history. Palynological data collected from one site, Brede Bridge, include detailed resolution of declines in Ulmus and Tilia pollen. Predominantly inorganic sediments were deposited in the valley during the early Flandrian. Marine conditions penetrated the lower valley under the general influence of sea level rise. After c, 6000 BP, peat formation became widespread and Alnus‐dominated communities occupied the valley floor. Despite forest clearance on the adjacent slopes, relatively little sediment was deposited in the period c. 3700 to c. 1800 BP. The lower valley again came under a marine influence after c. 1800 BP. The dryland forests of the valley were, during the mid‐Flandrian, dominated by Tilia. A general upward decline in Tilia pollen through the sequence is attributed to the valley floor widening and the Brede Bridge site becoming more distant from dryland areas. The first signs of human activity accompany the Ulmus decline, though major forest clearance is not evident until the Tilia decline c. 3700 BP. Comparison of the latter event with sires across south‐eastern and southern England offers support for a phase of human expansion in the late Neolithic/early Bronze Age involving the preferential exploitation of areas of lime forest.

Untersuchungen zur nacheiszeitlichen Vegetationsgeschichte des Meißners (Nordhessen)

Summary Palynological investigations from the Meisner-mountain give complete view of the postglacial vegetation history of this region. The profile of the Seewiese (560 m a.s.l) displays the zones IV—X (Firbas 1949), whereas the profile of the Weiberhemd peat-bog (710 m a.s.l) represents zones VIIIb to X. The Seewiese was a small pond formed by a landslide on the southern slope of the Meisner. It was filled in by the end of Subboreal times and is now covered by reeds. The Weiberhemd peat-bog developped on clays and sands impermeable to water. The Meisner is — and was always — situated outside the natural range of distribution of Picea and Abies. Contrary to the investigations in the adjacent mountainous areas the results from the Meisner seem to indicate the presence of Pinus until the Subboreal period in the eastern foothills of the Meisner. During the Atlanticum period Tilia expanded significantly over the Meisner area. Whilst this time, about 80 % of the Tilia pollen came from the T. cordata-type. During the Subboreal period, however, the share of the T. platyphyllos-type increased distinctly. According to the finds of anthropogenic indicators a colonisation started in the adjacent environs of the Meisner at the end of the Bronze Age. Pasture farming and perhaps to a less degree arable farming took place during the pre-Roman und Roman Iron Age. A decrease of the anthropogenic indicators gives knowledge of a declining settlement during the migration period. The forest clearances during high mediaeval times started in the 10th century and came to an end in the 13th century. On the Meisner plateau meadows and pastures were formed by forest clearing after the late mediaeval desertation. In 1876, this process of deforestation stopped when the Meisner was afforested with conifers (especially with Picea).

Influence of stemflow on the representation of pollen oftiliain soils

Abstract The pollen distribution in mineral soil in woodland containing Tilia × europaea L. was studied in an attempt to explain abnormally high percentages of Tilia pollen found in some podzol profiles. It was shown that a greater concentration of pollen containing greater proportions of Tilia pollen occurred in a narrow zone (c. 30 cm) around the trunk of Tilia trees than in the soil further from the trunk. This is attributed to the effect of stemflow concentrating pollen and possibly increasing the preservation of pollen at the trunk base. The percentages of Tilia pollen found were similar to the abnormally high values from the podzol profiles. It is suggested that these profiles mark the precise locations of trees in an earlier woodland. The implications of this to the interpretation of soil pollen diagrams are discussed.

FACTORS CONTROLLING THE DISTRIBUTION OF TILIA CORDATA AT THE NORTHERN LIMITS OF ITS GEOGRAPHICAL RANGE

SummaryPollen originating from small populations of Tilia cordata is largely deposited within a few hundred metres of the trees, so that their presence can only be detected by pollen analysis at sites within distances of this order. Pollen diagrams from such sites show a continuous curve for Tilia pollen extending to the present surface, although the values may be only about 1 % of arboreal pollen. Pollen analysis shows that T. cordata was present in the Lake District by about 5000 to 4800 B.C.; it then became plentiful in the southern valleys and extended to reach its present north‐western limit, or just beyond, by 3100 B.C., when migration ceased. While the tree was extending its range, it must have been able to produce frequent large crops of fertile seed but subsequently regeneration from seed ceased. After 3100 B.C. the proportion of its pollen initially may increase but then generally decreases. Although there are small recoveries at several horizons, these are not certain evidence of reproduction by seed. Failure to produce fertile seed renders the species particularly sensitive to woodland clearance and has resulted in a decrease in abundance within the Lake District and its virtual extinction in west Yorkshire and south Lancashire.

Flandrian sea level changes and vegetational history of the lower Thames estuary

A biostratigraphic study, investigating the interleaved Flandrian biogenic and inorganic deposits of the lower Thames Estuary, has been carried out between central London and the Isle of Grain. The vegetational and environmental history, showing the relation of the biogenic deposits to former sea level has been deduced from pollen, diatom and other microfossil studies. Radiocarbon dating has been used to establish an objective chronology. From this evidence the height of relative sea level movements, seen in marine transgression and regression surfaces, have been determined. These are plotted against time to show the rate of relative sea level change and subsidence trends for the Thames Estuary and southern England. Diatom studies show the early importance of marine and brackish water influences, at the beginning of Flandrian sedimentation in the Thames. Pollen and macrofossil analyses demonstrate the strong local effects of the saltmarsh and fen environment upon the vegetational history. The rise of Alms pollen is seen to occur before 8100 years b.p ., probably reflecting local physiographic conditions and valley flooding consequent upon the rising sea level. Elements of the regional vegetation development are recorded however, with the Ulmus and Tilia pollen declines shown. Five regression phases (Tilbury I-V), represented by the biogenic deposits and four marine transgressions (Thames I-IV), together with the possible existence of a fifth (Thames V), are recognized. The relative sea level for mean high water mark of spring tides (m.h.w.s.t.) is shown to rise at about 8500 b.p . from —26.5 m o.d . to above present Ordnance Datum (Newlyn) by about 1750 years b.p . Relative sea level curves for the Thames during Flandrian times correlate well with the form and rate of relative sea level changes shown for northwest Europe. Plotting these graphs against each other has allowed subsidence trends to be shown. Within the Thames, possible differential downwarping of approximately 1.5 m has been identified between Crossness and Tilbury for the Flandrian. The regional trends of west to east and north to south downwarping are supported. The amount of subsidence for southeast England, formerly given as 6.1 m since 6500 b.p ., is not confirmed. The figure for the Thames area relative to the Bristol Channel lies closer to 2-3 m since 7000 b.p., although rates of downwarping vary with the type of environment studied, making generalizations tenuous. Sea level only shows relative subsidence trends and is not as yet seen to provide an accurate fixed datum from which one can give precise figures for land subsidence.

FOSSIL POLLEN OF TILIA FROM THE EAST ANGLIAN FENLAND

SummaryAnalysis of a large number of fossil pollen grains of Tilia from the East Anglian Fenland, led to examination of the characters that might be employed to separate T. platyphyllos from T. cordata. Certain characters were discarded but mesh structure and size in surface reticulation, characters since accepted by other authors, were regarded as satisfactory and made the basis for classifying fossil grains. The results indicated native British status for both species of lime from pollen‐zone Vila onwards, with T. cordata much the commoner, and very high relative frequencies of Tilia pollen in zone Vila and diminution zone by zone thereafter to levels below 0.5% of total tree pollen.

THE TILIA DECLINE: AN ANTHROPOGENIC INTERPRETATION

SummaryEvidence is presented from five sites that the decrease in the Tilia pollen frequency seen in many British pollen diagrams is caused by human activity in the woodlands rather than by a change in climate. Analysis of the pollen diagrams makes it probable that there was considerable local variation in the composition of these woodlands and in the nature of prehistoric man's influence on them. Radiocarbon dates show that a major decline in the Tilia pollen frequency has taken place at various times. This means that the VII/VIII zone boundary, as originally defined by changes in tree‐pollen frequencies, has little or no climatic significance and the difficulty that has been encountered in defining its exact position follows from the fact that human activity is a much more variable influence upon vegetation than a change in climate.