Tree Pollen Types Research Articles

Relationship of Meteorological Variables with the Concentration of Various Tree Pollen Types in Madrid (Spain)

This study analyzes the behavior of airborne pollen in relation to meteorological parameters. It may be helpful to understand the consequences of this interaction on the health of the population of Madrid in the form of respiratory allergic pathologies. To this end, a multivariate analysis was carried out using Spearman’s linear correlation coefficient between the concentrations in the Madrid atmosphere of six types of tree pollen (Cupressaceae, Olea, Platanus, Pinus, Ulmus and Populus) and each of the six meteorological variables: relative humidity, precipitation, temperature, wind, radiation and insolation. The meteorological parameters most correlated with pollen types, with monthly values, are temperature and insolation, followed by radiation and relative humidity. In addition, there are more significant correlations of meteorological variables with Cupressaceae, Olea, Pinus and Platanus pollen types. Radiation is the meteorological parameter with the highest ρ values, especially with Olea, with ρ > 0.8. Wind is the only variable with significant correlations, all of them positive, with pollen types. The number of statistically significant results obtained from daily values is lower compared to monthly values, and only with Populus, Cupressaceae and Olea. The inter-relationship of meteorological variables with pollen grains can lead to an increase in the number of cases of pollinosis, when there are significant positive correlations.

Study of the Interrelations of the Concentrations of Six Tree Pollen Types and Six Atmospheric Pollutants with Rhinitis and Allergic Conjunctivitis in the Community of Madrid

Allergic pathologies of aerobiological origin, specifically those caused by exposure to pollen allergens, have shown a growing trend in recent decades worldwide. This trend is most evident in urban areas experiencing an incessant expansion of their territory. Several studies have shown an interaction between atmospheric pollutants and pollen grains, which implies a potentiation of the allergenicity of the latter. This study aims to analyze the possible influence, in the Community of Madrid (CAM), of the concentrations of six atmospheric pollutants (O3, particles PM10 and PM2.5, NO2, CO, and SO2), and of the pollen concentrations of six types of tree pollen (Cupressaceae, Olea, Platanus, Pinus, Ulmus, and Populus) on the episodes of attention of two pathologies, rhinitis and allergic conjunctivitis. The data collected came from the Air Quality Networks of the CAM and the Madrid City Council, the Palynological Network of the CAM, and the General Subdirectorate of Epidemiology of the Health Department of the CAM. Descriptive multiple linear regression models were used to analyze the interrelationships of the three variables. In most of the calculations performed, the adjusted R2 value is higher than 30%, and, in all cases, the p-values of the models obtained are less than 0.0001. All the models performed in the study period for allergic rhinitis indicate a reasonable correlation, and this is also true for almost all of the models calculated for allergic conjunctivitis. Moreover, it is allergic rhinitis for which the highest values of adjusted R2 were obtained. Pinus is the pollen type most frequently interrelated with conjunctivitis and allergic rhinitis (followed in both cases by Olea and Populus) throughout the study years. In this same period, O3 is the air pollutant most frequently present in the models calculated for allergic conjunctivitis (followed by NO2 and PM10), while particle PM10 is the most frequently included in the calculations made for allergic rhinitis, followed by O3 and SO2.

Analysis of Pollen Concentrations from Various Tree Pollen Types and Their Interrelation with Different Airborne Pollutants in the Madrid Region (Spain)

Several studies show that the interaction between airborne pollutants and pollen grains can lead to greater pollen allergenicity, and thus increase and exacerbate the incidence of pollinosis, all of which represents a major public health problem. This article analyses the possible influence of various airborne pollutants (O3, PM10 and PM2.5, NO2, CO and SO2) on the tree-type pollen grains of Cupressaceae, Olea, Platanus, Pinus, Ulmus and Populus. The 11 areas around the stations in the Madrid Region’s pollen monitoring network (Red Palinocam) were taken as a geographic reference for this study. The degree of interaction between airborne pollutants and pollen types was explored using the rank correlation analysis. O3 and NO2 are the pollutants with the highest rate of significant correlations with pollen types. Olea, Cupressaceae and Platanus—the most highly allergenic in this study—are among the pollen types with the greatest number of significant correlations with almost all the air pollutants in the different areas. This could point to a potential associative effect between both variables which would exacerbate the negative effects on public health.

Modern Pollen Rain in the Tibetan Plateau

The basis for the interpretation of fossil-pollen assemblages in terms of vegetation and climate is the present-day relationship of vegetation and climate to pollen rain. Detailed modern pollen spectra from the Tibetan Plateau are described here to explore the relationship between modern pollen rain and vegetation. Two hundred and thirty four (234) pollen surface samples were collected from moss polsters, top soil, and lake surface sediments from forests, shrublands, shrub meadows, meadows, steppes, and deserts in the Tibetan Plateau. Pollen assemblages from each vegetation type are detailed described using pollen percentage data, and compared descriptively and numerically using cluster analysis. Pollen spectra from forests are characterized by high percentages of tree pollen types including Pinus, Abies, Picea, Quercus, and Betula. Pollen spectra from shrublands have highest amounts of shrub pollen. The dominants of shrublands, such as Rhododendron, Juniperus, Salix, and shrub Quercus, are well-represented in most of these pollen spectra. Pollen spectra from shrub meadows have less shrub pollen than those from shrublands, but more than those from meadows, steppes and deserts. The most frequent shrub pollen in this vegetation type is Rosaceae. Most of pollen spectra from shrub meadows are dominated by Cyperaceae pollen. Pollen spectra from meadows are characterized by the very high percentages of Cyperaceae pollen. The highest amounts of Cyperaceae pollen occur in pollen spectra from alpine-marshy meadows. Pollen spectra from Stipa steppes are characterized by the highest percentages of Poaceae pollen, and high Cyperaceae pollen percentages, whereas pollen spectra from Artemisia steppes have the highest percentages of Artemisia pollen. Pollen spectra from arid deserts are dominated by Chenopodiaceae. Main vegetation types can be distinguished by their modern pollen rain, i.e., modern pollen spectra do reflect the modern vegetation at local and regional scale in the Tibetan Plateau. This modern pollen database can thus be used to explore the pollen/vegetation and pollen/climate relationships by a variety of numerical methods.

Ambient daily pollen levels in association with asthma exacerbation among children in Philadelphia, Pennsylvania

Pollen from trees, grasses, and weeds can trigger asthma exacerbation in sensitized individuals. However, there are gaps in knowledge about the effects, such as the relative risks from different plant taxa and threshold levels of effect. We aimed to describe the local association between pollen and asthma exacerbation among children in the City of Philadelphia, and to evaluate whether effects are modified by children’s characteristics and clinical factors (e.g., child’s age, race/ethnicity, comorbidities). We conducted a time-stratified case-crossover study of pediatric (age <18 years) asthma exacerbation, with cases identified through electronic health records (EHR) of the Children’s Hospital of Philadelphia (CHOP) health system from March through October in the years 2011–2016. Daily pollen counts were obtained from the local National Allergy Bureau certified pollen counter. We applied conditional logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) for the association between the pollen level (vs. none detected) and odds of asthma exacerbation, adjusting for temperature, relative humidity, and holidays. We estimated same-day exposure effects, as well as effects from exposure lagged by up to 5 days. There were 35,040 asthma exacerbation events during the study period, with the majority occurring among black, non-Hispanic children (81.8%) and boys (60.4%). We found increased odds of asthma exacerbation among Philadelphia children in association with tree pollen, both for total tree pollen and most individual tree types. Increased odds from total tree pollen were observed at the lowest levels studied (≤5 grains/m3, unlagged, OR = 1.06, 95% CI: 1.02, 1.10), and exhibited a positive exposure-response pattern of effect; tree pollen levels above 1000 grains/m3 (unlagged) were associated with 64% increased odds of asthma exacerbation (95% CI: 1.45, 1.84). Grass pollen was associated with asthma exacerbation only at levels above the 99th percentile (52 grains/m3), which occurred, on average, two days per year during the study period (with 2-day lag, OR = 1.38, 95% CI: 1.19, 1.60). There was an inverse association (reduced asthma exacerbation) with ragweed pollen that was consistent across analyses. Pollen from other weeds was associated with increased odds of asthma exacerbation, without a clear exposure-response pattern (2-day lag, significant increases ranging from 8% to 19%). Increased odds from tree pollen and weeds (other than ragweed) were higher among children with allergic rhinitis. While there are known benefits from urban vegetation for human health, there are risks as well. It is important to note, however, that pollen is released during a limited time frame each year, and advisories informed by local data can enable susceptible individuals to avoid outdoor exposure on high-risk days.

Vegetation succession and climate change during the early pleistocene (2.2-1.8 Ma) in the Nihewan Basin, northern China

The Nihewan Formation, northern China is ideal for studying environmental changes during the early Pleistocene. In conjunction with palaeomagnetic measurements, pollen and grain-size analyses were conducted on 120 samples from a ~24 m long section (2.2-1.8 Ma) of core NHA from the Nihewan Basin, in order to reconstruct past vegetation and climatic changes. The pollen assemblages were dominated by Pinus, indicating that the vegetation was primarily pine forest and that the climate was relatively warm and wet. From 2.15-1.92 Ma, deciduous broad-leaved tree pollen significantly increased to >10% of the total, showing that more broad-leaved trees grew in the study area during the warmest and wettest period in the study section. From 1.92-1.78 Ma (coeval with the Olduvai event), Pinus and broad-leaved tree pollen types decreased. The percentages of Picea (>20%), Artemisia and Chenopodiaceae increased, indicating that spruce forests expanded, the openness of the forested areas increased and the climate became cold and dry. The vegetation changes reconstructed during the Olduvai period indicates that the climate in the Nihewan Basin was cold and dry, relating to global cooling facilitated by the uplift of the Tibetan Plateau and the strengthening of the winter monsoon.

Altitudinal patterns of wind transport and deposition of Yungas tree pollen in northwestern Argentina: Implications for interpreting the Quaternary fossil record

The presence of pollen from Yungas tree species in fossil sequences located above the tree-line has led to alternative interpretations of past climate changes in tropical and subtropical Andes. We studied atmospheric and surface pollen deposition rates of Yungas trees along an altitudinal gradient (1700–3800 m a.s.l.) to understand the role of local wind patterns in modern pollen transport to mountain regions. Pollen from the Montane forest (Alnus and Juglans) and the Montane rainforest (Anadenanthera, Celtis and Myrtaceae) becomes airborne and is transported upslope well above the tree-line. The resulting patterns of pollen deposition show a secondary maximum in the Montane grassland, consistent with the development of a mountain-valley breeze system during the flowering period of the pollen producer species. Given that the pattern is also preserved in the surface sediment, we propose that these tree pollen types are good indicators of mesoscale atmospheric circulation and could provide a proxy for this circulation system in Quaternary records. This alternative approach to interpreting fossil pollen records of Yungas species in highlands of the Central Andes has implications for regional reconstructions of past climate.

The associations between daily spring pollen counts, over-the-counter allergy medication sales, and asthma syndrome emergency department visits in New York City, 2002-2012.

BackgroundMany types of tree pollen trigger seasonal allergic illness, but their population-level impacts on allergy and asthma morbidity are not well established, likely due to the paucity of long records of daily pollen data that allow analysis of multi-day effects. Our objective in this study was therefore to determine the impacts of individual spring tree pollen types on over-the-counter allergy medication sales and asthma emergency department (ED) visits.MethodsNine clinically-relevant spring tree pollen genera (elm, poplar, maple, birch, beech, ash, sycamore/London planetree, oak, and hickory) measured in Armonk, NY, were analyzed for their associations with over-the-counter allergy medication sales and daily asthma syndrome ED visits from patients’ chief complaints or diagnosis codes in New York City during March 1st through June 10th, 2002-2012. Multi-day impacts of pollen on the outcomes (0-3 days and 0-7 days for the medication sales and ED visits, respectively) were estimated using a distributed lag Poisson time-series model adjusting for temporal trends, day-of-week, weather, and air pollution. For asthma syndrome ED visits, age groups were also analyzed. Year-to-year variation in the average peak dates and the 10th-to-90th percentile duration between pollen and the outcomes were also examined with Spearman’s rank correlation.ResultsMid-spring pollen types (maple, birch, beech, ash, oak, and sycamore/London planetree) showed the strongest significant associations with both outcomes, with cumulative rate ratios up to 2.0 per 0-to-98th percentile pollen increase (e.g., 1.9 [95 % CI: 1.7, 2.1] and 1.7 [95 % CI: 1.5, 1.9] for the medication sales and ED visits, respectively, for ash). Lagged associations were longer for asthma syndrome ED visits than for the medication sales. Associations were strongest in children (ages 5-17; e.g., a cumulative rate ratio of 2.6 [95 % CI: 2.1, 3.1] per 0-to-98th percentile increase in ash). The average peak dates and durations of some of these mid-spring pollen types were also associated with those of the outcomes.ConclusionsTree pollen peaking in mid-spring exhibit substantive impacts on allergy, and asthma exacerbations, particularly in children. Given the narrow time window of these pollen peak occurrences, public health and clinical approaches to anticipate and reduce allergy/asthma exacerbation should be developed.Electronic supplementary materialThe online version of this article (doi:10.1186/s12940-015-0057-0) contains supplementary material, which is available to authorized users.

Pollen from alder (Alnus sp.), birch (Betula sp.) and oak (Quercus sp.) in the UK originate from small woodlands

We have analysed the pollen seasons in Worcester for the period 2005–12 for alder (Alnus), birch (Betula) and oak (Quercus) by using back trajectory calculations and produced the first detailed source maps for these three pollen types.The study shows considerable variations in the source–receptor relationship of three of the most important tree pollen types in England with respect to allergy. Long Distance Transport is observed for Quercus and Betula but not for Alnus. The new source maps show a number of high emitting areas for Betula and Quercus, mainly near London, in the Midlands and in Wales. The production of source maps is sensitive to the used type of land cover data and how well they incorporate small woodlands. Two satellite products, Corine Land Cover and Globcover, are compared with the detailed national land cover product Land Cover Map 2007. The broad scale satellite products show either up to 50% less woody coverage or a direct misplacement of woodlands.The Lagrangian back trajectory model, the pollen count observations and the source maps altogether suggest that small woodlands (below 25ha) play a major role in the overall pollen load in urban areas in England.

Association Between the Sensitization Rate for Inhalant Allergens in Patients with Respiratory Allergies and the Pollen Concentration in Ulsan, Korea

Background/Aims: Pollinosis is an increasing problem, with allergenic pollen causing rhinitis, asthma, and other allergic diseases. This study examined the patterns of sensitization to inhalant allergens in patients with respiratory allergies and analyzed the regional pollen concentrations in Ulsan, Korea. Methods: A skin prick test was performed with 21 common inhalant allergens, including 18 types of pollen, in 634 patients with respiratory allergies from January of 2008 through December of 2010. Airborne pollen was collected daily from three different stations in Ulsan using a Durham sampler. Daily records and identification of the pollen types were made (2009-2010). Results: The sensitization rates for inhalant allergens were as follows: Dermatophagoides pteronyssinus (38.2%), Dermatophagoides farinae (38.0%), birch (15.8%), alder (15.3%), hazel (14.2%), oak (13.5%), beech (10.8%), mugwort (9.6%), and hop Japanese (5.2%). Airborne pollen has two peak seasons: tree pollen from February to June, followed by weed pollen from August to October. Pine tree, oak, and alder were the most frequently found pollen types in spring, whereas hop Japanese and mugwort were the most frequently found pollen types in autumn. Conclusions: House dust mites are the most common offending allergen in Ulsan. The sensitization rates to some tree pollen types, including birch, alder, and hazel were higher than those of weed or grass pollen. Causative allergens are changing in response to climate change and air pollution. Continuous aerobiological monitoring is the cornerstone for observing changes in pollen and a prerequisite for the study of the effect of climate change on allergic diseases. (Korean J Med 2014;86:453-461)

Representativeness of tree diversity in the modern pollen rain of Andean montane forests

AbstractQuestionsTo assess the relationship between modern pollen rain and Andean montane forest vegetation for diversity, and provide a basis for interpretations of palaeoecological data in the northern Andes, we asked: (1) can the reduction of plant and pollen data to family level preserve information about diversity in both data sets; (2) how precisely do tree pollen and spore types represent richness patterns along an altitudinal gradient on tropical mountains; and (3) how similar are tree pollen and spore family richness in relationship to tree family richness?LocationTropical montane rain forests, Podocarpus National Park in the Andes of South Ecuador (3°S, 79°W, 1000–3000 m a.s.l.).MethodsWe analysed tree diversity and species composition in three different rain forest types: Premontane (PMF), lower montane (LMF) and upper montane (UMF). We investigated modern pollen rain using pollen traps. After testing the reliability of a taxonomic surrogacy on the plant data, we compared abundance and representation, as well as diversity of the two data sets at family level. This was done using rarefaction and Sørensen indices.ResultsThe correlation between tree species and families was high (r = 0.81, P &lt; 0.001). Sample rarefaction on tree pollen and plant family data revealed highest pollen diversity on sites of the UMF, but highest tree diversity on LMF and PMF sites. The Sørensen indices indicate down‐drift of pollen from higher altitudes in PMF and LMF and up‐drift in UMF. Between 1% and 50% of pollen taxa of each sample originate from outside the plot.ConclusionsTaxonomic surrogacy at family level is a good tool for comparing presence–absence patterns of plant and pollen data in tropical regions with high tree diversity. On a family basis, pollen presence–absence data represent the corresponding tree vegetation data, but uncertainties increase with decreasing altitude. The higher diversity in pollen data of the UMF, but slightly lower diversity in the LMF and PMF, can at least partly be explained by wind patterns, local abundance of shrubs and herbs and differences in evenness.

Human impact on vegetation at the Alpine tree-line ecotone during the last millennium: lessons from high temporal and palynological resolution

Three mires and a small lake in the Swiss and Austrian Alps were studied palynologically at high resolution, covering the last 1,000, 400, 50 and 1,200 years, respectively. Methodological lessons include: (1) Sub-decadal resolution in upper, little-decomposed peat layers reveals recurrent marked fluctuations in both percentages and influx of regional tree-pollen types, reflecting variations in pollen production rather than in plant-population sizes. (2) Intermittent, single-spectrum pollen maxima in samples of sub-decadal resolution indicate pollen transport in clumps. This type of pollen transport may remain unrecognized in sections with lower sampling resolution, which may then lead to inappropriate interpretation in terms of plant-population sizes. (3) The detection of short-lived phases of human impact in decomposed peat requires sampling intervals as close as 0.2 cm. (4) PAR (pollen influx) may reflect vegetation dynamics more faithfully than percentages. Reliable PAR, however, is difficult to achieve in Alpine mires due to past human impact on peat growth, even when complex depth–age modelling techniques are used. Critical comparison of PAR with percentages is therefore essential. (5) Careful consideration of spatial scales in pollen signals (local–regional and subdivisions) is essential for a realistic palaeo-ecological interpretation. Results in terms of past human impact on vegetation are summarized as follows: (1) Trends in pollen types reflecting regional human action are in general agreement with earlier findings for the western Swiss Alps, allowing for regional differences. (2) All mires in the Alps investigated here and in an earlier study experienced human impact during the last millennium. The studied small lake, lying in sub-alpine pasture, records forest dynamics at a lower elevation since a.d. 800.

African pollen database inventory of tree and shrub pollen types

African pollen data have been used in many empirical or quantitative palaeoenvironmental reconstructions. However, the pollen types used in these studies were not controlled and standardised, preventing the precise understanding of pollen–plant and pollen–climate relation that is necessary for the accurate quantification of continental scale climate change or ecological processes in the past. This paper presents a summary of the progress made with the African Pollen Database (APD) inventory of plant diversity from pollen data extracted from 276 fossil sites and more than 1500 modern samples, with a focus on tropical tree pollen types. This inventory (1145 taxa) gives, for each pollen taxon whose nomenclature is discussed, information on the habit, habitat and phytogeographical distribution of the plants they come from. Special attention has been paid to pollen types with similar morphology, which include several plant species or genera, whose biological or environmental parameters can differ considerably.

Kan (for-)historisk arealanvendelse rekonstrueres kvantitativt?

Based on a pilot study of historical land-use and contemporary pollen assemblages this paper discusses the possibility of estimating past area coverage of major vegetation units (woodland, agricultural land, heathland). Pollen assemblages dated to approximately AD 1800 from 21 mediumsized Danish lakes and bogs were compared to land use shown on contemporary land register maps. Percentage of Heather (Calluna) pollen shows strong positive correlation with area-coverage of heathland within 2 and 5 km circles around the sites. Similarly, a strong positive correlation is found between woodland cover and several tree pollen types, in particular Beech (Fagus). Percentage woodland and agricultural area in a 5 km radius accounts for almost 60% of the variation in the pollen data. In contrast, land-use data inside a 2 km radius account for less than 40% of the pollen variation. The highest correlation between pollen and land-use is achieved with distant-dependent down-weighting of land-use data. A Partial Least Square (PLS)-model based on this data set was used tentatively to estimate past (500 BC - present) woodland-cover from a late Holocene pollen record of the lake Gudme Sø in south-eastern Fyn, Denmark. The addition of more sites and a screening of outliers in the pollen/land-use data set are needed to reduce errors in estimation of past land-use from pollen data.

Detecting woodland remnants in cultural landscapes: modern pollen deposition around small woodlands in northwest Scotland

Modern pollen deposition in and around woodland fragments in a largely open cultural landscape in northwest Scotland is investigated using moss polsters and surface sediment samples from small lakes. The percentage of local arboreal (tree and shrub) pollen types declines rapidly with distance from the woodland edge, generally reaching background levels in less than 100 m. Even at the woodland edge or under the canopy, some samples contain less than 30% local arboreal pollen. The relationship between percentage of local arboreal pollen and distance from the woodland edge does not vary with changing topographic relationship between sample location and the woodland edge, but does differ according to the vegetation community outside the woodland. Comparison of pollen assemblages from 11 small lake basins (mean size 1.0 hectare) with assemblages from moss polsters collected near the lake edge suggests that the pollen source area for arboreal pollen types is in the order of 300 m for peat samples and over 400 m for lake sediments. Implications for interpretation of palaeorecords are considered.

Modern pollen samples from alpine vegetation on the Tibetan Plateau

Abstract A set of 316 modern surface pollen samples, sampling all the alpine vegetation types that occur on the Tibetan Plateau, has been compiled and analysed. Between 82 and 92% of the pollen present in these samples is derived from only 28 major taxa. These 28 taxa include examples of both tree (AP) and herb (NAP) pollen types. Most of the modern surface pollen samples accurately reflect the composition of the modern vegetation in the sampling region. However, airborne dust‐trap pollen samples do not provide a reliable assessment of the modern vegetation. Dust‐trap samples contain much higher percentages of tree pollen than non‐dust‐trap samples, and many of the taxa present are exotic. In the extremely windy environments of the Tibetan Plateau, contamination of dust‐trap samples by long‐distance transport of exotic pollen is a serious problem. The most characteristic vegetation types present on the Tibetan Plateau are alpine meadows, steppe and desert. Non‐arboreal pollen (NAP) therefore dominates the pollen samples in most regions. Percentages of arboreal pollen (AP) are high in samples from the southern and eastern Tibetan Plateau, where alpine forests are an important component of the vegetation. The relative importance of forest and non‐forest vegetation across the Plateau clearly follows climatic gradients: forests occur on the southern and eastern margins of the Plateau, supported by the penetration of moisture‐bearing airmasses associated with the Indian and Pacific summer monsoons; open, treeless vegetation is dominant in the interior and northern margins of the Plateau, far from these moisture sources. The different types of non‐forest vegetation are characterized by different modern pollen assemblages. Thus, alpine deserts are characterized by high percentages of Chenopodiaceae and Artemisia, with Ephedra and Nitraria. Alpine meadows are characterized by high percentages of Cyperaceae and Artemisia, with Ranunculaceae and Polygonaceae. Alpine steppe is characterized by high abundances of Artemisia, with Compositae, Cruciferae and Chenopodiaceae. Although Artemisia is a common component of all non‐forest vegetation types on the Tibetan Plateau, the presence of other taxa makes it possible to discriminate between the different vegetation types. The good agreement between modern vegetation and modern surface pollen samples across the Tibetan Plateau provides a measure of the reliability of using pollen data to reconstruct past vegetation patterns in non‐forested areas.

The fluctuations of the allergenic pollen content of the air in Brussels (1982 to 1997)

The pollen content of the air was studied from1982 to 1997 in Brussels. Fluctuations weremainly observed in the tree pollen content whilethe amount of pollen originating from herbaceousplants remained more stable during theinvestigation period.The number of allergenic tree pollen grains didnot rise steadily during this period. We noted,however, the existence of years with high pollenproduction following the physiological biorhythmof the trees. Years with high annual sums for agiven tree pollen type did not coincide withyears with high annual sums for another treepollen type. Variations in annual sums of allergenicherbaceous pollen types were less important thanthose of tree pollen types. No rise, nor cyclicpatterns were observed. The most important allergenic pollen types(Betulaceae, Fagaceae, Gramineae and Artemisia) have been presented in histograms.

Trends of some airborne tree pollen in the Nordic countries and Austria, 1980—1993

Abstract Long term trends in the occurrence of airborne pollen might help in elucidating the probability or unlikelihood of developments which have been predicted in theory such as global warming or forest decline. We have investigated and compared the trends over a 14 year period (1980–1993) of five selected common tree pollen types (Alnus, Corylus, Betula, Pinus, and Ulmus) from three sites in North Europe (Stockholm, Trondheim, Turku) and one in Central Europe (Vienna) in terms of the start, peak, end, and duration of the season, peak values and annual totals, using data from the European pollen data bank. The existence of trends has been investigated by calculating correlation against years and the statistical significance of the regression lines has been examined at the 5% probability level (p<0.05). A consistent trend in the earlier commencement of the flowering season is observed in all cases, as well as an earlier incidence of peak days. A marked trend to an earlier end of the season was also foun...

European allergenic pollen types

Pollen data have been collected from 66 stations, situated in 19 European countries thanks to the initiative of both the Working Group «European Aeroallergen Network» (of the Int. Assoc. of Aerobiology) and the Subcommittee «Aerobiology of inhalant allergens» of the European Academy of Allergology and Clinical Immunology. Volumetric data over periods of 3 to 5 years (up to 1988) were included, and 15 both aerobiologically and allergologically relevant taxa were selected. Geographically adjacent stations were grouped together into regions looking at the peak period of the airborne grass-pollen presence. The result is a collection of 21 regional European pollen calendars, some of which are covering several countries (e.g. «Western Europe»), others are applicable only to a part of one country (e.g. «Southern Italy»). Comparing the calendars, general features are the South-to-North delay shift in the appearance of tree-pollen types in Spring, and the reverse shift for the weed-pollen types in late summer. The presence ofAmbrosia pollen in the air in several parts of Central Europe is clearly shown.

Contemporary pollen assemblages from the Vosges (France)

This paper comprises a comparative study of the recent relative regional pollen deposition and the forest vegetation in a 70 km long transect across the Vosges. The forest vegetation was mapped with the aid of the qualitative data from individual forest lots, available from the “Office National des Forêts”. Eight landscape regions were established and defined on the basis of forest vegetation, geology, topography and precipitation. Pollen was analysed from surface samples and the ranges, frequencies and median values of the individual pollen types were calculated for each of the landscape regions and compared with the distribution of forest vegetation types and the relative abundancies of Abies alba, Castanea sativa, Fagus sylvatica, Larix decidua, Picea abies, Pinus sylvestris, Pseudotsuga menziesii, and Quercus sp. Next to tree pollen types, all the pollen types of herbs and shrubs were fully accounted for in order to establish the relation between the pollen values and the regional and local occurrence of the relevant taxa. In general the major vegetation sequence of the forest dominants, from west to east across the mountains, viz. Quercus—Pinus, Fagus—Abies—Picea, Fagus and again Fagus—Abies—Picea and Quercus—Pinus is well reflected in the pollen deposition. It is concluded that the landscape regions can be characterized by their regional pollen assemblages, mainly by the values of the tree pollen types; to a lesser extent by those of herbs and shrubs. Herb pollen types that characterize landscape regions include Genista, Pteridium and Dryopteris type. The degre of aforestation an d cultivation is reflected in the pollen values of Anthemis type, Chenopodiaceae, Plantago lanceolata, Cerealia and by Corylus, Betula and Alnus. Three additional landscape regions were recognized on the basis of vegetation only.