The effect of climate conditions on inter-annual flowering variability monitored by pollen traps below the canopy in Draved Forest, Denmark

Abstract

Since 1967 annual pollen deposition has been monitored in the semi-natural mixed deciduous woodland Draved Forest by the Geological Survey of Denmark. In this paper, we analyse the variability in pollen accumulation rates for the eight most common deciduous trees, and their relationships to monthly temperature and precipitation. High summer temperatures in the year before flowering have a positive effect on pollen deposition for several species. A positive correlation between temperatures during the flowering season and pollen accumulation rates is found for Fagus sylvatica, Quercus robur, Fraxinus excelsior and Corylus avellana. The amount of precipitation can have both positive and negative effects on pollen accumulation, depending on species and on time of year. Linear modelling showed that combinations of monthly climate parameters could explain between 10 and 80% of the variation observed in different species. There were marked differences in the time series of pollen accumulation and pollen/climate relationships for some species between traps within the forest related to the location of trees near the traps. This underlines the importance of using multiple traps in a region for this type of study. Time series analyses were used to test for cyclicity in pollen accumulation rates, which could be caused by resource limitations or internal biological factors. No significant autocorrelations were found, although Alnus glutinosa showed a tendency towards 3-year cyclicity. These results indicate that, with the possible exception of Alnus glutinosa, temperature and precipitation are the main factors controlling the annual variability in pollen deposition of the trees in Draved Forest.

Pollen production estimates (PPEs) and fall speeds for major tree taxa and relevant source areas of pollen (RSAP) in Changbai Mountain, northeastern China

“…Climate variation may affect pollen production differentially for different species (Nielsen et al, 2010;Matthias et al, 2012;Mazier et al, 2012), and is likely also to affect relative PPE values in climatically different regions. The PPEs for the same pollen taxon in different regions, where there exist different plant species, may then be found to vary .…”

Plant subsistence and environment at the Mesolithic site Tågerup, southern Sweden: new insights on the “Nut Age”

“…4700 B.C., as interpreted from charcoal data inferring decrease in forest fire intensity (Greisman and Gaillard 2009;Olsson et al 2010), as well as from stable isotope records (Hammarlund et al 2003). Wetter and colder climate may have affected the hazel populations during this phase, since a positive correlation between temperature during the flowering season and pollen accumulation rate for Corylus has been found (Nielsen et al 2010).…”

From early pollen trapping experiments to the Pollen Monitoring Programme

“…So it is no surprise that Andersen had already installed traps of Tauber's design in the forest by 1967 (Andersen 1974). What is astonishing is that this monitoring experiment has been kept going, so that this dataset is the longest continuous pollen monitoring record in existence, much to the credit of Peter Friis Møller at the Geological Survey of Denmark and Greenland (Nielsen et al 2010). Andersen also played a part in the development of tablets with Lycopodium spores (Stockmarr 1971) for 'spiking' samples prior to preparation as a means of estimating pollen concentrations and accumulation rates (Birks 2009).…”

“…The present volume brings together three investigations that combine most of the local and regional pollen trapping experiments to investigate the variation in PAR of Fagus , differences in the representation of pollen in moss samples versus pollen traps , and the interaction between inter-annual climate variability and annual pollen deposition (van der . estimate pollen productivity based on Bulgarian and Georgian pollen monitoring results, Sjögren et al (2010) further develop the method of estimating absolute pollen productivity based on Swiss results, Birks and Bjune (2010) compare the trapping of pollen to that of macroscopic plant remains, and Nielsen et al (2010) present the continuation of Andersen's (1974) trapping experiments. As many of the questions asked in these investigations have already been addressed by Sheila Hicks (Hicks 1999), her long monitoring series from northern Finland were not included in the analyses above.…”