Use of Quercus ilex subsp. ballota phenological and pollen-production data for interpreting Quercus pollen curves

Abstract

Although aerobiological data are often used in phenological research as an indicator of flowering, airborne pollen concentrations are influenced by a number of factors that could affect pollen curves. This paper reports on a study of various aspects of reproductive biology in Q. ilex subsp. ballota, together with environmental factors influencing pollen release and transport, with a view of achieving reliable interpretation of Quercus pollen curves in Ourense (NW Spain). Aerobiological data were recorded from 2002 to 2004 at two sites in the province of Ourense. From 1st February to the end of the flowering period, phenological observations were carried out on 19 trees from the Q. ilex subsp. ballota population found in the Ourense area. Pollen production was calculated for the same trees. The chilling and heating requirements for triggering development were also calculated. The mean flowering period lasted 11-15 days. Reduced pollen output per catkin and, especially, a reduced number of catkins per tree in 2003 and 2004, prompted a marked decline in overall pollen production. Major differences observed in Q. ilex subsp. ballota pollen curves were attributed to the considerable influence both of weather conditions during pollination and pollen production. In years with high pollen production and weather conditions favouring pollen release, Q. ilex subsp. ballota contributed almost 10% to the total Quercus pollen curve. Around 20% of the pollen trapped was captured before or after flowering periods.

Changes in flowering of birch in the Czech Republic in recent 25 years (1991–2015) in connection with meteorological variables

“…21 The occurrence of synoptic situations between phenophases in the period 1991-2015. these dates were between 17th April and 2nd June (beginning of flowering 10 %) and 16th May and 10th June (end of flowering). Airborne pollen counts do not always match flowering periods.…”

“…The pollen season start-date can be greatly influenced by dispersal types and this fact should therefore be taken into account when using airborne pollen data in phenological surveys. As recommended by Jato et al [21], phenological studies should include major wind-pollinated tree species in order to improve the interpretation of airborne pollen data. Over recent years, Hirst volumetric pollen traps [15] have proved to be an accurate tool for crop forecasting [22,23].…”

Allerjenik Betula (Huş Ağacı) Polenlerinin Türkiye’deki Dağılımları

“…Bir huş ağacında silindir şeklindeki çiçek kurullarında 8 milyondan fazla, bir ağaçta ise 90-110 milyar civarı polen üretilmektedir (12,13 …”

A prognostic pollen emissions model for climate models (PECM1.0)

“…Morus has no known reference for production factor and was assumed to be 10 × 10 7 grains m −2 year −1 , conservatively at the low end of the range for other deciduous broadleaf taxa. Other tree taxa and grasses are reported in grains m −2 year −1 , while ragweed is reported in grains stem −1 year −1 (Helbig et al, 2004;Jato et al, 2007;Hidalgo et al, 1999;Prieto-Baena et al, 2003;Fumanal et al, 2007). To convert the production factors from Tormo Molina et al (1996) (grains tree −1 year −1 ), the production factors for each representative tree are multiplied by the tree crown area, calculated as the circular area of the tree crown diameter given in Table II of Tormo Molina et al (1996).…”