<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Jato, V</style></author><author><style face="normal" font="default" size="100%">Rodríguez-Rajo, F J</style></author><author><style face="normal" font="default" size="100%">Aira, M J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Use of Quercus ilex subsp. ballota phenological and pollen-production data for interpreting Quercus pollen curves</style></title><secondary-title><style face="normal" font="default" size="100%">Aerobiologia</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">airborne pollen</style></keyword><keyword><style  face="normal" font="default" size="100%">Phenology</style></keyword><keyword><style  face="normal" font="default" size="100%">pollen production</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2007</style></year></dates><volume><style face="normal" font="default" size="100%">23</style></volume><pages><style face="normal" font="default" size="100%">91-105</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">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.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">García-Mozo, H</style></author><author><style face="normal" font="default" size="100%">Galán, C</style></author><author><style face="normal" font="default" size="100%">Aira, M J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Modelling start of oak pollen season in different climatic zones in Spain</style></title><secondary-title><style face="normal" font="default" size="100%">Agricultural and Forest Meteorology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Aerobiology</style></keyword><keyword><style  face="normal" font="default" size="100%">oak forest</style></keyword><keyword><style  face="normal" font="default" size="100%">Phenology</style></keyword><keyword><style  face="normal" font="default" size="100%">pollen</style></keyword><keyword><style  face="normal" font="default" size="100%">threshold temperature</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2002</style></year></dates><volume><style face="normal" font="default" size="100%">110</style></volume><pages><style face="normal" font="default" size="100%">247-257</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Quercus pollen and meteorological data for several years from eight sites in Spain have been statistically analysed to select the threshold temperature and calculate the mean heat accumulation for predicting the Quercus pollination start in different climatic areas. The growing degree days method, which assumes the daily temperature varies as a sine wave, was used for heat accumulation calculations. Threshold temperatures between 4 and 12 ◦ C were chosen using linear regression equations forced through the origin and their root mean square error (RMSE) of predicted against the observed dates for each observation site. Above the threshold, the average growing degree days (up to 1999) for the studied years was taken as the predictor value. Results showed a relationship between the selected threshold and elevation and a stronger and statistically signiﬁcant correlation between threshold and yearly mean temperature, for each site. Regression analysis indicated that the selected threshold and the calculated heat accumulation were optimum for most of the localities. The validity of the results was tested using the meteorological data for the year 2000 as independent variable and this conﬁrmed that there were only a few days difference between the predicted and observed day of the ﬁrst pollen release for most of the studied localities</style></abstract></record></records></xml>