Pollination Study

Individuals afflicted by seasonal rhinitis (hay fever) and asthma generally exhibit symptoms during pollen release of local species of trees. Over 80 species of trees that are recognized as allergenic occur in Oklahoma. The tree pollen season often begins in February and continues through May with other tree species pollinating in the fall and early winter. Knowledge of the pollen season is of significant value in the treatment of seasonal rhinitis and asthma, since both are severely affected by the amount of allergens in the air.

In this study, the atmosphere in Tulsa was monitored with a Burkard Spore Trap situated on the roof of a building at the University of Tulsa, as seen in the photograph at the right. Microscope counts were converted into average daily concentrations and expressed in grains/m³.

In totaling up the amounts of various pollen grains, several criteria were used to determine patterns in the seasonal fluctuations. The Start Date of the season of each type of pollen was defined as 5% of the cumulative season total, whereas the End Date was defined as 95% of the season total. The Peak Date of each season was recorded as the date of maximum average daily concentration. The study was conducted from 1987 to 1996, and the pollen levels for species of Betula, Quercus, Ulmus, Juniperus/Cupressaceae, Morus and Carya were examined.

The collecting apparatus of the Burkard Spore Trap slowly revolves at a constant rate, and the solid components of the atmosphere- -pollen and spores, as well as dust--are caught on a sticky plastic film. This film can then be removed and analyzed to determine the concentration of pollen in the air at a specific time.

After the study was completed, it was concluded that, during the spring, the pollination periods for allergenic tree species are highly variable in Oklahoma, both in timing and in abundance. The high variability in timing suggests that it is difficult for allergic individuals to prepare for the allergy season. Furthermore, the high variability in abundance indicates that exposures are inconsistent from year to year, and therefore symptoms may be equally variable. Due to such high variability, more similar studies are needed to estimate the average season, and more research is necessary to understand the mechanisms which govern the onset and magnitude of the pollen season.