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Brown Bag Seminar 10 -10 -12)


"The Effects of Meteorology on Airborne Juniper Pollen Concentrations"
Presentation by: Landon Bunderson (Univ. of Tulsa)

Juniperus ashei (mountain cedar) pollen is considered one of the most allergenic species of Cupressaceae in North America. Mountain cedar is primarily distributed across Central Texas and South Central Oklahoma and produces large quantities of pollen that can be transported great distances. In order to create a dynamic forecast system, pollen production was estimated and the relationship between pollen release and meteorology was evaluated. Two locations in the Arbuckle Mountains of Oklahoma and 4 locations in the Edwards Plateau region of Texas were chosen as sampling sites. Trees in each location were measured, cone production was evaluated based on a rating system, and percent tree cover was determined. Cone production was estimated by counting cones from 1/8th sections of 10 representative trees. The 10 representative trees were used to test three models describing the relationship of pollen production to tree size: height, surface area, and volume. Additionally, vials of cones collected at each location were used to determine the number of pollen grains per cone. Using the pollen count data, tree measurements, the rating system, and the three models, three estimates of total pollen grains per hectare were produced. Hygroscopic weight gain was also investigated in order to determine how high humidity events may affect the deposition of pollen already suspended in the atmosphere. Air sampling was conducted using Burkard volumetric pollen traps established at all 6 sites for two consecutive winter seasons. Airborne pollen concentrations were positively correlated with temperature and negatively correlated with humidity and rainfall. Pollen production estimates found that a single representative tree in the Arbuckle Mountains produced 5.5 × 1011 million pollen grains and estimated pollen production varied greatly between locations.


Past Brown Bag Abstracts