Botanical sexism
Description
Description
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According to horticulturist Tom Ogren, who coined the term, [pollen allergies](/wiki/Allergic_rhinitis "Allergic rhinitis") have been amplified due to the planting in urban areas of male [clones](/wiki/Cloning "Cloning"), which increases the amount of pollen in the air. The planting of more female plants would decrease the overall amount of pollen since they do not produce pollen and remove pollen from the air for [pollination](/wiki/Pollination "Pollination"). The theory has existed since at least the 2000s. Biological sexism is used in the [Ogren Plant Allergy Scale](/wiki/OPALS_%28Ogren_Plant_Allergy_Scale%29 "OPALS (Ogren Plant Allergy Scale)") (OPALS), which has been adopted by the [United States Department of Agriculture](/wiki/United_States_Department_of_Agriculture "United States Department of Agriculture"). Botanical sexism has found some scientific acceptance as a reason for increased allergies and asthma; however, other scientists have also been critical of it, stating that it only applies to certain trees and is not as widespread as Ogren alleges.

The [dioecious](/wiki/Dioecy "Dioecy") species affected by botanical sexism include [willows](/wiki/Willow "Willow"), [poplars](/wiki/Populus "Populus"), [aspens](/wiki/Aspen "Aspen"), [ashes](/wiki/Fraxinus "Fraxinus"), [silver maples](/wiki/Silver_maple "Silver maple"), [pistache](/wiki/Pistache "Pistache"), [mulberry](/wiki/Mulberry "Mulberry"), [pepper tree](/wiki/Pepper_tree "Pepper tree") and other woody plants such as [junipers](/wiki/Juniper "Juniper"), [yew pines](/wiki/Podocarpus_macrophyllus "Podocarpus macrophyllus"), [fern pines](/wiki/Afrocarpus "Afrocarpus"), [wax myrtles](/wiki/Wax_myrtle "Wax myrtle"), [alpine currants](/wiki/Alpine_currant "Alpine currant"), [plum yews](/wiki/Plum_yew "Plum yew"), and [yews](/wiki/Yew "Yew").


How does Ogren Plant Allergy Scale (OPALS) work?