Which Trees Cause Allergies?
The tree-pollinating season can vary by as much as a month from one year to the next depending on the severity of the winter and spring weather conditions.
Fluctuations in daily temperature, rain and sun can also affect the amount of pollen released by trees during the pollen season.
Some species of trees cause allergies more than others.
- Alder: many people with tree pollen allergies are allergic to this species, found throughout most of North America.
- Box elder: a member of the maple family that is abundant in Quebec, Ontario and the western provinces except British Columbia. Other species of maple trees cause fewer allergy problems.
- Birch: it is known to produce large amounts of pollen and is a common source of allergy troubles.
- American elm: widespread in Canada from western Newfoundland to Saskatchewan, this species can cause severe allergies in some people.
- Mulberry: the Red mulberry, widespread in southern Ontario has been known to cause severe hay fever symptoms.
- Oaks: shed more pollen than any other tree and are an important source of allergies. They are found throughout Canada with many species in Ontario, Quebec and the Maritimes.
Fortunately, there are many trees around us unlikely to cause allergy problems, either because they don't usually produce enough pollen or because fewer people are allergic to these trees:
- Chestnut (not including Horse chestnut)
- Maple (not including Box elder)
- Poplar, aspen and cottonwood
- Fir, pine and spruce