Trees that can Trigger Allergies in Human Beings 

Birch They grow throughout the continental U.S., except in the southernmost and westernmost states, and their pollen is very likely to trigger allergies.

Elm This tree grows in all but the coldest northern parts of the continental U.S. and makes pollen in the fall.

Cedar There are about 70 different kinds of these trees and bushes, including juniper and cypress, and some of them can cause major allergy issues.

Oak Many people are allergic to oak pollen, and because the trees are common in residential areas and parks.

Pine These evergreen trees found all over U.S. make a huge amount of pollen in the spring.

Poplar They’re most likely to cause allergy issues in Minnesota and areas in the Southwest.

Walnut Their pollen can be a big trigger for allergies, but it’s heavy and usually drops to the ground.

Ragweed This grows everywhere and may be the most common allergy trigger in North America.