A Tennessee tree trimming company shared video of the moment a falling birch tree exploded into a "pollen bomb." The video, shared by Timberline Outdoors, shows the river birch tree being felled in Hixson. The tree hits the ground, sending up a thick cloud of pollen that the company branded a "pollen bomb." "If you think your allergies are trying to kill you, you'd be right!" the company quipped.