Apparently, Claritin -- a science-based company -- recently discovered that only male trees produce pollen. Go figure. I think I learned about sexual reproduction of plants in 5th or 6th grade science.
Anyway, they now want to plant more female trees to reduce the amount of pollen released each Spring. Not sure how that reduces pollen unless they are also chopping down male trees.

They call it
The DiversiTree™ Project.
Sounds like a misnomer. Planting only one sex tree seems more like less diversity!

Now, I'm not a botanist, but I would think planting more female trees increases the chances of the existing pollen finding a recipient in order for more seeds to be spread around. Unless Claritin has found a
Jurassic Park method to control naturally germinated trees' sex, the number of male trees is bound to increase -- simply because there are more female trees making baby trees.
The main reason I doubt this Project's objectives is the fact that an allergy medicine manufacturer is sponsoring a movement to reduce allergies. I really don't believe it's anything more than a publicity campaign capitalizing on the current "diversity" issues in our society such as the ruling against college admissions based on affirmative action.
Just a thought.
https://www.claritin.com/diversitree