Millions of allergy sufferers would disagree - as would the kind folks that came up with the term "pollen count", as part of the pollution index.
But everyone is entitled to their opinion, to be sure.
And I couldn't speak to what Reagan was actually referring to - though if he was referring to pollen, he would've been more widely understood, and also correct.
I would suggest that Reagan wasn't talking about pollen. If he had been, he wouldn't have qualified his comments about 'some trees'. He would have said all trees.
As for the pollen count, the inclusion of it in the daily index reporting doesn't make it pollution. It does make it bothersome for people with allergies, which is why they report it.
Thanks for the additional comments.