Sounds like a job for a few unpaid interns!
Actually, that’s the type of botanical research I was wondering about - if anyone had done any studies like that. It’s not such a terrible way to get a fairly good estimate. If one were to pick up the leaves from around a tree for several weeks and do such calculations, it might give one a general number that might be reliable. And maybe the number of leaves that blow away would be more or less offset by the ones from other trees that blow into the collecting area. If I were a botanist, or if I had the opportunity - and the leaf collecting facility - i.e. a grant that would cover the time and expenses, I’d think that would be a perfectly good way to generate some beginning numbers. Doing that with selected trees in a variety of conditions should help you derive SOME sort of number to work with. Not a bad idea, I think. Works for me.