A note about hay fever - not sure how bad yours is but mine was debilitating (hated leave the house during spring). The last two years I've been doing immunotherapy shots in the winter and this year my allergies are almost completely gone. It's been an unbelievable quality of life change. Would highly recommend if you have insurance that covers it (tho looking back now, I'd also gladly pay out of pocket).

This comment sounded very strange to me, but as the linked article says about "male" trees:

> Growers’ breeding of purely male diodar trees had created, said Ogren, “something that doesn’t even exist in nature”.

Ironically the tree outside my house was recently removed because the fruit annoyed people. Personally I thought the tree was well worth the hour or two a year it took to remove the fruit in autumn.

Would the female trees do that if there weren't any male trees around?

Not many male trees are needed to breed so even if one is around you get the problem.

Not all trees have separate male and female trees as well. If you only have one type of tree you have no biodiversity and that is almost as bad as no trees.