I have a huge Osage orange tree. Generally nothing eats them, but when the snow stays on the ground for weeks, and forms a crust of ice… eventually the squirrels will tear apart the fruit and eat a few of the hundreds of oranges. It might be that the squirrels using it as a famine food in anomalous weather years is enough to spread it.
In my neighborhood the big Osage oranges were planted in the late 1800s along the property lines, so they are long lived. A once in a hundred year weather event would be enough to keep a population going.
On the hillside behind my parent's house are a few varieties of ivy and some St. John's wort. Based on what is getting eaten we can estimate the local deer population's hunger level - they have a distinct preference order.
That gives me a funny science fiction idea. Once we have self-building, self-repairing devices and infrastructure. Nanobots? Whatever. A tornado goes through destroying houses and in the aftermath cornfields are littered with little growing houses seeded from the debris.
> A once in a hundred year weather event would be enough to keep a population going.
The article notes that it was nowhere near enough, and with the loss of its primary dispersers the once-widespread genus had enormously shrunk in variety and range both before it got recycled as natural fencing:
> According to my field guide, Osage-orange has a limited natural range in the Red River region of east-central Texas, southeastern Oklahoma, and adjacent Arkansas.
> [...]
> fossils tell us that Osage-orange was much more widespread and diverse before the megafaunal extinctions. Back then, Osage-oranges could be found north up to Ontario, and there were seven, not just one, species in the Osage-orange genus, Maclura.
(sp: there are 12 extant species of Maclura according to the wiki — most of them from asia though one is native to south america and one central america, I expect the author implied "in NA")
In my neighborhood the big Osage oranges were planted in the late 1800s along the property lines, so they are long lived. A once in a hundred year weather event would be enough to keep a population going.