wind dispersion

Why are Douglas-fir cones falling when they're still green?

Something is causing green Douglas-fir cones to fall from the trees before they are ripe. And, the cones are getting piled up into mounds. Who’s doing this?

Maple seeds: nature's helicopters

This is the season that winged seeds of maple trees helicopter down to the ground. What advantage do the whirling seeds provide to maple trees?