Posted: 11/07/2012 at 15:14
We have a Vranja quince tree about the same age that behaves in a similar way - it blossoms profusely, but only has a few fruit. By last year we had maybe a dozen decent quinces, which was great, but that was out of hundreds of blossoms. This year I am not so hopeful of getting any fruit.
I think, as Leggi says, it's probably due to a lack of pollinators at a critical time. I've also noticed that the fruits our quince tree had were towards the top of the tree, which also suggests it's to do with pollenators.
We love our quince tree anyway, as it's an elegant tree, its leaves open early in the year, it's pretty in blossom, and it's one of the last to drop its leaves.