Here is the fruit

Here is one more picture

Quince, Cydonia oblonga I believe.

Quince fruit is commonly mistaken for pears. If this is a recent picture, as lack of leaves would indicate, the "no taste" could be from very aged fruit that would normally have a strong flavor in autumn.

Thank you!
Quince fruit it is!
I guess we will keep the trees!

Be sure to look for the blooms come spring. They are large and beautiful. I included a link to see some pictures of my quince in bloom and its fruits. FYI, quince fruits are generally cooked before eating hence the lack of flavor.

FataMorgana

Here is a link that might be useful: Quince

Raw quince is very flavorful and aromatic when newly ripe; most cooking recipes use lots of sugar and long cooking times, resulting in a pink or reddish product, but the flavor is retained.

I have tasted "mild" quince from a tree just once, about the intensity of an average pear. Also, your trees may be of an old variety or even seedlings, and have lower-quality fruit. Try some of yours next October and see what you think. The springtime flowers are nice.