Trees, Shrubs and Conifers: what is this tree?, 2 by qterhrs

qterhrs wrote:
We found a group of trees growing but dont know what they are and where they came from. They have been growing very fast, in fact we wanted to identify and transplant but in the last 2 years they went from knee high twigs to 6'. Thought they were some type of pear but the fruits look like cherries but are rock hard. Any help is appreciated because we wont be able to transplant the trees but my husband suggested picking and planting the fruit.