I have a friend of mine that has older established apple trees (variety unknown)that have produced loads of apples in the past. For the past couple of years the trees have bloomed nicely, but then the blooms fall off and very little fruit appears. The very small amount of fruit that does appear grows normally through the season.
This friend had bought the house his grandmother lived in, so he is very familiar with these trees and through all the years this is the first time he can remember this happening. I dont think this is an early frost problem. I would appreciate any advice on what may be causing this to happen. Thanks, Budman-

It sounds like the trees are not being adequately pollinated. When the blossoms bloom, see if there are lots of bees and things collecting pollen. Honeybee populations have been devestated in recent years.
It could also be that there was an apple tree or trees nearby that were chopped down or died, which once provided superior pollination. If all the trees your friend has are of one or two varieties, they may not be getting the type of pollination they need...some apples are picky about this.
Other issues...freezes, drought...could be to blame, though.

Blossom drop could also be caused by variation in temperature. To rejuvinate an old apple tree, a few things needs to be one. Prune out dead, weak and crossing branches to open the center and let the sun in. Do the pruning when the apple is dormant or when there is no longer danger of frost or just before it leafs out. If lacking pollinator, place a fresh bouquet of blossoms from another variety (in a can of water) at the base of the apple tree. Thin out fruit clusters to about 4 or 5 apples per cluster to channel enegies to the remaining fruit on the clusters.

Thanks Peppereater and papito. I will relay this good info to my friend and hope he can apply it to his situation. Take care, Budman-