Overfertilization: If the tree is receiving high amounts of nitrogen, it will produce a lot of tree but not blooms. Fertilization can come from what you put on your grass. Rain can move the nitrogen down past the grass roots where the trees can take it up. Apply extra fertilizer to the lawn within 5 feet of the spread of the tree's branches. Be careful, because under fertilization can also occur. The need for fertilizer in the home orchard should be based on soil test results and annual shoot growth. Bearing fruit trees should average 12 to 18 inches of shoot growth per year. Nonbearing young trees should average 18 to 30 inches. If your trees have less growth than this, then increase the nitrogen rate by 25% the next spring. If they have greater amount of annual shoot growth it would indicate either you are over pruning or over fertilizing.

Heavy winter pruning will also stimulate excessive growth. Fruit trees should be pruned each winter. However, indiscriminate heading cuts will delay flowering and fruiting. Heading cuts are the main culprit. Before pruning your trees make sure you know where the tree produces flowers and how to prune to encourage flower production. In general, thinning out cuts (those that remove an entire branch back to its point of origin) are less stimulating and encourage more flower production. Heading cuts (the removal of a portion of the branch) will stimulate more vegetative growth and delay flowering. In extreme cases continual heading cuts will totally prevent flowering in apples.

Here are a couple of important publications to check out:

https://extension.oregonstate.edu/gardening/berries-fruit/restore-those-old-fruit-trees

https://catalog.extension.oregonstate.edu/ec1005/html

Hope this helps!