There are a number of reasons a fruit tree might not set fruit. It typically takes fruit trees a few years to produce fruit, so you may just need to wait a few more years for the Italian plum and pear tree to bear fruit. The four-year-old plum is just reaching fruit bearing age. Pears typically take 2-4 years, and plums 3-6 years to bear fruit, though they would reach fruit bearing age earlier in dwarf varieties. The ice storm was in January when the trees were dormant and would not have affected blooms, however, we did experience some spring frosts, and if that coincided with bloom time then the blossoms may have been killed. Pears need a second pear tree to act as a pollinizer, so it is possible that your pear tree is not being sufficiently pollinated. Plums are partially self-fertile but some plum varieties require a pollinizer. Italian plums are self-fertile, but I don’t know about the second variety that you have. Since the trees look otherwise healthy, I am guessing this is a combination of age of trees and cold spring weather. You should look into the pear tree and depending on variety, plant a second variety to improve pollination. You can find a list of pollinizers for pears at this link: https://treefruit.wsu.edu/orchard-management/pollination/, and refer to the article I linked to above about why fruit trees fail to bear.

Thank you so much for this thorough information.  I really appreciate it!   I forgot that I had one more question.  I have a peach tree and an apricot,  both of which have serious leaf curl disease.   I sprayed them last fall with a copper spray I got at Jerry's.  Unfortunately this did absolutely nothing to deter the leaf curl.  I guess I am asking is there a particular type of copper I should use or should I just assume these trees are not going to make it in this area?   Thank you so much for your knowledge.

Two fungicide applications are recommended for peach leaf curl, one in the fall at about 50% leaf fall (late October-early
November,) and the second in the dormant season just before floral buds begin to open (which is usually in late February). Ziram is what many commercial growers use since it is very effective against peach leaf curl. For home gardeners, your best options are chlorothalonil or fixed copper, and chlorothalonil is the more effective fungicide of the two. Since you tried a copper product, I recommend looking for a product with chlorothalonil to use (for home gardeners, trade names with chlorothalonil include Bonide Fung-onil, GardenTech Draconil, and Ortho MAX Garden Disease Control), and make sure you time the two sprays properly. Shothole fungus is another common disease of peaches and apricots in Western Oregon, and also requires two sprays. Fixed coppers are effective against shothole, and to control it you need to spray copper around Thanksgiving, and again around Christmas. 

You can find more information on Managing Diseases and Insects in Home Orchards in OSU Extension publication ec631 https://catalog.extension.oregonstate.edu/ec631.

Oh thank you so much!  I will definitely look into this.  I am grateful for the knowledge provided by your program.