Hi Russ,

Thank you for reaching out to us at the UNH Extension Infoline. I am sorry to hear that squirrels and other animals removed all of the apples from your fruit trees!

I've reached out to one of my coworkers that has a specialty in fruit tree production to make sure our answers align. It is unfortunately a very tricky question to answer with a great resolution plan!

We both have concluded that your best option to try to prevent squirrels and other animals from climbing your apple trees/eating the fruit is to collar the trees.

"Keep squirrels from climbing trees by installing a 2-foot-wide collar or metal 6 feet off the ground around the tree, or using 2 foot sections of 2-3 inch pipe over utility lines (consult the electrical company for assistance if placing sleeves over electrical wires)." https://extension.usu.edu/planthealth/schoolipm/structural-pest-id-guide/tree-squirrels#:~:text=Keep%20squirrels%20from%20climbing%20trees,placing%20sleeves%20over%20electrical%20wires)

We would not recommend trying any sort of electrical line as an option, either. My coworker shared that the squirrels would likely not be well-grounded when/if they touch the wire. The safety hazards involved with the electrical wiring and fruit trees is not something you'd want to mix.

Regarding the damage and timing of damage, he also shared that he has seen this squirrel damage increase during drought years, which we have been in one for much of the season.

One other method you can try is testing different type of repellants that are on the market for this purpose. 

https://extension.unh.edu/resource/nuisance-wildlife-around-home#:~:text=May%20be%20deterred%20by%20wire,eight%20to%2010%20inches%20high

I hope this information helps! Have a great rest of your week!