I'd like some help determining if it is worth it to clean the wound and try to save the new trees or better just to replace. I'm starting a small espalier garden and planted two apple trees last fall but failed to put screens around the trunks and they were chewed on quite significantly. Neither tree is girdled, but the larger one (first picture) has a vertical strip of bark remaining that is probably a little less the 25% of the circumference. The small tree (second picture) has about 50% of the circumference remaining.
Since these are still young trees it will be much easier to replace them than to wait a year or longer to see if they will survive. This is significant damage and even if the trees don't die right away they will struggle for the rest of their lives.
Trunk protection can, and should be used for the first few years of the tree's life - summer and winter. Just make sure that the protection isn't rubbing, or becoming too tight on the bark. There are many commercial products available, and lots of do-it-yourself ideas on the internet.
I hope this is helpful. Please contact AaE again if you have further questions.