Also, it seems that a common cultivating practice, especially for lowbush varieties, is to burn down the plants after every two harvest years! The plant then regrows more healthfully from the stem. I assume that for orla purposes this would still be considered the same “tree”, but it could have a “marit `ayin” effect as the tree would look new, even though it’s grown from the same stem that was in the ground for many years.

In my humble opinion, I wouldn’t be satisfied with asking an agronomically knowledgeable Rav; I would want one who knew the plants in question, and the history of the “orchard” under question, before making a decision.

Nonetheless, I fundamentally don’t understand the problem – since the stems produce fruits for many years, why can’t the growers just wait until the plants have had four halachic years? It seems to me that you could have an orchard divided into sections where the new plants are “l’kula” (lenient – treated as vegetables) and the old pants are “machmir” (strict – treated as trees). Then people who were concerned could go to pick in the “mehadrin” sections and be done with it.