northern country guilds

In the north country (zone 4), some of us start hardening off our fruit trees by late August -- meaning that we don't want to disturb soil (eg., pulling roots or tilling) or water the plants within an area that contains the rhizosphere of any given tree. (We don't want to stimulate microbial activity.) Thus, for 2 months or so, these areas are not suitable for growing annuals. As the trees mature and the rhizosphere expands, this area grows and adds up to a large area considering all the trees in a food forest garden. Do you have any suggestions for coping with this use-conflict?