What is a fruit tree guild?

A guild is a group of plants around a fruit tree, each with a job: white clover fixes nitrogen, borage or comfrey are cut and left as mulch, dill, phacelia and chamomile bring helpful insects, garlic or chives by the trunk deter pests, strawberries and nasturtiums cover the ground. Keep grass out of a 1 m circle round the trunk. Put a fruit tree on the plot drawing and the app reminds you in the plan.