I got some advice here in the past from Tapla about the best medium for growing fruit trees in raised beds. I followed his suggestions for the mix, and my trees are now growing well in the raised beds, but one thing that was never discussed in that thread was mulching. Thusfar I have not mulched my raised beds but I've watched a few backyard orchard videos recently which strongly encouraged mulching for its ability to retain moisture as well as benefit the soil system below as it breaks down over time. Should I be applying mulch to my raised beds containing fruit trees, and if so what is the recommended amount? (I am growing each tree in a 4x4 raised bed, 12" high).