The problem with clay soils - rain or drought

Okay. I expect this to be a bit of a test of the mound approach to planting apple trees in my area of poorly draining clay. The remnants of Ian gave us a fairly evenly dispersed 6"-ish of rain over the last 4 days. I expect the ground around the mounds to be squishy for another 2 or 3 days while things dry out. Although the temperatures have been much lower than in summer (highs only in the mid 60s), the trees are certainly not dormant and some, like Bramtot, were still putting out a few leaves. So… what signs of root rot might one keep an eye peeled for in mid-October? Any thoughts?