These "tulip tree morels" were all found growing near white ash trees. This forest also includes plenty of tulip poplar, but I found none of these morels near the tulip poplar. Some years, all or most of these are found in the same forest near tulip poplar. I interpret this as an indication of how the fruiting of these small forest yellows likely depends upon the relative timing of the trees preparing to foliate, the soil temperature, and moisture level. This year the weather warmed and the tulip poplar started to leaf out, but there was no rainfall for about 10 days. The rain seems to have returned too late for the early-foliating poplar but in time for the late-foliating ash trees to stimulate the reproductive mechanism of this Morchella.