The fallen tree here is, I am almost certain, a red oak I watched fall on a windy afternoon between 1994 and '98 in Wingra Woods, UW Madison Arboretum. I returned to it last week to get a sense of what 25 years of decomposition looks like for a red oak in an upland oak forest, north-facing slope, south-central Wisconsin.
Lake Wingra in the background, with white and red oaks and planted sugar maples.