27 May 2025
On my walks through Schenley Park I am often curious about the demise of sturdy trees. Why did this intact red oak fall?
The simple answer is that it blew over during the 29 April wind storm as did so many other trees in Pittsburgh. But a closer look reveals a weakness that contributed to its demise.
Looking at the root ball, there are no obviously broken big roots that would have anchored the tree to the ground and it appears that the trunk is hollow. Something “ate” the tap and anchor roots. When a big wind came the tree fell over. My guess at the culprit is the fungus armillaria or honey mushrooms.
Along the same trail I found this structurally compromised tree still standing. Only the bark, cambium and sapwood are holding it up.
Inside, the trunk is hollowed out by major insect damage. Now that the exterior is cracked it won’t take much wind to knock the tree over.
I’m always amazed when a tree snaps in the middle of the trunk. This black cherry fell over in May 2014 to reveal white sheets — armillaria — that weakened the tree.
Read more about it in this Quiz+Answer from June 2014.
.
.
.