Took me 6 hours to diagnose a lightning strike on a single white oak in Raleigh

I was out on a job last Tuesday where this big white oak had a weird crack running up the trunk but no sign of rot or insects. Turned out there was internal damage from a lightning strike that happened like 3 months ago, and I only caught it because I happened to look up at a funny angle. Has anyone else spent way longer than expected figuring out what's wrong with a tree that looks mostly healthy?

2 comments

2 Comments

johnson.lee4d agoMost Upvoted

Crack the bark open with a pocket knife next time you see a weird vertical seam like that. If the cambium underneath is brown or black instead of green, you've got lightning damage even if the tree looks fine from 10 feet away. That internal electrical burn can take months to show up on the surface. I've started carrying a small moisture meter too, dry spots along the trunk line are a dead giveaway. Saves you the headache of staring up at a tree for half a day wondering what's wrong.

uma_lopez4d ago

Johnson from Raleigh Arborist Society actually showed me a white oak last month that had a perfect lightning scar on the outside but when we cut into it the cambium was totally green and healthy underneath, so the pocket knife trick isn't a sure thing every time. I've also seen trees where the dry spots on the trunk were just from old pruning wounds healing over, not lightning. The moisture meter gives you false positives if the tree has any kind of bark damage from lawn equipment. I don't carry one anymore because I spent two hours chasing a dry reading that turned out to be a string trimmer scar from two years ago. Visual inspection from multiple angles and looking for that specific spiral crack pattern has been my best bet, and even then I still miss some.