Vine maple leaf corky "trails"

Asked June 8, 2019, 10:00 PM EDT

I'm in the rural Cascade foothills outside of Oakridge at 2300' elevation, and one of the many vine maples on our forested 2 acres has this pale green corkiness running through its leaves. It's the only one with this issue. Is it a pest, a disease, or what? Do I need to take action to avoid it spreading? It's near where a fir was beetle- killed that we had cut down a few months ago.

Lane County Oregon

1 Response


I believe if you look under a hand lens, you should see crystalized sap.

The leaves were growing very fast three weeks ago, splitting the epidermal layer of the leaf and the sap began to leak out. I have seen this only once before but in looking under the microscope, the sap is very crystalized and dried to the leaf.

The weather about three weeks ago, plants were growing like crazy and caused a lot of leaf cracks, splits and breakage on many plants. The sap leaked out and is trying to heal where the leaf epidermal lay is probably cracked or split open.

Nothing needs to be done other than enjoy this weird /rare situation.