Why is Black oozing tar like sap coming out of my maple tree trunk? - Ask Extension
Why is Black oozing tar like sap coming out of my maple tree trunk? It showed up about 4 weeks ago. It's hard now. It's only on the shady side at the...
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Why is Black oozing tar like sap coming out of my maple tree trunk? #814286
Asked October 14, 2022, 9:09 PM EDT
Why is Black oozing tar like sap coming out of my maple tree trunk? It showed up about 4 weeks ago. It's hard now. It's only on the shady side at the ground level. There are no holes in the sap or signs of a boarer like our pine trees had. I had treated those trees and this one with Bayer bush pesticide for the last 4 years except this year. Is it a desease or drought stress?
There is also a cluster of small 1/4" dia. holes about 30" directly above it that may have been caused by woodpeckers. The tree is about 13 years old and looks otherwise healthy. It's planted over a French drain which soaks the roots half the year and has a lawn sprinkler hit it the rest of the year, 3 days a week. We live in Tigard on the boarder of Portland in a residential area. There is a small grassy area on the other side of the fence.
Also is it too late to cut off the lower branch because of it's size.
I wonder if the tree would be healthier if I thinned it out. It's coming over into the yard and looks like it would some day break off, if it lives long enough.
Thank you,
Kevin
Washington County Oregon
Expert Response
General advice for a leaky or oozing tree is this, from Iowa State.
I see evidence of some decline in the tree crown, and circular roots possibly causing girdling issues in addition to the severe oozing area. A certified arborist hired to make a site visit for your tree can provide safety information for your home and the tree.
I also note that occasional deep watering of landscape trees is recommended. The shallow lawn irrigation isn’t helping the tree roots. Here’s a newspaper article featuring OSU Extension, and this Department of Forestry page from Oregon, have good information. Your trees are planted very closely, so proper watering will allow them to grow longer in these locations.
I see evidence of some decline in the tree crown, and circular roots possibly causing girdling issues in addition to the severe oozing area. A certified arborist hired to make a site visit for your tree can provide safety information for your home and the tree.
I also note that occasional deep watering of landscape trees is recommended. The shallow lawn irrigation isn’t helping the tree roots. Here’s a newspaper article featuring OSU Extension, and this Department of Forestry page from Oregon, have good information. Your trees are planted very closely, so proper watering will allow them to grow longer in these locations.
I was asked to comment. We have seen this before here on the OSU campus. In that case we did get Phytophthora out of the lesions. Interestingly, the tree is still there and looking ok except for the back in that area that has soughed off. You can see images of it here:
https://pnwhandbooks.org/plantdisease/host-disease/maple-acer-spp-phytophthora-root-rot
Main thing is to not let the irrigation water hit the tree trunk. Put up a shield to protect that area or change the water pattern. Hope it does well in the future.
https://pnwhandbooks.org/plantdisease/host-disease/maple-acer-spp-phytophthora-root-rot
Main thing is to not let the irrigation water hit the tree trunk. Put up a shield to protect that area or change the water pattern. Hope it does well in the future.
