Stem exudates on Acer and Tilia

[Paul Barton]

I came across two trees, a Field Maple and a Lime, both displaying similar black tarry substances on their stems. The two trees are situated on a patch of 'amenity' grass on the corner of a road in a residential area.

 

The black goo is mildly sticky and did not smell.

 

At first I thought perhaps localised fire damage but it wasn't sooty and the patterns were too random. Then perhaps a Phytophthora bleed as the substance is around areas of damaged or broken bark - however I normally note the fresh ooze is a red colour with Phytophthora, plus I've never seen it on Acer before.

 

I am intrigued as whatever it is isn't species specific and didn't appear to be 'abiotic' to use a nobby term.

 

Grateful for any suggestions....

[Tony Croft aka hamadryad]

look at the root re iterations, mower damage and mellea!

[Paul Barton]

Ah, thanks Tony. Is the black exudate a common indicator of honey fungus? I haven't made that link before.

[Tony Croft aka hamadryad]

Ah, thanks Tony. Is the black exudate a common indicator of honey fungus? I haven't made that link before.

 

very much so, though im also aware kretz can, and phtopthoras

[treeseer]

very much so, though im also aware kretz can, and phtopthoras

Yes, exudate can also be related to these and others, therefore exudate does not strongly indicate any of the above organisms. In any case, assessing the tissue is the first job.

By sounding the wood you can see if cambium is dead.

By scraping off (and removing!) exudate and probing dead areas you can learn the extent of the damage, and get a better idea of the cause. At the very least you'll be able to rule out vandalism!

[Paul Barton]

Here are the same two trees, two years on.

 

The exudate is now thick and gooey like black encrusted caramel. I have not seen exudates emerging in such a thick band shape around the stem. Any ideas?! I am thinking it must be a Phytophthora fungal problem.

[Jon Heuch]

Here are the same two trees, two years on.

 

The exudate is now thick and gooey like black encrusted caramel. I have not seen exudates emerging in such a thick band shape around the stem. Any ideas?! I am thinking it must be a Phytophthora fungal problem.

 

Paul

 

Are you aware of these:

 

https://www.pocketdiagnostic.com/onlineshop/pocketdiagnostic/phytophthora/

 

I am afraid I have never used one, although someone gave me a sample a few years ago. They have a shelf life and I never came across a situation to use them so they went in the bin.

[Paul Barton]

Thanks Jon. I've not seen those - probably worth a try.

[se7enthdevil]

whenever i've seen trees looking like that i've always thought that it was fire damage.

[Gary Prentice]

Thanks Jon. I've not seen those - probably worth a try.

 

If you go down that avenue, could you report back? I've seen these but never had the opportunity to use them.