Causes of sap oozing on trunk

[mikewhite85]

I see this often, particularly in conifers. It seems that if can be a result of:

Drought
Overpruning
Cambial wounds
Borers
???

What is the science behind this and what other causes are there? A took a very quick skim through Shigo's A New Tree Biology and nothing jumped out at me.

It's obvious why sap oozes in regards to wounds but why for other reasons?

 

[Iustinian]

is it sap, or those big gooey yellowish popcorn looking masses? If you're talking about the big yellowish popcorn looking stuff then it's Zimmerman pine moth.

 

[2dogs]

This is pine pitch canker, a fungus. It will destroy 85% of Monterey pines by 2015. Horrible stuff.

 

[scaramuccia]

nice pic

This is pine pitch canker, a fungus. It will destroy 85% of Monterey pines by 2015. Horrible stuff.

also bad for scotch and austrians is pine wilt nematode -- in our area anyway. Often misdiagnosed as a fungus though by "arborists" who dont know

 

[Iustinian]

This is pine pitch canker, a fungus. It will destroy 85% of Monterey pines by 2015. Horrible stuff.

what area are you seeing that, and what is the best control for that? (time of year, product, etc.)

 

[beastmaster]

The type of conifer and location of the sap can tell a lot. Pine Canker normally has a lot of sap like in the pictures posted. There are whole areas out in Newport beach where its infecting stone pines. If its coming from branch unions or pitch tubes its probably borers or mites. Here in So. Calif urban areas most of our pines come from other places, Spain, Italy , Canary islands and didn't suffer to much from beetle and borer infestation. But in recent years pest from these places have found their way to So. Calif. and are becoming a common killer of ornamental conifers Some others just feed in the branches and drip sap.
Out your way the red haired borer has started getting a footholed and being a real problem. That is why you shouldn't trim conifers during the summer months while these pest are active. A fresh wound is like a dinner bell. Its very comming to see a pine that was trimmed in the summer, dying next season. Other times the tree if healthy can fight off the attact, and one way it does this is using sap to push them out. Oh did i Mention woodpecker?
Hope all is going well with you Mike.