Aesculus carnea pruning cuts ooozing white liquid

Today I had to prune off a 3-4" diameter branch from a Aesculus carnea that was hanging too low over the driveway.

After the cut I noticed a white, very thin, runny liquid oozing from the centre of the cut -- NOT from the edge of the bark. The red arrow points to the centre and the source of the ooze. The red loop shows the ooze running down from the branch collar onto the trunk.

See attached photo - apologies for blurriness as I had to zoom in from ground with a low quality lens.

Can anyone suggest what this is?

 

The heartwood stain might be taken to indicate there is a decay problem developing. If that is a fork above the cut perhaps there is a chronic opening in the bark where the two trunks are in contact, which has admitted decay agents.

 

http://www.mobot.org/gardeninghelp/plantfinder/IPM.asp?code=143&group=21&level=s
Bacterial Wetwood