I wouldn't eat that syrup

:( poor tree. Thanks for the info, now I'll have to figure out how to save it if possible.

Probably slime flux (bacterial wet wood), not uncommon on maples. Attached is just one of many university based fact sheets regarding slime flux.

Maple syrup is made by collecting the rising sap in the late winter and boiling it down to a thick, condensed sweet syrup.

Bacterial wetwood information.

The foliage above the Christmas lights makes me think Maple.

The bacterial Westwood seems likely! I'm wondering if we had caused it. We've placed quite a hefty amount wood chips last summer to even out the area next to the tree. The wood chips touch one side of the trunk. It acts as somewhat of a barrier. They've begun to decompose on the bottom and middle layers. I bet we caused this tree harm now that I think of it. We will dig around the base, and place stone in between the tree and the chips. Unless the trunk looks like it needs to air out a bit. If so we'll leave it open for as long as we can.

Piling anything over the roots of a tree--even just 3-4 inches puts the tree at risk.

lacey, the use of a three or so inch layer of coarse wood chips, bark nuggets, or pine straw is one of the most beneficial things we can do for trees. Just avoid piling it against the trunk.

Kate, the bacteria can be introduced into a tree's system by many means: broken branches, pruning cuts, insect or animal injury, weedeater or mower damage, etc.

I'm not at all enthusiastic about piling rocks on the roots, though.

"I wouldn't eat that syrup"

LOL. When you kill a large poison ivy vine with triclopyr ester, a couple weeks later a black sap oozes out of it. Also, a syrup not to eat!

3 inches of the wrong soil over the roots of a sensitive enough tree could start to cause trouble. 6 inches greater expands the possibilities...a cranky neighbor of mine let his hayseed landscaper grade the root zone of a junky Norway maple with 4-6" inches of soil. I immediate warned him of the possibility of injury. "Oh no, blah blah blah knows what he's doing"...like, how dare I question the intelligence and knowledge of a landscaper working in the biggest backwater along the northeast corridor between Boston and DC. LMAO. Needless to say, the following summer, sections of the canopy started dying! It's still there though, over 5 years later...it managed to outgrow the damage. It's actually a shame it didn't die because the seedlings are a pest.

Bark is wrong for sugar maple -- looks like Norway maple.

Could this be the cause of the fungal infection?

It's not a fungal, but a systemic bacterial disease. Though the bark should be pulled well away from the trunk, it's not the cause of the problem. You need to look up, Kate. I see broken branches and improper pruning in your pictures.

Bacterial wetwood occurs everywhere, even in the middle of a healthy forest. It doesn't need human malpractice by any means.