Q: I noticed this gelatinous mass on the trunk of my six-year-old cherry tree. Can you tell me what the fungus is?
A: Your actual condition is called gummosis, which is most often caused by stress.
From your photo I can tell what the stress is: your tree was planted too deeply originally.
When the trunk of a young tree comes straight out of the ground, like a telephone pole, I know that the root system is hidden underground somewhere below.
On a properly planted tree, I should be able to see the flare of the trunk becoming the root system a few inches above ground.
Planted too deep and unable to breathe, the roots gradually weaken and tree decline begins.