Hi, 

 You can refer to our webpage on Ornamental Cherry Trees, Abiotic Problems for Ornamental Cherry. Gummosis is a secondary problem that is usually due to boring insects or mechanical or environmental damage. The tree responds to the 'injury' by producing more sap. 

Before you treating or spraying anything on trees, shrubs, flowers, you should look to see what is causing the stress response first to determine the best approach for care. You can try to investigate and see if the tree has borer holes or look for 'sawdust' frass (insect poop) being pushed out of the borer holes along the tree or at the base about 6-8 inches up from the ground. Borers in cherry might be near the trunk base but can also occur higher in the trunk or even in larger branch bases.

It's hard to tell though what the original cause of the damage was, as it likely began one or several years ago, even if it wasn't creating obvious symptoms at the time.

Unfortunately, you probably should not have removed the degraded/split bark, as now the underlying wood is even more exposed (even though it's dead or nearly so, it's now more exposed to the weather) and the dead bark if left in place would not have hurt anything because the tree (if it's able) can compartmentalize the live wood damage from within, walling-off the ability of wood decay to advance further into the inner wood. Probably best not to remove any more.

This compartmentalization doesn't always work or if there are too many wounds for the tree to seal before decay becomes too advanced, so it's not a given that this inner process is going to be enough to keep the tree alive.

The roots are growing from callus tissue that (normally) would be sealing-over a wound
if cutting away damaged bark (rarely recommended) was done improperly, then injuries to this callus tissue can occur which will prevent the wound from closing-over (this does not mean, though, that wounds should be coated with any type of sealant. sealant can hinder air flow and actually trap any infection in the tree). We're not sure why roots developed here but it's not likely those roots will remain functional for long since they're not reaching soil and now that the bark they were under has been removed, nothing is left to retain moisture and humidity to keep them alive (not that their presence should be encouraged, because they're not "normal" roots).

The tree can't be treated for whatever serious issue it currently has (borers, infection, or wood decay) so really what you can do is to enjoy it while it lasts, since it is still flowering and leafing out!

You can seek the opinion of a certified arborist but we expect an arborist will similarly say there's not much that can be done, and any pesticide or fungicide treatments will not cure anything existing...at best they'll just delay the spread of damage but even then are probably not worth the expense given how much significant damage is already done; a consulting arborist that isn't employed by a tree-care company may have the most unbiased assessment of what can be done.

We can't predict how much longer the tree will survive, but expect at the very least that the exposed area of wood decay in the photo will make it more vulnerable to storm breakage at this spot on the trunk. 

Also some information about ornamental cherries that is on the diagnostic page as well: 

Cherries tend to have shorter lives when grown as ornamental trees. Their lifespan is about 20-25 years.

• Anything that stresses them may encourage insect (especially borers) and disease problems. Stressors include drought, physical damage to the trunk, compacted or poorly drained soil, defoliation, winter damage, poor planting stock, etc.
• Do not apply mulch too deeply. Mulch should be no more than 2-3” deep and keep it 6” away from the base of the trunk to prevent vole damage, borer problems, and trunk diseases.
• Prune out water sprouts and root suckers.

Sorry for the grave answer, but when its time to replace the tree feel free to contact us for help with suggestions of a flowering native tree that would add environmental benefits and still create curb appeal for your home!

Emily