This type of sap oozing is called gummosis, and it can arise from a variety of sources -- general tree stress, wood-boring insects, and infections by bacteria or fungi. They cannot be treated because a fungicide or insecticide will not be effective at this point, though you can try to carefully scrape off the sap to see how often it returns and if it takes-on any different characteristics. (For example, borer-caused gummosis tends to have particles of sawdust in it, and bacterial-caused gummosis tends to smell bad.) Do not injure the bark in the process of removing the sap and do not use any type of coating or sealant on any wounds. Sap flow is one way a tree tries to defend itself from pests and pathogens, by smothering them or pushing them out of a hole in the trunk, though it doesn't always work.

Depending on the reason for the trunk wrap we see in the photos, you should probably remove it because you don't want to constrict growth or give wood-boring insect adults nice sheltered spots in which to lay eggs. If it's padding for a stake tie, the tree shouldn't need staking any more. For now, keep monitoring the tree for watering needs, as cherries are both stressed by drought and notoriously intolerant of soil that stays too wet, either through over-watering or poor drainage. Feel the soil about six inches deep in the root zone and water well only when it's becoming relatively dry to the touch at that depth.

We can't tell from the photos if this is an edible cherry or an ornamental (flowering only) cherry, so you can explore the resources below for potential problems with each. (There will be lots of overlap because they share a lot of vulnerabilities.)

• ornamental cherry diagnostic page
• cherries -- a collection of links that include individual pages about pests and diseases

If this gummosis winds-up being due to environmental stress and not a pest or disease, the tree may recover on its own in time. If the sap flow ceases and the canopy continues to look normal (you may need to wait until next year when it leafs-out again to check this) then the situation may have resolved itself. Any preventative pesticide choice that may be warranted for future issues will depend on whether this is an edible or decorative cherry. Edible cherries are high-maintenance and usually require regular treatments throughout most of the growing season each year in order to keep trees healthy and productive; ornamental cherries do not and, if they are too vulnerable and routinely stressed to the point of dieback, they should simply be replaced with a different type of tree instead.

Miri