Weeping Tree

Question:

 My tree trunk was oozing like a weepy sore does. I just looked at it again and now it isn't wet but the bark when I try to break a small piece or pull on it, sounds hollow and breaks easily. The tree is huge and the branches and leaves are in good condition being that they are green and growing.

Minnesota Master Gardeners say:

 Since the tree is green and growing well, it might have a phenomenon called "wetwood". The most noticeable symptom of bacterial wetwood is liquid weeping from wounds in the tree bark. This liquid ooze is known as "slime flux". During warm weather, the bacterial activity increases, resulting in increased gas pressure, which forces moisture out cracks, wounds or branch crotches. Flux activity may start and stop from time to time. It is not fatal to trees and most trees live to a ripe old age with it. There is no chemical that stops or controls wetwood. Avoiding unnecessary wounding of the bark helps the most. Keep the tree growing well and free from unnecessary stress, may also help. Aerating the lawn area around the tree, fertilizing in spring and watering during dry spells at one inch a week helps keep the tree healthy.

Check this Yard & Garden publication:
http://www.extension.umn.edu/projects/yardandgarden/ygbriefs/p441wetwood.htmll