Some types of trees make a habit of leaking sticky resin all over the place, and active dogs can have a thoroughly enjoyable time getting covered in the stuff. Dealing with the gluey combination of tree sap and dog hair is unlikely to be your idea of fun, but it is usually doable.
WOW! Easy Way to Get Tree Sap OUT of your Clothing! This really works! I had tons on a couple of pairs of pants (jeans & sweat), & the stuff worked like magic & so quickly. On the jeans, a couple of spots had to be done twice, but it really was so easy!