kinda sounds like a waste of our time.  sorry to bother you.  

Hi Tim, the Ask Extension system has been a little glitchy recently. Sorry for the delayed response. We’d like to help you with your boxelder.

It looks like your tree may be affected by a leafroller. The curling sounds like it might be boxelder leafroller. I can't tell exactly from the photos. You may also have some boxelder bug activity. Are you able to bring in a sample to our office at the Mesa County Fairgrounds? We're open 8am-5pm. Generally speaking, the trees should push out another set of leaves (if necessary) and recover without any intervention. You can use horticultural oil next late winter/early spring to target eggs, if you like. (Insect Control: Horticultural Oils (Fact Sheet 5.569))

Without seeing more of the branch, it is hard to say what is causing the sap to run, staining the branch. Boxelders do run a lot of sap in the spring, so if there was something feeding on a twig, that could cause this.  

How do the trees look overall? If you can upload photos that show the whole tree(s) in their setting and photos where the base is visible, that can help give us the big picture. 

Be sure to keep the trees as free of stress as possible. Our biggest source of stress is water (too much, too little, wrong place, etc., so be sure the trees are receiving adequate water, where and when they need it. Below are some resources on watering:

Watering Mature Shade Trees (GN 657)

Fall and Winter Watering (Fact Sheet 7.211)