i have a single fairly large pecan tree in my front yard that is quite healthy but bagworms are forming scattered thru out the tree. should i be doing something about them and if so, what??

The time to act is before the leaves come out, around March. Put beneficial wasp eggs (get from any organic nursery) on a pin and stick it onto the tree trunk. Do this once a week for several weeks. they will hatch and take care of the tent caterpillars before you can really see them. If you can reach any of the "bags", cut them down and tear them open. You may be surprised to see hungry wasp go for them immediately. If not, spray them with orange oil for a quick death.

thanks, I will give it a try

At this point dust with BT worm killer. It is a bacterium that kills caterpillars. For the long term, do everything you can to encourage paper wasps to build nests in your eaves. They will forever take care of your caterpillar problems.