After doing some research on snags (standing dead trees) I'm leaning towards letting the snag stay. This one is on the short side, but it might still appeal to wildlife -- and I don't have anything like it already. There are some high dead branches left for woodpeckers and raptors to enjoy, but not a big dead upright trunk. If I had some friends to help reduce the fallen tree to its usable parts, I'd save a section of trunk for a fallen log, but that probably won't be feasible with hired help. Ah well. I can still cut a wand from the upper branches, plenty of which are in decent shape. I may be able to cut a thicker section of pole for a climbing vine.
Remember we talked about sunlight? The fallen tree has opened up about a third of the forest section to substantially more light, including several saplings that I planted some time ago. They will probably grow faster now. (That's a normal response to falling trees in a forest: nearby saplings scramble to plug the hole.) The forest is also in the process of creating a dense verge at its border with the south lot, mostly using tree seedlings. That could use some care to fill it in with more useful species, although part of it is gooseberries and black raspberries already.
Here are some articles that I found on the topic of standing dead trees (whole or partial) and their role in a forest:
"Protect a Fallen Log Habitat"
"Save a Snag for Wildlife"
"Snags, Coarse Woody Debris, and Wildlife"
"Snags and Den Trees"
"Snags and Downed Logs"
"There's Life in Dead Trees"
"Turning Deadwood into Homes for Wildlife"
"Wildlife Management Guide: Snags and Downed Logs" (with species lists)