You will not be able to root the entire (whole) thick branch.... do take tip cuttings of firm new growth. at lest 3 nodes and 4 inckes long apply 1-2 % IBA (rooting hormone) stick in well drained soil & mist taking 6-8 weeks to root.

Did you check for any life anywhere in the bark up and down the tree? You can use your fingernail and check for any green, but actually with Japanese maple you can see if the tree is alive as it goes from green to brownish-red where it is dead. If it has any life, you might be able to save it but may need to cut it back quite a bit and protect from direct sun. We had two in a pot on the deck that burned and leafed out again when moved to our garage to recooperate. Good luck, let us know what you find out.

I pruned it last night, took a couple of hours. Still could do more but it looks much better (it's hard to reach the higher branches). What kind of ladder do you use to trim something like this? I have an 8' stepladder but can't reach the middle/highest areas. Any other recommended cuts based on photo, let me know. About the green meatballs (boxwoods) - my whole landscaping is being changed in about a week. That is why I posted - the JM was slated to go (replaced by miss kim lilac but I can't bring myself to like that). In that area underneath the tree will be huechera, coreopsis, hydrangea. New landscape lighting/wiring. I don't know if what is planned will "relate" to the JM though. The whole area will be much more filled in with plants and rock mulch replaced with hardwood mulch. I will ask my landscaper about the Hokone grass. He is already being driven crazy by me as I've changed my mind about things a gazillion times.

Not sure there is a lot you can do for it at this point. JM's are prone to a variety of soil pathogens that can severely damage or even kill the tree. This one looks like it might be dying a slow death :-(( What I would suggest is getting rid of all the rocks - they are not helping and could be hurting the tree. And carefully prune out all the dead wood you see. It will be a pale color, often gray, compared to the dark color of healthy tissue. Dead wood tends to harbor insects and allows an inroad for other disease issues. Then just keep the tree adequately watered - not too much, not too little. Just don't allow the soil to dry completely. And no fertilizer!! If the tree does not respond or seems to get worse, then it's time to contemplate removal. But I would be cautious about replanting with another JM until you can confirm what caused the problem (and that may involve a path lab analysis), as some of these soil pathogens will infect any other susceptible species planted that space. Going forward, you might want to post any other questions you have about Japanese maples on the Maples forum. This one is pretty much inactive and most JM enthusiasts post there.