Hard to say with the limited info....how much are you watering? These are xeriscape trees and need little water, especially in winter.

Its probably just the change in the weather. I have 7 or 8 DM Palo Verdes on my property and the leaves on them I have noticed are changing colors. Its probably from the cooler nights that we have been having. I usually water mine once a week during the summer months, but will cut waaaay back in the fall and winter.

My 1 year old DM Palo Verdes are showing a little bit of browning also. I live in downtown Phoenix and just watered them deep a few weeks ago.

Palo verde are a deciduous tree -- they do lose their leaves in the winter, like mesquites. So this is probably just its natural time to lose its leaves.

Is it normal for the palo verde bark to go yellow during winter to spring?

We have two Desert Museum PV and thier bark doesn't change color with the seasons. Do you have a pic you can post? Also there is a kind of Palo Verde with yellow green bark but I doubt it changes either.

Base is green but the rest is yellow

@mojavemaria I added the photo if that helps at all. Thank you so much!

I‘m to say this but I think your tree is dead. you can start trying to bend the branches at the ends and if the are brittle instead of flexible start pruning back but I really think it is a lost cause. The good news is that desert Museum is a fast growing tree and a new one should quickly be a nice tree.

@mojavemaria should I just prune back to where it isn't brittle?

is everything else there leafed out? Here in las vegas every tree and bush including our palo verdes have leafed out. Are you in a high altitude area? If so perhaps your winters are too cold for this tree. If not the fact that this hasn't leafed out when everything else has points to its being dead.

you can feel the difference between a live and dead branch by dead by its being brittle and lighter in weight. Go ahead and prune but it just doesn't appear from your pic that this palo verde is alive.

@mojavemaria thank you very much for the information. We live at about 3,500 feet and get a lot of wind at times. Perhaps that contributed to it. Most all the other trees are leafing out. But the base of the palo verde is still very green.