Wanted to add one more thing regarding the use of Lime Sulphur, seeing this was brought up with this tree and the other tree posted..
For me I am not a fan necessarily of lime sulphered wood... but do see it's potential use. Often I will use it on trees to help add a different tonal value. A lot of trees I have their is not really a separation in these values between what is live and what is dead, so this helps to achieve this. Although when I do go to display a tree with it, I will often work this "whitewood" look down to something more natural looking, but still has the contrast needed.
During the times of not being shown, I will not bother to much with it's appearance due to the fact that it is not being shown. The photos of both these trees were taken during a time of the trees obviously not being shown.
I will apply sulpher even if eventually when shown the area might instead be completely changed in color to something more of a black, like in a uro... it is easy to adjust, takes very little time to do, and in the meantime, I have found that the sulpher often helps deter insects like termites and carpenter ants. Will not prevent rot.