AusBonsai

Which species is most susceptible to branch die back....................

I had a few Taiwan Maple which suffers severe branch die back after profuse flowering.............

BTW, how to prevent branches die back?

There are a few trees prone to die back like willows and tamarisk and some that will die back if you prune at the wrong time of the year like some prunus varieties. If you are having problems with any make sure not to prune after mid summer.

... and make sure you immediately seal the wounds after cutting back the branches! Die back is often caused by a fungus disease, especially where maples are concerned. However, it applies to other deciduous trees as well, e.g. flowering fruit trees.