Friends are worried about their Acer palmatum ‘Beni Sazanami’ whose leaves look healthy and green on some branches but dried on others, together with dead branches (no green under the bark) and, at the same time, beautifully coloured fall leaves on most of the tree. They planted it about 4 years ago but it was quite large at the time. The thing that worries them the most is the development of blackening bark on many branches. Some we scratched show no green underneath. This has been an exceptionally dry summer here on Vancouver Island, BC and they worry that they may have over or underwatered it; personally I don't think so as it has fared pretty well up until now. I suggested to them that there's not really anything they can do but hope that it will bounce back in the spring. They're worriers though. Is there any consolation anyone can offer or do they have good reason to worry?