What can cause bark split/cracks in this moonfire JPM? I planted this a few weeks ago. I noticed sever bark split in a few branches, I went ahead pruned those, now I noticed bark split in several other branches. can high heat cause this? The temps have been in 90s the past couple of days.
I agree with @Osoyoung, no action required. Old splitting or bites that is healing nicely. As to the cause, well that is possibly vermin of some kind having a nibble at the fresh shoots last season. But as this has not girdled them, the branches will survive. Mice are quite partial to fresh new shoots btw.
OK, then I think you have a vermin problem. Over here it's grey squirrels, but your area and the size of the wounds is something akin to mice damage. Check for any droppings around your tree or nearby. If it is mice then they are very persistent so hard to get rid of. A garlic spray is very good at deterring a lot of vermin, so that is what I would do. It doesn't look like borers btw.
Wound wood can clearly be seen attempting to scab over the wounds in some of the photographs. This is a long process and very unlikely to have progressed this far in 3-4 weeks. If the splits have only appeared very recently then it is possible that the damage in the cambiam layer was already present but covered by dead, dessicated outer bark that has now split as the stem swells in the growing season, revealing "new" old damage. If the wounds are on the sides of the twigs exposed to most sun, they may even be old sun burn injuries from last year.
