pin oak growth damage

[mrs.nospam]

I have a 3 year old pin oak which has shown some strange growth related trunk and limb damage. A local nursery (Pike's) said I should trim the branches in the spring if they then don't produce leaves. Here are the pics:

believe it's even gotten much worse since Aug 28th when these pictures were taken. I live right outside Atlanta, Ga and we've gotten TONS of rain this year.

Should I just prune these branches right away? Is there harm in waiting until the spring and seeing if they can be salvaged? I absolutely love this tree and I planted it myself, I get so many comments on how beautiful it is.

Thanks, Mark

[paghat]

Cracked bark can be caused by growth spurts; a small amount of such cracking would not be unhealthy. It can also be caused by rapid freezing & thawing, which need not be a threat to the tree's overall health. Cracking can also go deep into the wood, structural damage caused by wind or being knocked into by other trees that were felled against it, or started from shrinkage during drought. A tree can live quite healthily with such cracks but will be more susceptible to blow down when it gets really large, plus the cracks can provide ingress to borers or sap eaters, or permit pockets of decay.

Pin oaks are susceptible to canker diseases Phytophthora or Botryosphaeria, pretty much untreatable especially when it shows on the trunk & can't be trimmed out; but if there is no attendant oozing of darkened resins, and/or branch tip-death, it is not likely such a pathogen. Trees ill from wilt fungus will also exude copious amounts of sap; many leaves will show "half leaf syndrome" drying out on one side of a leaf only; with severe summer bronzing of leaves; & you may detect a fruity smell from the crack which is the wilt fungus's odor. In areas where oak wilt is prevalent, sap-eating beetles enter these cracks & track in fungus that causes overall wilt & death.

There are sap-depleting pests such as scale which can cause bark cracking, also with stunted, yellowing, or dead leaves, & overall tree weakness. Wood-eating borer infestations can also cause it, but you would be able to spot the exit-holes.

Sick trees will often have a really great year of producing excessive numbers of acorns trying to reproduce before dying.

But there's every chance the tree is not having any actual problem but is just outgrowing its outer layer of bark & callousing over the cracks. You need to first establish a specific pest or pathogen before treating a tree, & if there is no problem, but only growth causing bark cracking, you wouldn't want to stress the tree with any unecessary treatments of any kind. It might be worth an hour of an arborist's time to get it right; an arborist can cause about $100 for one hour of help & you'd get a good prescription for ongoing care far more reliable than what some random nursery owner or worker guessed.

If pruning is all that is called for, the best time is mid-summer or early to mid winter; spring or autumn pruning will further injure a stressed deciduous tree.