I'll take a photo, but in the meantime....
I have a lot of bitternut hickory and some shagbark as well. I haven't yet noticed any on the shagbark, but about half of the bitternut have gall's. They get up to about 3 inches in diameter. Some tree's have just a couple, others have dozens and dozens.
A couple questions..
Is it a disease, or something caused by insects?
Is it terminal to the tree?
Should I cull all tree's with the gall, or just those showing decline, or none of the above?
Any advice is welcome!
A few of my bitternuts have some light gall, and the shagbarks do not. I believe it's fungal. It causes no harm to any of my trees that have it, and I have a lot of hickory that I've been harvesting for over 30 years.
Jerry, I'm interested to know if these galled trees of yours show normal grain in the stem. I have some bitternuts that are affected as well. I had not examined them closely before, but I recently felled one (about 11 inches DBH) and its bole had very contorted grain, with some small bark inclusions throughout. I would think that sawmills would not want to pay good money for the pleasure of trying to make merchantable lumber out of such logs.
Most of my hickory is cut/culled around 24 " to 30 " DBH and goes into my furnace. A few logs have gone to locals for furniture and flooring; they want more which says something, but are low volume buyers. What I see from their finished products, and what I see 18 inches at a time as I split it all appears good to me, but I'm no forester. All of the galls are on limbs, not the main logs. Again, I see no adverse effects from a little gall. In my situation hickory has more value as a heating oil replacement than as sawtimber. I estimate it replaces 800 or so gallons of oil each year while culling it releases the more valuable species.
Do they look like this?
http://www.forestryimages.org/browse/detail.cfm?imgnum=1470116http://(photo by A. Steven Munson, USDA Forest Service, Bugwood.org)
That is Phomopsis gall. The gall is caused by a fungus, and there are other trees and shrubs that can have Phomosis galls, and it's relatively common. When you have multiple galls on a branch you can have some twig or branch dieback, but as Jerry mentioned, that's about it for damage. Some hickories are genetically more susceptible, so you could cull out severely infected ones to increase the genetics in your stand. No "controls" are necessary.
You can read a little more about it at:
Pretty much. I would have posted a picture but my camera broke, and so am I.
The state forester for my area said to cull the heavily infested ones. Recently, a buddy of mine needed some hickory for his smoker, so I dropped a number of heavily infested ones. The trees seemed otherwise healthy, so I don't know if I would cull for that reason alone. ps. The smoked pig was awesome!
I've noticed galls on shagbark hickories. On page 149 of the 2nd Edition of Diseases of Trees and Shrubs by Wayne Sinclair and Howard Lyons there is a good picture of a bitternut hickory with several Phomopsis galls.