I have been contacted to care for some construction damaged trees.

There is a large red oak (Quercus rubra) that is showing unusual colouration. Some of the leaves, not all, are a deep red/brown colour on the upper surface and a green colour on the underside. There are groups of unusual coloured leaves and normal leaves on the next twig. The green is not as dark as I would expect, but is by no means chlorotic. The veins are green.

I have grow gunned the tree as well as applying sulphur and fertilizer. After one day the leaves (well some) are changing colour to green.

Does anybody have an idea of this "disorder" and treatment methods. I think that chlorophyll is not present but why?

Michael

Reply to post by Michael, on June 12, 2002 at 19:17:03:

Michael, have you done a soil test? Whenever you suspect a nutrient problem, and in fact before you fertilize, you should get a complete soil test, including micronutrients. Cost is not much, and its well worth it to know what is needed instead of just throwing stuff at it. (A300 recommends tests first before any fertilizing)

There is a protocol for diagnosis of this type of problem. Work though the problem, eliminating the possibilities. Don't treat until you know what you're dealing with. It gets costly, and may make the problem worse instead of better.

Reply to post by Michael, on June 12, 2002 at 19:17:03:

The coloration may be explained to a degree in some of the articles I found in a simple search using Google. I wonder if it may be mostly dryness that causes the oaks in question to be this color. Perhaps water stress combined with sudden heat? Has the area been under drought conditions? If this is the case, I would expect sufficient water applications to have some positive results.