weed free lawn in first pic... what are you using on it.. and it appears there is not a mulch circle around the tree ..

where are you.. and how much drought and high heat have you had ... and how do you water the trees??

im thinking there is a combination of things happening ..

oh.. and how about a pic of the whole tree ... im thinking they are pretty small

ken

I am north of troonto. There are weeds in the lawn just not around that tree as ive been diligent about pulling weeds. why do you ask?

Everything I've read so far indicates chlorosis, with the oak experiemcing advanced stages. Now white oaks are not comming here, but sugar maples are everywhere - it is our national tree! And they are healthy all around me.

Yup. They have some sort of deficiency. Whether that's iron or magnesium or something else I'm not sure. It can be caused by high ph or super soggy waterlogged soil. So I guess make sure that the moisture is perfect and maybe do a soil drench with cheleated iron. That's all you can do, but honestly it doesn't look good. Seems like they should be able to grow if you harvested them from nearby.

Definitely NOT soggy soil both dry spots. its weird - i habe a few other plants showing signs of .chlorosis..

can this be corrected with sulfur ? is the oak a gonner??

Yeah, what tsuga said. If this is a recurring problem it would sure be nice to know what it is. imo, it's likely iron or magnesium deficiency caused by high ph. I would try the chelated iron. It's an extremely temporary fix, but what the heck, right? If the plants perk up you'll know it's that.

I have heard that it is extremely difficult to lower the ph of soil. Especially so if there are sources of high ph material in your native soil, like limestone. I think it can be done with say potting soil if you want to grow blueberries in a small area, but on a large scale I've been told almost impossible.