i have red oaks in bak yard, all ~18 years old. two still bear many leaves while one is almost bare. why?

Question

soli should be same, it was all brought in from same source.

Answer 1

If you refer to the brown leaves held still on the tree in January (Northern Hemisphere), then don't worry about it. It is genetic variation in the trees.
If you refer to the number of green leaves produced in the spring and remaining until fall, your third oak has a definite problem. Without looking closely at it, it would be difficult for me to diagnose the problem. If it was planted by a landscape company 18 years ago, the very first thing I would do is pull back the mulch and the soil around the trunk and see if a strap, wire, string, or root is girdling (choking) the trunk near or just below soil level. If one is, cut it loose immediately and the tree may return to normal. Regardless, I would call a professional tree service to look at it and diagnose it. Ask them, if nothing else, to do a injection of mycorrhizae. That is good stuff, and often brings trees back from the brink of death.

Answer 2

Sometimes trees, flowers and bushes contract certain types of Fungus's and diseases. Try spraying the bare tree with an antifungus Spray. You may have to apply several times before it does the trick.. Good Luck, now go save that tree :)

Answer 3

Some experts will tell you, the ones losing leaves early are sick. Others will say, they catch more wind. Watch them next season and if their leaves are smaller, you might have a problem

Answer 4

winter hit it hard.