Question
Dear Jim...I planted 50 Nutall Oaks on my place two years ago. I have done
my best to keep them watered and properly fertilized....they were about 10 ft
tall when I planted them. I lost about 16 of them the first year and replaced
them last Jan. I am still experiencing some problems with some, and have lost
about another dozen this season. We have had fair to good rainfall this
spring/summer, but I have continued to water them when necessary.
The ones that are unhealthy show a darkening on the bark. No lichens
present...just a sort of grayish black color on the bark, and in some cases the
bark is peeling. Some of the healthy trees have a nice dark green color on the
leaves....but many are more of a yellowish color. Any ideas? Thanks, Chuck
Leavell

Answer
Sounds like a problem with the root system. There are a lot of unknowns here such as-type of soil, how they were planted.
Clay soils tend to bind up nutrients and the roots can not receive the amount needed to grow--this shows up in the yellowing of leaves. If a tree is planted too deep the tree will start to die back. The proper way to plant a tree is dig the hole twice the size of the root ball and as deep and keep the top of the root ball at ground level. Fill with good top soil or potting soil. For heavy clay soils dig the hole 3 times the width of the root ball.  Mulch around the tree with not more than 3 inches deep of organic mulch not piled up on the trunk. Not much that can be done to correct this unless it is too deep then removing some of the soil around the trunk will help.

What can happen in clay soils is the hole is dug the size of the root ball and the sides of the hole are smooth and this makes a "pot" in the ground and the roots get root bound and can not spread out. If a tree dies dig the tree up and look at the roots -if there is little roots past the original root ball this is a sign of this being root bound.

I would fertilize the trees with 10-10-10 at a rate of 1 lb per inch of trunk diameter scattered around the tree and watered in good. This should encourage root development.

It is very difficult with out seeing the trees and the growing situation to give a precise answer. I would suggest you call the local office of the State Forestry agency and ask one of their Foresters to come take a look. This is a free service and they should be able to either help themselves or give you the name of someone local to call.