Question
Hi. Thanks for your good answer. A thin layer of
topsoil it will be for now. The browning patches
started happening right after the duff was starting
to be removed. They are actually a light green
compared to the rest and are dried out. This happened
right in the moddle of the midwest drought we just
went through. My brother, also, started pruning that
tree, and I thought that was a bad idea when rainfall
was a .1-inch for weeks at a time and the heat was
in the 90s. There are now about 3 patches of dry outer
patches composed of
about 1 or two branches of tree each. If I cut 'em
off, there is a obvious hole amid the otherwise nice
green branches. --I hope this info helps. Maybe to dump
gallons of water on the roots before the 1st frost?

Thanks, again! --from Max / Chicago


-------------------------
Followup To
Question -
Hello.
Well, of course our backyard evergreen is|
growing upward. It's about 20' tall...but ever
since we scraped away the old needles from
below it, surface roots are sticking up
here and there underneath the tree.

Question: Cover them all up with topsoil? --The
tree itself is browning in various small patches
along its side.

Thanks. --maybe evergreens aren't your specialty,
but I thought you'd know about topsoil and such.
--Max/Chicago
Answer -
Max,

That accumulation of needles under the tree is called "duff".  It's slowly breaking down and becoming soil again, so the roots of the tree take advantage of the situation, and start growing in it.

I usually don't clean away the duff.  It's providing insulation for the roots, and suppressing weeds in an area (under the tree) where very little else is going to be able to grow anyway, especially as the tree gets older.  But that ship's already sailed, so...

The roots that are exposed can be covered up with a light layer of topsoil, but keep it just thick enough to do the job.  Too much soil added around a tree can can smother the roots (they need air as much as dirt and water) and kill the tree.

If you don't want to bother with the topsoil, you can just let another layer of duff build up.  Until it does, you can just snip off the roots that are exposed.  It doesn't sound like they are of significant size.

The browning at this time of year is probably just the tree loosing it's needles for the fall.  But I'd need more information to be sure.

Mark in Portland

Answer
Max,

You are right.  Removing the duff during the hot, dry weather, might have allowed the roots to dry out suddenly.   But water now won't help very much.  It won't reverse the damage.  If roots dry out, they stop working, and if they stop working, the tree may have to shut off branches that those roots supplied.  Usually though,  drought damage, or damage to roots effects the whole tree, not just patches.

If the brown patches are not just natural needle drop, and the more you describe, I think it might not be, there could be other explanations, also.

I have seen both insects and fungus cause brown patches like you describe.

If it were insects, I'd see areas of the bark (usually where branches meet) broken or holed, and oozing sap.

If it were a fungus, I would either see tiny black (or white or orange) spots on the needles that have turned brown, OR a large round lump surrounding the branch behind the brown needles.  There are fungus diseases that effect pines (I don't know what kind of tree you have) that enter the tree only during hot dry weather through pruning cuts or other wounds to the tree.

For what it's worth,
Mark in Portland