Can you post a pic or two? If you're not sure how, please let us know and I am sure someone will be happy to help you.

I just took a picture of one of the plants with my camera phone in fading light. I posted it in the Gardenweb galleries but it automatically increased the resolution, which makes it look a bit blurry. If you wanted to save it to your desktop and use any graphical application to decrease the magnification (by zooming out), then you should be able to see what I am talking about.

Maybe it's completely natural for the plant to do this, but I don't know.

Here is a link that might be useful: My Red Emerald

Browning on the inside of conifers is completely normal in the fall - especially on newly planted conifers. Keep the plants well watered and maybe protect them from the winter sun during their first winter (depending on the zone you live in.)

Please note, the correct spelling of the cultivar name is 'Smaragd'. That will help with online searches for info.
Mike

Thanks Mike. I was hoping that this was the case. I read on this site about the browning of conifers in the fall but Thuja Smaragds were suppose to keep their color so I presumed that something was going on.

By the way, how do you pronounce "Smaragd" (phonetically).
Is it Smar-agg-ed?

When did you first notice the branches turning brown ? There has been some problems with aphid attack on Thuja occidentalis in the UK this year, grab hold of the inner branches rub your hand up and down inside the plants, if you hand turns a bit sooty and black looking, it's probably aphids.
Bluespruce.

Yes, that's how I would pronounce it. 'Smaragd' is Danish, I believe, for Emerald' so it's easier to simply call them Emerald Arborvitae (the common name in America). (:o)
Mike

The -gd in Smaragd in Danish is nearly silent, just a glottal stop; the -r- is rolled.

Not easy for a non-Dane to pronounce accurately!

Resin

Reddish-brown... Hmm, my arbs are turning more of a yellow-brown on the interiors, and then dropping off. Below are my pics -- but mine are the 'Nigra' arbs.

Deadon, if you want to post your pic in your message, just upload them to Photobucket (you can open a free account very easily). Then when you view your pics in your Album, it shows you the HTML Tag to copy and paste into your message on here. So easy a caveman can do it! heehee

I carefully examined the plants for signs of aphids or other insects. I have greenfly on some roses about 100 feet away, but nothing on the Emeralds. It's their first year and the soil isn't great where they were planted so I'll just keep an eye on them and water regularly. Is there a nutrient I could spray on them I wonder?

Do yours look similar to the photos I posted above? Or are they turning more of a crispy brown?

No, they are not like the photos above. More of a crispy red/brown as you say.

I bought several of these 6 years ago and I love em. Funny but I found them at K-Mart. They were 1' tall and they were priced at $2.50 ea. :) They're now at least 8' and beautiful. Mine have never yellowed up like your picture.

I too was curious as to how it's pronounced. The website below pronounces it "smargged" and it does mean emerald.

Here is a link that might be useful: Pronunciation

"The website below ..."

Just ran that link past a native Danish speaker. They have it hopelessly wrong. A complete pig's ear.

Resin

how about Sma-raged ?

Lol! I just ran it by a Dutch friend and he didn't pronounce it smargged either. I can't twist my mouth right to pronounce it like he did.

I don't know about a nutrient spray, but I have heard that some evergreens benefit from an anti-dessicant spray which helps the plant retain moisture during the winter...?

See link for an article about spraying "living Christmas trees" which mentions two anti-dessicants by name in the last line. Some people spell it antidessicant, without the hyphen, if you want to do your own search.

Here is a link that might be useful: Anti-Dessicant Spray Names

Something else to watch for on Smaragd is bagworms. Mine had a heavy infestation last summer. I haven't had them bother any other conifer so far, and I have numerous others in close proximity.