I don't think its a big deal and I have observed this myself a few times.

My theory is my small transplants don't suffer much transplant shock at all. The first year they are in the ground with their roots largely in the nursery's super fertilized potting mix and are getting watered regular like by me.

The second year I pull back on the watering and the've used up all the weird chemical soil and have to grow in my yard soil.

That's my theory anyways. Does it fit your situation? Were your arbs planted bare root or in rootballs? Did you water as much this year?

Interesting theory. They were in a container. The first year was hot, dry and sunny so I used a soaker hose on them for a couple hours once per week. This past summer was the exact opposite, cool, cloudy, rainy, so I didn't use the soaker on them at all until September when it got hot and dry.

Another question I have is these emeralds take on a yellow tinge during the winter but the few others I have stay, well, emerald. What's up with that?

Sure look good to me. There's always going to be some differences between individuals w/regard to the amount of yellowing.

many plants.. across many spectrums .... do as you note ...

with potted plants... i always presumed they were hyper fertilized for fast growth.. for sale ... and it takes them a few years ... after planting ... to return to normal growth ...

that you got great growth.. with no losses .. over a large number.. indicates to me.. that you did a very good job with planting.. and aftercare ... two thumbs up .... its nice to see success.. rather than the usual problems we get posted here ...

they should be rather free range from here on out ... i would probably stop watering them .. except maybe a sip in very severe drought next season ... and i would never fert them again ... just let them start growing.. like the forest trees they are supposed to be ...

besides... it looks like you probably fert the lawn.. and soon enough they will get roots out under that... and steal the LITTLE they might enjoy ...

good job..

ken