Thuja are great, for many reasons mentioned. With that, there are many different varieties, with good and not so good characteristics for our bonsai creations.
Being that I see them a lot, more in yard wind breaker landscapes sadly, but will say the west coast wild ones are impressive! We don't see that type if girth too much, wait, what did I just say, hahaha!
with the fronds being a major concern with them, I did some minor homework some might call research, ha, and found the Degroots Spire variety to have the smaller fronds for our bonsai liking.
@MACH5 thuja that he has(with a shot out to Suthin) is the reason I started my homework and want Thuja's in my collection.
I have a few landscape ones that got beat up years ago and are now what we like in "yamadori" characteristics, still pondering the fronds, but the wood will be the main feature with these.
not knockinng anyones selection for trees to work on, but I get the feeling from my homework and talking with nurseries that the Emerald variety is almost bred for windbreaker landscape plantings(fast n easy). But again I am not criticizing, just passing on some info I found with Thuja.
I will also add like Mach5 said they are native to East coast too, just think the west coast ones are a bit larger is all.
but then again, the west coast was not where Europeans first arrived in America, so maybe our large ones got cut earlier and by the time generations of people got to the west, they finally started thinking maybe we should save some of these Ancient trees of size, haha, just a wild thought I have with east coast and west coast characteristics. Im no way a history scholar, just a side thought. ha
Cedar's for everyone!!!