root depth? western red cedar

[20ozjolt]

I have a western red cedar that I don't want to kill as its such a nice specimen that nature put there but I want to put a garden where it is.... before I start digging I'm wondering if its worth it... 

the tree is about 4" tall thanks all 

western side of Mt. Hood.... 

[pine]

Confused as to your intent.  Do you plan on transplanting it and want to know how big a root ball you have to have?  If you are transplanting wait for it to harden off this late fall before doing it.

[20ozjolt]

yes effectively i want to know how deep Im going to have to dig if i want to save it... or how deep the roots are likely to be 

its one of a few trees I'm thinking about moving away from where nature put them to places where I can let them grow come the fall. 

[DelawhereJoe]

If I remember right its 1" diameter per foot for the root ball, but if your tree in only 4' tall then I would measure the base diameter and go down no more then 12"-14". Back in high school in a horticulture class we had to ball & burlap a 6"dbh Bradford pear. Once we had in all wrapped up the teacher then figured out we couldn't move a tree that large, we had to barrow a forklift from one of the other shops to relocate the 2 trees we had to move.

[Stuart Caruk]

You noted 4" tall. We move these all the time. Take a shovel full of dirt from about 6" away and as far down as you can go, lift it up and set it in another hole that you've removed the same amount of dirt. Tamp well, add water, wait...

We have a few that I've ignored, and now my wife wants them gone. They are about 15' tall and 6" across on the stump. To big to transplant with my little excavator. Although, I'm buying a Blade Runner.... so maybe I should try.

[pine]

Well I have planted many thousands of WRC seedings in the past years and have watched them take off.  

Since yours are a natural regen of WRC I would expect that at only 4 feet tall that they don't have a stem caliper of much more than 3/4 inch unless they have had a lot of browse damage.  When they lift seedling at the nurseries for out-planting they root prune them pretty significantly but those are nursery grown before lifting.
In your case I would think that you would be fine if you did an 12 inch root ball (maybe a little more on the depth depending upon the quality of your soil).  You might get away with less, but for best survival go a little larger.  You will always lose some root but think of it as a root pruning.

If you have a back-hoe just use it and take the whole thing out at once.  Pretty simple and clean if you are careful.  

I would not do it before 15 December but I would do it before 1 Feb.  Of course if we get a delayed late winter hardening of the plants that might cause you to wait a bit later.
You can also do a initial root prune now by driving a long blade planting shovel down in a circle around the stems at the diameter that you are going to transplant to let them build up their energy and sugars in the fall in the more concentrated inner core of roots.