To reduce checking before you cut, wax the ends of the logs now. At that thickness, you might want to see about it getting kiln dried because it will check quite a lot at that thickness of cut.

It's going to both check and move as it dries (whether air dried of kiln), so plan for that. Cut your slab both over thick (I'd do 5" for a 4" finished thickness) and long by at least a foot on each end. Or, plan to make a feature of the cracks that will appear, either the rustic look or fill them, perhaps with something contrasting and interesting. Air drying typically take one year per inch of thickness. Kiln drying wood that thick is typically pretty difficult and done successfully only by skilled and patient kiln operators. Getting that kind of care and long cycle for a single board is unlikely. Treat the ends with Anchorseal or equivalent.

Aside from that, sticker it, keep it out of the sun and rain, and turn the boards every six months or so. Good luck!

I recently rough turned some big bowls out of a cedar tree I cut down. They checked badly, despite reasonably careful treatment -- eg anchorseal on the end grain, packing with wet shavings etc. After a couple months the checks have closed back up and it's hard to see where they once were, so there's some pretty unusual differential shrinkage going on.

Thanks for the tips! I have some thinner 6-ish" straight branches that I was thinking about cutting to the angle of where the sheetrock meets the brick of the fireplace. Thinking that will frame out the fireplace nicely. I will make sure to do those long to fill in at the edges of the mantel incase it does shrink that much in length. Right now. The main log is only about 5-6" longer than the existing mantle.

If all else fails, i have another red cedar I'm dropping next weekend. That one has a trunk about 28" wide, and nice and straight for close to 12' from the ground.

We have mantles made from big pine slabs that we got from a local salvage yard. They are great. I think it's lovely that you are going to use your own tree for a mantle.

The branches are likely to warp more than the trunk since the two sides of the branch responded differently to gravity, unlike the trunk which grows upright.

I didnt clarify in original post. The fireplace is located in the corner of the room. So the side edges of the mantle wont even show, as they will be flush against the wall. The 5-6" long is in reference to the face of the mantle, which is a good 18" wider than the back edge. I didnt even think about the gravity effect on the horizontal branches. May just rip those in half down the length, sticker, weigh down, and let sit in my garage for a year or 2 before angling off and installing(if they dont warp too much). Again, I really appreciate the comments. I would have messed this all up if I hadn't found this site. Will post photo of actual fireplace when I get home Friday so you guys can visualize what I'm talking about a little better.

To be certain we are talking about the same species,my experience is with Juniperus virginiana, known as red cedar, eastern redcedar, Virginian juniper, eastern juniper, red juniper, pencil cedar, and aromatic cedar. I have built dozens of things from it and never once experienced movement during drying,after drying nor after project was complete. I air dry 1"-3" boards as little as 90 days between stump and using. I've never sawn and milled limbs because I know Oak,Walnut and Pine limbs never stop moving,even after 10 years. Most of my projects were boxes, chests and furniture with tight,mitered,finger and dove tail joints,100% glued. I've only experience two occasions where a joint separated. After close inspection,I concluded I overlooked twisted grain that caused separation in that spot. IMO,a mantel constructed from newly cut log would never move enough to notice. One thing's for certain,your shop will smell good! (:

honestly, not really sure of the exact type of cedar. It has a red core and is very aromatic when cut. The one on the ground is going toward the mantle. The one in the back is going to get planked for a bar top and a few other small projects. Not sure if age matters, but they are both around 40-45 years

Beautiful tree you have to work with there, uncle!

Please do show us some pics of the finished product later on. :o)

That's the same tree I used in my projects. You will love working with it so I suggest keeping the surplus for future use. If you expect to get a lath or would like to gift some to a friend who has one,the trunk where limbs grew from has stunning grain. I would recommend drying material from that area for a long time before processing.

I'm not planning on going full bore with the woodworking equipment. At the moment, I'm just looking into mill jigs for my chainsaw. Will post some photos of the projects I have in mind as they progress.

Here is a photo of the fireplace as it is today. The cedar should look really good in place of that fake wood atrocity that is there now. Playing with the idea of covering the 2 brick supports with hollowed out quarters of cedar as well. It's not very often that you see full on wood burning fireplaces in my area. Most are gas with faux logs anymore. Need to get it up to it's full potential of being the focal point of the room

We're lucky enough to still have a few private saw mills in the area. If you did, you could trailer that one over and let them do the hard part. Might cost a few dollars but not bad usually.

We have a few outside of town around here. Their prices for processing are ridiculous though. Between $700 and $1,000 for the single board I need for the mantle.

Sheesh, I would look into a chain saw jig for sawing logs. < smile >

The prices here have went up some too but last I looked they went up from around $50/TBF to maybe ~$100/TBF.

The last load I hauled to the mill was sawed into 2x8's for the lean-to on one of my sheds. Probably 8 years ago now so it might be that much higher again but still. This load cost me around $100 IIRC.

The kind of guys that want to run a small mill are getting few and far between but it's hard to understand that much of a price hike.

Too bad you are not down here in MO, I'd probably saw that for you for $25.

Eastern Redcedar, by the way. It looks beautifully purple when first cut but keep in mind it will aged to a more dull reddish brown. No real way to prevent that, just enjoy the magic purple color while you can. Something few people get to see.

Finally got my hands on a chainsaw mill, and bought a ripping chain. This is just a small piece of one trunk for test cuts. The grain is freaking amazing. Planning on planking out both trunks this week. Will post pics of the final stack when I finish em off. Thanks for all the suggestions and tips!

Nice! That one would be a nice board for an antler or fish mount.

My son just got his tree back from the saw mill, though not as big of a tree as yours, he plans to make an end table or something to that effect.

Do you have a hand planer? Or just using a belt sander? I'd be tempted to put a few broad ax marks in it just for character. :^)

I have a small hand planer for any large blemishes. Otherwise I have a couple different Sanders to clean and smooth the big pieces. Most of it will end up getting ripped into thinner boards for boxes and such. I'm gonna have so much between the 2 trees, I'll probably end up lining all of my closets with it too.

Update for anyone still following this thread. Took way longer than I wanted, but both logs are planked and stacked. The fatter one sat in the sun too long and started to check a bit on 1 end. After 6+ weeks in the garage, they seem to be holding their color surprisingly well.

Very nice! Cedar is underappreciated. I have a customer right now who's building a 'craft shed' for grandma and lining the whole inside with cedar, so they will buy as many boards as I can come up with. It's going to look spectacular.

I'm definitely lining my closet with some of this stuff. Should make for a good winter project.