I am just starting my shop and I have always used a compound miter saws is there one for big timbers and if not what would you use thanks for all your help in advance

Generally, the material is too large to bring to a stationary power tool, so we use larger portable power tools. One exception is knee braces. We have a stationary 16" 5HP radial arm saw that we use for that.

this fella' claims "12” sliding miter saws can easily handle 3x5 and 4x5 timber"

http://www.frame1.org/

I use a Stanley Sharptooth. Has worked well on timbers up to 12"x14" so far.

A good sharp hand saw(like the Stanley Sharptooth) and the knowledge on how to properly use one. I did a pictorial on another website:
How to use a handsaw

Many also use a 16+ inch diameter Makita circular saw. Handsaw will be more accurate and square with little to no cleanup of the end. Each have their pros and cons.

Thanks I have learned a lot at first I thought when you suggested the Stanley Sharptooth you were making fun of me but I learned something. but I have to cut a lot of 8X8s 10X10s & 12X12s and I only have Douglas Fur available and a little Cedar. I was wondering if anyone has used the Morgan Chop Saw
Pivot Saw or Mafell ZSX Ec/400 HM Chain Beam Saw
or something else thanks again for all your help

I don't think anyone was making fun, we might get hen pecked once and a while, though.

What size of operation are you wanting to set up? Hundegger comes to mind. I use a chain saw, its orange and white with a little black. I find very few operations which need nice butt cuts. If it is the end of a tenon I drop it off with the chain saw and trim the end of the tenon when I am all done with it. and don't forget that french snap. On ends of plates and such, a pull saw is now my first choice, right to the center of my line, regardless of the wanky timber.

Once you start mechanizing the machinery you force your self into s4s timber, limiting your self to that. A full on production shop, the competition will be stiff.

How does this mesh with your new shop plans? Just curious.

We do outdoor structures Pergolas and Gazebos and such and we are starting to do a lot, most of my post on the Pergolas are flat on top so they need to be nice and square. We rarely use s4s its almost all rough sawed. But are timbers are nice and true we live in a desert so timbers are not right next door.

It sounds like you found a nice source for timber. Usually a little background helps in understanding the situation.

What have you been using to cut the timber?

I would not use the lower priced versions of the Mafell. I had a bolt on to a Skill worm drive which was nothing compared to the Mafell, I have not used a Mafell. This salesman sure makes it look fun.
http://www.timberwolftools.com/tools/mafell/MAF-ZSXEc400HM.html

I was impressed with the protool saw from timberwolf. Right price at the right time for me. Had I planned to stay more in the crafting side of things I would have upgraded to the mafell. Really nice tools - I used a whole complement of them in both a CNC shop and a small hand craft shop.