We are planning on building  a straw bale home and want to use material already on our land.  We have trees available for the post and beams but have several questions.  Is there any particular tree that is better for this application or ones that we should definately avoid?  I have searched everywhere on the drying process too.  Some post and beam builders say you should build with green lumber others dry it for a year or so.  If we build with green lumber, will it seep moisture into the straw as it dries?  And will we need to replaster where the straw wall meets the posts?  It may also make a difference if we use the whole tree or have the tree cut to actual beams. 

Any help will be appreciated.  Thanks

I built a house this year with the great room being timber framed . I cut hard maple from my bush in jan 2007
and had it made into the timbers it was erected in july of this year and . I did not kiln dry it,` its just been air drying on its own . It is structurly holding my roof up and i have had no problems with drywall cracking around it. i would say its around 10-15% moisture now the wood itself has lots of checks in it from naturally drying some people like that look others dont. So if you dont want any cracks in the wood you will need to kiln dry it. As far as the wood to use genarlly soft woods such as pine or fur are used mainly becuase there cheaper to buy then a hard wood but if your using your own like i did that cost isnt a factor. You should however only use the heart of the tree for your timbers this is the strongest part of the tree especially if your using it as structure also checking is less in timbers made from the hearts

What kind of trees do you have available? I would be wary of very green woods(freshly cut), even woods than can be used green should get a little time to rest in a dry place. I agree with jimmy, if you can use all heart wood from hard wood trees.

Then there is the shrinkage from green wood. Usually the slower the wood drys the less it shrinks, that is why they cover furniture lumber in wax, or at least the end.

We built out strawbale home with a post & beam structure. The wood we chose was white pine which was green and dried as the structure was raised and it was readily available (Ontario, Canada). There are many types of trees you can use, hardwood or softwood. All have different characteristics and some a easy to work with, others are harder. You need to determine whether the trees you have are the correct size and depending on the type, what their strength is related to sheer, compression, etc. If you look at the timerframe companies, you note they often build with: pine, oak, fir.

As for your questions:

- Green wood is easier to work with, e.g. cut, drill, etc., especially you are going to use a hardwood

- I would not worry about the moisture from the wood passing into the strawbales if you are plastering the inside

- It is difficult to get plaster behind the posts and you need to think about how you are going to do this unless you are 'embedding' the posts. We did not and it was not easy to get behind them when plastering

What type of trees do you have on your property?

Feel free to ask me whatever you want on the build process, what to look out for, etc.