Wood smoking.

[Skippy]

I've seen that some people on here smoke their own food and have built their own smokers. This is something I've thought about for a while now but like so many things haven't quite got round to it.
I understand the principals and to begin with I am just going to aim at smoking for taste rather than preserving. There seems to be a decent amount of information about using different woods although little about what not to use.
As a woodworker I have always got access to sawdust and chippings and use a variety of timbers. Woods like oak I know I can use , I've even seen bags of it sold on e-bay which is something else that has crossed my mind too.Fruit woods are again ok and I have some pear logs that I was laying aside for turning but which has unfortunately developed shakes or small splits pretty much rendering it useless.
But , what should I not use. Obviously anything treated won't be useable and I'd assume yew and laburnem would be a no no. However, what about softwoods as they are always being used in the workshop? Some I know have a high level of resins such as pitch pine but others such as whitewood are "bland" for want of a better word. Then there are the African hardwoods , some of which can be difficult to determine exactly ( I commonly refer to african hardwoods as SAS or "some african stuff" or words to that effect).The dust itsself can he hazardous to breath in but I don't know about the smoke.
Does the age of the timber effect the taste of the smoke? I have green oak but also some that is tudor in age and is a rich dark brown colour.
Sorry for what might seem a long post just full of questions but being essentially tight I don't want to waste food by smoking it in an acrid smog.


Pete