Is there anyway to steal a material (copy and save as a Bryce mat preset) from an imported object,
i.e. import a piece of furniture in .obj format render in in Bryce and copy the
wood mat for use on other object?
Most likely this is easy but there are a couple of considerations. You should upload an image to show us an exact example of what you are trying to do. Generally, any material can be saved and reapplied to another geometry, the issue comes in if there is UV mapping involved.
Yes, click on the mesh that has that mat on it and save it to your mat presets library. It is as simple as that.
Edited to add if it is a simple jpg texture, and not as Rashad says, mapped to fit a specific shape (UV map)