I make finials from larch or Western red cedar. I can get these in 4" or 6" square section, without the pith, or with the pith on the edge of the blank. Larch is getting more expensive, cedar is becoming as expensive as some hardwoods. It is not very nice to turn, but it is very durable. Have a look at oldfern on the internet, or search for Summerhouse finials on Google. Feel free to contact me directly for more advice.