This is a large massive fan palm that grows naturally in open woodlands on Taiwan and the southern islands of Japan. It's trunk can reach heights of 40 feet and a diameter of 1 foot. It has become naturalized in the forests behind Honolulu and may be considered a pest by some. The thorns on it's petioles can be nasty when they "grab" you.
I bought mine from a guy selling out of a container that he brought over from the "Big Island". He called his company "Big Island Palm" and usually could be found in portions of a parking lot across the highway from the Pearl Ridge shopping center. I believe it was in 1998 when I picked it up.
Here it is in December of 2000. I see a pick and an empty pot in the background so perhaps this is when I planted it.
And again in July of 2005. It has been in a lot of shade and the petioles are getting long.