Beautiful pen, Stephan & thanks for posting the video.
For those who aren't familiar with tiger oak, it is not a species of oak - it is merely a term for quarter sawn oak because it results in those beautiful grain lines you can see in this pen.
Quarter sawn oak & sycamore both make great turning projects. Quarter sawn oak & sycamore are often used in furniture & cabinets because it's stronger & more stable than plain-sawn wood, so I'm always on the lookout for someone throwing out old furniture. I've salvaged some nice q-sawn oak from an old office chair & some q-sawn sycamore from an old coffee table (that one was stained to look like cherry & I didn't realize what neat wood I had until I started cutting it up).