The origin "Tannenbauer" looks like a sensible explanation. I would interprete it as the farmer where the firs grow. A name with identical meaning would be Tannenhofer. Versions perhaps include Tannhofer, Danhofer, Thonhofer etc.
The tree Tanne translates to "fir." The pine tree would be Kiefer or Föhre. The most common conifer in Austria is the Fichte (spruce) which often is wrongly called Tanne. Where I grew up, the Tanne was considered to be the most noble tree.