Posted: Mon Feb 18, 2013 12:16 pm
by tomhoward
That is a fantastic tree, and a tree I knew well years ago, when I worked as a cave guide at Oregon Caves. It is called Big Tree, an appropriate name. When I was out there, a sign by the tree said it was 1200-1500 years old, and 182 ft. tall - these figures are almost certainly exaggerations, as few Douglas-firs are known to be that old. According to Oregon Caves Forest and Fire History by James Agee, Laura Potash, Michael Gracz (National Park Service Cooperative Park Studies Unit Cooperative Report CPSU/UW 90-1, 1990), a book I downloaded through Google Scholar, Big Tree is most likely about 600 years old, a more reasonable age. As far as I know, no tree heights have been measured with the NTS sine method at Oregon Caves, and Big Tree never seemed to be as much as 182 ft. tall. In Agee's 1990 book, maximum heights are Douglas-fir - 42 m. (137.8 ft.), White Fir - 38 m. (124.6 ft.), Sugar Pine - 51 m. (167.3 ft.), Ponderosa Pine - 49 m. (160.7 ft.) - these height seem reasonable, even if the method used was the inaccurate tangent method - I don't know what method was used. Agee gives the ages of most of the old growth Douglas-fir at Oregon Caves as 240- up to 300 years, and this also is reasonable. I remember counting 300 rings on the stump of an average sized Douglas-fir in the old growth forest there.

Tom Howard