We have always thought our tuliptree near the visitor center at Crow’s Nest was pretty big. The kids at camp in 2006 measured it and submitted it to the list of Big Trees of Pennsylvania.
Big trees are scored on a formula that includes circumference at 4.5 feet above the ground (182 inches, for ours), the height in feet, and the average breadth of the canopy divided by four. But getting the numbers for height and average breadth is difficult, especially on uneven ground and when the tree is surrounded by other (admittedly smaller) ones. In our estimates in 2006 the students used forestry tools to generate the numbers, but the figures were still estimates.
But there is some technology that can generate extremely precise measurements that is used in geography, geology, geomorphology, seismology, forestry, atmospheric physics, laser altimetry, and contour mapping. That is LIDAR, LIght Detecting And Ranging, technology that we can use for remote sensing and scientific research on our preserves. Mike McGeehin from our GIS Department analyzed LIDAR images of the Hopewell Big Woods (in which Crow’s Nest Preserve lies) and determined that our tuliptree is 117 feet tall and has a spread in one direction of 76 feet in one direction and 51 feet in the other.
Added into the big tree formula, our tuliptree scores 315 points. The state champion scores 420 and is at Tyler Arboretum. Even the tenth largest (at Longwood Gardens, with a score of 329) is a bit bigger than ours. That’s as far as they list tuliptrees on the Big Tree List in the Commonwealth, so we’re just short of the list—literally. Still, we have an impressive tree, with a trunk diameter of nearly five feet as you face it.
The best part is that trees are living beings, and that they continue to grow—although slowly at these trees’ ages. And many of the trees on the Big Trees list are located in places where you can go see them. Check out the Big Trees website for details.
Posted by Daniel Barringer on January 5, 2013