Forest Redwoods

Mystery Coast Redwood #9

The challenges of measuring coast redwoods

Continued from: Coast Redwoods Main Page

Copyright 2017 by Mario Vaden


In the image below, Giacomo Renzullo is standing near a coast redwood, the week we measured several close-proximity redwoods including 353.3 ft. "Hairpin" in Prairie Creek. Giacomo is one of several climbers shown on the October 2009 National Geographic magazine cover. He helped Dr. Steve Sillett and National Geographic for three weeks in the same park to produce a huge composite image for the cover, centerfold and poster. My two photos below were taken September 17, 2009, a few days before the release of that Nat Geo redwood story.

The redwoods we measured were all done with a laser on one tripod and prism on another tripod. The open view of the coast redwood may seem to imply that it's easy. But even if 90% of the trunk is open to view, reaching the top with the laser can be difficult. Chris Atkins had to set up his laser several hundred feet away over the top of a ridge, and I recall doing this one twice, which was unusual. One Chris gets a reading on the tallest leader apex, his next target becomes the prism, beginning a series of leap-frog where the laser person and prism person pass each other, going up and down through the forest. Eventually, all the measurements are added and subtracted to determine how high the redwoods' top is above the ground around it's trunk.

In this area, Giacomo and I took turns for positioning the prism or holding foliage back so the laser's beam would have a clear path. Sometimes cardboard or bag was held to shade Chris's laser to prevent direct sunlight, which is apparently harmful to the unit. The orange bag below is the one Chris carries the tripods in. The smallest it becomes is a 3 foot package with a strap, and can be very difficult to bushwhack with through dense hucklerberry and other vegetation.


Giacomon Renzullo helping Chris Atkins measure LiDAR coast redwoods in Prairie Creek

Giacomo Renzullo helping Chris Atkins measure coast redwoods