Weblog: Dr. Jon Ranson in Siberia

Monday, August 6, 2007

From Evenkiyskiy Region, 10:15 p.m. Siberia (10:15 a.m. EDT)

From Jon Ranson

This morning we had the hardest rain yet. It would slack up a little then just pour down. Finally, about 9 a.m., it lightened up enough to start the day. And then it turned gorgeous. The sky is a beautiful blue. It feels great to be in sunlight again!

We worked 11 GLAS footprints today and measured over 600 trees. The laser tool we used for tree height measurement was damaged in the rain, so we can’t use it. We used to be able to stand in one spot to measure tree height. Now we have to do it all by hand: pull out our 50-meter tapes and other forestry tools, measure distance and angles from different viewpoints, and calculate the heights using trigonometry. It’s physically harder and takes longer, but it works.

We’re in a area scarred by fire. The regenerated forest here is about the same height and age as the old forest was when the fire burned it down. So we see the green and the blackened trees, the living and the dead, all standing at similar heights.

It is a great opportunity to use our ground-truth to see how the satellite lidar system records an area like this. The tree heights are similar, but the dead trees don’t have any branches, so we aren’t sure that the system will even take a reading from them. It’s possible they are being ignored entirely, but we don’t know. We’ll take our measurements back to the lab and compare data, and we’ll see.

  Guoqing Sun and Jon Ranson

This is one great reason to get out in the field. We have the data for this area from various satellite systems. We did know it was a fire scar. But it’s our time and our eyes on the ground that let us know there are unusual conditions here—conditions that our remote-sensing tools may not be designed to handle.

One of the essential uses of our systems is to help estimate carbon storage of these forests. Living trees store a great deal of carbon. But dead wood stores carbon, too. The carbon in deadwood should be released when temperature increases because the wood will decompose faster when it warms. Living trees should grow larger and the forest should expand, increasing carbon storage. Not only to understand present conditions, but also to make future predictions, we need to make sure our remote-sensing systems can both record standing dead wood and differentiate it from living trees.

So this has been an important day for our science. But that’s not the only thing important about today. One year ago today Gouqing became a grandfather for the first time. He wants to be with his first granddaughter, Jasmine, on her first birthday. But he is here, a half-world away, measuring trees to help understand the forest, the carbon cycle, the local forest ecosystems and how they all combine in the global ecosystem of which we are each a vital part.

We are studying changes here, in this remote and wild world. The world you grow up in, Jasmine, may be much different than the world we knew as children. Your Grandfather let me know that he is here with us not because he loves you less, but because he longs to see your Earth be vibrant, beautiful, and healthy. We have a responsibility, each person in this world, to pass on to you a world worth living in.

So today, Jasmine, in Russian tradition, we raise a toast to you from the wilderness—С днём рождения! Happy Birthday!


Guoqing Sun (left) and Jon Ranson (right) plan the day’s work. One of the major goals of the expedition is to acquire ground-truth data to verify tree height measurements made by the Geosciences Laser Altimeter System (GLAS) on NASA’s ICESat Satellite. To decide how to reach these GLAS “footprint” areas, they use a combination of topographic maps and images from sensors on NASA’s Landsat and Terra satellites.