The Duke Forest is more than just a place to run the trails or harvest timber. It’s also an important living laboratory for Duke’s research community.
On Dec. 4, we joined the annual tour of research sites in the 7,000-acre forest, led by forest Director Sara Childs and Operations Manager Jenna Schreiber. Nearly two dozen of us learned about water and bugs, climate change and nanoparticle pollution.
At the first stop, in the Edeburn Division south of Hillsborough, Nicholas School graduate student Maggie Zimmer showed us a densely instrumented watershed for studying how a raindrop reaches a stream. A little valley of 130 hectares is studded with wells and dammed by a weir that measures every drop flowing out of the watershed. Zimmer and her thesis advisor Brian McGlynn are trying to get a handle on how a drop of water falling on a leaf or the ground eventually makes its way through several feet of soil and clay, in and around chunks of old rock, to the stream.
It’s not as simple as you think, says Zimmer, who has hand-augured 35 test wells in the study area and spent many dark, wet nights tending to her delicate equipment. For example, the rain gauge measures .01 millimeters at a time!
Across the road from the hydrology lab, we visited a global warming forest built by Jim Clark’s research team and overseen by lab manager Jordan Siminitz.
There are 24 plastic enclosures for studying how temperature increases in the soil might affect the growth of young trees. The warming scenarios were produced by a network of propane-heated pipes under the soil in each enclosure. The funding that built the site and operated it for four years has stopped, but the trees are still there and the team is hopeful they can restart the experiment.
Here and in Harvard Forest, the team was looking at soil temperature increases of 3 degrees or 5 degrees Celsius. The surprising finding out of four years of data was that southern tree species seemed to be more adversely affected by the temperature increase than northern species.
“Long term research like this is really hard to get funding for,” Childs said. But without long term studies, we won’t know much about what to expect from climate change. Incidentally, NC State was conducting a parallel study of ants and warmer soils in the same experimental booths, but they’ll be shutting down this year as well.
At the next stop, we found nattily uniformed NC Forest Service ranger Philip Ramsey standing next to an elaborate plastic contraption like 10 black funnels in a series leading down to a reservoir of antifreeze at the bottom. It’s a pheromone trap for the Southern Pine Beetle and its predator, the Clerid beetle. All is well with those bugs for now, but the devastating enemy of ash trees, the Emerald Ash Borer, is on the march and due to arrive any month now, Ramsey said, passing around pickled specimens of the bugs for our inspection.
Our last stop was an update on the nanotechnology test site called the mesocosm facility – 30 boxes filled with water, silt and plant life. They’re meant to mimic a tiny slice of a shoreline ecosystem to see how various nanoparticle materials are taken up by plant and animal life.
Research analyst Steve Anderson from Emily Bernhardt’s lab explained the latest experiments on what happens to all the poisonous stuff infused into anti-bacterial socks and pressure-treated lumber. The good news so far is that nanoparticies don’t seem to get taken up by ecosystems as readily as some had feared.
This isn’t really forest research per se, but where else are you going to put 30 big bunkers of mud, surrounded by an electrified raccoon fence, a super-fine frog fence and a Quonset hut enclosure for the cooler months?
Duke Forest houses 71 research projects at the moment, 16 of them started in just the last year. We’ll look forward to more fun discoveries on next year’s tour!
Post by Karl Leif Bates