Christmas is about tradition. For a few geeks, Christmas is also an ideal time to get in a little bit of scientific research. What could be better than to combine some of the traditional activities of the season with the chance to learn a bit more about the natural world?

Katie McKeever is a graduate student in plant pathology at the Washington State University Research and Extension Center (REC) in Puyallup, Wash. She has been hard at work in recent weeks learning about how moisture is lost or retained from a truly mega-Christmas tree. An 88-foot-tall Engelmann spruce was recently shipped from north-central Washington State to what we natives of the Northwest call the "other Washington," namely the District of Columbia.
It took some 25 days for the spruce to move from its home in Washington State to a place of pride at the capitol in D.C. The 2013 National Christmas Tree was harvested from the Colville National Forest in Pend Oreille County. The last time Washington State gave the capitol its Christmas tree was in 2006. That one came from the Olympic National Forest in the northwestern part of the state.
Once this year's tree was cut, McKeever placed three small sensors in the canopy of the great tree as it lay on the bed of the semi that would haul it across the country.
"The sensors are data loggers that automatically record temperature every 15 minutes to provide statistics about the ambient environment inside the tree canopy," McKeever told me.
Professor Gary Chastagner, also at the Puyallup REC, has long worked on various Christmas tree issues. He's an expert on what's called the post-harvest moisture and retention of needles of Christmas trees. To be sure, most Christmas trees are not 88 feet tall, but some of the issues with mega-trees and the kind in your living room are similar
In general, helping Christmas trees retain moisture can help them keep their needles. If you are tired of trying to get a lot of needles out of your living room carpet each January (one tradition I would gladly skip), you might wish McKeever and Chastagner well with their work.
The research on the National Christmas Tree involves cooperation between the U.S. Forest Service and WSU. Forest Service technicians from the Colville National Forest who have accompanied the tree are taking periodic samples of small twigs from the enormous tannenbaum. The samples are sent to Puyallup where they are carefully weighed, dried thoroughly in an oven, and then reweighed to determine how much moisture was in the twigs.
The data the WSU researchers are gathering is part of their on-going work to make recommendations that can help improve the quality of Christmas trees for consumers. That's the technical challenge for the tree specialists. For the rest of us, their work is just a way of improving our live tannenbaum tradition, year after year.
Studying Gold Rush's impact on soil
When I was a younger and more sprightly woman, I spent part of my life investigating unusual hot springs in rural California. They were salty and quite stinky springs out in the middle of nowhere, and several of them occurred right in the center of an old gold-laced mercury deposit.
The fieldwork had its challenges. In the afternoon it was routinely over 100 degrees, and the sun was relentless. One afternoon I even flirted with heat stroke. Another problem was that the rattlesnakes were numerous and big.
But the springs were fascinating from a scientific point of view. I spent a lot of time in the laboratory back east analyzing the waters of the springs. They were transporting gold, and the important question was how. It was the sulfur in the spring water, I ultimately concluded, that made this unusual trick possible. In short, the stinky aroma of the springs was key to their ability to transport gold up to the very surface of the Earth.
The area where I worked in California didn't play a direct role in the Gold Rush of 1849. There just wasn't enough gold around the hot springs to have caught the attention of the Old Timers who made fortunes elsewhere in California. But the place where I worked had been mined for mercury, including back in the old days. That was because mercury was used to concentrate gold in materials miners elsewhere were processing.
In the past, miners worked with pans, hydraulic hoses, and sluices to remove and concentrate gold-rich sediment. Because gold is attracted to mercury, the miners poured liquid mercury on the earthen material they had concentrated. The gold particles moved into the mercury. The miners could then heat the mercury and boil it away, leaving a concentrated "button" of gold behind.
There was a lot of mercury being slopped around in the old processes the miners used. Much of it went into the air when the miners heated the mercury-gold mixture, but some of the mercury stayed behind, in the sediments. That was an environmental hazard in the past, and it still is today.
New research is highlighting the environmental challenges those old mining techniques continue to create for us. As explained in a recent piece on the website Inside Science, one of the key places at issue is the Yuba Fan, a volume of sediment built up around the Yuba River, a tributary of the Sacramento River.
The Yuba Fan contains more than a billion cubic yards of sediment. Terraces in the fan act like small dams, keeping the material from moving downstream. But about once every 10 years there is a substantial flood that kicks loose materials that then move downhill toward the lowlands — which include agricultural areas like California's rice fields.
The recent research was published in the Proceedings of the National Academy of Sciences, which is a measure of its importance. In part because California's agricultural bounty is a keystone to all of us who like to eat, I'm sure more follow-up research will be done.
Dr. E. Kirsten Peters, a native of the rural Northwest, was trained as a geologist at Princeton and Harvard. This column is a service of the College of Agricultural, Human and Natural Resource Sciences at Washington State University.