Fieldwork in Great Smoky Mountains National Park

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The 17th annual North American Dendroecological Fieldweek (NADEF) was held on June 1-9, 2007 in Great Smoky Mountains National Park in Tennessee. Our group developed an Eastern Hemlock (Tsuga canadensis) chronology from Albright Grove and assessed its potential for reconstructing climate. A copy of the group's presentation can be downloaded here. Following are photographs from the field and lab activities.

Eastern hemlock forest in Great Smoky Mountains National Park. The brown trees are hemlocks killed en mass by the hemlock woolly adelgid. Fog is moving in over the mountain in this shot. The hazy conditions often present give the mountains their name. Natural haze results from a combination of tree hydrocarbon emissions and high humidity, but is lately exacerbated by airborne pollutants blown over the mountains. Elevated ozone in particular is a serious problem and contributes to ill health of the trees making them more susceptible to insect attack. For more information on fog-borne pollutants and on pathogens in this and other forest ecosystems visit the webpage of Dr. Kathleen Weathers.

What seem like thousands of fraser fir skeletons, killed by balsam woolly adelgid attack, can be seen on Clingman's Dome, at 6643 feet - the highest point on the Appalachian Trail/Tennessee and second highest peak east of the Mississippi.

Our group arriving at Albright Grove for dendro sampling. Group leader Chris Gentry is at image center, with hat.

Members of our group debating the sampling strategy

Here I am in front of a downed tree in Albright Grove. Strong winds are a frequent cause for such tree downfalls. Notice that the root system of this tree is fairly shallow and the ground is quite rocky.

Our group making its way to the final coring site.

Group co-leader Jim Speer demonstrating the use of the increment borer

Coring of eastern hemlocks underway in Albright Grove by two of our subgroups. The large diameter tree at the center was the oldest one in our dataset. I cored this one with the use of a long 24-inch borer, recovering a sequence of rings back to 1784. As with several other trees, this one showed barely any growth in year 2007, indicating stress from woolly adelgid infestation. It is unlikely that this tree will survive much longer.

Coring a young hemlock in the rain

More coring...

... and more...

Hemlock branch infested with woolly adelgid

Taking diameter at breast height

A brief rest stop by the stream side

After 3 hours of coring in the rain on a slippery slope the sun comes out as we hit the trail back...

Log cabin, ca 18th century, on the trail toward Albright Grove

Mounting the cores

Sanding the mounted cores in the wood shop

Chris Gentry inspecting core surfaces following belt-sanding

After the core surfaces have been polished, rings are examined, counted and marked under the microscope

Skeleton plotting and crossdating

 Amy preparing to measure a sample on the Velmex linear encoder

This is an interesting sample of an eastern hemlock core section viewed through the microscope. The sample illustrates large variations in ring width, from very narrow micro-rings (left of center) to fairly wide rings on right. The pencil markings denote decadal years, in this sample corresponding to 1960, '70 and '80, from left to right. Year 1981 is a classic example of a false ring associated with injury.

Chris (right) and Jim (middle) preparing the chainsaw for action

The group hits the trail again armed with chainsaw to acquire cross sections

Jim Speer at work sawing off a cross section from a recently toppled eastern hemlock

Me and Neil Pederson (top) working on a bottle of bourbon by the campfire

Social hour

On the night before the group presentations, our group assembles to compile the data and run them through COFECHA, a crossdating quality control software.

Here our group is preparing to run ARSTAN to standardize the tree ring series and derive a mean chronology.

Making tough decisions during standardization

 Here I am presenting part of our findings during the group presentations on the final day of the fieldweek

Group photo

Friday night bluegrass festival at a local school in Maryville, Tennessee. You can watch a video of this group on YouTube (click here)

A last hike in the woods before leaving...

Back in New York - Port Authority bus terminal