State of the Planet

News from the Columbia Climate School

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Tree-Ring Science in a Log Yard?

The cool, snowy weather really put a crimp in our plans. Dario, Tuncay, Cengis, and others spent two days trying to find potential sampling locations before Nesibe and I arrived. Even though it had been well above freezing during the day and above freezing at night, the snow had only retreated so far in the mountain roads. So, much of the areas we had access to were areas that loggers have had access to: lower elevations and (likely) productive forests. After two days of driving, Field Crue One didn’t find much.

The valley we hit the day before was the best of what they had seen. While it looked like it had some potential as we drove through it, once we spent a few hours in it taking test samples, it was clear the prodigious rainfall in the region produced large trees in no time (no time for a dendrochronologist = 80-150 years). We had two days left to make something out of this trip. I was keeping it to myself, but I wasn’t feeling too hopeful.

Luckily, we had Nesibe on our team!

Our team, Tuncay Guner (left), Dario Martin, led by Nesibe Kose (right). (N. Pederson)

Nesibe is a young and rising scientist. Her short career has been filled with a range of experiences that normally might take a decade or two. Most impressively, she is pretty much self-taught in tree rings. Her excellent mentor, Ünal Akkemik, is a very good botanist/forest ecologist who has done some very good work in dendrochronology. Nearly a decade earlier he conducted some work with Gordon Jacoby and Rosanne D’Arrigo of our lab. But, much in the field has changed over the last 15 years. There are more scientists and methodologies have become quite complex. Today you would be hard-pressed to get a single chronology published in mid-level journals unless it was more than 2000 years in length or showed something completely in the field. To get into the upper-level journals today, you likely need many records –30? 80? 100? 400? spread over a large geographic area so that you can discern differences in regional-scale climate or ecology, for example.

So, for young scientists, the mastery of skills (ecological, geochemical, geographical, etc., on top of statistics, plant physiology, some wood anatomy) needed today might seem daunting for many of the scientists from 30-40 years ago (not saying earlier science was bad or weak. Just the opposite: earlier work was so outstanding that the stakes have been raised). Nesibe has taken this challenge on by reading and digesting perhaps the most complex book in our field. It is truly impressive. Her determination to learn and will to succeed was on display when facing the snow barrier.

She said, “I have an idea. Tomorrow morning we’ll go to the depot.”

What initially ensued was a discussion of the North American forestry terms and English. We determined a depot was a log yard. This led to the realization that when you break down some English words, they are comically simple. Log yard for the place to put logs before they are sold. Other similar terms – woodstove, stovepipe, waterpipe, etc. It was a fun conversation, the kind you can have when you have hours to kill in a jeep.

Anyhow, Nesibe had been to the log yard previously and made a collection of Oriental beech dating back 400 years. Nesibe explained to us that the records kept at the log yard could be used to tell which valleys or locations the logs came from, what elevation they grew at, etc. Her resourcefulness was in full display. Away to the log yard we went.

A log yard in Artvin Province. (N. Pederson)

Perhaps it was the heavy snow, but there was only about 25-33% of the normal amount of logs in the depot. But, the logs in the yard were an indication of what can be found in the forest. Logs of spruce, fir, and beach were 1-1.5 meters in diameter. Logs of chestnut and oak were 0.5-0.75 meters in diameter.

Spruce and fir logs. For perspective, Dario is >2 m tall. (N. Pederson)

It was hard to sense the age of these trees. It didn’t seem outrageous that many were 150-300 years old. The potential of conducting tree-ring science in the depots of the Artvin Province were also on display.

Closeup of an oak log. (N. Pederson)

There was still a challenge. How do we take samples from multiple logs and not cause pseudoreplication in our collection? (Psuedoreplication is where replicates, in our case logs, are not independent, as in, they are not from different trees, which is ideal for our work). We didn’t want to take 3-4 samples from the same tree and think they were different trees. Thus, our combined skills in science of tree-ring analysis came into play. We studied each log, not only looking at its shape, wounds, sapwood, etc, but identifying patterns of ring width to match multiple logs to the same tree. We cannot claim we were 100% correct. That will take lab analysis.

I have to be honest: conducting science in a log yard with no shade was tough. Not only did it turn out to be the hottest day of our visit to northeastern Turkey, once we got over the fascination of the larger logs, it was somewhat boring. When you are in the forest and seeking the oldest trees in rugged terrain is a challenge that keeps one’s body and mind engaged and focused. Conducting science in the hot, sunny log yard lulled me into a stupor. It might have made us a little silly with boredom, even.

Logs of Oriental beech as backdrop for the 'gangstas' of the Borçka Depot. (N. Pederson)

After the log yard we headed towards our second destination of the day. We were hot, thirsty, hungry, a little cranky, and with a substitute driver that didn’t seemed thrilled to be driving us to where we needed to go (drivers can make or break these trips, sometimes). It didn’t feel hopeful. With hindsight, I can tell you that afternoon turned out to be one of the most important discoveries of this trip.

See those dark-green scruffy trees in the center of the picture (just to the right and above the clearing), that was our afternoon destination – the umbrella pine forest just outside of Artvin. (N. Pederson)
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