Emerald

Dendrochronology

Mil sits at her station, intently studying her instruments. Carlos already asked her if she was actually living from air and science. Admittedly she is not sure herself if she prefers to be outside in the forest to collect more vegetation samples or to analyse them afterwards at her microscope. In between, there is not much time left for eating and sleeping. Today, Koshi and Dray finally brought her the long awaited slice of one of the fallen giants. Although it was by far not the thickest of the trunks, it wasn't easy to cut it with a laser, transport the slice to the ship, bring it through the airlock and up into the lab. Reluctantly she had to allow Carlos to cut the giant piece of wood into several sections to allow transport and the necessary sterilisation. After the process, the technician helped her to reassemble the slice on the lab table.

The last several hours she spent studying the growth structure of the tree and counting the year rings. She managed to adapt the programming of one of her medical sensor-scanners to counting the rings and at the same time logging their width while she slowly moves the instrument from the core to the bark of the tree. With this method, she already took the measures of twenty different radii of her slice and started to compare the results on screen.

Silently Andrej sits down besides her to watch her progress. Mil doesn't even spare him a glance, she feels that she is on the brim of an important discovery. After a while the astrophysicist clears his throat. Frowning, Mil looks up.

"Something wrong?"

"That's what I wanted to ask you. As doggedly as you concentrate on this tree, you must have made an interesting observation. Would you mind to share?"

Mil can't help but smile. It's easy to imagine Koshi fretting, afraid of her trying to keep important results from Spacecorp. Andrej smiles back. As a scientist himself, he seems to read her thoughts. She certainly doesn't mind discussing her working hypothesis with him.

"I'm trying to use a rather ancient method to solve the riddle of Emerald and its forest. Have you ever heard of dendrochronology?"

"Not really. This would mean 'the science of trees and time', am I right?"

"Exactly. It is the official name of something called tree-ring dating. While already Leonardo da Vinci knew that tree rings showed annual growth, the method took time to develop. Andrew Ellicott Douglass made the final break through in the early twentieth century."

"Wait, are you talking about the astronomer Andrew E. Douglass? The one studying the sunspots and canals on Mars?"

"I don't know about the canals on Mars. But he suspected a connection of sunspot activity and growth of tree-rings. From there he went on to become famous for his successes with dendrochronology. It's easy, actually. Trees growing in the same area under comparable climatic conditions develop comparable tree-ring patterns. Douglass logged the rings of recently felled trees and overlapped the patterns with older timbers from buildings and archaeological excavations. Thus he managed to assemble a continuous chronology of tree-ring patters reaching centuries back. In time he was able to exactly date individual trees by referencing them onto his standard chronology. This method revolutionised the archaeological sciences."

Andrej leans over the tree slice to study the ring patterns closely.

"The principle is clear. But with one single tree slice you can't work with this method."
"I can't date anything, that's true. It's also true that not all tree species grow regularly enough to be used in dating. But I do know this tree shows 9365 rings, with a high probability that they signify an annual growth dependent on the planetary rotation cycle around its star. 9365 years, that's older than any known tree on Earth. Douglass proved that growth stays in direct relation with climatic conditions. The rings mirror droughts, cold winters, and wet summers. Even events like volcanic eruptions and pest infestations leave their mark in the tree-ring patterns."

Andrej raises his eyebrows and runs his finger over the smooth, laser cut surface of the tree slice. The rings are only discernible as narrow lighter and darker zones. Mil follow his actions expectantly. She is convinced the astrophysicist guesses her thoughts. A knowing smile on his face proves her right.

"You found a method to look back into Emeralds history. And this is not even one of the bigger trunks, other might have far more rings. Maybe we will finally be able to find out why on this planet there are only plants and no animal life forms. Mil, that's brilliant!"