While researching for one of WUWT’s previous posts by Caleb Shaw, which is a must read essay on the simple things that can explain tree ring records to scientists that have never actually touched the tree or understood its local growth environment, I came across this photo of two larch trees in the Kotuykan river area of Siberia, not far from the Yamal peninsula. The photographer stated that an accompanying scientist who is familiar with the region named the two trees “Tyranny and Freedom” because of the differing situations they had been exposed to.
The question: which of the two trees below is the oldest?
The researchers write:
Forest ecologist Slava Kharuk called this a picture of tyranny and freedom. The trees are growing at the top of a mountain in the Siberian Traps. The climate at the location is near the limit of the coldest temperatures larch trees can tolerate. The smaller of the two trees in the foreground is many centuries older than the bigger tree.
Dr. Kharuk describes the tree on the right as living under the tyranny of colder climates of the past. It grew slowly: its form is twisted, its needles are sparse, the diameter is small, and it is not very tall. The younger tree has grown, he says, under the freedom of recent, milder climates. It is shooting up tall, straight, and full. It grows a relatively large amount each year, which results in a larger trunk diameter. (Photograph by Jon Ranson.)
In the cold Siberian climate, trees reproduce slowly. These larch cones document three years of growth. The lightest, reddish cones in the foreground are this year’s cones, which are forming and have not yet released their seeds. The medium-brown cones are from last year’s growth. The darkest brown cones are fully open and spent, yet still hang tenaciously on the tree. (Photograph by Jon Ranson.)
The harsh climate of Siberia is a challenging one for Larch trees. The photo shows the fates of several trees. A tree without bark or branches leans across the center of the photo. This tree died centuries ago, but the frigid climate has kept it from decaying. In the foreground, a tree that broke at the trunk and toppled managed to survive: a side branch grew into a vigorous new tree. In front and to the right of the “reborn” tree is a small dead tree that still has branches and bark. It is an ancient tree that died recently. In its last years, it put energy into making seed. Pinecones from the previous two years still cling to its branches. (Photograph by Jon Ranson.)
While the notion of temperature differences being the driver for the trees “Tyranny and Freedom” might be valid:
Dr. Kharuk describes the tree on the right as living under the tyranny of colder climates of the past. It grew slowly: its form is twisted, its needles are sparse, the diameter is small, and it is not very tall. The younger tree has grown, he says, under the freedom of recent, milder climates.
Without looking at all of the growth factors, one can’t be certain what is the true reason for growth difference. One tree might have better access to water or more nutrients available to it. We just don’t know, anything pinning a cause without a thorough investigation of the tree health and soil is simply speculation.
The idea posed by Caleb Shaw in this previous post seems to be well illustrated by these photos:
The bristlecone records seemed a lousy proxy, because at the altitude where they grow it is below freezing nearly every night, and daytime temperatures are only above freezing for something like 10% of the year. They live on the borderline of existence, for trees, because trees go dormant when water freezes. (As soon as it drops below freezing the sap stops dripping into the sugar maple buckets.) Therefore the bristlecone pines were dormant 90% of all days and 99% of all nights, in a sense failing to collect temperature data all that time, yet they were supposedly a very important proxy for the entire planet.
So in the case of larch trees in Siberia, how much of the time are they recording temperature? Without the proper metadata from Briffa telling us where these trees were situated, figuring out the response of trees like the now famous YAD06 is a tall order. Even with the metadata, when you find such wide variations in tree response growing next to one another, it isn’t much help. The only thing that can help is a large sample size so that individual responses like what we see in the core, YAD061, are statistically minimized in total impact.