Thursday, September 14, 2017


Bristlecone pines rank among the slowest growing organisms on Earth-  their girth increases by roughly a meter per millennium, and some have sat atop  the California tree line since before the invention of writing.  As the world's oldest trees, they naturally contain the world's oldest living climate record, reflected in the rings of their growth, and play an important role in efforts to understand palaeoclimate.

But they record a lot more than changes in the weather over time- each  set of rings is a palimsest overwritten by changes in ecology that change micronutrient availability, a capsule history of all the natural fertilizers left behind by generations of animals, dead and alive. In the last half century isotopic systemics and mass specroscopy  have done much to improve and deconvolute the proxy climate record tree rings provide, much as  they have figured in advances in atmosphic chemistry and transport.  Most observers embrace this as normative scientific progress, but some deny the most advanced  instrumental results in favor of 19th century  natural history- guess who?

Study reveals that Mann’s Bristlecone pine trees may not be good “treemometers” after all

Dr. Michael Mann used tree ring core samples from Bristlecone pines in the Western United states as one of the most heavily weighted proxies used to make his infamous “hockey stick” Now it seems that even though temperature in these areas has been rising, the Bristlecones aren’t responding to it by increasing their range, and other tree species are jumping ahead in the same area.
I pointed out some years ago that Mann didn’t seem to be aware of Liebigs Law of the Minimum which regulates plant growth."

Mike Mann is indeed aware of it- the problem is Watts  incomprehension  of  its  biogeographic meaning- or lack thereof : he  glosses over  the obvious fact that anthopogenic climate change has already contributed to species displacement in  the former Chico TV weatherman's own Californian back yard: Changes that have nothing to do with limiting trace elements or Liebig, who, born in 1803, is better remembered for inventing bullion cubes:

Watts links to 
 Global Change Biology, article that far from criticizing the "hockey stick," or discussing Liebig's Principle, 

"shows that the tree line has been steadily moving upslope over the past 50 years in the Great Basin. The region extends from California’s Sierra Nevada, across Nevada to Utah’s Uinta Mountains. Its north and south are framed by the Columbia and Colorado rivers’ watersheds.
The study also found that limber pine is successfully ? “leapfrogging” over bristlecone pine. They are growing in soils once almost completely dominated by bristlecone pine, and they are moving upslope at a faster rate than the bristlecone pine...
Earth’s oldest trees in climate-induced race up the tree line
Bristlecone pine trees in great basin are losing game of leapfrog with limber pine

Smithers said he doesn’t expect bristlecone pine adult trees to be impacted much by current climatic shifts, as those trees are well-established. But how, if and where new bristlecone pine trees will regenerate is less certain, particularly as other species like limber pine take up valuable space for them to germinate.
“The things we’re doing today have legacy effects for thousands of years in the Great Basin,” Smithers said. “When those trees do start to die, they won’t likely be replaced because it’s just too hot and dry.”
The study suggests that land managers identify the specific bottlenecks for a species to live long enough to reproduce, and focus on that stage. For long-lived trees like bristlecone and limber pines, the bottleneck is at the time of their initial establishment, not hundreds and thousands of years into their adulthoods."