SF Chronicle, Ariz. Daily Star, New Scientist: Ancient trees growing faster than ever. Maybe it’s the CO2??
Out in the side halls of the debate, such as it is, over global warming is the issue of CO2 fertilization. That is, aside from warming things up and turning oceans more acid, CO2 can stimulate plant growth (unless their growth is squelched by some other nutrient or water shortage). Ergo, CO2 good, IPCC bad.
Now along comes news that one iconic species, the Bristlecone pine tree of which some individuals are thousands of years old, appears to be putting on growth rings now that are fatter than any they’ve ever been before. Soon’s I saw the headlines I thought CO2 Fertilization by golly!!
Or, maybe not. The lead hypothesis, it appears, is that it’s simply gotten warmer, and hence more hospitable for the trees, high in the White Mountains along the California-Nevada border and in other Great Basin peaks where they grow.
Anyway, a few outlets jumped on the news given extra prominence by press releases including one from the National Science Foundation (in Grist below).The formal publication, by researchers at the universities of Arizona, or Western Washington, and Minnesota, is in the Proceedings of the Nat’l Acad. of Sciences. Which I just looked at as I write. The news stories below don’t say very much about CO2 fertilization but the paper does. It calls it an unlikely cause. The growth spurt is restricted to the uppermost part of the trees’ range. Temp changes are distinct there, not so for CO2.
In fact, the paper has far more ifs and maybes and other qualifiers than does the press release. But its authors are emphatic: at and near treeline the late 20th century has seen bristlecone pine growth rings of unprecedented width. And they looked at more than 20,000 rings.
Stories:
- Arizona Daily Star- Tom Beal: Tree Growth Faster At Higher Elevations / Rapid Warming Cited ;
- San Francisco Chronicle – David Perlman: Bristlecone growth may reflect global warming ; Perlman cites another phenomenon in his lede – coral growth – which as it happens is topic of another post a few items down. Story is written by a man who has looked at bristlecones himself, back when they were younger, and who called the PNAS paper’s editor, a Stanford man, for more detail.
- Redding Record Searchlight – Doug Craig: Meanwhile, Some Trees are Thriving ; This tiny paper gives the story a nice ride, but mainly by rewriting (with citation) the version in New Scientist.
- New Scientist – Shanta Barley : Climate change gives ancient trees growth spurt ; Barley gets a distinct angle – by growing faster the old trees may be flirting with a quicker demise. But there’s a big maybe on that.
Grist for the Mill:
NSF Press Release ; Univ. of Arizona Press Release ; PNAS paper ;
- Charlie Petit
