Guest Essay by Kip Hansen
Last week I had the opportunity to attend a presentation by Dr. Seth Bigelow, previously of the US Forest Service and currently doing original Forest Adaptation Research at the Huyck Biological Research Station near Rensselaerville, New York (about 20 miles southwest of Albany). Dr. Bigelow has been conducting such research for 20 years.
Bigelow’s presentation focused on the results of his latest paper published in March 2014 in the journal Climatic Change entitled: “Faster growth in warmer winters for large trees in a Mediterranean-climate ecosystem” (journal article paywalled but a free full .pdf is available here).
The study, which took place in Plumas County, California, in the conifer-covered mountains at the junction of the northern Sierra Nevada and the southwestern end of the Cascade Mountain ranges, “analyzed growth rings of five conifer species against 20th century climate trends from local weather stations” in order to predict the “likely performance of large trees [those having breast-height diameter >76 cm / ~ 30 in] in a rapidly changing climate.” This is a question of high interest because of the generally accepted view that:
“Large trees are an iconic and functionally irreplaceable element of the lower montane mixed-conifer forest, and the steady rise in surface temperature in California throughout the 20th century has rightfully engendered concern about their performance, raising the specter of a positive feedback loop in which elevated temperatures due to anthropogenic carbon emissions inhibit the ability of trees to take up carbon.”
This climate change worry seems to have been put to rest by this study – at least for the large conifers studied at this location – in which the authors state that “Our findings may help to allay such fears as regards large trees.” The authors conclude that:
“Minimum winter temperatures have been a major determinant of growth of large trees in the lower montane mixed-conifer forest in northern California over the 20th century, eclipsing even precipitation in importance. The five species studied show increased growth with higher minimum winter temperatures, a pattern that was stronger and more prevalent than decreasing growth with higher summer maximum temperatures.”
This study that shows, as with temperature-related human mortality, that the lowest temperatures may be more of a determining factor of biological success or failure than highest temperatures, at least in the temperature ranges experienced today.
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Note: Dr. Bigelow’s current study, using tree rings and tree neighborhoods to understand growth in a changing climate in sugar maple, yellow birch and hemlock, is ongoing this summer at the Huyck Preserve Biological Field Station near Rensselaerville, NY. Dr. Bigelow welcomes volunteers. Contact the Huyck Preserve at 518-797-3400.
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Millar et al. looked at trees killed on Whitewing Mountain in the Sierra Nevada by a volcanic explosion in 1350. They concluded that between the years 815–1350 the climate was some 3°C warmer and slightly drier.
They write “The modeled Whitewing Medieval climate closely compares to climate projections for California in AD 2070–2099….Recognizing significant CO2 differences between future projected and Medieval climates, our empirical findings of significant increase in subalpine forest extent and diversity during similar climate conditions nonetheless raise questions about modeled results of future forest reductions in the subalpine zone.”
Late Holocene forest dynamics, volcanism, and climate change at Whitewing Mountain and San Joaquin Ridge, Mono County, Sierra Nevada, CA, USA
http://www.fs.fed.us/psw/publications/millar/psw_2006_millar027.pdf
Seems that they forgot to check whether increasing CO2 levels had any thing to do with plant growth!
” raising the specter of a positive feedback loop in which elevated temperatures due to anthropogenic carbon emissions inhibit the ability of trees to take up carbon.”
I read a paper, maybe 5-8 years ago, on the California land based temperature record. When the authors removed all the badly sited stations, they found no trend in CA temperatures for the past several decades. That is, there was no instrumental evidence of warming in California.
I can’t find this article now. Can anybody help?
Not a bristlecone pine in sight. And no reference in the bibliography to Michael Mann. I wonder why?
“…breast-height…” Is that a metric or English breast? Before or after three children and 40 years of gravity?
“nickreality65 says:
July 6, 2014 at 6:25 am
“…breast-height…” Is that a metric or English breast? Before or after three children and 40 years of gravity?”
That’s a standard lumber industry way of measuring a tree…
“Our findings may help to allay such fears”
I doubt it; they’re afflicted with the disease:
https://www.youtube.com/watch?v=I8ibl4nPmRE
I applaud the effort to insert calm rational evidence based science into the alarm machine though.
“The five species studied show increased growth with higher minimum winter temperatures”
——————–
If one has …. “higher minimum winter temperatures” …… does not earlier spring temperatures follow?
The quicker the ground warms up, ….. the quicker you can plant your potatoes.
These are lovely areas to hike, and that Whitewing paper ^^^is very interesting. Roughly 3.5 degrees warmer during the MWP?
Most of these trees are in very dry areas. I’d expect water stress (especially in late summer) might have more to do with growing seasons than minimum temperatures, but I ought to read the papers more carefully before saying that. But I’ve hiked some of these areas in August, and the mountain tops above the treeline are very dry & rocky. During the winter they are covered in snow (e.g. dry) and then by the end of the summer they are also dry. As usual, I have trouble seeing how to separate the temperature from the moisture component of historical tree studies…
p.s. Higher minimum winter temperature may actually be a proxy for winter water availability. When you ski these areas, you notice that even in areas with deep powder, there is a marked tendency around the base of these big evergreen trees to have what looks like melted snow at the base near the bark. I can’t help but wonder whether reflected sunlight is melting some of the snow right around the tree resulting in slightly more water flowing down to the roots during warmer winters. Freshly fallen snow frequently piles up near the trees, but after a few weeks of sun, you’ll see a gap between the snow and the bark leading down, sometimes though several feet of snow.
Found a good picture: http://www.theearthconnection.org/blog/wp-content/uploads/2010/02/snow-making-way-for-a-tree1.jpg
Nickreality65 inquires: ““…breast-height…” Is that a metric or English breast? Before or after three children and 40 years of gravity?”
Strangely enough, there is indeed an English breast height — 4.5′ (1.37m) and two metric breast heights (1.3m and 1.4m). As in many cases, the standard isn’t standard.
Ref: Wikipedia: http://en.wikipedia.org/wiki/Diameter_at_breast_height
Here’s an even better example: http://www.pyroenergen.com/articles10/images/bamboo-snow2.jpg
So higher minimum temperature may actually mean greater usable water in the winter…
joel says:
July 6, 2014 at 5:38 am
There is a short comment by Jim Goodridge in 1996 that help turn our host into a skeptic, see
http://www.scribd.com/doc/67524224/PDF-1996-Goodridge-Comments-on-Regional-Simulations-of-Greenhouse-Warming-Including-Natural-Variability
http://wattsupwiththat.com/2010/01/31/uhi-is-alive-and-well/
It features a graphic showing very little warming in low population counties and much greater warming in high population counties.
Digging up something involving weather stations will take more time than I have, was it a spinoff of the SurfaceStations project?
I am pleased to see this paper uploaded since it is relevant to the article by Willis onThe Revenge of the Climate Raparations.
In that article, I have made a couple of comments regarding what I see as a ‘false’ accounting scam that governments are using to close down coal powered generators in favour of biomass powered generators. See my posts at July 5, 2014 at 9:16 pm and at July 6, 2014 at 8:23 am (which is awaiting moderation).
We are told that biomass is carbon neutral in the sense that the CO2 that is emitted when biomass is burnt is offset by the CO2 that they absorbed during the lifetime of the trees. However, that reasoning is false since the position is either
1. We are cutting down virgin forest to be used for biomass and that virgin forest is not being replanted, or
2 we are cutting down a forest which is an existing carbon sink and would continue to act as a carbon sink if it were not cut down. If we cut down that forest and replant, all we are doing is replacing an existing carbon sink with the ‘exact’ same sink, so we are not thereby taking out any additional CO2. On a global basis nothing has changed and we are in the same position that would be the case if we never cut down the trees.
Burning biomass produces more CO2 than does burning coal or gas (it has a far lower calorific value and per tonne produces considerably less energy). Since biomass creates more CO2 emissions, if you desire to reduce global CO2 emissions you need to add an additional carbon sink. Replacing an existing sink with the ‘exact’ same sink does not achieve that result.
In my earlier post (July 5, 2014 at 9:16 pm on the Willis article), I stated that I thought the ‘false’ accounting was based upon the assumption that new young trees absorb more CO2 than old trees, such that replacing old trees with young trees absorbs more CO2. I could never see why that assumption was being made given the volume of a cylinder (compare growth of a large tree with that of a young tree) and the canopy of a large tree is much larger than that of a young tree so large trees have more leaves (or needles).
This paper shows the error in that assumption. Old trees are just as efficient at removing CO2 as young trees. There is no gain in CO2 sink in cutting down an old forest and replacing it with a young forest.
This paper therefore confirms why the switch to biomass is madness.
Moderators
My last 2 posts (one on this thread and the other on The Revenge of the Climate Raparations) are awaiting moderation. I can see no reason why that should be the case. I would much appreciate you advising why my posts are caught up so that I can amend my style or content to avoid that happening.
As I say, I consider my last 2 posts to be inoffensive and uncontroversial, so I can see no reason why they should be dragged into the net.
Your explanation would be much appreciated.
Thanks and kind regards
Richard Verney
Wow! Just Wow! During the first part of the Carboniferous Period during the Devonian had average temps around 68 degrees (F) with CO2 at around 1500 ppm. Then somewhere around the mid-point of the period, the Earth cooled to around 55 degree (F) with CO2 around 350 ppm.
The Carboniferous Period produced all that balck coal from plants the Greenies don’t want to recycle into more plants. Oh, and the Jurassic Period had around 1800 ppm. We’re actually starving our tomatoes today and, if Greens have their way, will kill them along with those the trees they hug so much.
One can deduce the Greens and our esteemed tree folks just don’t want the Earth never make coal again.
“The strong coherent response to increasing minimum temperatures bodes well for growth of large trees in Sierra/Cascades region mixed conifer forest under continued climatic warming, but these trees will still be under threat by the increased fire intensity that is a indirect effect of warming.”
Yes, of course. Even though any observed increase in fire intensity probably has more to do with poor forestry practices and fire supression, leaving more available dead wood available as fuel. But yeah, in the future it will happen, because the CO2 climate wizards know all, and can see all.
The one in this thread contains the word “madness,” which might have got caught in the filter. (I’ll know when I hit the button on this comment.)
@ur momisugly richard verney: Bingo! “M*dness” triggered the moderation filter.
but tree rings
but a hoaxed temperature series.
but the pause.
funny how we forget things when we like the answer
Reply: and funny how you insert the word hoax regarding temperature series when I don’t recall having ever published anything here saying that was a hoax.
Not helpful.
My position has been and always has been that the temperature record is over adjusted and does not deal with long period Signals such as UHI and station encroachment very well. Anthony
oh my
“Monthly precipitation and minimum and maximum temperature data were obtained from
four weather stations within the sampled area (Fig. 1; URL: http://www.wrcc.dri.edu). Precipitation
data were averaged at monthly intervals then summed based on a hydrologic year beginning in
November. Temperature data were gap-filled, averaged at monthly intervals, extrapolated to
1,400 m elevation based on l”
they filled gaps and extroplated.. thats not real data, thats adjusted, made up, data
/snide off
/sarc off
One of the reasons folks like NOAA create in filled, adjusted data series, one of the reasons folks
extrapolate and interpolate is Other science ( like this study) need the best estimate of data in places
where you dont have a station. So, for example, the forest management guys use this kind of data
when they dont have a thermometer exactly where they need one.
They have a practical need and this data fulfills that use.
Yes but when you have eight thousand thermometers and Gavin says 50 or so will do what’s the point in doing all this extrapolation?
cedarhillr says:
July 6, 2014 at 9:03 am
Do you mean “and during the Devonian”, which Period preceded the Carboniferous? CO2 fell during the Devonian, perhaps thanks to the spread of land plants, which responded to the drop by evolving more stomata, offering a selective advantage to large laminate leaves. Its level declined even more during the Carboniferous. At the same time, O2 increased. In the Late Devonian, the first semi-terrestrial vertebrates (tetrapods) evolved from lobe-finned fish, then developed shelled eggs in the Early Carboniferous, freeing our ancestors from the need for water to reproduce.
Reply to Indur Goklany: Comparing across the 20th Century for CO2 induced growth should then have presented general increasing growth pattern similar to CO2 atmosphereic concentrations for them same period. This is not what Bigelow found.
Reply to joel: Dr. Bigelow co/mpares tree growth rings with reports from four local weather stations. “Monthly precipitation and minimum and maximum temperature data were obtained from four weather stations within the sampled area. Precipitation data were averaged at monthly intervals then summed based on a hydrologic year beginning in November. Temperature data were gap-filled, averaged at monthly intervals, extrapolated to 1,400 m elevation based on locally computed lapse rates, and averaged by season”. Thus, the data that there has been “no trend in CA temperatures for the past several decades” is irrelevant to this study.
Reply to nickreality65: “Breast-height” is an generic measurement used in the timber industry and amongst arborists. Thanks to the several readers [mjc, and others] who answered this for nick.
Reply to John West: Science advances by this mechanism: a common “everybody knows that…” is investigated scientifically someone like Dr. Bigelow and found to be false. Rather, the scientist finds that something else is the case. Knowledge is now advanced “uno pocito” — fake latin for a little bit.
Reply to Samuel C Cogar: Your question “If one has “higher minimum winter temperatures” …… does not earlier spring temperatures follow?” Early springs are not directly related to “minimum winter temperatures”. In layman’s terms, we might call a winter with a “higher minimum winter temperature” a MILD winter, and a winter with a very low minimum temperature a HARD winter, neither of these relate to the length of winter, or the arrival of the melt and growth seasons. Here in NY State, we can have short, hard winters, or long mild winters, or any combination of hard/mild and short/long (along with al the other variables — snowy, rainy, dry, etc).
Reply to Ashby: “As usual, I have trouble seeing how to separate the temperature from the moisture component of historical tree studies…” Read Dr. Bigelow’s study at http://www.forestadapt.org/bigelowpapaikcaumnorth.pdf It is only 11 pages, and quite informative.
Reply to Bruce Cobb: re: “trees will still be under threat by the increased fire intensity that is a indirect effect of warming.” You are right, of course, Bigelow states in his conclusion: “Vigilant forest management will nonetheless be required to protect and recruit large trees, which despite their exceptional fire resistance are still vulnerable to the increasingly large, intense, and frequent fires characteristic of present-day western conifer forests.” Included in this statement is the fact of the negative results of a long-term fire-suppression regime in the region.
Reply to Steven Mosher: Read closer — and more accurately. This is a study of tree growth as indicated by tree rings compared against three local measured climatic factors — taking data from the raw records of four local weather stations. It is a million intellectual miles away from trying the reverse — turning trees ring records into a thermometer.
Please try to keep your criticisms germane to the topic at hand. If you have issues with the use of proxies of various types, management and adjustment of climatic records and use of historical climate data with the host of this blog (or any other individual, other than my self), please take it up with them by private email. Otherwise, you are just “mouthing-off” — like a bully on the schoolyard.