New study: Temperate Plants Love Milder Temperatures

View from near the top of Eagle Mountain, the highest point in Minnesota. Visible are the surrounding Misquah Hills and the North Branch of the Cascade River. Eagle Lake can be seen at the right of the photo, and Shrike Lake at the left. Photo taken by Douglas Kaye in 2006, from the last clear view near the end of the trail to the peak. Public domain image, source Wikimedia

View from near the top of Eagle Mountain, the highest point in Minnesota. Visible are the surrounding Misquah Hills and the North Branch of the Cascade River. Eagle Lake can be seen at the right of the photo, and Shrike Lake at the left. Photo taken by Douglas Kaye in 2006, from the last clear view near the end of the trail to the peak. Public domain image, source Wikimedia

Guest essay by Eric Worrall

A field study has suggested that plants growing in cool temperate regions respond well to milder temperatures.

The abstract of the study;

Boreal and temperate trees show strong acclimation of respiration to warming

Plant respiration results in an annual flux of carbon dioxide (CO2) to the atmosphere that is six times as large as that due to the emissions from fossil fuel burning, so changes in either will impact future climate. As plant respiration responds positively to temperature, a warming world may result in additional respiratory CO2 release, and hence further atmospheric warming. Plant respiration can acclimate to altered temperatures, however, weakening the positive feedback of plant respiration to rising global air temperature, but a lack of evidence on long-term (weeks to years) acclimation to climate warming in field settings currently hinders realistic predictions of respiratory release of CO2 under future climatic conditions. Here we demonstrate strong acclimation of leaf respiration to both experimental warming and seasonal temperature variation for juveniles of ten North American tree species growing for several years in forest conditions. Plants grown and measured at 3.4 °C above ambient temperature increased leaf respiration by an average of 5% compared to plants grown and measured at ambient temperature; without acclimation, these increases would have been 23%. Thus, acclimation eliminated 80% of the expected increase in leaf respiration of non-acclimated plants. Acclimation of leaf respiration per degree temperature change was similar for experimental warming and seasonal temperature variation. Moreover, the observed increase in leaf respiration per degree increase in temperature was less than half as large as the average reported for previous studies, which were conducted largely over shorter time scales in laboratory settings. If such dampening effects of leaf thermal acclimation occur generally, the increase in respiration rates of terrestrial plants in response to climate warming may be less than predicted, and thus may not raise atmospheric CO2 concentrations as much as anticipated.

Read more (paywalled): http://www.nature.com/nature/journal/vaop/ncurrent/full/nature17142.html

From the press release;

Plants may be better at acclimatising to rising temperatures and contribute less to carbon dioxide in a warming world than some have previously thought, a new study suggests.

Concern carbon dioxide from plant growth could make global warming worse in the future
Study suggests plants are better at acclimatising to rising temperatures than previously thought
This means they are less likely to become a net source of CO2 for the planet in the future
“Maybe some of our models are over-predicting the degree to which plant respiration will cause accelerating feedback that speeds up climate change,” said Professor Peter Reich, an ecologist and plant physiologist from the University of Minnesota who led the study published today in Nature.

Plants absorb carbon dioxide through photosynthesis and release it when they burn sugar to produce energy in a process known as respiration.

For every 10 degrees Celsius of temperature increase, plants are known to double their rate of metabolism, which has led to fears that global warming will trigger a positive-feedback loop, switching plants from being a net carbon dioxide sink — absorbing more carbon dioxide than they release — to becoming a net source of the warming gas.

According to Dr Reich, however, the jury is still out on how big this problem is.

The best models on the planet disagree wildly about what will happen in 40 or 50 years, with some saying that the land surfaces will still be a strong sink, but others saying they will become a big source,” he said.

Read more: http://www.abc.net.au/news/2016-03-17/carbon-dioxide-from-plants-less-less-of-a-global-warming-problem/7248052

The authors of the study reference another study performed in Australia, which suggested that elevated CO2 and warmer temperatures are mildly beneficial.

In my opinion, this study is yet more evidence that plants are adaptable – that a few degrees global warming would have a negligible impact, on most of the world’s ecosystems.


Added by Anthony

Here’s the press release

Plants’ ability to adapt could change conventional wisdom on climate change, U of M study finds

UNIVERSITY OF MINNESOTA

MINNEAPOLIS/ST.PAUL (3/16/2016) – Plants speed up their respiratory metabolism as temperatures rise, leading to a long-held concern that as climate warms the elevated carbon release from a ramped-up metabolism could flip global forests from a long-term carbon sink to a carbon source, further accelerating climate change.

However, a new University of Minnesota study with more than 1,000 young trees has found that plants also adjust – or acclimate – to a warmer climate and may release only one-fifth as much additional carbon dioxide than scientists previously believed, The study, published today in the journal Nature, is based on a five-year project, known as “B4Warmed,” that simulated the effects of climate change on 10 boreal and temperate tree species growing in an open-air setting in 48 plots in two forests in northern Minnesota. Scientists measured how much carbon dioxide the artificially warmed plants respired – released into the air via their leaves – and learned that over time, the trees acclimated to warmer temperatures and increased their carbon emissions less than expected.

Researchers increased temperatures at the test plots by 3.4 degrees C, an increase that might happen by the end of the 21st century, and learned that plants grown and measured at those higher temperatures increased their leaf respiration by an average 5 percent, compared to plants in ambient temperatures. Had the juvenile plants not been acclimated to the higher temperatures, their respiration would have increased by 23 percent over the plants in ambient temperatures.

The findings are important to climate change research because prior research with tiny plants in laboratory settings had found that warming over a period of weeks accelerated plants’ release of carbon much more than the Minnesota team found in the more realistic long-term forest experiment, which measured change from 2009 through 2013 and considered both experimental and seasonal temperature variations.

“This work is important because most global C cycle models ignore this respiratory adjustment and project accelerated climate warming because of elevated respiratory CO2 release,” says Peter Reich, professor of forest resources at the University of Minnesota, who led the project and is the paper’s lead author. “Now, with better data we can make those models more realistic. ”

“Although these results are ‘good news’ in the sense that the underlying physiology of plants is not going to make the warming of the planet radically worse, the problem we have created in the first place with our greenhouse gas emissions from fossil fuel burning still exists,” he says. “So, we very much still need to cut our carbon emissions in the coming decades by enough to stop climate change.”

###

 

98 thoughts on “New study: Temperate Plants Love Milder Temperatures

    • What is clearly obvious is that they completely ignore that photosynthesis also ramps up with more CO2 and higher temperatures. Why is that not measured? And the only talk about respiration? The comes from the We Know What Results We Want Department.

      • Growth happens because photosynthesis > respiration. Where is the biomass accumulation variable?

      • I must be misunderstanding this. I thought that Plants Breathed In CO2, used the C to make Sugar with H2O from the Roots, and breathe out O2 in their respiration process. The only tome CO2 was released was in the biomass decomposition process.
        But the study is indicating “As plant respiration responds positively to temperature, a warming world may result in additional respiratory CO2 release”
        Seems that they are indicating that Plants Breathe out CO2???

      • An alternate title based on their results could be, “Temperate Plants Defy Physics, Create Carbon Dioxide as They Grow Faster”

      • When temperature goes up enough, plant dies. No respiration. However, at the moderate temperatures of Minnesota, rising temperatures cause more growth in existing species. While respiration increases, the net effect is a negative feedback.

        Why this very obvious and easily measurable effect is ignored, is not really an enigma.

  1. I doubt Man-Made global warming. I also doubt that global warming will be catastrophic. The earth has been warming since that last ice age so if there is warming it likely has little to do with human beings. With increased CO2, which is good for plants, and strong plant amicability to milder temperatures, I can only expect huge increases in plant growth, better crop yields, and lower risk for world hunger.

    This is good for the world poor.

    Thanks Eric.

    • Anthony’s Update…
      “and project accelerated climate warming because of elevated respiratory CO2 release,” says Peter Reich”

      Increased respiration varies with increased plant metabolism, growth and therefore carbon sequestering in plant bodies. So the update, which negates the thrust of Eric’s spin, is nonsense and ignores plant mass increase. That is OK.

      The Big IF… CO2 > planetary temp increase?

      Peter Reich make that his initial, unfounded assumption, then he ignores biomass increase.

      Eric’s original slice of the release is valid since the hypothesis under Reich’s work is total propaganda.

      The UPDATE serves the broader discussion and serves WUWT’s truthiness, but the kernal of plant amicability to TEMP increase is, in itself, important.

    • Oh wait, then the liberals will start complaining about OBESE plants and demand we put them on a diet !

    • New Zealand is in the temperate zone.

      I’m fairly sure we learned in Geography class in school that the temperate zone means cooler. (milder)

      New Zealand is cooler; it is also cool; excuse me, that’s Way Cool !

      g

  2. I’ve been told that on hot, humid, quiet nights in July …… you can hear the corn growing. :) :)

    • Having grown up in the corn belt, I can attest to that.

      I don’t understand why there isn’t a counter PR blitz on the benefits of a degree or two warming. I guess the “Tomato harvest at all time high” headlines just don’t generate many clicks. “Incinerate”, “bake”, “roast”, “blast furnace” are just better headline words.

      Maybe in a few years “freeze”, “ice age”, “glaciate”, “chill to the bone” will finally make it to above the fold line.

    • That’s just what they tell the youngsters, so they don’t have to explain the Children of the Corn

  3. Just thinking about the Douglas Fir tree. It ranges from at least as far south as Colorado to middle Alaska. Such a wide range of growing conditions, I think it will be just fine with more food. With a temperature change of at least 80 degrees (F) in the above range, I doubt the Douglas fir will notice much change in temps either.

    • Same goes for the White Pine and all species of Oak, they grow in such diverse environments it’s hard to believe that plus or minus a couple degrees amounts to a hill of beans, which leads me to soy and white beans, where yields are also highly oblivious to variations in temperature that it becomes chicken scratch …

    • Well Douglas Fir goes way south of Colorado. It probably grows as far south as Wellington.

      But that could be because they changed the name to ‘Oregon Pine’.

      See how that works, it morphs from a fir to a pine, and then grows in an entirely new climate.

      g

      • Who dat Papatotara ?

        I know that Papatoetoe character, he’s close by Otahuhu, where I went to high school (name’s on the wall, second from the top)

        But Papatotara is a new one on me; where izzat ??

        Anyhow, Totara izza tree all by itself. So I guess it’s good that Oregon Pine grows near Papatotara.

        G

    • The Douglas-fir genus (Pseudotsuga sp.) occurs from Mexico to Alaska, from the Pacific coast to the east side of the Rockies, as well as in Kamchatka, Japan, China, and North Vietnam. That’s quite a few climatic zones.

      Pseudotsuga sp. has 13 haploid chromosomes. Other genera in the Pine family have only 12. Pseudotsuga sp. is a genetic freak, a super tree, the fastest growing, tallest, with the strongest wood, an invasive weed that will come up through cracks in pavement, sidewalks, and apparently solid rock.

      Douglas-fir will grow virtually anywhere, and has been widely planted (and grows phenomenally well) in diverse places including Chile, New Zealand, Scotland, and Germany.

      Douglas-fir won’t grow on solid ice (nothing will), but it was one of the first plants to invade western NA after the LGM (preceding even the Younger Dryas).

      Come Thermageddon and/or Nuclear Winter, humanity may well go extinct. But don’t worry about Douglas-fir; it will survive and thrive regardless.

      • Thanx for the Botanicals Mike.

        So I guess it is not surprising that Doug Fir is listed in books about structural materials. In fact I designed myself a bridge which was to have a Douglas Fir glue lami deck, made out of 14 ft long 6 x 2 Doug Fir planks. In fact I have a garage full of the planks I selected from the lumber yard. I would visit the place every weekend and go through all of their 14 footers, to select the few that I could find that were a superior grade. My short term memory can’t recall the structural grade designators, but I seem to recall there was a No.2 in there somewhere, as really the minimum for structural usage. I always bought only ones that were one or sometimes two grades above that, and didn’t have any knots.

        My bridge was required to be able to handle an H-20 truck load. You can’t legally drive an H-20 truck on any road in the USA, to even get up to my bridge.

        It’s a 20 ton truck with 16 tons on the rear duallies (8 tires on two axles), and 4 tons on the front two steering wheels.

        Actually, if the bridge is steel, and wood deck, a H-20 truck only needs to be 14 tons total; but 20 if it’s a concrete deck.

        My bridge could carry an A-1 Abrams main battle tank, with another one of those sitting on top of it.

        So that is interesting; there really is a botanical reason to use Doug Fir.

        G

      • By volume. However, atmospheric pressure is lower so the mass of CO2 (and the mass of O2) per liter is lower.

    • The atmosphere is constantly and thoroughly stirred, which almost completely negates density stratification.

      • Yeah, but the higher the elevation, the lower the atmospheric pressure. Still is 400 ppm, but distributed on a larger volume. The concentration in ppm does not change but the concentration in moles per liter does change.

        The enzyme that fixes CO2 is called Rubisco. The rate of carboxylation catalyzed by rubisco is related to the molar concentration of CO2, and that concentration decreases with altitude. It is logical, if the pressure is lower, the air composition does not change but there are less molecules in a liter of air. So the chances of a CO2 molecule hitting the active center of a rubisco enzyme are less. If the CO2 does not hit the enzyme, the tree cannot assimilate CO2, and it cannot grow.

        So, yes, elevation matters.

    • Well the tree line on Mt. Everest has never gone above Base Camp, so it doesn’t seem to pay any attention to CO2.

      g

    • I have a feeling that the density/gravity argument has relevance in a largely discredited application to planetary thermodynamics promoted by an infamous thread bomber….whom I will not mention. Density wrt metabolism of plants at the tree line is a different subject.

    • Yes, it does, but the effect is partially compensated by 1) lower O2 levels — oxygen inhibits photosynthesis, 2.) lower overall pressure, which accelerates gas diffusion. However, CO2 transport through the aqueous space in the plant tissue is not accelerated, so at that stage a slowdown happens. Plants respond with increasing the levels of CO2-fixing enzymes.

      It just so happens that I looked into this over the last couple of days.

      • Ok. Lucky us that you have looked into this. Since I haven’t looked into this, where do you fall on the general principle of increased temperature INCREASES atmospheric CO2? What of growth? How does that fall out?

      • CO2 and temperatures are closely associated in the ice core records, and the general idea is that is due to lower solubility of CO2 in warmer oceans.

        The effect of temperature on growth depends on CO2 availability. Reaction rates in general go up with temperature, and that also goes for plant biochemistry. However, the affinity of the CO2-fixing enzymes for CO2 decreases at higher temperature. So, when CO2 is plentiful, growth accelerates with temperature; at limiting CO2 levels, growth may decrease as temperatures rise.

    • Tree growth at higher elevations, yes, tree line elevation, no. The tree line is due to temperature, up to 5,000 m in the tropics and a few hundred meters at high latitudes.

    • Tree line and average temperature go “hand in hand”.

      So, going up in elevation or going north to the pole, the tree line follows.

  4. “Concern carbon dioxide from plant growth could make global warming worse in the future
    Study suggests plants are better at acclimatising to rising temperatures than previously thought”

    I’m in need of an explanation, but first, it is painfully obvious that a the modest warming and the CO2 fertilization has been greening the planet. I recall that a university’s research forest (Harvard?) a few years ago showed increased girth of the trees, etc. The question: how can warming which has resulted in net mass increase of vegetation result in increased CO2 burden in the atmosphere if the plant isn’t dying? Is this one of those half assed analyses where the actual net is increased sequestration of CO2, but because of the much more massive green life it respires more CO2 than before? This type of malarkey is a disgrace if this is what it is.

  5. Hmm… Nothing in either the abstract or the press release about how photosynthesis rates vary with temperature. The field of dendroclimatology relies on the idea that tree ring growth increases with temperature (at least for the cold end of a tree’s range). Increased growth obviously requires increased photosynthesis.

    This reminds me of the studies touting how air conditioning loads increase with warming (a positive feedback!) without ever mentioning how heating loads would decrease.

  6. This is obviously very important, although I had not heard of this before.

    All the O2 in the atmosphere comes from photosynthesis. Plants also respire, which uses up some of the O2 and releases CO2. Increased plant photosynthesis will reduce CO2, but increased respiration will increase CO2. The relative rates of change of these will affect the CO2 balance.

    The rate of respiration is not controlled as well as it is in warm blooded animals. If the temperature goes up, all else being equal we would expect respiration to go up as well. This would probably not be useful to the plant, since the previous respiration rate was adapted to its needs. Long term, we would expect plants to adapt to this, and reduce respiration at the higher temperature.

    However, in the short term we do not know how plants will respond unless we measure it. They may or may not be able to aclimatise (rather than adapt). This study shows how much these plants are able to aclimatise -about 80% of the “all else being equal” was aclimatised.

    • seaice1,

      You appear to believe that any increase in respiration is gratuitous and that plants just do it for fun.
      Respiration releases the energy accumulated by photosynthesis, such that metabolism proceeds and the plant grows; ie gets bigger.
      Getting bigger means sequestering more photosynthate as structural plant tissue.
      I would be interested to see your non-atmospheric source of carbon for plant respiration.

      • mebbe – have a look back at what I said. I did no suggest they do it for fun but that they may have little control over respiration rate. I said “This would probably not be useful to the plant, since the previous respiration rate was adapted to its needs.”

    • We have been measuring the changes for a long time, ever since we built the first actual Green House and increased the CO2 content within and we are not talking about a few 10s of ppm we are talking up to 1000-1200 ppm.
      ie double or treble normal.

  7. Interesting. So plant respiration puts carbon dioxide into the atmosphere. Apparently no one told them that this carbon dioxide originally came from the atmosphere and is being merely recycled, not created, as part of the plant life cycle.

      • UCSB Science Line

        ” Plants make a lot more oxygen than they produce CO2 (remember: most of the plant’s body is made out of carbon-containing compounds. That carbon didn’t get released as CO2 during the night, but the oxygen associated with it did get released). I don’t know when the minimum oxygen concentration is, but I guess it would be in the early morning shortly after dawn, as you say. Incidentally, temperature does the same thing, for related reasons (no energy coming in during the night…).”

      • If plants grow, they take in more CO2 thatn they put out.

        Simply as that. You don’t need to run a model on a one million dollar computer cluster. Heck, you don’t even need a calculator. You just have to think that if plants grow, it is because they take in more CO2 that they put out.

    • Almost all this CO2 is given off by roots and is consumed by carboniferous bacteria or remains otherwise sequestered in the ground. It’s heavier than air therefore remains in place generally until some ground water pushes a little out. Not much of it ever comes back out of the ground.

      Arno Arrak (@ArnoArrak)
      March 17, 2016 at 7:28 am

      Interesting. So plant respiration puts carbon dioxide into the atmosphere. Apparently no one told them that this carbon dioxide originally came from the atmosphere and is being merely recycled, not created, as part of the plant life cycle.

  8. Study: Plants love milder temperature. No kidding!! Ever seen trees growing in Arctic or Antarctica?

    • Gosh! Every plant species has an optimum! The delicate balance of Nature is about to trip over! /sarc

  9. “… these results are ‘good news’ in the sense that the underlying physiology of plants is not going to make the warming of the planet radically worse, …”

    The Obama administration has just announced that they are eliminating any future research grant funding to the University of Minnesota due to its apparent violation of federal affirmative action guidelines. The FBI has also launched an investigation into alleged abuse and assault charges concerning the men’s LaCrosse team and the men’s (what other kind are there?) fraternities at the University. The Treasury Department has launched its own investigation into allegations of university funds deposited in tax shelters in the Grand Caymans. The EPA is looking into claims that the University of Minnesota has violated the Clean Air Act. And, OSHA is investigation potential violations of university employee safety regulation rules. A potential EEOC lawsuit is alleged to be underway.

    Additionally, this reporter has been informed by anonymous sources that Professor Peter Reich’s tax returns are likely to be audited by the IRS; that, supposedly, a young undergrad is being pressured to claim he made unwanted advances; and he is going through a nasty divorce over it (although his marital status is unknown to the source, and the undergrad actually attends Oxford).

    “… the problem we have created in the first place with our greenhouse gas emissions from fossil fuel burning still exists,” he [Prof. Reich] says. “So, we very much still need to cut our carbon emissions in the coming decades by enough to stop climate change.”

    The Obama administration has just renewed future grant funding to the University of Minnesota; the FBI has found no wrongdoing; the Treasury Department has suspended its investigation; and the EPA, OSHA, EEOC, and IRS are attending to other matters.

    The University has suspended its termination proceedings against Prof. Reich following 30 lashes, and writing, ‘I will never be so stupid again’ 100 times on the blackboard (oops, I meant board of color).

    sarc

  10. Somebody got tax dollars to go out in the woods and warm up trees…. For 5 years….

    Oh yeah, that sounds like money well spent…. NOT.

    Have we properly accounted for the evil carbon emissions caused by warming up trees…..

    Leave the dang trees alone….#TreeLivesMatter

  11. Assuming the plant is maintaining constant mass, wouldn’t every molecule of emitted CO2 have to been absorbed from the atmosphere at some point in the past?

    • Exactly.

      The main point here is whether mature deciduous forests lose, gain or maintain constant mass, Since the trunk of the tree grows thicker as years pass by, my bet is on gaining mass. So, they consume more CO2 than they produce.

      • Not only that, many of them produce fruits, leaves and other “Litter” that unlike our green friends might want to believe persists for a long time. Each gram of this litter has a carbon dioxide cost. A lot of it is eaten by birds which preserve it for all time as superphosphate (bird poo).

  12. So is there a common denominator in the tree line for altitude and latitude? Is it the same as that for the difference in deciduous and conifer forest at lower altitude?

  13. How much of that extra CO2 was coming from the trees, and how much was coming from certain undergraduates taking advantage of being alone in the woods on a warm summer night?

  14. “The findings are important to climate change research because prior research with tiny plants in laboratory settings had found that warming over a period of weeks accelerated plants’ release of carbon much more than the Minnesota team found in the more realistic long-term forest experiment, which measured change from 2009 through 2013 and considered both experimental and seasonal temperature variations.”

    The real world is different than the laboratory. What a surprise.

  15. Truly Insane:

    Maybe some of our models are over-predicting the degree to which plant respiration will cause accelerating feedback that speeds up climate change,” said Professor Peter Reich

    They have a model which holds that plants are net producers of CO2.
    Mind boggling.
    “Maybe our models over-predict”
    This utterly beggars belief.
    A professor, no less, has no clue that plants are consumers of CO2, and has no problem writing about it.
    If I was that stupid, I would try to keep it to myself.

    • …Maybe they should read more ??

      UCSB Science…….

      ” During their lifetimes, plants generally give off about half of the carbon dioxide (CO2), that they absorb, although this varies a great deal between different kinds of plants. Once they die, almost all of the carbon that they stored up in their bodies is released again into the atmosphere.
      As you may know, plants use the energy in sunlight to convert CO2 (from the air) and water (from the soil) into sugars. This is called photosynthesis.Plants use some of these sugars as food to stay alive, and some of them to build new stems and leaves so they can grow. When plants burn their sugars for food, CO2 is produced as a waste product, just like the CO2 that we exhale is a waste product from the food we burn for energy. This happens day and night, but since photosynthesis is powered by sunlight, plants absorb much more CO2 than they give off during the daytime. At night, when photosynthesis is not happening, they give off much more CO2 than they absorb. While they’re alive, overall, about half of the CO2 that plants absorb is given off as waste.
      When you look at a tree, almost all of the body of the tree is made of sugars, which are made from carbon (from CO2) and hydrogen and oxygen (from water). When the tree dies, it rots as decomposers, like bacteria, fungi,and insects eat away at it. Those decomposers gradually release almost all of the tree’s stored carbon back into the atmosphere as CO2. Only a very small portion of the carbon in the tree ends up staying in the soil or washing out to sea without changing back into CO2. “

    • TonyL I cannot believe that Prof Reich believes that plants are net producers of CO2 , because , if true , it would appear to make nonsense of the reasoning behind deliberately growing plants for biofuels. Since fuels when burnt give CO2 and H2O , it would be seem to be better for controlling CO2 emissions to use fossil fuels where the plants responsible for the combustible material have long since stopped respiring than to grow, at the present age, the equivalent mass in plants that are net producers of CO2 even before they are burnt.
      Perhaps we should suggest that to save the planet we need to convert Drax back to coal as soon as possible – thank goodness the Chinese are leading the way .

    • Nobody with any brains buys pulp fiction about covering the surface of a sun-warmed rock with cold water 70+ %, then fanning it with frigid wind, and that making the rock hotter than if there was no frigid wind, and there was no chilled water.

      vukcevic
      March 17, 2016 at 9:12 am

      Guardian’s AGW stories aren’t selling as well as expected.
      “Guardian Media Group to cut 250 jobs in bid to break even within three years”
      http://www.theguardian.com/media/2016/mar/17/guardian-media-group-to-cut-250-jobs

  16. “Temperate Plants Love Milder Temperatures”

    Isn’t that definitional? If they loved cold temperatures, they would be arctic plants and if they loved hot temperatures they would be tropical.

    • Actually many temperate plants love warmer temps, but may loose competition to plants that require warmer temps. Net productivity depends on the whole biotope. And the more there is CO2, growing season, sun and rain, the better the plants grow.

  17. Fine to talk of plants / trees being able to “acclimate” to elevated temperatures but Previous studies have found that trees and plants are able to control the leaf temperature to the optimum level despite elevated temperatures. It seems they have not bothered to look at previous studies.

    Trees and plants produce more CO2 in higher temperatures when they are growing …. ???? that flies in the face of everything I have ever understood about photosyntehsis.

    • I was just trying to locate the link to this old post

      https://wattsupwiththat.com/2008/06/13/surprise-leaves-maintain-temperature-new-findings-may-put-dendroclimatology-as-metric-of-past-temperature-into-question/

      ” “The assumption in all of these studies was that tree leaf temperatures were equal to ambient temperatures,” lead researcher Brent Helliker told AFP. “It turns out that they are not.”

      Helliker and University of Pennsylvania colleague Suzanna Richter turned those assumptions upside down in examining 39 tree species, across 50 degrees of latitude ranging from sub-tropical Columbia to boreal Canada.

      They compared current observed records of humidity and temperature against the isotope ratios in the trees, and found that tree leaves were internally cooler than surrounding air temperatures in warm climes, and warmer in cool climes.

      Even more startling was that in all cases the average temperature – over the course of a growing season – was about 21degC.”

      • The assumption in all of these studies was that tree leaf temperatures were equal to ambient temperatures….

        Oh this is funny. Of course a plant will optimize its evotranspiration to available water and need to cool. It doesn’t want to fry!

  18. Experimental species field test results prove that Douglas fir survival is very poor east of 115 deg. lat and north of 54 deg. longitude. It has an extremely difficult time handling temperatures below -30C and many trees perish do to winter desiccation.

  19. Experimental species field test results prove that Douglas fir survival is very poor east of 115 deg. lat and north of 54 deg. longitude. It has an extremely difficult time handling temperatures below -30C and many trees perish due to winter desiccation.

  20. Who would have thaught that plants grow where they like it, And what they like is not just an average temperature, but the total climate at the place, being soil, wind, summer and winter, rain and drought.
    Plants is not diminished by changing climate as such, but because other species outperform them.

  21. Any gardener with a greenhouse knows that plants grow better in warmer environments with increased CO2 if possible. There is no reason for further study.

  22. I would have thought that regional changes in rainfall and soil moisture would have a bigger impact on land CO2 uptakes than changes in global mean surface temperature, and would itself cause much larger local temperature variability than mean global surface warming rates.

  23. My mate in Anchorage says he just cant get cactus to grow in his front garden.
    Does anyone have any clues as to why the cactus won’t grow?
    Is it because there is too much CO2 in Anchorage?
    If so, should we tell the people to turn off their central heating and walk to work?

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