Climate change is helping older trees grow better

From the American Geophysical Union and the Mann-o-matic school of treemometer proxies, comes this news that on the surface looks good, but as in the case with any climate news, has disaster lurking in the future.

Climate change is giving old trees a growth spurt

WASHINGTON–Larch trees in the permafrost forests of northeastern China–the northernmost tree species on Earth – are growing faster as a result of climate change, according to new research.

A new study of growth rings from Dahurian larch in China’s northern forests finds the hardy trees grew more from 2005 to 2014 than in the preceding 40 years. The findings also show the oldest trees have had the biggest growth spurts: Trees older than 400 years grew more rapidly in those 10 years than in the past 300 years, according to the new study.


Tree rings collected from old-growth Dahurian larch trees. Trees grow one ring per year.
CREDIT Xianliang Zhang

The study’s authors suspect warmer soil temperatures are fueling the growth spurts by lowering the depth of the permafrost layer, allowing the trees’ roots to expand and suck up more nutrients.

The increased growth is good for the trees in the short-term but may be disastrous for the forests in the long-term, according to the authors. As the climate continues to warm, the permafrost underneath the trees may eventually degrade and no longer be able to support the slow-growing trees.

No other tree species can survive the permafrost plains this far north, so if the larch forests of northern Asia disappear, the entire ecosystem would change, according to the study’s authors.

“The disappearance of larch would be a disaster to the forest ecosystem in this region,” said Xianliang Zhang, an ecologist at Shenyang Agricultural University in Shenhang, China, and lead author of the new study in AGU’s Journal of Geophysical Research: Biogeosciences.

Earth’s hardiest trees

Dahurian larch is Earth’s northernmost tree species and its most cold-hardy: These larches are the only trees that can tolerate the frigid permafrost plains of Russia, Mongolia and northern China. Chinese locals refer to Dahurian larch as “thin-old-trees,” because they grow slowly in the thin active layer of soil above the permafrost and can live for more than 400 years.

Permafrost regions around the world have been thawing in recent decades due to rising temperatures, sometimes degrading into swamps and wetlands. In the new study, Zhang and his colleagues analyzed growth rings from more than 400 Dahurian larch in old-growth forests of northeastern China, the southernmost portion of the tree’s range, to see how the trees are faring in a warming climate.

Tree rings allow scientists to measure how much trees grow from year to year. Much like people, trees do most of their growing while young. Dahurian larch generally grow rapidly until they become around 150 years old, at which point their growth slows. When the trees hit 300 years old, their growth basically stalls.

The researchers used the width of each tree’s growth rings to calculate how much area each tree gained in cross-section each year over the course of its lifetime.

The results show Dahurian larch trees grew more from 2005 to 2014 than from 1964 to 2004. Interestingly, the effect was most pronounced in the oldest trees: Trees older than 300 years grew 80 percent more from 2005 to 2014 than in the preceding 40 years. Trees between 250 and 300 years old grew 35 percent more during that time period, while trees younger than 250 years grew between 11 and 13 percent more.

The old trees’ growth is unusual – it’s akin to a 100-year-old person suddenly getting taller, according to Zhang. The authors suspect older trees are growing more than younger trees because they have more developed root systems that can harvest resources from the soil more efficiently.

The researchers compared the trees’ growth rates to climate factors like soil temperatures and precipitation data over the past 50 years to see what was causing the unusual growth. They found increased soil temperatures, especially in winter, are likely powering the growth spurts. They suspect the warmer temperatures lower the depth of the permafrost layer, providing the trees’ roots more room to expand and access to more nutrients.

While this initial soil warming has benefitted Dahurian larch, further permafrost thaw could likely decrease tree growth and even cause the forest to decay, according to the authors. Dahurian larch can’t survive in wet conditions, so permafrost changing to wetlands or peatlands would be detrimental to the forest as a whole, they said.

“If the larch forest retreat in this region in the future, it is also not a good sign for the whole boreal forest,” Zhang said.

While other research has examined the effects of a warming climate on temperature-sensitive trees in North America, the new study examined temperature-sensitive trees in permafrost areas, which have been less widely studied but are a vast component of the boreal forest, said Erika Wise, an associate professor of geography at the University of North Carolina – Chapel Hill, who was not involved in the new study. Additionally, previous studies on these larch trees have focused on the effects of air temperature and precipitation, but the new study looked at the influence of ground surface temperatures, which has also not been studied widely, she added.

“Their arguments make a lot of logical sense in terms of why the trees might benefit from the increased winter ground surface temperatures, which is that especially things like an earlier spring thaw could really help trees get growing earlier, more ability to have root activity in the cold months, these sort of things would make sense in why trees would benefit from warmer winters in particular,” Wise said.

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The paper: http://dx.doi.org/10.1029/2018JG004882

Warmer Winter Ground Temperatures Trigger Rapid Growth of Dahurian Larch in the Permafrost Forests of Northeast China

Abstract

Permafrost degradation due to rapid increase in ground surface temperature (GST) in recent years may strongly affect boreal forest ecosystems. However, comparatively few studies have explored how changes in permafrost affect tree growth dynamics in boreal forest. Here, we used a tree ring network of 12 Dahurian larch (Larix gmelinii) sites across permafrost regions in northeast China. We observed an increase in L. gmelinii growth over the past decade, seemingly linked to a shift in their climatic limitations, where winter GST has become the most strongly limiting factor for L. gmelinii growth. The recent increase in growth was particularly strong in older trees (>300 years), which could be related to older trees having a more developed root system. GST was the main limiting factor for tree growth. While summer GST had a somewhat consistently positive correlation with tree growth, winter GST has shifted from a negative to a strongly positive correlation with growth in the last decade, coincidental with a sharp increase in winter GST since 2004. Winter GST is also strongly correlated with the rapidly thawing permafrost dynamics. Overall, our results suggest a link between recent changes in the permafrost and shifts in climate‐growth correlations for one of the main boreal tree species. As a result, L. gmelinii has experienced an important increase in radial growth that may indicate that, unlike what has been reported for other boreal species, it may temporally benefit from warming climate in the continuous permafrost region of the Asian boreal forests.

Plain Language Summary

Dahurian larch (Larix gmelinii) is widely distributed in northeastern Asian boreal forests and the only tree species that can endure the extreme cold climate in the permafrost plains of Asian boreal forests. Permafrost regions have degraded greatly with the rapid warming in the recent decade, posing a serious threat to the survival of larch. We sampled a tree ring network of Dahurian larch from the southern edge of its natural distribution to detect how climate warming has influenced larch growth in the permafrost regions. Our results showed that soil temperature is the dominant climatic factor limiting tree growth. With increasing soil temperatures, larch showed a rapid increase in growth in the last 10 years, especially pronounced in older trees. This unusual phenomenon was linked to a sharp increase in winter soil temperature, which determines the soil freezing depth of the permafrost. We also found that the larch grew more quickly in the region where the soil freezing depth is shallow. We concluded that warmer winter soil temperatures have caused an increase in larch growth in recent decades.

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58 thoughts on “Climate change is helping older trees grow better

  1. No other tree species can survive the permafrost plains this far north, so if the larch forests of northern Asia disappear, the entire ecosystem would change, according to the study’s authors.

    Kudos for utilizing the word “Change” rather than a term more fear inducing.
    Change, they will…Change, the world does…there is no Climate Stasis.

    Guaranteed, if the Larch fails to maintain it’s hold on the zone, something will move in that can adapt to the environment

    • I reckon instead of using the term “climate CHANGE” we should be saying “climate SWINGS”

      • I agree. All other things being equal (astronomical influences etc) Climate ”change” in the current definition is in my opinion, impossible.
        A one degree shift in temps is not climate change and either is the supposed weather variation which results from it. Swing is a much better term and a swing over thirty years or 100 years does not change the underlying dominant climate which is determined by a region’s position on the ”ball”
        Temperate, tropical, polar etc; climates will remain. Everything else is weather.

        • Yup, yup, Mike. Temperature is not Climate.

          You wrote, […] the underlying dominant climate which is determined by a region’s position on the ”ball”, which I liked. It gave me a nice way to visualize the whole gamut of climates instead of thinking about the regional climates one at a time.

    • ” ….there is no Climate Stasis”
      Which prompts the question; do we have evidence that there has ever been a period of climate-stasis?
      -say, two thirty year periods where the climate has remained the same?
      Perhaps two 30 year periods is too big an ask given the length of the meteorological record. But what would be a time period that would be fair to those worried about climate change?

  2. Ho hum. Another study providing interesting facts about trees in the far northern reaches of China, which seem to have benefited from the “ever-warming climate change” taking place in the PAST 100 YEARS.

    But then, the authors go on to speculate about the future of these kinds of forests in general, while admitting that not a whole lot of study has been done on the phenomenon of how and why these trees grow at the rate they do and how they utilize the forest conditions. Extrapolation much from so little?

    I wonder how well these trees grew when everybody was panicking about the new ice age that was coming in the mid-1970s. After all, they were talking about the past 100 years.

    I may not know much about science, but I can smell a rat when it shows up.

  3. Maybe, just maybe, it has something to do with increasing CO2! Do they have any proof of increasing temperatures thawing the permafrost? Generally global temperatures have been static for about 20 years, and if anything are very slowly reducing. Correlation is not proof of causation – how many times do we have to point this out?

    • My first thought exactly. They went right to soil and minerals,.. avoided the air mix of fertilizer increase — rest of the plants like it,.. why not the rare perms plants,…

    • China has no CO2 comrade. China is green. So the glorious Peoples Party has decreed. Only the decadent Imperialist nations have CO2.

    • Yes, my first thought as well. The more than 50% increase in CO2 over the last century will have a significantly larger effect on plant growth then a few tenths of a degree of warming, especially since CO2 ‘warming’ primarily affects nighttime temperatures.

  4. The old trees’ growth is unusual – it’s akin to a 100-year-old person suddenly getting taller, according to Zhang. The authors suspect older trees are growing more than younger trees because they have more developed root systems that can harvest resources from the soil more efficiently.

    Not so fast Zhang… People don’t get taller once they reach maturity, they get shorter due to compression of their spinal columns. Not I suppose you could get taller by an inch or so if your disks were suddenly rejuvenated but it would be more akin to a 100 year old suddenly having the body of a 20 year old (if the trees were putting on mass as they did when they were 50 instead of 300

  5. Because having larch north of its current extent, where no trees currently grow, and having pine and birch displace larch at the southern end of what is currently larch range, would be a catastrophe!

    The reflexive assumption that “change” is always, necessarily bad is the very definition of “reactionary.” It’s an appellation traditionally reserved for conservatives, but it is a strange fact that, these days, it is fits liberals much better.

    • You beat me to this comment. Exactly right. If it’s temperature driving this, and not CO2 fertilization. In fact, the next study ought to look to see if larch is expanding northward beyond its current range. If it is, that’s a finding that supports the temperature change theory. If it’s not, that’s data in favor of the CO2 fertilization explanation.

      • I am surprised CO2 doesn’t get a mention at all. Surely the concentration has an effect?

        Also consider that the CO2 level in the forest may be significantly higher than the global average due to emissions from the ground.

        • Bingo Crispin!

          “The study’s authors suspect warmer soil temperatures are fueling the growth spurts by lowering the depth of the permafrost layer, allowing the trees’ roots to expand and suck up more nutrients.”

          Assumption drives their conclusions, not research.
          Not that they are likely competent enough to test CO₂’s influence. Especially when they allow confirmation bias to drive their conclusions.

      • If it’s temperature driving this,

        ”YES”, ….. temperature is driving this.

        The temperature of the ocean waters is rising.

        The rising ocean water temperature is causing both a rise in CO2 and a rise in wintertime near surface air temperatures.

  6. 400-year-old larch trees miss the medieval warm period. I wonder how they survived through it if increased temperatures are a threat now?

    Were any thoughts given to CO2-fertilization being the cause of rejuvenated geriatric trees?

    Inquiring minds want to know.

  7. …”Much like people, trees do most of their growing while young.”
    =============
    To a hammer everything looks like a nail.
    Ask any hammer.

  8. A special kind of genius is required to take results about trees becoming so unexpectedly healthy that they experience unprecedented growth, and make it a story about how this threatens to wipe them out.

    If growth had stalled, what would the story be about?

    I have a wild theory that if the permafrost gives way to soils that other trees can survive in, they’ll begin to replace the larch, which will gradually take root further North.

  9. I propose that we start a movement to transform the phrase, “climate change” to “climate change-for-the-better”.

    The implication now is “climate-change-for-the-worst”.

    Life has always been about change.

    • I like “Climate Progress” myself, it is short and to the point.

      Best of all it will cause the self-defined “Progressives” heads to explode.

      • When I refer to planned new streets, water mains, san swr, etc. as property improvements I always watch for the reactions of the bureaucrat on the other side of the counter to see if they are an anti.

        The hard core Anti’s have to consciously control their reactions.

        “Climate Progress” will be one of my new favorite terms.

  10. Bosh. Larches grow far beyond northern China. The east Siberian taiga, ya know, is dominated by larch and extends nearly as far north as the Arctic Ocean.

  11. FFS, just trying to interpret their Fig. 1a is like trying to interpret instructions from one of these small Amazon vendors that ship directly from China.

    The species ranges from just north of 40 degrees, on the coast around Peter the Great Gulf, all the way to the Arctic Ocean, something tells me there is more than permafrost that controls this species’ distribution.

  12. and can live for more than 400 years.

    I see, so they are an invasive species…..it’s been a lot warmer before

  13. ‘Larch trees in the permafrost forests of northeastern China–the northernmost tree species on Earth – are growing faster as a result of climate change, according to new research.’

    A contrived factoid. What does ‘the northernmost tree species’ have to do with a story of trees in China? The Dahurian larch trees in northeastern China certainly aren’t the northernmost. They’ve got them up in Siberia.

  14. So the people who like to talk at length on the global-warming chat shows about how well trees will grow in the future (or even now), essentially don’t know jacksh, right?

    Who’d have guessed it?

  15. Tell me something I don’t know.
    A few years ago I went on an Alaskan tour. Near the road between Denali and Fairbanks were growing Black Spruce trees, short evergreens. The tour guide explained that they were the trees that grew best there because the root system was shallow. As the permafrost melted, other, larger trees moved in because the lack of permafrost allowed trees that needed deeper root systems to survive. I assume that the tour guide was correct. If not, tell me.

    I don’t recall Northeastern China being as close to the Arctic Circle as Fairbanks is. Therefore either those Black Spruce trees grew farther North than the Chinese Larch trees or the Larch are not the Northernmost tree species on Earth.

    Which is it?

    • It is the northernmost tree species. It grows to 73 north in Taimyr in Siberia. Those trees in Heilongjiang are at about 53 north and are among the southernmost of their species. The absolute southern limit is at about 41 degrees in North Korea. So it extends from the latitude of Chicago to about 100 miles north of Point Barrow.

      I think European White Birch might some second. It extends well north of 70 degrees in Norway.

      • Thank you. Now that we know that the Larch trees are growing better in the Southernmost pat of their range, I wonder if they are also growing better in the Northernmost part of their range.

  16. Admittedly the trees in Heilongjiang is close to the species southern limit. However it will definitely grow on non-permafrost soil. There are experimental plantations in Sweden for example. However it grows too slowly to be a good timber tree, even in a milder climate.
    This is probably the most widespread and most numerous of all coniferous trees, and if climate grows warmer it will probably become even more numerous. During the previous (warmer) interglacial it extended all the way to the northern coast of Siberia and even grew on Lyakhov island, the southernmost of the New Siberian Islands.

    “These larches are the only trees that can tolerate the frigid permafrost plains of Russia, Mongolia and northern China”

    Nonsense, I’ve seen them grow mixed with Pinus sylvestris, Pinus cembra, Picea obovata and Abies sibirica on permafrost. However it is true that they go further north than any othes species. Pine extends to 70 north in Norway and birch to 70.5.

    • Does China really extend further North than Norway? Are they using Chinese maps? How about willows?

  17. I don’t see that they have actually documented the temperatures getting warmer, they just assume that they have.
    More likely this extra growth is caused by CO2 fertilization, rather than an increase of a few tenths at the most.

    • Slightly off topic.

      Recent I was in San Diego in March and Wyoming yesterday. I noticed those two places are a as “vivid green” as I can remember. I know both places have above normal precipitation. But after reading this article, I wonder if the “ vivid green” is related to the 400+ ppm CO2? To me visually, it was stunning.

  18. ” This unusual phenomenon was linked to a sharp increase in winter soil temperature, which determines the soil freezing depth of the permafrost. We also found that the larch grew more quickly in the region where the soil freezing depth is shallow.”

    This is quite incomprehensible. Permafrost is by definition permanent. It can’t freeze in winter because it doesn’t thaw in summer. What will increase in a warmer climate is the depth of the active layer, i e the layer that thaws in summer and refreezes in winter. This would certainly allow the trees to grow a deeper root system. No tree or other plant can grow roots in permafrost.

    Ultimately the active layer may get so thick that it completely melts the permafrost.

  19. I always like to do reality checks on these types of claims. Assuming a generally warming world, then one can also assume that non-permafrost areas due south of the current “permafrost line” (or whatever you call it) were also permafrost areas themselves in the not-too-distant past. So, assuming that these areas went through the “scary” defrost process already, what is their current state? Are they mostly degraded swamps and wetlands? Has the soil generally collapsed across wide areas? Are there any larch trees left, and if not, what have they been replaced with?

    Articles like the above would seem to encourage an impending fear of something akin to ecological devastation in such areas. But I’m thinking that a little research would show that’s not the case.

  20. The acolytes are in denial when it comes to the many positive impacts of enhanced CO2.

  21. Historical Aspects of the Northern Canadian Treeline HARVEY NICHOLS

    http://pubs.aina.ucalgary.ca/arctic/Arctic29-1-38.pdf

    ABSTRACT From palynological studies it appears that northernmost dwarf spruces of the tundra and parts of the forest-tundra boundary may be relicts from times of prior warmth, and if felled might not regenerate. This disequilibrium may help explain the partial incongruence of modern climatic limits with the present forest edge. Seedlings established as a result of recent warming should therefore be found within the northernmost woodlands rather than in the southern tundra.

    • Trigger warning
      Note that this was published in 1976, before the era of post-normal science, and may contain facts and opinions injurious to your faith.

  22. I’m curious about the simple claim that “trees do most of their growing when they are young.” I’m quite sure I saw a documentary about giant sequoias that claimed their increase in mass accelerated as they got older. So on a percentage basis, sure, greater gains when young. But in terms of total mass? Not so sure.

    National Geographic article I just found to support my memory, “Aging giant sequoia trees are growing faster than ever, with some of the oldest and tallest trees producing more wood, on average, in old age than they did when they were younger. ” https://news.nationalgeographic.com/news/2012/12/121205-sequoia-redwoods-trees-old-national-park-science-environment/

    I’m new to posting here, so hope providing the link is ok. Not exactly a science journal.

    • That is however unusual. Normally growth slows down as trees grow older, though not dramatically.

  23. While this initial soil warming has benefitted Dahurian larch, further permafrost thaw could likely decrease tree growth and even cause the forest to decay, according to the authors

    Phew. That’s a relief. For a moment there, I thought they were going to say something positive about CO2 and global warming.

  24. So color this non-scientist confused. What “nutrients” in the soil contribute that much to weight/size of rings? I was taught a long time ago that the dry weight of trees was about 50% carbon, 40% oxygen, 7% hydrogen, all a result of photosynthesis. …. with the rest being multiple elements like nitrogen, nitrogen, phosphorus, and potassium.
    So there is a new scientific evidence that warmer soil increases nutrient uptake that increases size of trees?? Perhaps warmer soil allows more uptake of water to enable better photosynthesis with CO2? Was there any discussion in the base document about CO2 increase fueling more photosynthesis leading to more growth?

  25. Anybody know enough about tree rings to confirm whether I can conclude I’m seeing the Little Ice Age in those rings pictured…?

    Looks to me like they “survived” warmer periods prior to that quite well, thank you – based on the fast growth. If anything it’s the LIA that’s the terrible anomaly and the Hubris of Mann (et al, of course) lies in standing things on their head – up is down, war is peace, warm is bad.

    Maybe God created Man – no tongue in cheek this time – specifically to dig up and burn sequestered carbon before those damn plants kill everything and Earth in a massive Tragedy Of The Commons…? As an economist, I’m curious to hear from anyone interested in helping write THAT up, eh.

  26. “Permafrost regions around the world have been thawing in recent decades due to rising temperatures, sometimes degrading into swamps and wetlands.”

    What’s wrong with swamps and wetlands? When they get drained or filled in populated areas, the enviros whine about that LOSS.

  27. “Climate change is helping older trees grow better”
    What if they had started with just saying what kind of changes it was that could have given the responce.
    Climate change could be anything also colder temperature or less precipitation.

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