Forget polar bears and global warming, witness the terrible tragedy of stunted shrub growth

Dracophyllum on Campbell Island, New Zealand.From the University of Washington and the Department of Pointless NSF Grants, comes this: Shrub growth decreases as winter temperatures fluctuate up

Many have assumed that warmer winters as a result of climate change would increase the growth of trees and shrubs because the growing season would be longer. But shrubs achieve less yearly growth when cold winter temperatures are interrupted by temperatures warm enough to trigger growth. 

“When winter temperatures fluctuate between being cold and warm enough for growth, plants deplete their resources trying to photosynthesize and end the winter with fewer reserves than they initially had. In the summer they have to play catch up,” said Melanie Harsch, a University of Washington postdoctoral researcher in biology and applied mathematics. She is lead author of a paper on the subject recently published in PLOS One.

The roots are especially sensitive to temperature fluctuations, Harsch said. Warming winters result in higher root respiration, which uses up carbon reserves as plants make and release oxygen, leading to less carbon available during the regular growing season.

 

Harsch and her colleagues studied two species of shrubs on Campbell Island, an uninhabited UNESCO World Heritage site in the southwest Pacific Ocean about 375 miles south of New Zealand’s mainland. They studied two large shrubs, Dracophyllum longifolium and Dracophyllum scoparium, which are evergreen broadleaf species that can grow up to about 15 feet tall and live up to 240 years.

Researchers found that while warmer, drier winters helped seedlings get established, it adversely affected growth of older plants.

“For growth to occur you need sufficient precipitation and temperature and nutrients. Growth should only happen during the summer on Campbell Island when temperatures are above 5 degrees Celsius,” Harsch said. Five degrees C is about 40 F. “On Campbell Island most winters are cool and below this 5 degrees Celsius, so the plants are not active. The plants we studied are evergreen and there is little snow cover, so they are sensitive to changes in temperature.”

In this study, researchers cut out discs, called “cookies,” from just above the shrubs’ root collar, and measured the width between each ring to determine growth. They found that plant growth decreased as winter temperatures went up.

“On Campbell Island the snow is ephemeral, so the plants usually are not covered,” Harsch said. “If we’re going to see an effect in changing winter conditions, we’re going to see it at Campbell Island decades before we see it at, say, Mt. Rainier, where there is a lot of snow and winters are colder.”

Discs cut from just above the shrubs' root collar were studied to determine growth.

Harsch said plants in areas like Campbell Island may eventually adjust to warmer winters, but the transition period will be tough as temperatures bounce above and below what plants need to stay dormant, causing the plants to draw down their resources.

“It may eventually be warm enough in the winters so that plants can photosynthesize and grow year round, like they do in the tropics,” she said. “It’s this transition part that plants are not adapted for.”

Harsch plans to do a follow-up study that would measure the microbes and carbon reserves in the soil, and manipulate snow packs to see how it affects establishment and growth.

“How much of this can our tree species withstand?” Harsch said. “Will summer growth eventually compensate for these hard winters, or is this some sort of extra stressor on trees that will be one more nail in the coffin? If you think of all the different factors of increasing vulnerability in climate change, is this really significant? We just don’t know.”

Co-authors are Matt McGlone and Janet Wilmshurst at Landcare Research in New Zealand. Harsch started the work while pursuing her doctorate at Lincoln University in New Zealand and finished the analysis at the UW. The work was supported in part by the National Science Foundation.

# # #

For more information, contact Harsch at harsch.melanie@gmail.com or 253-365-1555.

NSF grant: DEB-1103734.

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65 thoughts on “Forget polar bears and global warming, witness the terrible tragedy of stunted shrub growth

  1. Was that it. They studied two shrubs and then came to this conclusion! Unreal.

    [rather: Two shrub species? Mod]

  2. If I understand this right, warm periods in winter will cause me to prune my shrubbery less often. Sounds good to me.

  3. Is there anyone out there who has ever grown an outdoor plant, who didn’t know that a warm spell during the winter followed by more winter weather would screw up the plant’s growth

  4. At one time, it was common knowledge (at least in non-academic circles) that young trees and shrubs have to be shielded from sunlight (covered with snow) to prevent them from growing during periods of warmer winter temperatures. It is unlikely that depletion of nutrients is the cause of winter-kill; common sense would suggest that plants trying to grow in frozen ground are rapidly and severely stressed by the lack of available moisture.

  5. Notice the unstated assumption that any change is for the worse if anything is affected by that change. The assumption is that this is the most perfect of worlds and any change means less perfection. Considering the vast and never ending changes in our planet’s climate, one has to look upon these true believers as utterly chauvinistic, climate-wise. Perhaps we should have them recite the names of species that have come and gone. That will take them a very long time and may finally bring them to understand that change is this planet’s middle name.

  6. @Brian:
    “Is there anyone out there who has ever grown an outdoor plant, who didn’t know that a warm spell during the winter followed by more winter weather would screw up the plant’s growth”

    You have a good point, but these clever people got paid to find out for sure.

  7. As with many of these type of research projects, this might be a bit of a boondoggle in terms of a cool place to go. The scientists have to justify the expense of going there. Reminds me of the study of growing seasons for grapes that required that every winery in France had to be visited in August. Of course they would have to stop in ChristChurch for a holiday going and coming – and take some time to see New Zealand.

  8. uses up carbon reserves as plants make and release oxygen, leading to less carbon available during the regular growing season.

    so…burn more fossil fuels.
    win-win for everyone and everything.

  9. This paper is a laugh. So many problems with it as others point out. It is just another blowhard AGW, oh no the sky is falling. Here is one where I laughed.

    “It may eventually be warm enough in the winters so that plants can photosynthesize and grow year round, like they do in the tropics,” she said. “It’s this transition part that plants are not adapted for.”

    What a joke. Even with the most ludicrous and extreme modeled temperature rise that time will be many, many centuries down the road. The island’s yearly average temperature is 9.4 C or 48.9 F.
    In order to qualify as tropical the average temperature would need to rise 25.6 C or 28.1 F. Also the coldest parts of the year would even need to warm more.

    Of course some people will wring their hands and moan about it, lapping up every word as gospel.

  10. This is not the first study trying to link climate change to biota at Campbell Island. For example Cunningham and Moors (1994) suggested that the declining numbers of Rockhopper a Penguins was due to rising sea surface temperatures. Unfortunately while there are decadal swings of up 0.7 degrees C, there is negligible long term trend in sea surface temperature or air temperature.

  11. What if they found [an] increase in shrub growth? Find another ‘cherry’? You know that is the way they work. If they fail, they fail to get money. That is it.

    Harsch and her colleagues studied two species of shrubs on Campbell Island, an uninhabited UNESCO World Heritage site in the southwest Pacific Ocean about 375 miles south of New Zealand’s mainland.

    Oh my goodness, we are doomed. TWO shrubs, are they edible? I think they meant to pick real cherries, but missed.

    Please remember what happened the last time the Arctic was ice free, vegetation moved north. Most of the pending global warming, we are told, will be felt as you head away from the equator and towards the poles, in winter and at night. They can swing this one how they like but LONGER growing seasons is what will happen IN GENERAL. Don’t believe me just look at the past.

    Eat these. I hear they taste yummy.
    Dracophyllum longifolium

    http://en.wikipedia.org/wiki/Dracophyllum_longifolium

    Dracophyllum scoparium

    http://nzpcn.org.nz/flora_details.aspx?ID=1816

  12. Here is evidence of SHORTER GROWING SEASONS from Dr. Michael Mann.

    Medieval Climatic Optimum
    Michael E Mann – University of Virginia, Charlottesville, VA, USA

    It is evident that Europe experienced, on the whole, relatively mild climate conditions during the earliest centuries of the second millennium (i.e., the early Medieval period). Agriculture was possible at higher latitudes (and higher elevations in the mountains) than is currently possible in many regions, and there are numerous anecdotal reports of especially bountiful harvests (e.g., documented yields of grain) throughout Europe during this interval of time. Grapes were grown in England several hundred kilometers north of their current limits of growth, and subtropical flora such as fig trees and olive trees grew in regions of Europe (northern Italy and parts of Germany) well north of their current range. Geological evidence indicates that mountain glaciers throughout Europe retreated substantially at this time, relative to the glacial advances of later centuries (Grove and Switsur, 1994). A host of historical documentary proxy information such as records of frost dates, freezing of water bodies, duration of snowcover, and phenological evidence (e.g., the dates of flowering of plants) indicates that severe winters were less frequent and less extreme at times during the period from about 900 – 1300 AD in central Europe……………………

    Some of the most dramatic evidence for Medieval warmth has been argued to come from Iceland and Greenland (see Ogilvie, 1991). In Greenland, the Norse settlers, arriving around AD 1000, maintained a settlement, raising dairy cattle and sheep. Greenland existed, in effect, as a thriving European colony for several centuries. While a deteriorating climate and the onset of the Little Ice Age are broadly blamed for the demise of these settlements around AD 1400,

    http://www.meteo.psu.edu/holocene/public_html/shared/articles/medclimopt.pdf

  13. A longer period of average summer temperature in the UK, Germany, France, Denmark, Poland and Russia means a shorter growing season. Please do not apply logic, use the climate models.

  14. Another PhD thesis that should not have been granted, then hyped by PR.
    Goodness, quite the academic machine grinding away to make sausage.

  15. If this were the case…..there wouldn’t be an evergreen alive in the south

    This people are idiots

  16. New Zealand is not the best place to cut out discs to discover how our global biosphere will react to warmer temperatures. The vegetation there is more isolated than I care to remember and this is just from the top of my stupid head. In nearby Australia they even have unique fauna.

  17. Brian says:
    May 20, 2014 at 4:02 pm

    Is there anyone out there who has ever grown an outdoor plant, who didn’t know that a warm spell during the winter followed by more winter weather would screw up the plant’s growth

    I hear it can happen with Spring frosts too. ;-)

  18. Jimbo says:
    May 20, 2014 at 4:58 pm
    I hear it can happen with Spring frosts too. ;-)
    ====
    Jim, it’s in direct proportion to how much money they spend on azaleas

  19. the public seems to have FORGOTTEN cagw altogether! LOL.

    “Years of Living Dangerously” doesn’t make the Top 100:

    TV By The Numbers: Amanda Kondolojy: Cable News Ratings for Monday May 19

    http://tvbythenumbers.zap2it.com/2014/05/20/monday-cable-ratings-nba-basketball-leads-night-love-hip-hop-monday-night-raw-t-i-tiny-more/265855/

    19 May: SeattlePostIntelligencer Blog: Joel Connelly: Gov. Inslee links Jimi Hendrix, the Beach Boys, Nirvana and solar panels
    Gov. Jay Inslee played the happy warrior, TV executive producer David Gelber (“Years of Living Dangerously”) played the angry media critic and Episcopal priest the Rev. Kathleen Patton brought Lucifer into the coal train debate, as the group Climate Solutions roused a packed breakfast at the Westin on Monday…
    Gelber, who was Ed Bradley’s producer at “60 Minutes” for 25 years, touted his climate production on Showtime while lamenting the glacial pace at which the TV networks have discovered a rapidly warming world and its consequences…
    Gelber was scathing on networks’ lack of climate coverage.
    He noted the recent NBC piece by Ann Curry, the exiled “Today Show” co-host, titled “Our Year of Extremes,” but said such efforts get little promotion.
    “They usually put those things against the Super Bowl,” he added. ”The whole emphasis is numbers (ratings). They think they can win an Emmy.”
    At the same time, argued Gelber, newspapers have “let go” highly competent environmental reporters. ”Its ranks have been so thinned that the press doesn’t have people to do this story,” he said…

    http://blog.seattlepi.com/seattlepolitics/2014/05/19/jimi-hendrix-the-beach-boys-nirvana-and-solar-panels-inslee-sees-links/

    21 May: OneEarth: Jason Bittel: The Governator’s Back—and Going After Climate Change
    Last week on Showtime’s climate-change miniseries, Years of Living Dangerously, Harrison Ford hit the peat swamps of Indonesia, Don Cheadle tried to reconcile religion and science in the Bible Belt, and Thomas Friedman braved the frontlines of Syria’s civil war. It was a star-studded episode, filled with human drama, high stakes, and good journalism. So, how did it stack up against other prime time premieres?
    Well, according to the Nielson Ratings, YOLD pulled in about 294,000 viewers. Sounds like a big number, but Boss Hog, a new series about a guy who hunts pigs, reeled in almost four times as many watchers at 1.1 million…

    http://www.onearth.org/articles/2014/04/years-of-recapping-dangerously-schwarzenegger

  20. Mark and two Cats on May 20, 2014 at 3:44 pm

    It’s bushes fault.

    —————————————-

    That is a classic keeper. Thankfully, my phone did not break when I dropped it laughing.

    I think this study does actually do some good. It shows how much we think we understand, but really don’t. That does not exclude study methodologies.

    Always find a positive in everything! 😎

  21. I recently saw the temperature graphs of the not-so-distant Macquarie Island over the last several decades (they might have been here on WUWT); absolutely rock steady, no warming at all.
    So now Campbell Is. experiences a different climate to its 20thC past! And its bush species are suffering, it seems. How about that.

    You could not make this stuff up…hold on…

  22. I am interested in how they pulled off this junket to the southern hemisphere? Could this study not have been done outside their door.

  23. Nothing wrong with the study other than the hupe. CC is mentioned to make the paper seem important but actually they didn’t measure any climate change or note any CC caused changes to vegetation. All they did was notice that in winters with warm spells the shrubs grew less than in winters with no warm spells. That is a weather related phenomenon. The rest is all narrative license.

    What I think is more interesting is that this study calls into question the use of tree ring proxies for temperature in cold regions. On Campbell Island tree rings are not simple thermometers. To the extent that they are influenecd by temeprature, they seem to operate backwards with less growth in warmer winters.

  24. Jimbo says:
    May 20, 2014 at 4:40 pm
    Here is evidence of SHORTER GROWING SEASONS from Dr. Michael Mann.

    Medieval Climatic Optimum
    Michael E Mann – University of Virginia, Charlottesville, VA, USA

    It is evident that Europe experienced, on the whole, relatively mild climate conditions during the earliest centuries of the second millennium (i.e., the early Medieval period).

    This is interesting as this is Mann’s celebrated paper that attempts to do away with the Medieval Warm Period. Later in the paper he goes on to prove that the MWP left no evidence outside Europe. Well he didn’t look very hard because I have a bunch of papers linked on my blog which record the MWP as being apparent in records from China to New Zealand, not to mention Antarctic Ice cores and the Pacific Warm Pool.

    If this interests anyone the address is http://www.rogerfromnewzealand.wordpress.com.
    Look on the right hand column for the heading in red “Links to illustrate the Globalness of the Medieval Warm Period and other Warmings”.

    Cheers

    Roger

  25. Mark and two Cats says:
    May 20, 2014 at 3:44 pm
    “It’s bushes fault.”

    Well thank you very much. I was intending to clean my keyboard this week and now I’ll have to clean the screen too. :)

  26. That is the final straw as far as I am concerned. I have been able to put up with all the problems and injustices of the world because deep down I have always told myself that at least the shrubs on Campbell Island are reaching their full height.
    Now that is all gone. Destroyed. Shattered.
    If I can ever find a shrub tall enough I will throw a noosed rope over one of its branches ….

  27. In typical AGW speak everything is a stressor: more snow=stressor, less snow=stressor, more heat=stressor cold=stressor. With every direction of motion a biological stressor, we should freeze time right now. Gaia must be in perfect harmony with her ying yang and her feng shue must have brought the perfect colors to her karma. Omm…..

  28. Parts of this study seem correct to me. Interruption of a dormant cycle could easily put stress on a plant, and it’s possible that the stress could lead to change in the phenotype. In classical lore you would look for the stress to be severe enough to actually kill some of the plants, which in this scenario I think is unlikely. But if there were deaths the surviving plants would be those, obviously, which had some way to deal with the stress. Actually, and this is mildly interesting, the shrubs could adapt in two different ways. One would be to thrive in the warmer temperatures, building resources through photosynthesis in winter warm periods. Occasionally I see trees in my area going into a growth phase too early in a mild Northern Hemisphere winter, for example, cherry trees blossoming in November. This has got to have a negative impact on them, since they are wasting nutrition on growth which will then quickly be destroyed. But if they could merely retain leaves for an extra month, without blossoming, the longer warm period could turn out to be beneficial. So these shrubs on Campbell Island could adapt by extending their growing season into newly warmer autumnal or winter months, but they could also adapt by maintaining dormancy at slightly higher temperatures. In fact, it’s possible that some plants would thrive by using each of these strategies, in which case there would be the beginnings of two distinct subspecies. As I said, interesting, but only mildly.

    The weakness of the study seems to be: what warming? The PR doesn’t say what period is covered by the study, but it would have to be at least three decades to capture effects of global warming. However, a shorter study could capture effects of a local warming. But if the climate at Campbell Island includes the possibility of local warming independent of global trends, it is a good bet that plants there are exposed to warming fairly regularly over the centuries, and that they have already learned to cope with such conditions.

  29. During the Medieval Warm Period the Maori people colonized New Zealand because of the lack of rainfall in Polynesia. They settled as far south as Stuart Island, which is just South of the South Island (mainland) of New Zealand. During the little ice-age temperatures got too cold for Maori habitation on Stuart Island and indeed for much of the South Island of New Zealand so tribes had to move north. So it would seem reasonable that Cambell Island would have been warmer during the Medieval warm period than it has been in recent centuries. I suspect this would have been the reason why some of these plants have adapted to periodical climate changes.

  30. Turney of the Ship of Fools was coauthor of a paleolimnology article on a couple of sites on Campbell Island. The Ship of Fools stopped in Campbell Island before going to Antarctica.

  31. Have I understood this? These people have been allocated public money so they can assess the growth characteristics of two related plant species. On a remote island. In the Pacific. And, of course, follow-up studies will be required. Why not just take the money and throw it on the fire? Baffling.

  32. Oooooohhhhhhh Nnnnnnooooooooooo!
    Stunted shrubbery!

    Cry ‘Bonsai!’ and let slip the tiny, twisted shrubbery!

  33. Dracophyllum is a distant relative of The Bristlecone Pine and Siberian Larch (all members of Plantae) and is an ideal material for the construction of hockey-sticks.
    Treatment with Tijander Expedient, an extract of Baltic mud, permits the shaping of the blade into a robust piece of sporting equipment.
    The traditional finish is Institutional whitewash, which is applied in several coats.

  34. “It may eventually be warm enough in the winters so that plants can photosynthesize and grow year round, like they do in the tropics,” she said.

    Does this mean the claim that “children will not know snow” is back in vogue, and extreme weather with colder winters and more snow is out? Or is it the case that with summer just around the corner, it’s safe to talk about warmer winters again? I guess any talk about extreme cold and snow can wait until next winter when they’ll have to explain why the Great Lakes have frozen over again.

  35. They could have studied the impact of highly variable winter temperatures on plants much more easily in Britain, with the added bonus of a variety of microclimates available on a large island with mountainous areas. In Britain, warm winters tend to be wet, while cold winters tend to be dry, largely dependent on the dominant direction of the wind. Our recent winter was very wet and exceptionally mild with many plants growing in January & February – unlike the previous few years which had harsh cold spells.
    Some plants do not like the fluctuation of temperatures, but others seem to thrive – it is notable that much of the Wheat grown in Britain is winter wheat – planted in October and growing throughout the winter.

  36. Mike Edwards says:

    “They could have studied the impact of highly variable winter temperatures on plants much more easily in Britain, with the added bonus of a variety of microclimates available on a large island with mountainous areas.”

    Are you crazy?? Campbell Island has a subarctic hypermaritime climate with extremely small inter- and intraannual variation. The plants there have adapted to a climate that is exceptionally constant and will therefore react strongly to change. Britain has a very variable climate and plants there are probably not nearly so sensitive to changes. You wouldn’t get the right results at all.
    By the way anyone who has tried to make his way through the bush on Campbell Island would probably think that the shrubs are doing very well. Particularly since they managed to get rid of the sheep and rats on the island.

  37. “How much of this can our tree species withstand?” Harsch said. “Will summer growth eventually compensate for these hard winters, or is this some sort of extra stressor on trees that will be one more nail in the coffin? If you think of all the different factors of increasing vulnerability in climate change, is this really significant? We just don’t know.”

    Oh for crying out loud!

  38. “It may eventually be warm enough in the winters so that plants can photosynthesize and grow year round, like they do in the tropics,” she said. “It’s this transition part that plants are not adapted for.”
    Possibly. But at the moment Cambell Island is a long way south and the main ocean currents do not come from anywhere warm, or hot. Plus there is the slight problem of Earth’s inclination which really gets in the way of extending the growing season.

  39. This is yet another case of, “We couldn’t find any information about what actually happened to shrub growth during other warmer times like during the Medieval so we’ll just make stuff up to score points and get some grant money.”

  40. David Ball says:
    May 20, 2014 at 3:41 pm

    “It’s worse than we thought”- The Shrubs

    They are the canary in the coalmine. :-P

  41. The winter was so warm here in the high desert that two of my clematis died and the month of December had the lowest average temperature ever recorded. Spring was so warm that my garden froze in May. Bring on the warming.

  42. “What doesn’t kill you, makes you stronger.” Works for plants too. So who cares if they have some odd years of less growth? It’s not like anyone is harvesting these shrubs and if they are not killed, it is just nature being natural.

  43. How did the plants do in their 240 lifespan which included parts of the Little Ice Age? Funny there is no mention of that period.

  44. Speaking of Bushes and Texas, makes me think of Ladybird Johnson and her “Shroooobs”….
    (goes back a ways, I know, sorry…).

  45. I wonder if these shrubs might benefit from some robust pruning every winter to discourage them from growing too quickly in the spring? I’m sure they could do a lot better with some proper management.

  46. Living in Colorado at high altitude we have temeratures swinging from well below frezeeing to well above freezing in cycles for a large part of the year. Our last snow this year was on May 12th. I see no problem for the shrubs and trees.

    Also, a result she seems to ignore for the conditions that she describes is that the growing season will be longer for those shrubs and that should more than compensate for her transiations. Plus added CO2 and moisture in the air should also help.

  47. ““How much of this can our tree species withstand?”

    oh I dunno… how did the TEMPERATE RAIN FOREST of WASHINGTON survive the 2.5 km THICK ice that used to be normal for the area until about 6000 yrs ago?

  48. Jeff,
    My gosh, I remember that public service TV ad that Ladybird made in the 60′s.

    “Plant a tree, a booosh, or a shruoooob. Help beautifaaahh America!”

  49. “If you think of all the different factors of increasing vulnerability in climate change, is this really significant? We just don’t know.”

    You don’t? Really?

    [Excessive, not called for. .mod]

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