Anonymous
By Harrison Tasoff, UC Santa Barbara
Droughts can be good for trees. Certain trees, that is.
Contrary to expectation, sometimes a record-breaking drought can increase tree growth. Why and where this happens is the subject of a new paper in Global Change Biology.
A team of scientists led by Joan Dudney at UC Santa Barbara examined the drought response of endangered whitebark pine over the past century. They found that in cold, harsh environments — often at high altitudes and latitudes — drought can actually benefit the trees by extending the growing season. This research provides insights into where the threats from extreme drought will be greatest, and how different species and ecosystems will respond to climate change.
Many factors can constrain tree growth, including temperature, sunlight and the availability of water and nutrients. The threshold between energy-limited and water-limited systems turns out to be particularly significant. Trees that try to grow in excessively cold temperatures — often energy-limited systems — can freeze to death. On the other hand, too little water can also kill a tree, particularly in water-limited systems. Over time, many tree species have adapted to these extreme conditions, and their responses are broadly similar. They often reduce growth-related activities, including photosynthesis and nutrient uptake, to protect themselves until the weather improves.
“Interestingly, the transition from energy- to water-limited growth can produce highly unexpected responses,” explained Dudney, an assistant professor in the Bren School of Environmental Science & Management and the Environmental Studies Program. “In cold, energy-limited environments, extreme drought can actually increase growth and productivity, even in California.”
Dudney and her colleagues extracted 800 tree cores from whitebark pine across the Sierra Nevada, comparing the tree rings to historical records of climate conditions. This climate data spanned 1900 to 2018, and included three extreme droughts: 1959–61, 1976–77, and 2012–15. They recorded where tree growth and temperature showed a positive relationship, and where the relationship was negative.
The authors found a pronounced shift in growth during times of drought when the average maximum temperature was roughly 8.4° Celsius (47.1° Fahrenheit) between October and May. Above this threshold, extreme drought reduced growth and photosynthesis. Below this temperature, trees grew more in response to drought.
“It’s basically, ‘how long is the growing season?’” Dudney said. Colder winters and higher snowpack often lead to shorter growing seasons that constrain tree growth. Even during an extreme drought, many of the trees growing in these extreme environments did not experience high water stress. This surprised the team of scientists, many of whom had observed and measured the unprecedented tree mortality that occurred at slightly lower elevations in the Sierra Nevada.
Dudney was curious whether drought impacts growth in just the main trunk, or the whole tree. Without more data, the trends they saw could be a result of disparate processes all responding to the drought differently, she explained. Fortunately, whitebark pine retains its needles for roughly eight years. This provided additional data that could address this question.
The researchers shifted their attention from dendrology to chemistry. Atoms of the same element can have different weights, or isotopes, thanks to the number of neutrons they contain. Several aspects of a plant’s metabolism can influence the relative abundance of heavy, carbon-13 and light, carbon-12 in tissues such as their leaves and needles. These changes provide a rough guide to the amount of water stress a tree experienced during drought. This was a boon for the researchers, because isotopic data from the pine needles spanned drought and non-drought years.
Analyzing needle growth, carbon and nitrogen isotopes revealed that the whole tree was affected by the threshold between water-limited and energy-limited systems. Trunk growth, needle growth, photosynthesis and nutrient cycling responded in opposite directions to drought above and below the threshold between energy- and water-limited systems.
The future of whitebark pine is highly uncertain. The species — recently listed as threatened under the Endangered Species Act — faces many threats, including disease, pine beetle infestation and impacts from altered fire regimes. It’s clear from this research that drought and warming will likely exacerbate these threats in water-limited regions, but warming may be beneficial for growth in energy-limited environments. “This research can help develop more targeted conservation strategies,” said Dudney, “to help restore this historically widespread tree species.” Indeed, the pine’s range encompasses a diverse region, stretching from California to British Columbia, and east to Wyoming.
The findings also have implications more broadly. Approximately 21% of forests are considered energy limited, and an even higher percentage can be classified as water limited. So transitions between these two climatic regimes likely occur around the globe. What’s more, the transition seems to have an effect on nitrogen cycling. Trees in water-limited environments appeared to rely less on symbiotic fungi for nitrogen, which is critical for tree growth in harsh, energy-limited environments.
“Droughts are leading to widespread tree mortality across the globe,” Dudney said, “which can accelerate global warming.”
Deciphering the many ways trees respond to drought will help us better predict where ecosystems are vulnerable to climate change and how to develop more targeted strategies to protect our forests.
Would you look at that… climate change isn’t ALL bad. I wonder what other benefits a changing climate can provide?
Just think – all the dead animals will make for happy vultures! Our diminished human population will ease the housing crunch! No more economy will eliminate poverty worries!
Always Look on the Bright Side of Life
Voice of Maga would make an inane comment like this. See! Look the beach houses are submarines now! And SB is the new Venice! Lol
AHAHAHAHAHA!!!
I saw this and literally knew some idiot would show up to champion climate change.
Never change, baby.
“Alex, you are 100% wrong on rich people.” – every single “rich” person? Wow, that is statement and a half, champ! So, I assume you have some PROOF that no “rich person” anywhere on the planet would spend millions on a temporary home without regard of its possible destruction (or sale) in the future?
LOL! Only 1 person here who is “100% wrong.” It’s not Alex…..
Chip, humans do have an impact on climate, that is fact, it’s just a very small impact, significantly dwarfed by natural factors well beyond our control.
Oh and Alex said “twenty years,” not “10 years.” Whoof! What a whopper!
“it’s just a very small impact,” – no, it’s not, according to most of the world’s respected scientists and (non-YouTube) experts.
The climate has changed quite a lot through history, and the extinction of the vast majority of all species that ever existed can be attributed in large part to historical changes in the earth’s climate. Now if it gets too cold or too hot it’s all because of humans generating CO2? Nonsense! Humans are not causing the air to warm or the seas to rise; there is no conclusive evidence that is even happening let alone that humans are responsible. However, humans are profiting off of the exploitation of mineral wealth and vulnerable populations overseas in the name of saving us from climate catastrophe. Follow the money and it’s clear what this is really all about…
Way to throw in another bit of Gish-galloping carbon shill manure.
Learn about climate here:
https://www.bbc.com/news/science-environment-24021772
https://climate.nasa.gov/evidence/
https://www.climate.gov/maps-data/climate-data-primer/predicting-climate/climate-forcing
HAHAHAHAHH!!!!!
CHIP, oh CHIP!!! LOL!!!!
“You keep trotting out that tired propaganda to try to scare people into believing the very air they exhale is a pollutant. ”
I’ll pay you ten thousand dollars to put a plastic bag over your head for ten minutes, no cheating, lock it off at the neck.
After ten minutes has passed you can tell me all about how a preponderance of CO2 in the atmosphere is treating you.
Our errorist group members are trotting out all of their usual debunked climate myths, despite having been shown on numerous occasions that they are totally false. “CO2 benefits crops”, “It’s all natural”, human CO2 emissions can’t compare with natural CO2 emissions”, “Climate has always changed”; all just a bunch of their politically-motivated hogwash distribution campaign.
You can see their postulates, and their refutation by climate scientists, at the Climate Myths page here:
https://skepticalscience.com/argument.php
You’re so funny. You literally believe that every one of the 1% that owns beach front property or a PJ and talks about climate change is lying.
You never fail to fail.
2:06, you are a shill for the rare earth mining industry. You keep trotting out that tired propaganda to try to scare people into believing the very air they exhale is a pollutant. You’re just trying to hide the widespread environmental destruction and humanitarian consequences wrought by the mining industry you support. Child labor, slavery, stealing water from native peoples, contaminating vast expanses of land with uranium and other mining byproducts, and slashing and burning rainforests to access minerals like lithium, among many other consequences are not justified by CO2. CO2 is a gas all animals exhale that plants absorb in order to grow.
CHIP – who said “children should be forced to labor in the mines?” Why are you making things up? Supporting renewable energy sources doesn’t mean we support child labor in mines. That’s like saying, if you support the 2nd amendment, you also support children being shot by other children. Or, if you support non-renewable energy, you support lung cancer. Or any number of faulty and false analogies.
If you’re so concerned about child labor, what have you done to stop purchasing any of the items listed here ? https://www.dol.gov/agencies/ilab/reports/child-labor/list-of-goods-print#:~:text=The%20most%20common%20agricultural%20goods,and%20fireworks%20appear%20most%20frequently.
I’m not obsessed with rare earth mining, nor have I denied the climate and human impact of it, that’s your issue.
Nice try at deflection. And just for the record, I am not actually suggesting that you put a bag over your head and breathe for ten minutes, because that would kill you, because an imbalance of CO2 is deadly for certain species.
What these denier idiots fail to admit is that the only times in the history of our planet when climate has changed this rapidly have been periods of mass extinctions, and that the current high (and still accelerating) rate of atmospheric warming is directly attributable to radiative forcing from our dumping of enormous amounts of carbon dioxide into the atmosphere.
@7:16 Why do you think climate change only means dead animals? You seriously believe a changing climate won’t make the climate in some areas more hospitable for animals and people, make some areas more arable? You really believe it’s ALL negative and zero positive? You’re line of climate apocoyse thinking is anti-science propaganda. Facts over feelings.
VOICE – the idea a couple species of high altitude trees may benefit from drought, therefore climate change is fine, is ignoring the millions of other species that will suffer and perish needlessly. Not a great thing no matter how you look at it.
Chillin, pull up Obama’s, Gates, and Kerry’s multiple mansions, many literally on the ocean, how many solar panels do you see on their roofs? Pull up how many private jet flights they take, knowing one flight on a private jet release more carbon than a lifetime of driving a car. If there was a snowballs chance in hell beach houses would be submarines and SB the new Venice they would be ditching their private jets, not buying mansions on the water and at least installing solar on their homes.
VOR, you’re wrong. Rich people don’t care about the future bro. They buy what they want when they want it. Stupid climate change deniers who like to cite “Democrat” billionaire’s beach houses as proof that there is not climate change miss the massive reality that for a Gates or Obama, they can drop 10m plus on a beach house and not give two fucks about it being above or under water in twenty years.
And before you go there, yes, yes, exactly, any billionaire who claims to care about the environment but travels everywhere by PJ and private yacht and owns multiple water and energy intensive properties is….dun…dun….dun, a hypocrite.
Beyond that, will some places in the world end up with a better climate for human or animal life as a result of climate change, of course, but if the majority of people and animals are negatively impacted, than pointing at a couple of positive spots is really, really, ridiculous.
Carry on.
Alex, you are 100% wrong on rich people. They absouteltly would not spend tens of millions on ocean front real estate, tens of millions more on renovations, if they thought it would be under water in 10 years. There are many more positive attributes to climate change, or at least a warming climate, than you are lead to believe most notably in increase food production. Not only are the positive consequences being ignored and silenced, but the negative ones are being grossly overstated.
We don’t exhale “air”, we exhale CO2. Next Chip will be telling us that his farts are “air”.
https://skepticalscience.com/co2-plant-food.htm
“You’re just trying to hide the widespread environmental destruction and humanitarian consequences wrought by the [fossil fuel] industry you support. ”
““Droughts are leading to widespread tree mortality across the globe,” Dudney said, “which can accelerate global warming.””
“Our diminished human population” you say? Couldn’t agree more, that is the single biggest problem facing the planet. Too many people.
Some people remain ignorant about conducting conversations on the web, it seems.
Some trees and benefit, some don’t. You heard it here – straight from UCSB researchers.
BASIC – yes. Your point?
My point is that they’re saying drought isn’t all bad. It happens. It part of natural cycles to which tree species have adapted over a very long time (tens/hundreds of thousands of years).
And some people *still* can’t figure out how to comment in a way that preserves a comment thread. Incredible!
“they’re saying drought isn’t all bad.” – Ehhhh no, that’s not really what they’re saying. All this is about is that a few species of trees do better than they thought in drought conditions. Drought is still pretty bad for everyone and everything else.
Exactly, what about “isn’t all bad” don’t you understand Sac? Some do well, some don’t. Surprise? Please don’t you take everyone down another rabbit hole of argument again. It’s getting old.
BASIC – lol whatever dude. You came in to say something wrong to mimic VOICE and start your own show. Fact is, the article is not saying “it’s not all that bad.” That’s like saying an article about dung beetles is saying rolling around balls of poo “isn’t all that bad.” I’m done, but you can keep on with your performance.