Study: cut down trees in California to save billions of gallons of water

From the NATIONAL SCIENCE FOUNDATION and the “tree huggers nightmare” department

Billions of gallons of water saved by thinning forests

Too many trees in Sierra Nevada forests stress water supplies, scientists say

There are too many trees in Sierra Nevada forests, say scientists affiliated with the National Science Foundation (NSF) Southern Sierra Critical Zone Observatory (CZO).

That may come as a surprise to those who see dense, verdant forests as signs of a healthy environment. After all, green is good, right? Not necessarily. When it comes to the number of trees in California forests, bigger isn’t always better.

That’s in part because trees use lots of water to carry out basic biological tasks. In addition, they act as forest steam stacks, raking up water stored in the ground and expelling it as vapor into the atmosphere, where it’s accessible to humans and forest ecosystems only when it falls back to Earth as rain and snow.

A restored forest grows in the foreground, with a dense, unthinned forest in the background. CREDIT
Eric Knapp, USFS

That process — by which plants emit water through tiny pores in their leaves — is known as evapotranspiration. And according to researchers, excessive evapotranspiration may harm a fragile California water system, especially during prolonged, warm droughts.

New research published this week in the journal Ecohydrology shows that water loss from evapotranspiration has decreased significantly over the past three decades. That’s due in large part to wildfire-driven forest thinning — a finding with important implications for forest and water management.

A century of forest management had kept wildfires to a minimum. But without fire, Sierra forests grew very dense. In recent decades, new policies have allowed nature to take its course, with wildfires helping to thin out overgrown forests.

“Forest wildfires are often considered disasters,” said Richard Yuretich, director of NSF’s CZO program, which funded the research. “But fire is part of healthy forest ecosystems. By thinning out trees, fires can reduce water stress in forests and ease water shortages during droughts. And by reducing the water used by plants, more rainfall flows into rivers and accumulates in groundwater.”

Using data from CZO measurement towers and U.S. Geological Survey satellites, researchers found that over the period 1990 to 2008, fire-thinned forests saved 3.7 billion gallons of water annually in California’s Kings River Basin and a whopping 17 billion gallons of water annually in the American River Basin — water that would otherwise have been lost through evapotranspiration.

Forest thinning has increased in recent decades in an effort to stave off disastrous wildfires fueled by dense forests. This study shows that restoring forests through mechanical thinning or wildfire can also save California billions of gallons of water each year.

A tower at NSF’s Southern Sierra CZO measures the exchange of water and carbon between forest and atmosphere. CREDIT
Roger Bales, UC Merced

“The need for forest restoration is being driven largely by the need to lower the risk of high-intensity wildfires and restore forest health,” said University of California Merced scientist Roger Bales, director of the Southern Sierra CZO and study co-author. “Downstream users who benefit from the increased water yield are an important potential revenue stream that can help offset some of the costs of restoration.”

Forested areas needing restoration are large, Bales said, but potential changes in water availability are significant. The total effect of wildfires over a 20-year period suggests that forest thinning could increase water flow from Sierra Nevada watersheds by as much as 10 percent.

The U.S. Forest Service says that 6 to 8 of the 21-million acres it manages in California need immediate restoration. Another 58 million acres nationally also require restoration. For California alone, restoration costs are estimated at $5 to $10 billion. But, according to the study authors, the restoration might help pay for itself.

“We’ve known for some time that managed forest fires are the only way to restore the majority of overstocked western forests and reduce the risk of catastrophic fires,” said James Roche, a National Park Service hydrologist and lead author of the new study. “We can now add the potential benefit of increased water yield from these watersheds.”

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81 thoughts on “Study: cut down trees in California to save billions of gallons of water

  1. The treehuggers would rather have uncontrollable raging forest fires that burn down entire towns, then allow the forests to be logged. They can also blame the fires on global warming as well.

    • “For California alone, restoration costs are estimated at $5 to $10 billion.” Such STUPID people!
      If California were to allow loggers to restore the forests, it could save the Billions while making money on the leases.

      • Gotta be careful of that Evapotranspiration. Di-Hydrogen-Monoxide is one nasty greenhouse gas. Just look at what thinning the trees on Kilimanjaro has done for evapotranspiration in that area. Not to mention it’s positive effect in reducing all that nasty white Ice that used to top the mountain. Just what California needs, another method to reduce snow cover and overall residual summer ice fields (not that the Sierras had much residual ice)

      • Bob,
        “If California were to allow loggers to restore the forests, it could save the Billions while making money on the leases.”
        Thinning isn’t always money-maker, it’s a management practice. The trees they cut are often the diseased, damaged misshapen, small, etc. It can be more expensive to remove thinned trees than they’re worth. However, the effects on the harvest (or the ecosystem) over the long run can make it worthwhile.

    • It’s a lot worse when those tree-huggers occupy government positions – like, oh, say, Governor – like ‘Burn it down, Brown,’ here in Oregon.
      Or, for that matter, California.

    • 45% of CA is federal government ‘owned’ land / forests.
      How about they allow citizens to take it over, manage it?
      Wait, realtors hate that idea.

      • I used to work for Bill Graham at the Fillmore Auditorium in SF back in the mid 1960s. I saw and heard almost everyone back then with the exception of the Beatles and a few others. But I remember Strawberry Alarm Clock, Janis Joplin, Otis Redding, and many greats from that time period.

      • The good old days! 🙂
        I used to listen to all those artists while I was sitting outside The Shell in Honolulu. We couldn’t see the performers, but we could hear them just fine, and it was free. 🙂

  2. But this is also a reason to increase CO2 because plants use/lose less water in higher CO2 concentrations by having fewer stomata.
    https://phys.org/news/2011-03-co2-atmosphere.html

    That model suggests that a doubling of today’s carbon dioxide levels — from 390 parts per million to 800 ppm — will halve the amount of water lost to the air, concluding in the second paper that “plant adaptation to rising CO2 is currently altering the hydrological cycle and climate and will continue to do so throughout this century.”

  3. If we just denuded the entire planet, it would save a lot of water. None o’ them pesky plants soaking it up, no annoying critters drinking from puddles and streams, no smelly fish doing whatever they do. If we could figure out a way to get rid of clouds, they wouldn’t wastefully float the stuff around in the air, either. The water could just sit there in a huge, lifeless ocean, where it all belongs.

    • Or put a prohibition on procreation in California which would eventually force the population to zero. (Immigration, legal or illegal, would have to be completely stopped, too!) With no people in California, it wouldn’t matter how much water the forests use.
      Problem solved!

    • “If we just denuded the entire planet …”
      Once a ray-gun is created and globally deployed that breaks the covalent bond of atmospheric CO2 such that the carbon falls from the sky, all life will perish and the world can revolve in peace.

  4. I guess none of these scientists have studies the effects of deforestation surrounding Kilimanjaro then. Declining precipitation leading to less snow/ice at the summit for summer use. If you remove the moisture from the ecosystem, you will eventually see a decline in snow/ice in the Sierra’s for summer use.

    • Yep — can’t remember now where I read it, but the gist of the story is, a town with a reservoir decided that they could get more water in the reservoir if they cut down the trees on the hills above the dam. The first year, sure enough, the reservoir filled right up.
      And in the following years, the rains fell off — locally, mind you; not a regional drought — and the reservoir practically dried up.
      It’s my understanding that local trees’ transpiration contribute to local humidity and therefore local rainfall.

    • …which conjures up the idea of “free rain”, and according to Californian politicians, we can never have that!
      Tax that rain; control those people, make them PAY! (I used to live in California and when I left, it was like a breath of fresh air where logic reigned without indoctrination.)

      • Just don’t use your vote to turn your new home into what you left behind. The first thing that happens if you continue to vote Democrat is the state is flipped and then you and your children will begin to suffer in the hell you thought you left behind.

  5. It should be noted that thinning would have to be heavier than what is optimal for standard timber production, so includes an opportunity cost, and would have to be repeated regularly to sustain the increased water yield. Well documented forest thinning experiments, with controls and randomized block designs, have shown the influence of thinning on water dynamics is only transitory as the trees left behind increase their leaf/needle area quickly to take advantage of more light/space, and therefore increase evapotranspiration. On top of that, on most sites other vegetation (brush, etc) will flourish in the understory to take advantage of the increased light, and add to the evapotranspiration. The study linked below for example indicates a stand density index below 50, and repeated thinning, is required to maintain the effect.
    https://www.fs.usda.gov/treesearch/pubs/54759

    • I assume this is why the Amazon rainforest is such a dry, infertile area – all those trees and underbrush sucking up the water and removing it from the ground/sarc.

      • Recognizing the /sarc, I’ll still venture a response. My professional experience is in the boreal forest, not the amazon, so can’t make claims about how transferable this is. A possibly similar boreal forest example would be a very wet spruce forest growing on saturated peat soils, basically a treed bog/swamp. Remove the spruce forest and you will see the water table go up, at or above the surface for a short period, and increased flow in streams draining from the area for several years after. So, unless the increased evaporation from the hot tropical sun hitting the now barren ground can compensate for the loss of the vegetative evapotranspiration in the amazon better than it does in the boreal, I would expect an already wet amazon would, at least temporarily, be even wetter after removing vegetation. Fertility-wise I would expect that to go down quickly, as nutrients cycle very quickly in tropical forests, and are held mostly in vegetation rather than organic soil layers like temperate and boreal forests where poorly decomposed vegetative litter can accumulate to several inches, even several yards on some poor/wet sites.

  6. …cut down trees in California to save billions of gallons of water…
    You CAN’T SAVE WATER!!!
    I’m tired of making this point. Water is never (except in small speicalist circumstances) created or destroyed. I don’t care how muct wate the trees use, the planet is not losing a drop of it. There is not, and never can be, any shortage of water.
    What there can easily be is a shortage of potable water in a specific place. But this is not a ‘shortage of water’ – it’s a shortage of water storage, purification and distribution facilities. In other words, it;’s a shortage of investment on the part of the water companies.
    It’s very important to stress this. ‘A water shortage’ makes it sound like a natural phenomenon which can’t be avoided. A shortage of water infrastructure immediately makes people think of the proper answer – what is the cost-benefit in providing more infrastructure, can we afford it and how should we go about it?

    • Sorry about the typos – mods improve if you want. It’s the anger making my fingers wobble.
      That, and the drink….

    • What’s the big idea, Dodgy? Are you trying to keep your head when all about you are losing theirs, and blaming it on you? Trying to observe facts and logic? What kind of a world do you think this is?

    • I suppose you’ve never heard of photosynthesis and the role of photon-excited chlorophyll a special pair in the reaction center to split water into hydrogen and release the oxygen?
      It was a tremendous biological innovation about 2.8 Gya. Altered the planet forever. The oxygen we breath came from water.
      And then we recreate the water during oxidative phosphorylation by cytochrome c complex in our mitochondria, where oxygen is reduced back to water.
      On the balance of things, far more water has been destroyed over geologic time than has been created, which is why most of the crustal minerals are now oxidized and our atmosphere is 21% O2. It all came from the ancient oceans to make the gas we breath.
      Biology… amazing stuff.

  7. We know the governor has stated that huge wildfires there are the new normal, caused by CO2 climate change; so he is not going to spend $5 billion to restore the forests and prove himself wrong.
    Talk about carbon offsets — cutting down millions of trees in California in order to delay their self-inflicted water management crisis would offset all those plant-a-tree programs elsewhere around the country aimed at removing CO2 from the air.

    • There is active thinning going on in the national parks. You could see this at Yosemite, Grand Canyon, and Rocky Mountain National Park over the last few years. So this is not just a California phenomenon.

    • Huge wildfires are the new normal because the enviros won’t allow controlled burns in optimal conditions to rake out excessive fuels. It has nothing to do with any natural change, just the political change brought on by the rise of idiot greens.

      • I once informed a “environmentalist” couple that the native Americans used controlled burns to improve hunting conditions.
        The couple got rather upset and informed me, that the native Americans respected nature and would never have done something so destructive.

      • And the Australian aboriginals, and the Kalahari bushmen of Africa.
        They all probably observed a big lightning-induced wildfire, and came to the reasonable conclusion of “small fire now, small fire later, no fire now, big fire later”.

  8. When my wife and I visited Yosemite last September, there were controlled burns going on all along the southern boundary. There were signs posted telling you not to tie up the lines calling 911.

  9. Whoa, I’m gonna be rich!
    I just ordered a ton of t-shirts with:
    “Save the planet
    Cut down a tree!”

  10. 40 million people in California don’t have a water shortage problem. They have a water storage and transport problem. That state, much of which is arid, was never able to have enough local water throughout to meet the needs of 40 million people. And as long as they build houses on hillsides prone to having intense brush/forest fires there will always be a big threat to lives and property. “Climate change” is not a factor in any of this.

    • And agriculture uses 80% of all water used in the state. That is where water savings should take place, imo. They squeeze the people for savings, when they only account for 20% of usage, but Gov Brown gives a pass to farmers as their lobby and their donations are strong. Brown knows how to butter both sides of the bread. My idea would be to give tax breaks for farmers to upgrade their water systems by installing the best highly efficient watering systems which the Israelis have developed over the years. The lost tax revenues would be quickly made up by the water savings over time, and by taking the stress off of communities to come up with dumb solutions.

    • Exactly! We are told there’s too much fresh water going into the oceans, and not enough fresh water falling on land. The challenge is to simply take what you have too much of, and put it where you don’t have enough of it. Which reminds me of the Mark Twain quote: “The trouble ain’t that there’s too many fools, it’s that the lightning ain’t distributed right.”

  11. Central Valley agriculture could sure use the water, and so could the valley aquifer. But the Nuts in CA will most likely want to use the water to save a smelt or other non-native species. Or try to reintroduce salmon to the rivers at $1M/fish.
    And since trees cool the environment, any temperature increase in the mountains will be blamed on Evil CO2. These things are predictable due to the influence of NGO’s on CA government.

  12. “In recent decades, new policies have allowed nature to take its course, with wildfires helping to thin out overgrown forests.” Nature? What a travesty. The course should be steered by ecologists only. Mother Nature frequently veers off the prescribed path.

    • That is historical revisionism. Should read “In recent decades a series of devastating wild fires have exposed the folly of the environmentalist and ecologists policy of not clearing or thinning forests. Ecologists and environmentalists should not be allowed to set new policy in this matter”.

  13. yeah right…….then they will complain that the lack of humidity downstream is killing something else
    ….you can’t win

  14. They’ve missed something – when the trees have been cut down, convert them to pellets, ship across the Atlantic (in diesel powered ships), and burn them in Drax power station. Then claim that no CO2 is emitted, and the world will be saved…

  15. I live on the Nevada side. As in every government function, Nevada does a far superior job in forest density reduction. Forests on the California side are sometimes impenetrably thick. Ours have lots of room between the trees.

  16. Increased CO2 reduces transpiration.

    If leaf area stays the same, this physiological response has the potential to reduce water losses from the land surface, increase soil moisture, and reduce plant water stress (13)—the opposite effect of an increase in drought stress and aridity as predicted by many drought metrics … link

    So, to solve the problem, we have to burn more fossil fuels.

  17. Trees increase atmospheric H2O resulting in global warming. Trees, not CO2, are causing the warming over land. Trees would explain the difference between land and sea measurements. More H2O, more warming.

  18. “By thinning out trees, fires can reduce water stress in forests and ease water shortages during droughts. And by reducing the water used by plants, more rainfall flows into rivers and accumulates in groundwater.”

    Quite a typical cure cancer, end war, save humanity type claim coming from a government official.
    Here’s hoping their superior is not gullible.
    You have to love their utter lack of observations in making this claim.
    No well depths, no long term forest humidity measurements, stream flow measurements, etc. Just a fancy claim.
    They could start by killing invasive water hogging plants along streams and spring outlets.

    • Here is a picture of a fire scarred tree in Sequoia’s Sherman Grove area:
      https://www.dropbox.com/s/5ezcz30soiby31z/Sherman-Grove-Sequoia-7-11-07-038.jpg?dl=0
      As I remember it, the park did have the burn scar dated. I do not remember the date, but it was not recent as the healing edges of the burn scar indicate.
      Preventative burns, may reduce severity of fires, but Sequoia and King’s Canyon parks have a long history of fires with the forest recovering biomass afterwards.

      • Sequoia tree cones require fire to open and become viable. Under natural conditions the fires are generally not large enough to hurt the giants much because of their mass and thick bark but it consumes the smaller species leaving their remains as fertilizer and open spaces in the canopy for the Sequoia seedlings to get the sunlight they need.

      • Indeed, RAH!
        Sequoia Park rangers admitted that during a long period of “fire prevention”, new sequoia saplings in the parks were nonexistent.
        After a lightning strike caused fire, there were a plethora of new seedlings.
        The Park rangers got the message.

  19. Conifers also reduce the water density of snowpack by increasing sublimation rates. Aggressive thinning of conifer forests would substantially increase water stored in snowpack. If thinning is done in a way that maximizes Winter and Spring shade over open areas, sublimation could be further reduced.

  20. Thinking of all the environmentalist’s heads exploding, I’m conjuring up, ‘Mars Attacks’. I haven’t had such a good laugh in a long time!

  21. Too many trees are at least partly caused by too many years of aggressively fighting all forest fires.

  22. It is amazing that Nature was able to survive all those millions, billions of years without constant advice and intervention from well-meaning but deluded scientists and tree-huggers.

  23. Oh the billions. Everybody think of the billions of gallons.
    Right then. I’ll think of the billions of gallons.
    While on my little patch of Cumbria, which extended to 255 acres (call it 100 Hectares), every rear typically, 225 million gallons of water fell onto that little patch.
    Call it one quarter of a billion.
    On 100 hectares.
    And the Sierra is how big….
    Somebody buy these muppets a One Big Phat Dlido and help them with their problem.

  24. To read something like this that has support from within the U.S. Forest Service and the National Park Service is absolutely astounding. Are there now rational thinking emanating from within the
    Department of interior? What has happened?
    Are the likes of Maureen Hyzer and associates within the US Forest Service being caged? Where are their shrill cries? They were certain that the National Forest system belongs to them and them only and everyone else should be restricted or forced retirement. Anyway, Hyzer got a big promotion to go back to Washington state from Virginia. She did all the damage she could do in VA with regards to the reputation of the Forest Service. Her appointments and policies in VA still linger, so her legacy continues but only viewed as positive by those appointed within her reign. My sympathies to WA but she spawned there and migrated back.

  25. So wild fires are good for California. It is far cheaper to start more fires than it is to fight them. California’s water supply would also increase if so much of it was no longer used by agriculture. So maybe California would be better off if all forms of agriculture were banned by law. Arson should be legalized in California and it should be illegal to fight fires. Such laws would also help to rid California of excess population. Drastically reducing population in California would serve to further reduce water usage and also very significantly reduce California’s carbon footprint. So in California instead of being prosecuted, arsonists should be paid for their services to humanity.

  26. What this article told me is that some people in California finally figured out that forests and the ecosystem are healthier when they don’t exclude fire in a fire driven system. They are also saying that they so screwed up for such a long time by excluding fire that it is going to cost a lot of taxpayers money to bring back the natural cycle. Of course they will not admit that selective harvest would speed up the process and offset cost. Still I am not sure about their billions of dollars required.

  27. A true Earth lover would say that trees were there first, and so it is TREES that have first rights to the water, NOT the HUMAN populations of surrounding (invading) cities that drink it.
    So, … tough cookies, California humans! You’ll just have to suffer, because trees are a more important part of this region of Mother Earth. Parasitic humans sucking down the trees’ water are the true problem, and, surely, California enviromaniacs can comprehend this and accept the consequences.
    Let the trees live and thrive, and force cities to thin their human numbers, either by foregoing child birth, dying of thirst, or systematic “harvesting” of the excess. It’s the only right way to handle things.

  28. 10% more water means 10% more water used means right back to water shortages and the same mess we have now. I have nothing against forest management—I think thinning and clearing are good—but it won’t fix the problem, just temporarily delay it.

  29. Responsible logging is a great way to manage forests. Maybe we will see a return of a logging industry in California.

  30. Mass balance in flows in processes are paramount in quantitative evaluation issues in climate, chemical engineering, metallurgy, medicine…and it is a metric that climate scientists seem to be totally unaware of. They talk in qualitative, compartmented ways one hears from a pupil presenting a highschool study project.
    Heck when you burn down a forest you likely release 3.5 billion gallons contained in the trees, shrubs and soil. How many gallons of water does a tree hold? And another bunch of gallons hosing the fires. And then new growth grows rampant to replace the cut forest. Also cutting will reduce the transpiration but exposure of the ground to the hot sun will increase direct evapo. Note, horrors of horrors, that elevated CO2 reduces a plant’s water demand so it has been mitigating itself.
    What about that 10% added flow in streams. It is also a change in a process ‘stream’. Since enviros are loathe to allow water control structures, a good part of it just goes to add itself to the ocean! In their mindset the increase is simply an unspecified benefit of it’s own.
    In their compartmented study of water conservation (for nothing in particular), they forgot to think about what happens in a heavy rainy season that’s certain to happen? NOW it would be handy to have all that vegetation to protect the soil and mitigate other common forms of preventable California disaster, mudslides and and floods. The Sierra Nevada rivers would be running not 10% more but 300% more, flooding communities, taking out infrastructure etc., killing people.
    Calfornia needlessly suffers all this because of the lock that Democrat, mentally bankrupt minds have on political office there. I’d love to manage a project that would make California a Garden of Eden state. I’d start with a water mass balance network averaged over a couple of decades or two with its variances . It would include repurposing the city rain water diversion channel flows.

  31. Or they could start charging almond farms for excessive water use. Natu forests don’t import water from other areas.

  32. “…A century of forest management had kept wildfires to a minimum. But without fire, Sierra forests grew very dense. In recent decades, new policies have allowed nature to take its course, with wildfires helping to thin out overgrown forests….”
    New policies? I thought climate change was causing those wildfires.

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