They are just now figuring this out?

From the University of Washington, something woodsmen, hunters, and campers have observed in forests for hundreds of years.  It’s all about the LWIR.

Snow melts faster under trees than in open areas in mild climates

A mounted camera captures snow sticking in a forest gap, while snow appears to have melted under the trees in dense, second-growth forest behind the gap site.

A mounted camera shows snow sticking in an open area, while it appears to have melted under the trees in dense, second-growth forest just behind.

It’s a foggy fall morning, and University of Washington researcher Susan Dickerson-Lange pokes her index finger into the damp soil beneath a canopy of second-growth conifers. The tree cover is dense here, and little light seeps in among the understory of the Cedar River Municipal Watershed about 30 miles east of Seattle.

She digs a small hole in the leaf-litter soil, then pushes a thumb-sized device, called an iButton, about an inch beneath the surface. If all goes well, this tiny, battery-powered instrument will collect a temperature reading every hour for 11 months. Researchers hope this tool and a handful of other instruments will help them map winter temperatures throughout the watershed as they track snow accumulation and melt.

This fieldwork piggybacks on a recent finding by Jessica Lundquist, a UW associate professor of civil and environmental engineering, and her lab that shows that tree cover actually causes snow to melt more quickly on the western slopes of the Pacific Northwest’s Cascade Mountains and other warm, Mediterranean-type climates around the world. Alternatively, open, clear gaps in the forests tend to keep snow on the ground longer into the spring and summer. Lundquist and her colleagues published their findings online this fall in Water Resources Research.

Common sense says that the shade of a tree will help retain snow, and snow exposed to sunlight in open areas will melt. This typically is the case in regions where winter temperatures are below freezing, such as the Northeast, Midwest and most of central and eastern Canada. But in Mediterranean climates – where the average winter temperatures usually are above 30 degrees Fahrenheit – a different phenomenon occurs. Snow tends to melt under the tree canopy and stay more intact in open meadows or gaps in a forest.

This happens in part because trees in warmer, maritime forests radiate heat in the form of long-wave radiation to a greater degree than the sky does. Heat radiating from the trees contributes to snow melting under the canopy first.

“Trees melt our snow, but it lasts longer if you open up some gaps in the forest,” Lundquist said. “The hope is that this paper gives us more of a global framework for how we manage our forests to conserve snowpack.”

For the study, Lundquist examined relevant published research the world over that listed paired snow measurements in neighboring forested and open areas; then she plotted those locations and noted their average winter temperatures. Places with similar winter climates – parts of the Swiss Alps, western Oregon and Washington, and the Sierra Nevada range in California – all had similar outcomes: Snow lasted longer in open areas.

“It’s remarkable that, given all the disparities in these studies, it did sort out by climate,” Lundquist said.

Even in the rainy Pacific Northwest, we depend on yearly snowpack for drinking water and healthy river flows for fish, said Rolf Gersonde, who designs and implements forest restoration projects in the Cedar River Watershed. Reservoirs in the western Cascades hold approximately a year’s supply of water. That means when our snowpack is gone – usually by the summer solstice – our water supply depends on often meager summer rainfall to get us through until fall, he said. Snowpack is a key component of the Northwest’s reservoir storage system, so watershed managers care about how forest changes due to management decisions or natural disturbances may impact that melting timetable.

The UW’s research in the watershed has been a beneficial partnership, researchers say. The 90,000-acre watershed is owned by the City of Seattle and provides drinking water to 1.4 million people. The area now is closed to recreation and commercial logging, but more than 80 percent of the land was logged during the early 20th century, and a large swath of dense, second-growth trees grows there now. Watershed managers have tried thinning and cutting gaps in parts of the forest to encourage more tree and plant diversity – that then leads to more diverse animal habitat – offering the UW a variety of sites to monitor.

The UW researchers acknowledge that temperature is a very broad predictor of snowmelt behavior, yet they expect their theory to hold true as they look more closely at the relationship between climate and snowmelt throughout the Pacific Northwest. They are collaborating with researchers at Oregon State University and the University of Idaho, and are ramping up a citizen science project asking hikers and snowshoers to share snow observations.

“This is really just a start,” said Dickerson-Lange, a doctoral student in Lundquist’s lab who is coordinating the citizen-science observations. “The plan is to refine this model. With climate change, a cold forest now might behave more like a warm forest 100 years from now. We want to be able to plan ahead.”

Co-authors of the recent paper are Nicoleta Cristea of UW civil and environmental engineering and James Lutz of Utah State University.

Funding for the research is from the National Science Foundation.

###

For more information, contact Lundquist at jdlund@uw.edu or 303-497-8257 and Dickerson-Lange at dickers@uw.edu or 253-225-9909. Lundquist is on sabbatical but is reachable by email or phone.

here is a video of the field work:

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Crispin in Waterloo

I am surprised to see no mention of the retention of ground water by treed areas that is released slowly and continuously into the streams. When the snow finishes melting there are the ground water springs that feed the brooks.
I heard a story from Mozambique where a development worker had arrived at a place with the whole mountainside clear-cut and the water supply gone. He systematically planted a local mahogany on it over a period of years. When it was once again fully forested, the springs returned and there was year-round running water in the streams. Trees create water supplies – at least some of them.
Evergreens create sponge-like forest floors that retain a great deal of moisture which ‘leaks’ slowly into the streams. Is their summer river level really dependent on summer rainfall?

Lord Galleywood

The edukation system over the last 35 years should be well proud of their efforts *shakes head on the wall*

In Minnesota we call it the “Pine Tree Effect” in the late spring when the sun gets higher in the sky things thaw very quickly in pine wooded forests like we have in the Boundary waters. Trees are excellent solar collectors. Maybe we need to cut them all down so winter will last longer.

Tim Collins

The trails and blind alleys that can be explored once you take that leap of faith and accept that AGW is real are boundless.
From polar bears to pacific island nation flooding – what a goldmine for the unemployable.

Eve

Oh Nos, they will target trees now

CK

Even sparse, fine branches of deciduous trees, like Birch (Betula spp) in open parkland radiate IR back to the ground, creating a a circular area of frost free grass around the tree when open grassland nearby is covered with thick hoar frost.
The “Birch branch effect” as I shall call it, is a better analogy for longwave backradiating entities in the air above the ground, than the mis-named “Greenhouse effect”.

geran

are they that stupid? Snow doesn’t fall under trees, duh.
(Sorry, made too many trips along I-90 east of Seattle, over Snowqualmie Pass.)
http://www.wsdot.com/Traffic/passes/snoqualmie/

geran says:
November 13, 2013 at 4:59 pm
are they that stupid? Snow doesn’t fall under trees, duh.

Yep. Much less to melt.
/Mr Lynn

Skiphil

Off-piste and backcountry skiers have known of this phenomenon for ages, as it is well known that a skier can plunge through the snow surface close to trees, due to unseen snowmelt around the tree….. This can be quite dangerous, even deadly, especially when the snowpack is deep and a skier may end up deeply buried or even upside down.

Did they account for less snowfall being on the ground under trees and more snow being in the clearings? Did they calculate that the melting snow trapped in the higher branches drips on the snow below the tree thus causing quicker melting? Ever seen a front-end loader pick up a fresh scoop of pine mulch that’s been in direct sunlight? An amazing amount of heat gets trapped in pine mulch and there is also a chemical reaction during putrification …I can recall it smoldering and spontaneously combusting.

ed bray

when it cools in fall the snow starts to stay on the bare ground and the trees in evergreens so there is less snow on the ground under the trees, it also freezes on the ground around the trees but less under the trees Ed

Alan Robertson

Eve says:
November 13, 2013 at 4:51 pm
“Oh Nos, they will target trees now”
_______________________________
It’s quite likely that these folks will evoke the law of unintended consequences, yet again.

u.k.(us)

“This is really just a start,” said Dickerson-Lange, a doctoral student in Lundquist’s lab who is coordinating the citizen-science observations. “The plan is to refine this model. With climate change, a cold forest now might behave more like a warm forest 100 years from now. We want to be able to plan ahead.”
=======================
Right now I’d plan for winter, surviving that I’d plan for spring/summer, and so on.
It has worked for many a generation, before studies such as these.
A plan helps, but the onset of cold weather really concentrates the mind.

J. Locke

facepalm. they shoulda spent a couple of years in the infantry. they would have known this.

I guess we needed a peer reviewed paper to tell us this before alarmist could believe it.

ROM

I think I should apply for a very substantial grant which going by the reports of hundreds of thousands of dollars for what turns out to be totally crap research and science of no use to anybody, such grants for this old pensioner would probably would be large enough to keep me in a comfortable style for the rest of whats left of my life.
And my research grant application would be for researching the day time heat retention of the Australian bush and how it often releases that heat as the ambient air temperatures cool down in the evenings and the warmer air trapped by those trees and bush land releases that warm air from around and below those trees and bushland and it slowly and sometimes quickly rises up in the form of vast, smooth columns of air called evening thermals.
To research this phenomena I would need of course a heavily instrumented high performance glider worth say around the $450,000 mark to find locate and measure the strength and map the location of these evening thermals. Plus ground crew. Plus a trailer and vehicle in case I didn’t get back to the field. Plus of course expenses and the need to consult with my fellow glider pilots in other countries to tap their experiences and fly in and research their conditions and measure this phenomena in other world wide locations.
Nothing that a million or so dollar grant wouldn’t cover to research this extraordinary phenomena of trees trapping heat during the warm part of the day and releasing it after temperatures cool down in the evening so forming these wondrous,known only by glider pilots for some 80 years past,, the atmospheric phenomena of “evening thermals”
The cold areas now have their research project on the heat trapped under trees melting snow under trees so I think it only fair that I apply for and get a grant for a warm to hot regions research project to ascertain how heat is trapped and released from under trees during the various hours of the day.

Barbee

Waitaminnit.
I had always observed that LESS snow made it to the ground under evergreens and conifers, THUS there was less snow to melt.
Only anecdotal but a foot falls on my lawn, only a few inches drift under the trees-is that a factor? Yeah or Nay? That doesn’t seem to b3e addressed here.
But yeah, I get it: Compost is hot. Compost accumulates under trees….

Aphan

geran and Mr Lynn,
But in many places the snow doesn’t fall straight down either. Where I live it often snows sideways. It blows and drifts under the trees and over a lot of the trees. But even then, it melts under the trees first. I can’t believe they pay people to “notice stuff” that the rest of us have always known and call it scientific discovery. Wow.

wayne

Does this mean the supposed “global warming” is just an artifact from a greening Earth as the satellite pictures clearly show occurred in the 80s and 90s? Possibly. NH civilization stopped cutting the trees and the SH started to clear much of their forests for agriculture purposes. Warmer NH, cooler SH.
I did notice if you take BESTs raw land temperature data and find the sine equation to level the annual waves in the data not only do you have a first large term for solar but it also requires a half harmonic (≈±0.4°C) to level the spring and fall temperatures. A simple sine correction didn’t work. I had to stop and ask myself, what is it about April and October that causes those sub-waves in the global temperatures? Hmm, related to snow cover?

There’s a spot on I 93 just before I get off on my northbound evening commute where I pass a pine grove, then a clearing, then more pines and another clearing. The northern edge of the pines act like a snow fence and by spring there’s a good sized drift just north of the trees. The trees also provide shade from the March sun, the clearing provide a lot of open sky, and I always like to see how long the snow lasts there. I’m glad that people in Washington are sharing the experience.
I have an IR thermometer – I’m always impressed at how “cold” dry sky is, even in June.

omegaman66

You do realize this is a sure sign of global warming crazyness, right!

scott

As someone who has grown up and lived their entire life in the PNW, including living in heavily forested areas and many trips into forests and the high country, less snow under trees and within forests is something I have experienced. As the UW is located in this region, I find it breathtaking that this phenomena has been effectively ignored until now by climatologists. I have always attributed it to less snow making it to the ground below the evergreen trees. As snow melts, the trees tend to suddenly dump their load of snow. Snow released in this way is broken up into clumps and a fine spray. I would guess that this melts faster than snow that lies on the ground. The trees themselves are very dark coloured, so the change from white to very dark green is a big albedo change as well. Being evergreen forests, being within one even in the rain, you often stay relatively dry. You are also warmer, but I have always attributed that to the trees blocking the wind. In short, it is painfully obvious that the inside of a forest is a microclimate that acts much differently than areas of open ground (urban, agricultural, or clearcuts in this region).

Tom Moran says:
November 13, 2013 at 5:11 pm
“Did they account for less snowfall being on the ground under trees and more snow being in the clearings?”
Exactly what I was thinking. Looks like common sense again.

Measuring ground temperature is not the right approach at all. Its part, but by no means the complete answer. They have to go out into those woods and forests and not just leave recording devices there while they sit in their offices.
If they do go out, they will see that less snow gets to the ground because a LOT of it ends up in the trees. Less snow – melts faster. That is part of the answer. Another part is that when the air temperature rises above freezing, the snow in the tree branches has more surface area exposed to that warm air, above and below it, not just above. As it melts, it drips onto the (less) snow beneath the trees and speeds up its melting. The dark wood of the tree also absorbs heat from the sun and creates a warm micro-climate which speeds up the melting of the snow in the branches.
Can I have my $5M now?

Craig

Considering this, in conjunction with the fact that we know from satellite readings that the Earth is getting greener (both naturally and by the countless organizations involved in tree planting worldwide), I wonder if anybody has done any research on how much heat radiation might be created in the newly “green” spaces during the winter and whether stations that are now closer to trees that might have recently been added might experience a moderate increase in temperatures.
Thanks to the surface stations project determining poor placement of stations in reference to parking structures, HVAC, chimneys, chimneys, etc., as well as poorly maintained temperature stations, we already know that there has been significant localized, artificial warming monitored that may be entirely based on a failure to maintain the stations properly. One must wonder if even slight changes at multiple sites due to radiation from new trees could cause even slight increases over time.

Greg Cavanagh

Quote “Trees melt our snow, but it lasts longer if you open up some gaps in the forest,” Lundquist said. “The hope is that this paper gives us more of a global framework for how we manage our forests to conserve snowpack.”
So; the new greens want to conserve snow pack, I guess by clearing the forest?

Fred Allen

And like Barbee, I would have explained it in my non-scientific term, as compost. Not only does rotting tree litter provide a comfortable place to sleep, it also provides a little extra warmth. But I’m not a scientist, so what would I know?

Heya

Warm air escapes through tree cover (slowly through large surface), dragging colder air from the open (smaller) spots – resulting there in sucking colder air directly from sky. As long these open gaps are colder then the air inside forrest, these spots will keeping on freezing up like a fridge. This mechanism stops when summer returns, and open spots getting warmer then inside forrest (due humidity and leaf cover)..

Hoser

There is a configuration effect from trees that can minimize solar melting and minimize radiant heat melting. The orientation of a chain of trees is ideal when it provides shade at mid-day over a broad area of snow. The spacing of the rows is best when it minimizes shortwave energy delivered to the snow (shadows), and minimizes the longwave energy delivered to the snow surface by radiating a larger fraction of energy to space instead of other trees. These ideas are several years old (some to at least 2004).
Another important loss of water content in snow is sublimation (not discussed).
http://www.webpages.uidaho.edu/watershed/Papers/The%20impact%20of%20coniferous%20forest%20temperature%20on%20incoming%20longwave%20radiation%20to%20melting%20snow.pdf
http://www.webpages.uidaho.edu/watershed/Papers/Ellis%202011.pdf
http://people.duke.edu/~mk176/publications/BijanEtAl_VegDensityVSRadiation_JGR.pdf

Keith Minto

Ric Werme

I have an IR thermometer – I’m always impressed at how “cold” dry sky is, even in June.

So do I ,remember Roy Spencer’s discussion ? A great toy.

Jeff L

As many have noted & must add my voice to, snowfall penetration to the ground is inversely proportional to the density of the woods. Clearly, these researchers have spent little time in the winter woods (at least that’s the way this reads).
As an avid backcounty skier & the owner of a large tract of conifer woods , I can assure your from observation that snow penetration is way more significant than any IR effects from the trees. How can I say this – just check out the new snow depth in the woods vs an opening during or right after a snow – before any IR effects could take hold – and you will see the there is an easily measurable effect , with the snow being substantially less in the woods compared to the openings.
What I have observed is that the effect is greatest on smaller snows – with smaller snows largely being caught on the tree limbs & a lot less making it to the ground. With bigger snows, the limbs reach a “saturation limit” so to speak , where they are holding all the snow they can, then more makes it the ground as a percentage relative to an open aspect.
It is also worth noting that most snow that is collected on limbs never makes it to the ground / ground water – it sublimates &/or evaporates prior to making to the ground. There are multiple studies on this – I know this based on research I did for a particular back country ski project I was involved in.

I love this:
“yet they expect their theory to hold true as they look more closely at the relationship between climate and snowmelt throughout the Pacific Northwest.”
Yeap nothing like starting off with a good dose of confirmational bias.

Theo Goodwin

So, the people studying forests have no experience of forests? How could you not know that snow does not collect under trees, at least many kinds of trees? Reminds me of my friend who grew up in a high rise in Queens and had not seen a bug inside a building until she moved to St. Louis.
How could you undertake the study and not learn that snow does not collect under trees? Did the investigators not go into a forest? Did they employ the usual method of the Paleo crowd and just find various “number series” on the internet and use them as their data?
How could you be a Phd researcher on forests and not have read Jack London’s “To Build A Fire?” They better read it or they might end up frozen to death, if they go into a forest.

Theo Goodwin

“Funding for the research is from the National Science Foundation.”
No oversight whatsoever. The people at the granting agency are just as clueless as the authors of the article. And the peer reviewers? Just as clueless.
By the way, I had collected my information about snow and trees by the time I was six years old. In fact, at the age of six I had learned to enjoy standing under a nice pine tree and watching the snow collect beyond the branches. The little trickles down through the branches were delightful.

Don Easterbrook

The study seems to have overlooked the most important aspect of the difference in snow depth beneath trees and open fields. Look at any clear-cut, snowy, mountain slope and you will notice immediately that the snow is (1) much deeper in the open fields, (2) persists longer into the melt season, and (3) is often absent altogether around the base of trees (the dreaded ‘tree wells’ well known to skiers). Is this because it is warmer under the trees and that melts the snow? Of course not! Trees are natural umbrellas–in a rainstorm where do you want to hang out, under a tree or out in the open? So in a snowstorm, where does the least snow accumulate? Guess what–in the forest where much less snow reaches the ground (50-70% less, depending on the vegetation) because the trees intercept a lot of the precipitation. Anybody who knows anything about hydrology knows this. And you have to ask the question, where does most of the snow melt take place, from the ground or from the atmosphere? Depending on the altitude and ambient air temperature, the ground is often frozen and not melting much, if any, snow, whereas the surface of the snow is melted by air temperature and solar energy. This study seems to fall in the category of a really dumb analysis.

Theo Goodwin

u.k.(us) says:
November 13, 2013 at 5:31 pm
“This is really just a start,” said Dickerson-Lange, a doctoral student in Lundquist’s lab who is coordinating the citizen-science observations. “The plan is to refine this model. With climate change, a cold forest now might behave more like a warm forest 100 years from now. We want to be able to plan ahead.”
=======================
“Right now I’d plan for winter, surviving that I’d plan for spring/summer, and so on.
It has worked for many a generation, before studies such as these.
A plan helps, but the onset of cold weather really concentrates the mind.”
How about a plan to find a spouse capable and willing to provide all necessary care for his “helpmate?”

BM

Happens here every spring under my pines in MA. My field is snow and ice covered for weeks after the sno melts under the trees.

Robert of Ottawa

So, if the snow pack is melting earlier to AGW, then all we need to do is cut down all the forests!
Brilliant! I like it. Complete anathema to the Warmista and Enviromentalist dogma.
Seriously, the key point is we don’t understand the natural cycles and therefore cannot discover the human effects. Oh, it’s all so complicated. I suggest the Crimotologists be sent to the nursery for a few hundred years while real scientists gather data.

Neil Jordan

Re Skiphil says: November 13, 2013 at 5:09 pm
and Don Easterbrook says: November 13, 2013 at 7:06 pm
You hit the nail(s) on the head(s). The term I learned from a backcountry ski instructor was “tree well”. Check on line for some technical details from the web site devoted to tree well safety:
http://www.deepsnowsafety.org/index.php/
http://www.ravallirepublic.com/lifestyles/recreation/article_ab180874-3012-11e0-9ac6-001cc4c002e0.html
The researchers need to get out more, but stay out of tree wells unless they have a buddy system.

Eric Gisin

Snow lands on conifer branches and sticks (unless it’s very cold). As long it’s not too cold, it will melt by afternoon and enter the soil as water. This allows the trees to grow slowly in the winter.
It can’t believe researchers on the west coast don’t know such basic information.

Robert Austin

Fenbeagle draws a hilarious rendering of Maurice Strong as an Ernest Stavro Bloefeld style super villain. Just scroll down to see his likeness.
http://fenbeagleblog.wordpress.com/2012/02/04/hanging-up-by-the-constables/

Robert Austin

Oops! Wrong post.

conscious1

We get big dumps in the Cascades! It can be 2ft deep in the open and only 6″ under the canopy. Way less snow falls in the woods. When it warms the snow on the trees melts and drips onto the forest floor melting the snow faster than in the open. I doubt LWIR has much of an effect compared to these other factors. It is cooler in the shade and the snow holds up better than in the open on a sunny day. It can be slushy/wet in the open and icy under the trees!

tobias

@ROM re your grant application , I mean really thanks that was a great lesson I am starting today!!! Thanks LOL 🙂 Most of you have already exposed this waste of money thanks.
And as far as tree wells in snow country are concerned ALL of you are more than correct, as an ex ski resort worker they were (and in 1 case tragically) the most dangerous spots on a ski hill. BUT they can also be a place you can survive in if used correctly.

Theo Goodwin;
Reminds me of my friend who grew up in a high rise in Queens and had not seen a bug inside a building until she moved to St. Louis.
>>>>>>>>>>>>>
Reminds me of my city slicker cousin who moved out to the prairies, determined to get back to agrarian roots. He called me over one day in mid summer to see if I could figure out what was wrong with his pumpkins. I said they looked great, there was nothing wrong with them that I could see. He looked at me as if I was daft and said, “….but, but… they’re green!”
We who grew up with nature in our back yards frequently forget how privileged we are to have had that opportunity, and that those who have not are coming from a completely different paradigm. Er, meme. Er, uhm….background.

milodonharlani

conscious1 says:
November 13, 2013 at 8:48 pm
Cross country skiing on the west side of the Cascades before modern skis in the ’70s & ’80s used to require changing waxes when moving out of the open into trees. Less so on the east side, except when it warmed up.
davidmhoffer says:
November 13, 2013 at 9:15 pm
Reminds me of my East Coast urban American classmate at Oxford who had never seen a swan before. When he saw them in England, his eyes got wide & he blurted out, “Look at the size of those ducks!”

Katherine

The UW’s research in the watershed has been a beneficial partnership, researchers say.
In other words, “keep the grant money flowing.”

John F. Hultquist

Which is why the “plant millions of trees” to combat global warming train went off the rails about 10 years ago.
Additionally, trees do hold some snow above the ground from where it can sublimate and melt more easily than in a deep layer on the ground.

ROM

You all realise of course that those same researcher’s will now apply for another grant and get it it past handout performance of the grants industry which uses OPM is any indication.
Then using all the knowledge of snow conditions in and around forests and trees that all of you have been posting about here for all to see,, they will never need to leave the comforts of their offices, which means lots of grant money left over to go partying on, to write another new paper on “snow holes” and how the concentration of CO2 around tree trunks creates warming and thereby creates the now famous [ lots around the world read this ] snow holes or some such!
OPM = Other People’s Money ie; yours and mine hard earned.

Julien

Indeed, wouldn’t that be because less snow is falling under trees than in open areas basically? Though it depends, the trees are as well blocking sunlight from melting the snow, so snow may melt faster away from the trees. But because less snow is falling under the trees (or rather, the snowfall is scattered along the trees height, and it falls to the ground only when it’s melted); it is actually tough to get to any conclusion. From experience, snow melts faster at spring in open areas, even if there’s basically more snow there. So i think sunlight blocking may well be the bigger factor here.
Just crazy thoughts from a dumb man out of shower. 🙂