How do birds keep warm?

I’m currently visiting Chicago, relishing the finger-stiffening, face-numbing cold and wind that make up a proper midwest winter. Whenever I look out from the warmth of my big puffy coat and see a bird, I feel a little bad for enjoying the weather so much. I can go home and make myself hot tea; they can’t.

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Very cold Tree Swallows (up in the Yukon, not Chicago!). Photo by Keith Williams

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Like mammals, birds are endothermic (“warm-blooded”), meaning that they maintain their body temperature independent of the outside environment. This almost always means keeping themselves warmer than the outside air. Birds have quite high natural body temperatures, even higher than ours, so any given outside temperature seems even colder to them than it does to us.

Birds are also smaller than we are (well, omitting the ostrich), which means that they have a higher surface-area-to-volume ratio than we do. This is a problem because the volume (inside) of an animal is where heat is produced and stored, while the surface (skin) of the animal is where heat is lost to the environment. Imagine holding your hand in a bitter wind: how would you keep it warm? By making a fist. Making a fist reduces the surface-area-to-volume ratio of your hand, and lets it keep warm longer. In contrast, if you hold your hand out flat with all the fingers spread, your surface-area-to-volume ratio is larger, and your hand will get cold very quickly. Because birds have higher surface-area-to-volume ratios than we do, keeping warm is harder for them. How do they do it?

Feathers: There is a reason why we fill our best coats with goose down. Feathers are fantastic insulation. Downy feathers trap tiny pockets of air next to the bird, allowing the bird to warm those pockets of air and hold that warm air around itself, preventing cold air from touching its skin. The more air trapped, the warmer the bird. Birds fluff up (the technical term for fluffing up is “ptiloerection”) in the cold to trap as much air in their feathers as possible.

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Goldfinch fluffed up against the cold. Photo by Jen Goellnitz

The legs and feet of almost all birds are thin and lack feathers, and so are vulnerable to rapid heat loss. Some birds handle this the obvious way:

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Dark-eyed Junco at zero degrees Fahrenheit, standing on one leg to tuck the other into her down. Photo by Pete Zarria

Why doesn’t the junco in the photo just sit down on both of her feet to keep them warm? Possibly because she wants to be able to escape predators. Juncos that are fluffed up and sitting on their feet in order to keep warm take more time to fly when startled, compared to sleek standing juncos, making them vulnerable to predators (Carr & Lima 2011). Carr & Lima didn’t study fluffy standing-on-one-foot juncos, but it’s possible that standing on one foot is a more flight-ready position than sitting.

Counter-current exchange: What if you can’t sit on your feet? What if, instead, you have to swish them around in frigid water?

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Male Mallard in Chicago in December. Cold feet!

Ducks and gulls can have such cold feet that they do not leave melted footprints in snow. The tissues in their feet are adapted to very cold conditions, and can still function close to freezing (Steen & Steen 1965). Yet if their feet are near freezing, and the blood that circulates through their feet then enters their bodies… those warm insulated bodies are going to cool off very quickly.

They deal with this by using counter-current heat exchange. Veins and arteries in the leg are close to each other, and as warm blood leaves the body, it heats up the cold blood returning to the body.

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Crude diagram of counter-current exchange in a duck foot. Red blood is warm, blue is cold; arrows indicate direction of blood flow.

Heat loss is minimized and the duck doesn’t freeze, even if its feet do.

(And if you’ve ever wondered, as I have, whether ducks are warmer on land or in the water: it appears that they lose 22% more heat while swimming than while standing on land in wind. So swimming is colder, but not by as much as you might expect (Van Sant & Bakken 2006).)

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Mallards on land in Chicago in December: 22% less cold than the other Mallard.

Huddling: Many birds, especially small birds, huddle together to conserve warmth (Gilbert et al. 2010). Huddling reduces the birds’ surface-area-to-volume ratio, since it turns many small birds into a single big group, and larger objects have higher surface-area-to-volume ratios than smaller objects.

Long-tailed Tits form single-file roosting “huddles” (lines, really) to keep warm at night. They are tiny, weighing 7-9 grams, and on average lose 9% of their body mass overnight. Energy conservation is crucial for them. The birds on the ends of the huddle lose more mass overnight than those in the middle, so the birds jockey for position, all trying not to be the cold one on the end (Hatchwell et al. 2009).

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Long-tailed Tit. Photo by Rich Mooney

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Long-tailed Tit. Photo by Sergey Yeliseev

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Okay, last Long-tailed Tit photo. I just love these little guys. Photo by Sergey Yeliseev

I once saw a photo of Long-tailed Tits huddling, but I can’t find it now, so here is my (very accurate, really!) recreation of the photo in Powerpoint.

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Long-tailed Tits huddling at night for warmth

References:

Carr JM, Lima SL. 2011. Heat-conserving postures hinder escape: a thermoregulation-predation trade-off in wintering birds. Behavioral Ecology 23:434-441.

Gilbert C, McCafferty D, Le Maho Y, Martrette J, Giroud S, Blanc S, Ancel A. 2010. One for all and all for one: the energetic benefits of huddling in endotherms. Biological Reviews 85:545-569.

Hatchwell BJ, Sharp SP, Simeoni M, McGowan A. 2009. Factors influencing overnight loss of body mass in the communal roosts of a social bird. Functional Ecology 23:367-372.

Steen I, Steen JB. 1965. The importance of legs in the thermoregulation of birds. Acta Physiologica Scandinavica 63:285-291.

Van Sant MJ, Bakken GS. 2006. Thermoregulation on the air-water interface – II: Foot conductance, activity metabolism and a two-dimensional heat transfer model. Journal of Thermal Biology 31:491-500.

 

Original from:
How do birds keep warm?

5 Major Causes of Land Pollution

Pollution is a serious problem worldwide. Land pollution is one of the more serious pollutions because it affects many people, animals and plants.

There various causes of land pollution – 5 major causes are listed below :

1. Landfills and other sites

Landfills are well known for their pollution because of the composition of waste that goes into them. The composition can vary depending on the landfill. Some landfills do have specific regulations on the wastes that are allowed to be dumped.

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One of the major causes of land pollution is the pollution of the soil that the landfills sit on. Toxic and hazardous substances are leaking into the soil and causing any change of supporting life to be nullified. The possible contaminates of soil are numerous and could include household waste, sewage waste, chemicals and waste materials from industries or factories, radioactive waste from nuclear plants and oily sludge waste from oil refineries.

Landfills are becoming over full and the conditions are becoming deplorable. People have taken dumping into their own hands and are dumping wastes of every kind into inappropriate containers and areas.

2. Construction activities

As populations increase and urbanization expounds, construction activities are on the rise. Construction activities are another major cause of land pollution.

Construction projects often require deforestation to free up land or to extract raw materials for projects. Large amounts of construction waste are also responsible for pollution.

Concrete and metal debris are pollutants that are put in landfills, increasing the burdens of the landfills that are close to capacity.

Other construction wastes are hazardous such as oils and paints. When they are not properly disposed, harmful chemicals can leach into the ground and cause land pollution.

5 Major Causes of Land Pollution

3. Soil erosion due to deforestation

Deforestation is causing soil erosion and is on the rise as the need for raw materials rises. More and more forests are being removed to make space for people and their cities.

Land erosion causes land pollution. Without roots to hold the soil particles they are more prone to being dislodged by both wind and water. The soil loses the nutrients and organic matter which leaves the soil infertile.

Floods are also being linked to deforestation. As the trees disappear, water has no where to go. Thus the water will rush downstream causing severe flooding. This flooding will contain debris which flows into the rivers and then into the oceans, causing pollution.

4. Agricultural activities

Demand for food increases as the population grows. The pressure on farmers to increase their yields is rising with the population. Nutrients in the soil are necessary for plant development, fertilizers and such are used to maintain the crops. The fertilizers are used to correct soil deficiencies and then pesticides are used to kills unwanted insects and fungi.

The fertilizers and pesticides run off into the streams and rivers or seep into the groundwater. These fertilizers and pesticides are a form of land pollution.

Farmers are developing natural alternatives to fertilizers and pesticides. These natural alternatives will only slightly alter the make-up of the soil and will not cause harm to the water supplies.

5. One of the largest causes of land pollution is mining activities

As the demand for goods increases along with the growing population, the demand for raw materials also increases. Metals, coal and precious stones are raw materials that have to be extracted from the earth through mining.

Mining has a huge impact on the environment and is a large cause of land pollution. Surface mining causes the destruction of existing plant life.

Mining related activities destabilizes the land structures that are in the area of the mines and increases soil erosion. A large amount of waste rocks need proper disposal and they cause significant environmental problems. Mining wastes that are exposed to the elements can leech harmful substances into the ground and cause land pollution by soil contamination.

 

Original from:
http://environmentinsider.com/causes-of-land-pollution/

How protecting forest community rights fights global climate change

Deforestation is a major contributor to climate change, as forests and the many forms of life they support are important for carbon sequestration. Yet an estimated 13 million hectares of forest are cleared every year. So, if we want to minimize the negative impacts of climate change, reducing the amount of forest that is destroyed annuallyshould be a priority.

Yet an important tool for preventing forest loss is often overlooked: legally recognizing the right of forest communities and indigenous peoples. A new report from the World Resources Institute lays out research that shows how these local communities in developing countries, which are often dependent on a thriving forest for their livelihoods, help prevent deforestation.

“If it were not for the legal recognition of the community protection of forests, then deforestation would have been substantially higher,” said Caleb Stevens, one of the report’s authors.

Other related article:

This finding isn’t entirely new. Over the past 10 years, as satellite mapping data of tree cover has become available, the relationship between local community rights and protecting forests has become more clear. A 2012 study from the Center for International Forestry Research showed that forests managed by local communities suffered from less deforestation than government-managed protected areas.

Stevens said that the new report is an effort to bring these findings into the larger discussion about climate change. “The climate change specialists, and the forest specialists, and the land-use specialists—their research and findings aren’t always talking to one another,” he said. “So, this report was really trying to bring these three things together.”

According to the report, there are 513 million hectares of legally recognized community forests, which account for about an eighth of the world’s forests. These forests store an estimated 37.7 billion tons of carbon, which is 29 times the carbon footprint of all passenger vehicles in the world.

In order to effectively protect their forests, indigenous peoples and local communities need a few key rights. One is the right to exclude or expel intruders or unwanted people from the area, which can cut down on activities like illegal logging. Another is giving local communities the right to choose how to manage the land and its resources. Finally, it’s important that communities have the right to compensation should the government choose to use their forests for other purposes.

How protecting forest community rights fights global climate change

However, the majority of community forests in Latin America, Africa and Asia are not legally recognized as such and are often owned by national governments. As heavily forested countries in the developing world are looking to accomplish their climate goals, protecting community forest rights is a key policy, the report argues.

“One of the most basic things that governments can do, is they can register the right,” said Stevens. “It’s one thing to recognize rights in the law or constitution, but it’s another thing to actually go out there and give communities official documentation that they in fact have legal rights to their forest.”

 

Original from:
http://www.treehugger.com/climate-change/how-protecting-forest-community-rights-fights-global-climate-change.html

Protecting Water Resources with Higher-Density Development

While growth and development can bring resources, amenities, and opportunities to communities, with these benefits come challenges. The environmental impacts of development can make it more difficult for communities to protect their natural resources.

Where and how communities accommodate growth profoundly affects the quality of streams, rivers, lakes, and beaches. Development that uses land efficiently and protects undisturbed natural lands lets a community grow and still protect its water resources.

Some communities have interpreted water quality research to mean that low-density development will best protect water resources. However, some water quality experts argue that this strategy can backfire and actually harm water resources. Higher-density development, they believe, is a better way to protect water resources. Protecting Water Resources with Higher-Density Development (2006) helps guide communities through this debate to better understand the impacts of high- and low-density development on water resources.

Other related article:

EPA modeled scenarios of different densities at three scales and at three different time-series build-out examples to examine whether lower-density development is always better for water quality. EPA examined stormwater runoff from different development densities at the one-acre, lot, and watershed levels to determine the differences among scenarios. This analysis demonstrated:

  • Higher-density scenarios generate less stormwater runoff per house at all scales and at all time-series build-out examples.
  • For the same amount of development, higher-density development produces less runoff and less impervious cover than low-density development.
  • For a given amount of growth, lower-density development affects more of the watershed.

Taken together, these findings indicate that low-density development might not always be preferable for protecting water resources. Higher densities might better protect water quality, especially at the lot and watershed levels. Denser developments consume less land to accommodate the same number of houses. Consuming less land creates less impervious cover in the watershed.

Protecting Water Resources with Higher-Density Development

Increasing development densities is one strategy communities can use to minimize regional water quality impacts. To fully protect water resources, communities need to employ a wide range of land use strategies that are based on their local conditions, context, and goals. Such strategies could include building a range of development densities, incorporating adequate open space, preserving critical ecological and buffer areas, and minimizing land disturbance.

 

Original from:
https://www.epa.gov/smartgrowth/protecting-water-resources-higher-density-development

10 things you can do to save the forests

The International Day of Forests is a great way to raise awareness, but most of the time, people don’t really know how they can contribute. So instead of writing an article on the importance of forests and how these are threatened, I will give you 10 simple tips that you can use at home or at work to reduce your impact and help save forests:

1. Go paperless: use technology at the office, at home or at the bank by requesting electronic documents, bills, etc. Send e-mails instead of faxes or paper mail, and use electronic memos and instead of paper bulletins.

2. Print less: First ask yourself if you really need to print that document. If the answer is no, then no need to print it out. This way you are already helping to save paper, and collectively, save trees and forests.

Other related article:

3. Print smart: If you really need to print that document, then print on both sides, and print a single copy that you can pass around. Also, if you have to print a large document, you can format the document to reduce amount of paper. Here is a video to guide you on the formatting.

4. Reuse paper: by collecting scrap paper and reusing it as note paper is a great idea. You can also reuse paper in different ways, for instance to support things such as computer screens.

5. Recycle all paper material: set up a paper recycling station at home or in your office. No need to wait to know how and where you will dispose of that paper. While your newly set paper bin is filling up (which should take a while), you will have plenty of time to find a public paper disposal or a private company that can come and collect your paper, often for free!

6. Choose recycled paper: Everything from recycled office paper to recycled toilet paper is available at your local shop. By choosing products made from recycled paper, we can save trees. For every 17 trees saved, you are helping the earth to absorb 250 pounds of carbon dioxide from the atmosphere each year.

7. Buy products with the FSC logo on: FSC certified wood and related products such as paper packages and others are sustainably harvested and benefit both people and environment. Watch this short video that explains what FSC is and how it helps save forests.

8. Don’t panic, eat organic: Organic and locally grown foods help reduce the clearing of forests for agricultural lands. In addition, visit your local food store and choose organic products, most likely these will be sold with no paper or plastic packaging, which will also help reduce your impact.

10 things you can do to save the forests

9. Support forest conservation work: Most organizations working on forest conservation are non-profit and rely on donations. Support by donating to WWF or other organizations working towards sustainable management of forests is always a good way to offset your paper consumption.

10. Share the message: raising awareness to take responsible action is a simple but important thing you can do. Share this blog post or the following video on your social medias, organize a walk in your nearby forest with family and colleagues to learn more about it, or even write a letter to your government asking what is it willing to commit for forests today, are all important actions to support and promote this International Day of forests.

Saving forests is simple and we can do it by changing little things in our everyday lives. By reducing our paper consumption at home or at work, we are making a huge difference for our planet. Remember that one’s action is important and if you think that you’re too small to make a difference, try sleeping in a closed room with a mosquito.

 

Original from:
http://blogsno.panda.org/blog/2013/03/21/international-day-of-forests-10-tips-on-how-you-can-help-save-the-forests/

Protecting Clean Water for People and Nature

We work with people all over the world to make our rivers and lakes clean, healthy and secure.

Most people in the world get our water from rivers and lakes, including the vast majority of the world’s poorest people.

But half of the world’s 500 most important rivers – water sources for hundreds of millions of people – are being seriously depleted or polluted.* Approximately 40 percent of the rivers in the U.S. are too polluted for fishing and swimming.**

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Water shortages will likely be a fact of life for most people on the planet within the next ten years.*** We can’t afford to pollute and destroy our drinking water sources. But that’s exactly what we’re doing – often without knowing it.

Forests, grasslands and wetlands are nature’s water filters. They help keep erosion and pollution from flowing into our waters and they slow rainwater down, sending more water into underground supplies. But every year we lose 32 million acres of forest – that’s a lot of water filters, gone, every year.

We are facing dirtier, unsafe water and more risk of water shortages and scarcity. This crisis is real, it’s happening now and it’s getting worse fast.

The Nature Conservancy partners with people communities in all 50 states and 30 countries to protect water sources. We work on the ground to:

– Prevent deforestation and destruction of grasslands – nature’s water filters

– Restore forests and grasslands that have already been lost or damaged and sending erosion into our waters

– Equip farmers with practical ways to keep harmful run-off out of our waters

– Restore floodplains that act as sponges and send water down into groundwater supplies and filter pollution out of rivers

– Create new science that helps pinpoint the greatest threats to our waters and the most effective ways to combat them

Protecting Clean Water for People and Nature

But we understand that nature won’t solve everything, so we’re finding new ways to reduce water use. More than 70 percent of water withdrawn from nature goes to agriculture, so we’re helping farmers access new technologies and practices that use less water while continuing to produce the food we need.

 

Original from:
http://www.nature.org/ourinitiatives/habitats/riverslakes/protecting-clean-water-for-people-and-nature.xml

How protecting forest community rights fights global climate change

Deforestation is a major contributor to climate change, as forests and the many forms of life they support are important for carbon sequestration. Yet an estimated 13 million hectares of forest are cleared every year. So, if we want to minimize the negative impacts of climate change, reducing the amount of forest that is destroyed annuallyshould be a priority.

Yet an important tool for preventing forest loss is often overlooked: legally recognizing the right of forest communities and indigenous peoples. A new report from the World Resources Institute lays out research that shows how these local communities in developing countries, which are often dependent on a thriving forest for their livelihoods, help prevent deforestation.

“If it were not for the legal recognition of the community protection of forests, then deforestation would have been substantially higher,” said Caleb Stevens, one of the report’s authors.

Other related article:

This finding isn’t entirely new. Over the past 10 years, as satellite mapping data of tree cover has become available, the relationship between local community rights and protecting forests has become more clear. A 2012 study from the Center for International Forestry Research showed that forests managed by local communities suffered from less deforestation than government-managed protected areas.

Stevens said that the new report is an effort to bring these findings into the larger discussion about climate change. “The climate change specialists, and the forest specialists, and the land-use specialists—their research and findings aren’t always talking to one another,” he said. “So, this report was really trying to bring these three things together.”

According to the report, there are 513 million hectares of legally recognized community forests, which account for about an eighth of the world’s forests. These forests store an estimated 37.7 billion tons of carbon, which is 29 times the carbon footprint of all passenger vehicles in the world.

In order to effectively protect their forests, indigenous peoples and local communities need a few key rights. One is the right to exclude or expel intruders or unwanted people from the area, which can cut down on activities like illegal logging. Another is giving local communities the right to choose how to manage the land and its resources. Finally, it’s important that communities have the right to compensation should the government choose to use their forests for other purposes.

How protecting forest community rights fights global climate changeHowever, the majority of community forests in Latin America, Africa and Asia are not legally recognized as such and are often owned by national governments. As heavily forested countries in the developing world are looking to accomplish their climate goals, protecting community forest rights is a key policy, the report argues.

“One of the most basic things that governments can do, is they can register the right,” said Stevens. “It’s one thing to recognize rights in the law or constitution, but it’s another thing to actually go out there and give communities official documentation that they in fact have legal rights to their forest.”

 

Original from:
http://www.treehugger.com/climate-change/how-protecting-forest-community-rights-fights-global-climate-change.html

Science Shows Hugging Trees Is Good For Health

I’m sure most people have heard of the term “tree-hugger,” often a nickname given to people who care about the environment and the planet. But did you know that hugging trees can actually improve your health? As a matter of fact, you don’t even have to hug a tree to reap the numerous health benefits, just being around trees and plants in nature is enough.

In a book that was published by author Matthew Silverstone entitled, “Blinded By Science” the evidence confirming the healthful benefits of trees includes the effects they have on various issues like depression, concentration levels and even the ability to alleviate headaches. This practice has been going on since ancient times so it’s not just a new discovery.

The book cites a large variety of various studies which showcase that children show extreme psychological and physiological effects in terms of their mental health and well-being when they regularly interact with plants and trees.

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A public health report that investigated the association between green space and mental health concluded “access to nature can significantly contribute to our mental and capital wellbeing.”

There has also been a study done that shows the effectiveness of nature to alleviate symptoms of depression, and even promote attention and working memory. Maybe getting back to the basics, and connected to who we are and where we came from is just what we need to center ourselves in this busy world.

Another report stated: “safe, green spaces may be as effective as prescription drugs in treating some forms of mental illnesses.”

Matthew however, argues that these health effects that have been previously mentioned have nothing to do with the green spaces, but rather proving scientifically that it is the vibrational properties of the trees and plants that give us the health benefits.

How Does The Vibration Of Plants Affect Us?

Everything in the entire world vibrates, everything is literally vibration. Different vibrations affect biological behaviours. So naturally, when one touches a tree, or is in the general vicinity of a tree, its different vibrational pattern will affect various biological behaviours within your body.

Science Shows Hugging Trees Is Good For Health

Imagine if doctors were able to prescribe, an hour a day in a forest, instead of various different pharmaceutical drugs with various different side effects.

This method may sound too good to be true, but what have you got to lose? It would be worth trying for sure! Perhaps this could even supplement other treatments.

In Japan, people practise ‘forest bathing’, where they spend quiet time absorbing the wisdom of ancient forests, taking long walks among the trees to stimulate their immune system. In Taoism, students are encouraged to meditate among trees, and it is believed that the trees will absorb negative energies, replacing them with healthy ones. Trees are seen as a source of emotional and physical healing, and themselves as meditators, absorbing universal energies.” NatureAndHealth.com

What You Can Start Doing

1. Bring plants into your office space or where you work.

2. When going for walks, choose paths where you will be walking through parks or nature with trees.

3. Bring your friends and family to treed areas more often when you go outside or play with the kids.

4. Plant a garden and be amongst nature. You connect with your food and the earth

5. Plant a tree in your own yard, or even in an area you feel could use a tree!

6. Make time to go be amongst trees daily or every other day. Don’t be afraid to jump right in and hug the tree!

 

Original from:
http://www.collective-evolution.com/2014/12/02/science-proves-hugging-trees-is-good-for-health/

Our Planet’s Lungs

We have all heard about how trees help the environment, but do we know how exactly? Metaphorically, trees are like the lungs of the planet. They breathe in carbon dioxide and breathe out oxygen. What does this mean?

Carbon Dioxide or CO2 is one of the major contributing elements to the greenhouse effect. Trees trap CO2 from the atmosphere. Studies have shown that urban forests of the U.S store 800 million tons of. Mature trees can absorb roughly 48 pounds of CO2 a year. The tree in turn releases enough oxygen to sustain two human beings.

In urban areas, trees can help reduce urban runoff and erosion by storing water and breaking the force of rain as it falls. The United States Department of Agriculture says that 100 mature trees can reduce runoff caused by rainfall by up to 100,000 gallons.

Other related article:

Trees have other benefits in urban areas as well. For one, they absorb sound and reduce thus noise pollution. If you live by a major freeway, you can appreciate sounds absorbed. Studies have shown that in some cases, a well planted group of trees can reduce noise pollution by up to 10 decibels.

For urban areas that are quite hot, such as Phoenix or Las Vegas, the addition of trees help shade asphalt and reduce what is called the “heat island” effect. Reducing heat is so important in regards to helping people save energy that the Environmental Protection Agency encourages cities to grow trees. To determine exactly how much energy is saved by a trees cooling effect, studies have shown that one tree is equivalent to 10 room-size air conditioners running 20 hours a day.

Trees aren’t only beneficial for warm climates and summer heat. In the winter, they can act as windbreaks for your home and help you save on heating costs. The Journal of Horticulture claims that saving on heating costs can reach as much as 25 percent!

our-planets-lungs

What are some other quick facts regarding trees and how they save energy and help the environment? Here are a few:

· As few as three trees properly positioned can save the average household between $100 and $250 annually in energy costs.

· Fifty million shade trees planted in strategic, energy-saving locations could eliminate the need for seven 100-megawatt power plants.

· Shade from two large trees on the west side of a house and one on the east side can save up to 30% of a typical residence’s annual air conditioning costs.

· Annual benefits provided by parking lot trees in Sacramento, California,(8.1% tree shade) were valued at approximately $700,000 for improved air quality. By increasing shade to 50% in all parking lots in Sacramento, the annual benefits will increase to $4 million.

· Rows of trees reduce wind speed by up to about 85%, with maximum reductions increasing in proportion to visual density. Because even a single row of dense conifers can cause large reductions in wind speed, effective windbreaks can be planted on relatively small house lots. Compared with an open area, a good windbreak that does not shade the house will save about 15% of the heat energy used in a typical home.

· Modest increases of 10% canopy cover in the New York City Area were shown to reduce peak ozone levels by up to 4 parts per billion or by nearly 3% of the maximum and 37% of the amount by which the area exceeded its air quality standard. Similar results were found in Los Angeles and along the East Coast from Baltimore to Boston.

· Leafy tree canopies catch precipitation before it reaches the ground, allowing some of it to gently drip and the rest to evaporate. This lessens the force of storms and reduces runoff and erosion. Research indicates that 100 mature tree crowns intercept about 100,000 gallons of rainfall per year, reducing runoff and providing cleaner water.

· Trees reduce noise pollution by absorbing sounds. A belt of trees 98 feet wide and 49 feet tall can reduce highway noise by 6 to 10 decibels.

· Trees in Davis, California, parking lots reduced asphalt temperatures by as much as 36 degrees Fahrenheit, and car interior temperatures by over 47 degrees Fahrenheit.

· Philadelphia’s 2.1 million trees currently store approximately 481,000 metric tons of carbon with an estimated value of $9.8 million.

· A typical community forest of 10,000 trees will retain approximately 10 million gallons of rainwater per year.

 

Original from:
http://www.nitrofill.com/TreeLungs.aspx

Scientists have discovered that living near trees is good for your health

In a new paper published Thursday, a team of researchers present a compelling case for why urban neighborhoods filled with trees are better for your physical health. The research appeared in the open access journal Scientific Reports.

The large study builds on a body of prior research showing the cognitive and psychological benefits of nature scenery — but also goes farther in actually beginning to quantify just how much an addition of trees in a neighborhood enhances health outcomes. The researchers, led by psychologist Omid Kardan of the University of Chicago, were able to do so because they were working with a vast dataset of public, urban trees kept by the city of Toronto — some 530,000 of them, categorized by species, location, and tree diameter — supplemented by satellite measurements of non-public green space (for instance, trees in a person’s back yard).

They also had the health records for over 30,000 Toronto residents, reporting not only individual self-perceptions of health but also heart conditions, prevalence of cancer, diabetes, mental health problems and much more.

Other related article:

“Controlling for income, age and education, we found a significant independent effect of trees on the street on health,” said Marc Berman, a co-author of the study and also a psychologist at the University of Chicago. “It seemed like the effect was strongest for the public [trees]. Not to say the other trees don’t have an impact, but we found stronger effects for the trees on the street.”

Indeed, given the large size of the study, the researchers were able to compare the beneficial effect of trees in a neighborhood to other well-known demographic factors that are related to improved health, such as age and wealth. Thus, they found that “having 10 more trees in a city block, on average, improves health perception in ways comparable to an increase in annual personal income of $10,000 and moving to a neighborhood with $10,000 higher median income or being 7 years younger.” (Berman notes that self-perception of health is admittedly subjective, but adds that it “correlates pretty strongly with the objective health measures” the study considered.)

Indeed, the finding wasn’t limited to self-perceived health. For cardio-metabolic conditions — a category that includes not only heart disease but stroke, diabetes, obesity and more — the study similarly found that an increase of 11 trees per city block was “comparable to an increase in annual personal income of $20,000 and moving to a neighborhood with $20,000 higher median income or being 1.4 years younger.”

The results are powerful because of the size of the study, however, because they are “correlational,” as scientists put it, they cannot definitively identify the precise mechanism by which trees seem to improve health. However, there are some obvious possibilities, including one explanation that seems likely to at least partly account for the results. This is that trees are known to improve urban air quality by pulling ozone, particulates, and other pollutants into their leaves and out of the air, and thus, partly protecting people from them.

trees is good for your health1

But that’s not the only possible explanation. Others, says Berman, include stress reduction that comes from being around greenery — a mental effect that translates into physical benefits — or the possibility that being around trees somehow increases one’s propensity to exercise. He also suggests that air quality improvement alone may not be able to explain why people subjectively perceive their health to be better when they live around more trees, in addition to the improvements seen in other health measures — implying a possible psychological factor.

“People have sort of neglected the psychological benefits of the environment,” said Berman. “And I think that’s sort of gotten reinvigorated now, with these kinds of studies.” Particularly beneficial to the research has been the availability of satellite techniques to precisely quantify the amount of green space in a given residential area, he said – and the ability to combine that kind of data with large health databases.

It’s important to note that while the research was conducted based on data from the city of Toronto — which being in Canada, its citizens have universal health care — that is not necessarily a problem, as health disparities still exist in Toronto. “Canadians with lower incomes and fewer years of schooling visit specialists at a lower rate than those with moderate or high incomes and higher levels of education despite the existence of universal health care,” the study notes.

One interesting finding — that street trees seemed to have a more beneficial effect than private or backyard trees — may be explained by the fact that they are “more accessible to all residents in a given neighborhood,” the paper notes.

The researchers are not shy about using these results to make policy prescriptions — they think it would be well worth the cost to plant more urban trees. “Ten more trees in every block is about [a] 4% increase in street tree density in a dissemination area in Toronto, which seems to be logistically feasible,” the study notes.

“I’d feel pretty confident to say to a municipality, increase the number of trees by 10″ per block, said Berman.

 

Original from:
https://www.washingtonpost.com/news/energy-environment/wp/2015/07/09/scientists-have-discovered-that-living-near-trees-is-good-for-your-health/