How valuable are trees?


Megacities are on the rise. There are currently 47 such areas around the globe, each housing more than 10 million residents.

More than half the global population now lives in urban areas, comprising about 3 percent of the Earth. The ecological footprint of this growth is vast and there’s far more that can be done to improve life for urban residents around the world.

When it comes to natural spaces, trees are keystone species in the urban ecosystem, providing a number of services that benefit people. My research team has calculated just how much a tree matters for many urban areas, particularly megacities. Trees clean the air and water, reduce stormwater floods, improve building energy use and mitigate climate change, among other things.

For every dollar invested in planting, cities see an average of $2.25 return on their investment each year.

Measuring trees

Our team, led by Dr. David Nowak of the USDA Forest Service and Scott Maco of Davey Institute, develops the tree benefits software i-Tree Tools.

These tools simulate the relationship between trees and ecosystem services they provide. These services can include food, clean air and water, climate and flood control, pollination, recreation and noise damping. We currently don’t simulate many services, so our calculations actually underestimate the value of urban trees.

Volunteers Dalia Elbihi and her father, Faycal Elbihi, dig holes for new trees at Milby Park in Houston. Photo: Leslie Plaza Johnson, Freelancer / For The Chronicle / Freelance

Our software can simulate how a tree’s structure – such as height, canopy size and leaf area – affects the services it provides. It can estimate how trees will reduce water flooding or explore how trees will affect air quality, building energy use and air pollution levels in their community. It can also allow users to inventory trees in their own area.

Our systematic aerial surveys of 35 megacities suggest that 20 percent of the average megacity’s urban core is covered by forest canopy. But this can vary greatly. Trees cover just 1 percent of Lima, Peru, versus 36 percent in New York City.

We wanted to determine how much trees contribute to human well-being in the places where humans are most concentrated, and nature perhaps most distant. In addition, we wanted to calculate how many additional trees could be planted in each megacity to improve the quality of life.

How tree density affects a city

We looked in detail at 10 megacities around the world, including Beijing, Cairo, Mexico City, Los Angeles and London. These megacities are distributed across five continents and represent different natural habitats. Cairo was the smallest, at 1173 square kilometers, while Tokyo measured in at a whopping 18,720.

For most cities, we looked at Google Maps aerial imagery, randomly selecting 500 points and classifying each as tree canopy, grass, shrub and so on. We calculated that tree cover was linked to significant cost savings. Each square kilometer saved about $0.93 million in air pollution health care costs, $20,000 by capturing water runoff and $478,000 in building energy heating and cooling savings.

What’s more, the median annual value of carbon dioxide sequestered by megacity tree cover was $7.9 million. That comes out to about $17,000 per square kilometer. The total CO2 stored was valued at $242 million, using a measure called the social cost of carbon.

The sum of all annual services provided by the megacity trees had a median annual value of $505 million. That provides a median value of $967,000 per square kilometer of tree cover.

Trees in your city

An entire urban forest can provide services for a good life.

All the cities we studied had the potential to add additional trees, with about 18 percent of the metropolitan area on average available. Potential spots included areas with sidewalks, parking lots and plaza areas. The tree’s canopy could extend above the human-occupied area, with the trunk positioned to allow for pedestrian passage or parking.

New trees are planted in the Eastern Glades of Memorial Park in April 2018. Photo: Michael Ciaglo, Houston Chronicle / Houston Chronicle / Michael Ciaglo

Want to conserve forests and plant more trees in your area? Everyone can take action. City and regional planners can continue to incorporate the planning for urban forests. Those who are elected to office can continue to share a vision that the urban forest is an important part of the community, and they can advocate and support groups that are looking to increase it.

The ConversationIndividuals who cannot plant a tree might add a potted shrub, which is smaller than a tree but has a leafy canopy that can contribute similar benefits. For the property owner wanting to take charge, our i-Tree software can assist with selecting a tree type and location. A local arborist or urban forester could also help.

Theodore Endreny is Professor of Water Resources & Ecological Engineering at the State University of New York College of Environmental Science and Forestry


(Dipla Katerina)

Trees are dying at unprecedented rates. Can we rethink conservation before it’s too late?


Each year, the Earth’s trees suck more than a hundred billion tons of carbon dioxide from the atmosphere. That’s an impossibly huge number to consider, about 60 times the weight of all the humans currently on the planet.

Our forests perform a cornucopia of services: Serving as a stabilizing force for nearly all of terrestrial life, they foster biodiversity and even make us happier. But as climate change accelerates, drawing that carbon out of the air has become trees’ most critical role.

Absorbing CO2 is key to avoiding the worst effects of climate change when each year matters so much. Carbon “sinks,” like the wood of trees and organic matter buried in dirt, prevent the gas from returning to the atmosphere for dozens or even hundreds of years. Right now, about a third of all human carbon emissions are absorbed by trees and other land plants — the rest remains in the atmosphere or gets buried at sea. That share will need to rise toward and beyond 100 percent in order to counter all of humanity’s emissions past and present.

For trees to pull this off, though, they have to be alive, thriving, and spreading. And at the moment, the world’s forests are trending in the opposite direction.

New evidence shows that the climate is shifting so quickly, it’s putting many of the world’s trees in jeopardy. Rising temperatures and increasingly unusual rainfall patterns inflict more frequent drought, pest outbreaks, and fires. Trees are dying at the fastest rate ever seen, on the backs of extreme events like the 2015 El Niño, which sparked massive forest fires across the tropics. In 2016, the world lost a New Zealand-sized amount of trees, the most in recorded history.

The declining health of trees globally is starting to have profound effects on Earth’s carbon cycle. The rise in atmospheric carbon dioxide has been picking up speed over the past few years, even though human CO2 emissions have flattened. The net effect: Climate change is starting to accelerate.

Some tropical forests — in the Congo, the Amazon, and in Southeast Asia — have already shifted to a net carbon source. That means they emit more greenhouse gases than they absorb, worsening the climate problem worldwide. And signs are emerging that the health of California’s forests is fading, too.

The world’s treescape is undergoing a significant shift in real time. And with the situation getting particularly desperate, conservationists are beginning to rethink which species belong where. They’re even considering speeding up forest transitions, so we can get to the next phase where trees are soaking up massive amounts of carbon again instead of bursting into flames.

Forests are our last, best natural defense against global warming. Without the world’s trees at peak physical condition, the rest of us don’t stand a chance.

The planet is warming, but it isn’t doing so evenly. The icy poles are heating up faster, throwing off the balance of global air circulation. The storms that ride the now-shifted jet stream have deviated away from their historical paths, resulting in an expansion of the dry zones that surround the tropics. In short, a disruption of rainfall patterns across the globe is forcing trees to migrate.

Even at relatively low levels of climate change, where the Earth’s average temperature increases by fewer than 2 degrees Celsius, the range of North American tree species will shift northward at a rate of about two miles per year.

Forests simply can’t migrate that quickly. Take the jack pine, a species that the fossil record shows can adapt relatively fast to climatic shifts. Yet even for the jack pine, the current rate of warming would force it to migrate six times more quickly than it ever has before.

Given all of this, it’s not surprising that a recent study shows that, should warming continue apace, virtually all U.S. forests are at risk of climate-related shifts this century.

For a clear window into how forests are changing in real time, look at a temperate place like California. In recent years, droughts have become more frequent as more of the state begins to take on a desert-like climate. Since 2014, more than 129 million trees have died in California. In aerial views, large swaths of brown pockmark previously pristine canopies. The Golden State’s forests have experienced a ten-fold increase in mortality in recent years, linked to drier and warmer weather and a beetle infestation made worse by the changing climate.

California’s arboreal apocalypse is being exacerbated by the raging wildfires that the state’s forestry department helped stoke. Unlike sub-Arctic and tropical forests, temperate ones are often densely populated with people. A state-funded watchdog report showed in February that California’s forests are sorely lacking prescribed burns, which remove overgrowth and dead trees. Seven of the 10 largest fires in California history have occurred since 2003, including December’s Thomas Fire, the largest on record and the state’s first wintertime megafire. The fires, of course, are reason enough to worry, but recent studies suggest California trees are struggling to regrow naturally after the blazes.

“Many forest ecosystems are not well equipped to do battle with climate-driven changes,” says Stella Cousins, a forest ecologist at the University of California, Berkeley.

She adds that across the globe, humans degrade forests through land clearing for agriculture and bad forestry practices. Ecosystems, therefore, are already fighting an uphill battle to thrive — and adding warming into the equation makes their ability to flourish nearly impossible.

For tree lovers — and for scientists who spend their lives in the forest — all of this bad news is a punch to the gut.

Yolanda Wiersma, a landscape ecologist at Canada’s Memorial University, is rattled, but she remains optimistic that forests will merely change — and not vanish entirely.

“Our forests in 100 years will not look like our forests today,” she says. “We’re not going to see forests disappear. They’re resilient; they’ll adapt in some way. They’re just going to be different kinds of forests than what we know now.”

Take the sub-Arctic boreal forest in Newfoundland, where Wiersma works. Trees there are, on average, growing taller now as the growing season lengthens. That’s expected to soon lead to bigger fires — because there’s simply more to burn — but also faster regrowth and a new mix of species in the aftermath. It will produce a forest that, according to Wiersma, “we haven’t quite seen before.”

It’s emergent ecosystems like the warmer, less frozen Arctic, that are giving some ecologists, like Wiersma, hope that forests will be able to muddle through. But to ensure forests’ survival amid such rapid change, some scientists believe further human intervention is necessary.

A set of conservationists are rethinking how we approach forests. They considering tinkering with the ecosystems in various ways, including introducing novel species, replanting forests with climate change in mind, and even planting fast-growing species just to burn them for energy.

All of these strategies amount to a radical departure from the static view of forest conservation that has dominated for decades. It’s a view that considers forests as inherently changing instead of inherently stable — at least on timescales that matter to humans.

Wiersma is apprehensive about these sorts of radical approaches. “If we’re going to try anything different,” she says, “it should be done very cautiously”.

But some forests simply aren’t going to be able to handle the next few decades on their own. A recent study used computer models to test the inherently changing point of view. Researchers looked at a forest ecosystem in a remote part of British Columbia that’s susceptible to fires and insect outbreaks. They found that artificially boosting tree diversity increased the forest’s capacity for regrowth by up to 40 percent. It’s an example of what forest ecologists call “assisted migration,” introducing novel species that are expected to do well in the years ahead.

In Minnesota, conservationists aren’t just modeling it with computers. They’re actually doing it.

At the southern edge of the boreal forest, spruce, fir, birch, and aspen dominate — but their days are likely numbered as warm, dry summers become increasingly commonplace. Researchers at the University of Minnesota-Duluth partnered with the Nature Conservancy to plant 100,000 seedlings of native species more representative of the forests of Minnesota’s future — oak, pine, and basswood — on 500 acres of public lands. While they’ve grown in the region before, those species are still relatively rare, so the researchers want to study how the trees fare in years to come.

It will likely take decades to study the ramifications of even this small experiment — and by that time, the climate will likely have moved on. That inherent pressure adds both urgency and controversy to bold actions like these.

Another idea, called bioenergy carbon capture and sequestration (BECCS), involves planting massive swaths of the planet’s arable land with quick-growing trees and other vegetation, and then burning the plant matter for fuel while capturing the resulting carbon dioxide.

It’s controversial on the scale that would be necessary — an area equivalent to the size of India would be needed by 2100 to remove enough carbon from the atmosphere to help stabilize the rise of global temperatures. New studies show it may have compounding negative effects for surrounding ecosystems, but BECCS continues to show up in climate change mitigation strategies simply because humans haven’t yet invented a technology as efficient as trees to suck CO2 out of the sky.

With a problem as big as the potential death of many of the world’s forests, the worst thing we could do is nothing. We’re well on our way to a planet in which forests have radically transformed, but that shouldn’t be mistaken for the end of the story. Trees and humans are now locked in a mutual struggle for survival, and a future that’s good for forests and people will require profound adjustments in the way we think.

Trees can teach us many lessons, including encouraging long-term thinking. “We’re not ready for this rate of climate change,” Wiersma concludes from watching what the current rate of warming is doing to forests.

“But, 500 years from now?” she says. “There’ll be trees. There’ll be forests. But we might not be here.”


(Dipla Katerina)

Country diary: trees stand as witnesses to history


Almost seven centuries ago, a great calamity 50 miles out to the east sent men with axes and saws into priory-owned Chicksands Wood. The Norman central tower of Ely Cathedral had collapsed, and the architect of its replacement chose to bridge the gap not with stone, but with wood. To this day, the Octagon Tower has Bedfordshire oak timbers holding up its roof to heaven.Not so long ago, another forester came into Chicksands Wood to take out the tallest, straightest trees. He cut them down on either side of the ride, the aisle of this cathedral. Buttressed stumps a metre wide were as fluted pillars brought low in the ruins of a church building.

On the flat top of an orangey-brown stump, I ran my finger down the timeline towards another catastrophe. Sixty-three annual growth rings took me to the centre of the tree and the period when owners of this wood and thousands of others like it lost patience with the old ways. In postwar Britain, two-thirds of Chicksands was cleared and replanted with conifers, including the trees like this one, which had just met its end.


Further down the ride, a shaft of sunlight enticed me to a place where the wood’s medieval heart beat still. Scrambling through sedges, I came to what was evidently the remnant of a coppiced ash, a moss-covered eye socket betraying where a stem of the same tree had been cut long ago and the base had rotted into a hollow.

A little way behind it was another ash of gigantic proportions – 10 trunks as thick as my waist rose from a stool about three metres in diameter. This tree, maybe 500 years old, had sprouted from the humped bank over a sinuous ditch. And since the bank had to pre-date anything growing on it, I guessed this trench had been dug in days when a woodland boundary would be marked from tree to tree, a twisting line that had outgrown its logic. The ditch was surely there on that day in the 1320s when woodsmen came here in search of oaks to fell.



(Skiada Georgia)

Trees Are Good For Your Health, And This Tool Shows Exactly Where Cities Should Plant Them


When cities plant trees, they help reduce pollution levels and improve people’s health. Studies show that America’s trees save thousands of lives a year, mainly by preventing breathing-related problems (they also make you feel like you have more money, if you’re into that sort of thing).

Ideally we’d have trees on every street in the country because trees are good for people, but the reality, of course, is nothing like that. Cities tend to have spotty canopies, with richer residential areas generally enjoying more cover and poorer industrial areas seeing less.

You can see how trees cover the landscape of 13 cities using a nice tool developed by researchers at Portland State University. From Sacramento to Pittsburgh, it shows how urban environments are served with trees down to a micro level, and how they cover vulnerable groups like the young and the old.

“We created an online platform that says where are the dirtiest, hottest, and most vulnerable people in each of these cities. Cities can then evaluate where they might plant trees spatially at a neighborhood level,” says Vivek Shandas, one of the academics behind the maps.

The tool grew out of work by P.S.U. in Portland (which we covered last year). Based on data from 144 sensors placed around the city, it showed the effect of tree planting and the impact on people’s health, for example in reducing the rate of asthma. The tool uses public data for 12 other cities, plotting the “heat island” effect, nitrogen dioxide levels, and demographic hotspots.

Because of the way they developed, cities like Atlanta and Houston have the most opportunity for planting trees to improve health. “Houston and Atlanta sprawled quite a bit with low-density housing and connected those places with freeways. They tend to have more places for plantings than places like Albuquerque, for instance,” Shandas says.

By switching to the “plan” tab in the tool, planners can begin to understand how many trees would be needed to reach certain canopy goals, though the tool isn’t meant to be the last word. Shandas describes it as an quick reference guide so cities can get a sense of where trees are most needed.

The tool, called the Trees and Health APP, was funded the U.S. Forest Service as part of a the larger research project. The Forest Service has its own tree mapping tools, as we wrote here, and there are many tree-mapping initiatives happening at a city level (see here). Cities really are beginning to take trees seriously.

Invest in forests and indigenous people to fight climate change – experts


Efforts to protect carbon-absorbing forests, which could have a massive impact on reducing global warming, only attract a tiny fraction of the billions of dollars spent on cutting emissions, experts said, as they called for greater investment.

Almost 40 times more money has been spent on promoting agriculture and land development – which have led to large-scale deforestation – than on forest protection, they said in a study.

Forests hold so much potential in the effort to limit climate change, and yet there’s a seemingly endless supply of money to help tear them down,” said Charlotte Streck, director of environmental group Climate Focus.

Under the Paris deal, countries pledged to keep the rise in average global temperatures below 2 degrees Celsius above pre-industrial levels and to strive for a lower 1.5 degree limit, to stave off the worst effects of climate change.

Experts say forests could absorb enough carbon to meet about a third of the efforts needed to stick to those goals. But just 2 per cent of the $167 billion spent on reducing planet-warming carbon emissions since 2010 was invested in forests, according to the study by Climate Focus and other environmental groups.

Research has shown at least a quarter of the world’s carbon stored above the ground in tropical forests is found in territories managed by indigenous people and local communities. But even though deforestation rates are lower in areas where indigenous people manage forests, much of their knowledge is not taken into account when international decisions about climate change are made, experts say.

“Us indigenous peoples are sad and worried that billions of dollars are being invested in corporations that drive agro-business and cause deforestation,” Candido Mezua, an indigenous leader from Panama, told an event on forests at the Royal Society in London. “But very little is invested in what works: indigenous peoples and our forests, which are the best guarantee for a stable climate.”

At least 200 people were killed in 2016 while defending their homes, lands and forests from mining, dams and agricultural projects, according to advocacy group Global Witness.

Follow the link to learn more:

Which Trees Offset Global Warming Best?


Trees are important tools in the fight to stave off global warming, because they absorb and store the key greenhouse gas emitted by our cars and power plants, carbon dioxide (CO2), before it has a chance to reach the upper atmosphere where it can help trap heat around the Earth’s surface.

All Plants Absorb Carbon Dioxide, but Trees are Best

While all living plant matter absorbs CO2 as part of photosynthesis, trees process significantly more than smaller plants due to their large size and extensive root structures. In essence, trees, as kings of the plant world, have much more “woody biomass” to store CO2 than smaller plants, and as a result, are considered nature’s most efficient “carbon sinks”. It is this characteristic which makes planting trees a form of climate change mitigation.

According to the U.S. Department of Energy (DOE), tree species that grow quickly and live long are ideal carbon sinks. Unfortunately, these two attributes are usually mutually exclusive. Given the choice, foresters interested in maximizing the absorption and storage of CO2 (known as “carbon sequestration”) usually favor younger trees that grow more quickly than their older cohorts. However, slower growing trees can store much more carbon over their significantly longer lives.

Plant the Right Tree in the Right Location

Scientists are busy studying the carbon sequestration potential of different types of trees in various parts of the U.S., including Eucalyptus in Hawaii, loblolly pine in the Southeast, bottomland hardwoods in Mississippi, and poplars (aspens) in the Great Lakes region.

There are literally dozens of tree species that could be planted depending upon location, climate, and soils, says Stan Wullschleger, a researcher at Tennessee’s Oak Ridge National Laboratory who specializes in the physiological response of plants to global climate change.

Plant Any Tree Appropriate for Region and Climate to Offset Global Warming

Ultimately, trees of any shape, size or genetic origin help absorb CO2. Most scientists agree that the least expensive and perhaps easiest way for individuals to help offset the CO2 that they generate in their everyday lives is to plant a tree…any tree, as long as it is appropriate for the given region and climate.

Follow the link to learn more:

Funding Trees for Health


Imagine if there were one simple action that city leaders could take to reduce obesity and depression, improve productivity, boost educational outcomes and reduce incidence of asthma and heart disease among their residents.

Urban trees offer all these benefits and more.

Yet American cities spend less than a third of a percent of municipal budgets on tree planting and maintenance, and as a result, U.S. cities are losing 4 million trees per year.

A new white paper, written by The Nature Conservancy with input from The Trust for Public Land and Analysis Group, identifies street trees as one of the most overlooked strategies for improving public health in our cities.

“For too long, we’ve seen trees and parks as luxury items, but bringing nature into our cities is a critical strategy for improving public health,” said Rob McDonald, lead scientist for global cities at The Nature Conservancy and first author of the white paper.

The white paper estimated that spending just $8 per person per year, on average, in an American city could meet the funding gap and stop the loss of urban trees and all their potential benefits.

The full paper offers several specific examples of innovative public-sector partnership and private sector investments that highlight the full societal value of urban trees. However, municipal leaders in communities of all sizes can begin to address significant health challenges by thinking creatively about the role of nature in cities and towns:

  • Establish codes to set minimum open space or maximum building lot coverage ratios for new development.
  • Implement policies to incentivize private tree planting.
  • Break down municipal silos to facilitate various departments – such as public health and environmental agencies – to collaborate.
  • Link funding for trees and parks to health goals and objectives.
  • Invest time and effort in educating the public about the tangible public health benefits and economic impact of trees.

5 Ways You Can Help The Environment In The Next Hour — Without Leaving Your Desk


The internet: The world’s arena for catching up on news, binge-watching TV, and replaying adorable videos . And with a little know-how, you can also use it as a tool for quick, meaningful environmental action.

These days, switching over to solar power and ditching plastic are just a few clicks away, and you can majorly cut down on your footprint without even leaving your desk. Here are five ways to help out the environment from the comfort of your home. Altogether, they’ll take less than an hour and leave you feeling majorly accomplished.

1. Calculate your carbon footprint

Carbon calculators make it easy to quantify your environmental impact in a matter of minutes. Answer a few questions about your transportation habits, energy use, and consumption patterns to get a better idea of where you’re acting in an eco-friendly way and where you could use a little improvement. Then, let these insights inform your habits moving forward.

2. Offset your next plane trip

While reducing your emissions should always be your first priority, offsetting is basically a way to press tare on your environmental impact. You can donate money to initiatives that take carbon out of the environment—like tree plantings and renewable energy projects—to balance out the carbon you’re putting into it with your daily routine. Offsetting your flights is a good place to start, since plane travel is a major emitter but one that most of us can’t realistically give up altogether.

3. Pledge to give up straws

The Lonely Whale Foundation, a nonprofit that uses clever campaigns to clean oceans, recently launched the #StopSucking challenge. By accepting, you’re committing to saying no to single-use plastic straws when drinking on the go.  Take the pledge, share on social, and challenge other individuals and companies in your area to do the same, all in under five minutes.

4. Tell your representative what you care about

If hopping on the phone to call your representative isn’t your thing, environmental groups have made it super easy to write to your congressional representative online using a pre-populated form. Just sign your name,  add a quick personal message at the end and you’re good to go.

5. Check to see if you can switch over to renewable energy

You don’t need to deck out your roof with solar panels or move closer to a wind farm to switch over to renewable energy in your home.  For example, in certain parts of the United States, Green Mountain Energy lets you switch over to renewables on the spot without changing energy providers. Just input your ZIP code and see if it’s a possibility for you.

Follow the link to learn more

These drones can plant 100,000 trees a day


It’s simple maths. We are chopping down about 15 billion trees a year and planting about 9 billion. So there’s a net loss of 6 billion trees a year. Hand planting trees is slow and expensive. To keep pace with the tractors and bulldozers clearing vast areas of land, we need an industrial-scale solution.

For example, a drone that can plant up to 100,000 trees a day.

BioCarbon Engineering, a UK-based company backed by drone manufacturer Parrot, has come up with a method of planting trees quickly and cheaply. Not only that, trees can also be planted in areas that are difficult to access or otherwise unviable.

Planting by drone

First a drone scans the topography to create a 3D map. Then the most efficient planting pattern for that area is calculated using algorithms.

A drone loaded with germinated seeds fires pods into the ground at a rate of one per second, or about 100,000 a day. Scale this up and 60 drone teams could plant 1 billion trees a year.

The system’s engineers estimate that their method is about 10 times faster and only 20% of the cost of hand planting. And because there is no heavy machinery involved, it’s possible to plant in hard-to-reach areas that have no roads or steep, inaccessible terrain.The BioCarbon team has tested its technology in various locations and recently trialled reseeding historic mining sites in Dungog, Australia.

Elsewhere, a similar idea is being used by Oregon start-up DroneSeed, which is attempting to create a new era of “precision forestry” with the use of drones to plant trees as well as spray fertilizer and herbicides.

Agriculture is one of the biggest drivers for deforestation, with vast swathes of forest cleared to make way for the cultivation of crops including soy, palm oil and cocoa, as well as for beef farming.

At the World Economic Forum’s Annual Meeting in Davos this year, Norway announced a $400 million fund to kick-start investments in deforestation-free agriculture in countries that are working to reduce their forest and peat degradation. It is estimated that the world loses between 74,000 and 95,000 square miles of forest a year – that’s an area the size of 48 football fields lost every minute.

You can find the article here: (The World Economic Forum):

“Importance and Value of Trees”


Since the beginning, trees have furnished us with two of life’s essentials, food and oxygen. As we evolved, they provided additional necessities such as shelter, medicine, and tools. Today, their value continues to increase and more benefits of trees are being discovered as their role expands to satisfy the needs created by our modern lifestyles.

Here, some important benefits of the trees that you probably didn’t know:

  1. An acre of nature trees absorbs the amount of CO2 produced when you drive your car 42.000 Km.
  1. An acre of nature trees provides enough oxygen for 18 people.
  1. Trees reduce UV-B exposure by about 40 percent.
  1. The evaporation from a single tree can produce the cooling effect of 10 room size air-conditioners operating 20 hours a day.
  1. A well placed tree can reduce noise by as much as 40 percent.
  1. One large tree can supply a days’ supply of oxygen for 4 people.
  1. A healthy tree can store 6 kg of carbon each year.
  1. An acre of trees can store 2.6 tons of carbon dioxide each year.
  1. For every 16.000 km you drive, it takes 7 trees to remove the amount of carbon dioxide produced.
  1. A hundred million new trees would absorb 18 million tons of CO2 and cut air-conditioning cost by 84 billion annually.
  1. A belt of trees 40 meters wide and 12 meters high can reduce highway noise by 40 percent.
  1. A tree can absorb as much as 24 kg of CO2 per year and can sequester on ton of CO2 by the time it reaches 40 years old.
  1. A mature tree can have an appraised value between 1.000$ and 10.000$ council of Tree and Landscape Appraisers.
  1. About 20 percent of the worlds’ emissions are a result of deforestation.
  1. CO2 worlds’ emission is 35.000.000 metric tons per year.
  1. CO2 sequestration is 25 kg per tree per year.
  1. One half the dry weight of wood is carbon.
  1. One person emit 20 ton of CO2 per year.

So, what you have to do is “take action”, and just plant a tree. It is so simple, but so important!! Protect the environment!! Do not destroy it!!

Dipla Aikaterini (Arid Zone Afforestation)