What happens if you cut down all of a city’s trees? – Stefan Al

Translator: Nawfal Aljabali Auditor: Shimaa Nabil This is a tale of two ancient cities The trees determined their fate. 3000 BC. M. The city of Warka was more densely populated than New York today. This busy metropolis had to keep expanding the irrigation system To meet the needs of a growing population. In Sri Lanka after 2,500 years, the city of Anuradhapura faced a similar problem. They were constantly multiplying too, And in the same footsteps as the city of Warka, their city relied on an accurate irrigation system. As Warka grew, its farmers began cutting down trees to make room for more crops. While the trees in Anuradhapura were sacred. Their city includes a branch of the Bodhi tree Under which the Buddha himself was said to have reached enlightenment. Religious sanctification slowed the felling of trees He even led the city to plant more trees in urban parks.

At first the Warka expansion was successful. But without the trees that filter their water sources, The irrigation system in Warka has become polluted. The evaporation of the water left mineral deposits This made the soil very salty for cultivation. On the contrary, the Anuradhapura irrigation system was designed to function In harmony with the surrounding jungle. Their city eventually grew to more than twice the population of Warka, Even today Anuradhapura still tends to a tree that was planted two thousand years ago. We might think that nature is not connected to our urban spaces. But trees have always been an essential part of successful cities. Trees act like natural sponges, absorbing rainwater Before you release it back into the atmosphere. Their root networks protect from mudslides While allowing the soil to retain water and purify toxins. Roots help prevent floods, While reducing the need for storm drainage and water treatment plants. Its porous leaves filter the air by trapping carbon and other pollutants. This makes them essential in the fight against climate change. Humanity has known the benefits of urban trees for centuries.

But trees aren't just important to city infrastructure; In fact, it plays a major role in the health of its citizens, too. In the 1870s, Manhattan had a few trees outside the island gardens. Without trees to provide shade, Buildings absorb up to nine times more solar radiation During the deadly summer heat waves. Besides the poor sanitation standards for that period, The sweltering heat made the city a breeding ground for bacteria like cholera. In modern Hong Kong, skyscrapers and underground infrastructure It made it difficult to grow trees. This contributes to dangerously poor air quality, This can cause bronchitis and reduced lung function. Trees affect our mental health, too. Research indicates that having green foliage increases attention span It reduces stress levels. It also showed hospital patients who had wall views They recover more slowly than those with tree landscapes. Fortunately, many cities are full of sights like these; This is not an accident. As early as the nineteenth century, City planners are beginning to realize the importance of trees. In 1733, Colonel James Oglethorpe planned the city of Savannah, Georgia To ensure that no neighborhood is more than a 2-minute walk from a park.

After World War II, Copenhagen directed all new developments along five arteries – Each of them is located between two parks. This design increased the resilience of the city Against pollution and natural disasters. And urban trees don't just benefit people. Portland Forest Park preserves the area's natural biodiversity. Which makes the city home to many local plants, And 112 species of birds and 62 species of mammals. No city is more tree-preserved than Singapore. Since 1967, the Singapore government has planted more than 1.2 million trees. Including trees 50 meters high which are called super trees. These structures supply themselves and adjacent buildings With solar energy and collected rainwater. Trees and plants currently cover more than 50% of Singapore's land area. This reduces the need for air conditioning Low-pollution transport is encouraged. By 2050, it is estimated that more than 65% of the world's population will live in cities. City planners can develop an environmentally friendly system, But the ball is in the court of the people who live in these urban jungles To make them homes for more than humans.

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What if there were 1 trillion more trees? – Jean-François Bastin

Translator: rami durbas verified: omar idmassaoud With a height of about 84 meters, This is the largest known living tree on the planet. It's called General Sherman, These giant sequoias have sequestered approximately 1,400 tons of carbon in the atmosphere Over its estimated life of 2,500 years on Earth. Few trees can compete with this carbon effect. Today, however, humanity produces more than 1,400 tons of carbon every minute. To combat climate change, We need to sharply reduce fossil fuel emissions And drawing in the excess carbon dioxide to restore the balance of our atmosphere Of greenhouse gases.

But what can trees do to help this struggle? And how do you sequester carbon in the first place? Like all plants, trees consume atmospheric carbon Through a chemical reaction called photosynthesis. This process uses energy from sunlight To convert water and carbon dioxide into oxygen And carbohydrates that store energy. Then the plants consume these carbohydrates in the opposite process It's called the breathing process, which turns it into energy It releases carbon back into the atmosphere. However, in trees, a large part of this carbon is not released. Instead, it's stocked in a new wood texture. During their lifetime, the trees act as carbon reservoirs And it keeps pulling in carbon as long as it grows. But when the tree dies and decays, Some of the carbon will be released back into the atmosphere. A large amount of carbon dioxide is stored in the soil.

Where it can survive for thousands of years. But eventually, that carbon will also leak back into the atmosphere. So if the trees will help combat a long-standing problem Like climate change, It needs to survive to sequester that carbon For as long as possible and at the same time to multiply quickly. Is there one type of tree that we can plant that meets these criteria? Some species are fast-growing, long-lived, and super insulated Can we spread it all over the world? Not to our knowledge? But if such trees exist, It will not be a good long-term solution. Forests are complex networks of living things. There is no single species that can thrive in every ecosystem. The trees that are most sustainable when planted are always native trees; Types have already played a role in their native environment. Initial research shows that ecosystems Those with a natural variety of trees have less competition Resource and better resistance to climate change. This means we can't just grow plants to pull carbon; We need to restore depleted ecosystems. There are many areas that have been cut short Or develop it and it is time to retrieve it.

In 2019, a study led by Crowther Zurich Laboratory It analyzed satellite images of tree cover located in the world. By combining these images with climate and soil data. By excluding areas essential for human use, They concluded that Earth could support About one billion hectares of additional forest. It is approximately 1.2 trillion trees. This stunned number surprised the scientific community, Which prompted more research. Scientists are now citing more conservatively but still noticeable. According to their revised estimates, these ecosystems can be restored Capture 100 to 200 billion tons of carbon, That's more than a sixth of human carbon emissions. More than half of the potential forest canopy As for the new restoration effort, it can only be found in 6 countries. The study can also provide an insight into current restoration projects.

Like the Bonn Challenge, It aims to restore 350 million hectares of forest by 2030. But here is where it gets complicated. Ecosystems are incredibly complex. It is unclear whether it would be better to restore them with human intervention. It could be the right thing to do in certain areas It is simply to leave her alone. Additionally, some researchers are concerned about forest restoration On this scale it may lead to unintended consequences. Such as the production of natural biochemicals At a pace that could actually accelerate climate change. Even if we manage to regain these areas, Future generations will need to protect it Of the natural and economic forces that previously depleted it. Collectively, these challenges weaken confidence In restoration projects around the world. And complexity in the process of rebuilding ecosystems It shows how important protecting our current forests is.

But we hope to recover some of these depleted areas It will give us the information and condemnation necessary to combat climate change On a larger scale. If we get it right, these modern trees may have time to grow Into carbon-bearing giants..

As found on YouTube


How to Plant 20 MILLION TREES – Smarter Every Day 227 #TeamTrees

– Hey it's me, Destin. Welcome back to Smarter Every Day. There's a really cool thing happening on the internet right now
and we want you to be a part. It's called Team Trees
and the goal is simple. 20 million trees by 2020 and we actually have a
mechanism to do this. If you go to the Arbor Day Foundation has agreed to plant one tree in the ground for every dollar that's donated there. That is a huge opportunity and internet content
creators from all over, every genre of content,
were all working together to do this but we need you. We need you to help us do this by going to and donating. Let's say that we're all on
board and we're all awesome and we make this happen. $20 million go to the Arbor Day Foundation and they're gonna plant 20 million trees. How do we do that scientifically? In order to figure this out, I wanna go look at this whole concept through the eyes of my granddaddy who attempted to plant hundreds of trees in a field back in the 60s.

My dad was there and he
remembers exactly what happened. (beep) – Early 60s, '61, '62, Daddy
had a group of students from Auburn come and
plant some longleaf pines. They planted them in different methods, some in a hill, some in a
furrow, hundreds of them. And only two of them lived. – Why did Auburn University come here to plant trees in this field? – It's not native to this
area and Auburn wanted to see if a longleaf pine could
survive this far north. – [Destin Voiceover] The fact that longleaf pines were planted
here is super interesting because Granddaddy's land was just north of the natural range for that species. Whenever I travel to different
regions of the world, I love to discover what
tree species thrive in that environment, whether
it be a strangler fig in Peru, a baobab tree in western Africa, or the famous Recoleta rubber tree in Buenos Aires, Argentina.

Certain species of trees always seem to thrive in certain areas. To learn more about why certain thrive in certain environments, I went to Auburn University School of Forestry and Wildlife Sciences where I met with Dr. Becky
Barlow and Dr. John Kush. Both are experts in sustainable forestry and both know a ton
about the longleaf pine. – [Destin] How does a
person find the right tree for the right location? Let's say someone lives
in Ohio for example, or they live in, I don't know, Wyoming and they need to figure out the exact tree they need to plant on their property. – The first thing that they need to do is, like Dr. Kush was saying, you need to think about the soils. You need to think about
what soils you have. You need to think about
what you are willing to do from a management standpoint.

How active are you willing to be in the management of your property? Some people are just, wanna
plant it and walk away and not have to do anything to it. And that's okay too and
there are certain things you can do from that standpoint. But most of the time, you're
gonna have to plant it. Then you're gonna have to monitor it and you're gonna have to
maybe do some thinnings in there to make sure that the trees have enough
water, light, nutrients to grow, because they
start to get too crowded and then they're gonna
start to die naturally. And so you wanna thin it so you don't have that natural mortality. You can actually capture that mortality. – [Destin] So there's science to it. – Yeah, a lot. And you also need to know about the trees. You need to think about the
tree that you want to plant and think about its life history, its silvics is what it's called. – [Destin] How do you spell that? – S-I-L-V-I-C-S. It's kind of its life history. Where does it normally occur? Where does it naturally occur? How does it grow? How tall does it get? Does it need a lot of sunlight
or can it tolerate shade? It's those things like that
that you need to understand about the trees that
you're wanting to plant and then making sure you, again, that's how you match
the tree to your site.

– [Destin Voiceover] Dr.
Kush pulled up a soil survey from Granddaddy's land and explained that the
different types of soil affect how trees grow differently. He said the main factor,
however, was probably that Granddaddy planted
them in a grassy area where the weeds probably
choked out the trees. – [Destin] So longleaf pine. – Longleaf pine. – [Destin] What do I need to know? – Burn it. (Destin laughs) – What? – Burn it.

– [Destin] What do you mean? – Plant it, burn it. – [Destin] What do you mean? – You gotta use prescribed fire, get your little area cleaned out, get your trees planted,
wait a year, burn it. – [Destin] So you're talking
about the undergrowth. – The undergrowth. – [Destin] Okay so you're not saying, "Cut the tree down and burn it." – No, don't cut the tree down. Please don't cut the tree. We're doing too much of that already. – [Destin] Okay so fires
can be a good thing if they're done correctly,
is what you're saying. – Fires are a excellent
thing if done correctly. But we have to do it correctly. – [Destin] What do you mean? – You have to prescribe,
get your conditions right, prescribe the fire, get a burn permit from the Forestry Commission
and do what's right for nature. You're just mimicking what nature did. If we weren't here it would be happening. If you have nobody here,
get away all the people, all the roads, and you just
have wildlife out there, a lightning strike hits
a tree, starts a fire.

It'd go for miles, tens of
miles, hundreds of miles. So the southeast was
seeing fire very frequent and thus you had longleaf pine there. – [Destin Voiceover] Dr. Kush explained to me that the longleaf pine is different. He explained that it
has adapted the ability to actually be burned during
its first few years of life. Dr. Barlow and Dr. Kush took me outside to see actual longleaf pines
and explain how they work. – We actually have a longleaf
pine in the grass stage here. – [Dr. Kush] I planted
this four years ago. The idea of trying to bring
longleaf pine back to this site.

It passed the stage where it doesn't really put
out any woody extension growth like all trees do. It waits for its chance to
take fires for a couple years and then that central bud,
it will one day decide that it's time to come
out of the grass stage and off it will go. – [Destin] Really? That is not,
– What that– – [Destin] That is not what I think of when I think of a small tree. – It is not. Any longleaf pine this size can take fire. Any other tree will die. – [Destin] So that's
why it exists like this. – That's why it exists like this. And then when it comes
out of that grass stage, it'll put on four or five
feet of growth in that year, get its quote unquote head above the fire, and it just hangs out for the next three, four hundred years.

– [Destin] So this is just a
completely different strategy for survival?
– Absolutely. Unique in the world. – [Destin Voiceover] When the longleaf pine is in the grass stage, it's busy
making a very deep taproot, which also means it's drought resistant. Check out the comparison
of this loblolly pine and this longleaf pine. – This is only two years old
and that's four years old.

– [Destin] We're in 35 days of drought. Did this die recently? – Yeah this probably just happened within the last three or four days. – [Destin] Oh really?
– Yeah. – [Destin] So we've got
some real data here. – This is real data. This is actual. – [Destin] Loblolly pine
died because of the drought. The longleaf pine is just kicking it. – He's just hanging out saying, "I'm not quite ready to come
out of the grass stage." What that trigger's gonna
be, nobody knows but– – [Destin] At some point
its gonna figure it out. – My guess just based on the size now, it's gonna come out next year. – [Destin Voiceover] Odd as it might sound, talking to Dr. Kush and
Dr. Barlow taught me that one of the reasons
Granddaddy's trees might have died would've been lack of fire. Four days after visiting
Auburn University, I'm driving across northern Florida. Trees on the left side of
the road are tall and healthy but they have burned trunks.

Trees on the right side
of the road are crowded and they look like scrub brush. It all clicked when I saw this sign. – I could not have
planned this if I tried. Turns out, there's a place down here called the E.O. Wilson Biophilia Center. They're all about the longleaf pine and I have to show you what I learned.

These people are awesome. This is Ashlyn.
(Ashlyn laughs) I just found this place. And I'm seeing that right there, which leads me to believe that
you guys believe in burning to promote longleaf pine
health, is that right? – Very controlled burning. – [Destin] Controlled burning.
(Ashlyn laughs) But the whole idea is to get the fuel at the bottom of the ecosystem to take out all the scrub brush right? – Exactly, yes. – [Destin] Cool and you said
there's somebody I can talk to? – Yeah definitely, we'll find Bob. – 'Kay we're gonna go see Turtle Bob who knows about burning longleaf pines. – Hi.
– [Destin] Nice to meet you. So you know about burning longleaf pines? – Well, we've burned a few. (laughter) – [Ashlyn] Planted a few as well. – Fire is important to keep the longleaf pine ecosystem alive because to start with, it
requires bare mineral soil to start germinating. And then what it does
is it opens it up enough for gopher tortoises to survive. Gopher tortoises have
to have an open habitat. – [Ashlyn] This is a gopher tortoise. – [Destin] And these are the turtles, or they're not turtles, they're tortoises, that make the burrows right?
– Yes.

– [Destin] And they make the burrows as a result of the longleaf pine? – They do make it in
that nice open sandy soil that can be found in the
longleaf pine ecosystem. And they dig those burrows
really far into the ground and it's not only important for them, but they are a keystone species because they're gonna dig those burrows which can house up to
200 or 350 other species, especially during those fires. – [Destin] She's waving. – Those animals need places to go. Really good place to do that is gonna be a big hole in the ground. – [Destin Voiceover] Ashlyn
took me out into the forest and showed me several young longleaf pines in the grass stage and
then the secondary stage known as the bottle brush phase, which then leads to the sapling phase and finally the mature trees. Ashlyn took me out further into the forest to show me the holes that
the gopher tortoises dig and this is where it all came together.

Because this tree can survive fire, the underbrush gets cleared away which paves way for this turtle to gain access to the forest floor where it can dig these holes. As Burning Bob explained, these holes support
hundreds of other species that're then able to
live on the forest floor, which creates an ecosystem which can sustain even
larger umbrella species such as the black bear. So it isn't about a single tree, it's about an entire ecosystem. An ecosystem which takes advantage of one particular tree's
ability to survive fire. – [Destin] So this is what
the natural forest looks like? – Yes, if we didn't burn
it, lightning would. And then it would eventually
have this nice open clear area. Lots of room for the wildlife to live in compared to this side.
– [Destin] But this side. (Destin laughs) – Lots of different kinds of trees. We've got some slash pines,
we've got some oak trees, yaupon hollies, taking
over, kind of crowding out some of those other pine trees
that would typically be here.

And then there's a ton
of leafler on the ground. We actually call that
pine straw our fuel load. If lightning were to strike that right now it would burn entirely
too hot entirely too quick and would definitely turn into a wildfire which would be very bad. – So if I were to decide to plant a tree, what would you tell me? What do I need to know? – I would say plant a longleaf if you live in an area
that'll sustain a longleaf. You're gonna need to
be upland, not too wet. Definitely stick to the native plants. – So look at the local
environment and the ecosystem and identify the silvics
of the trees in your area and figure out what trees will grow there and then pick something
like that, you'd say? – Yeah, something that's a lot of different animals are gonna use. – Okay, so think about
the whole ecosystem. Don't just think about the one tree.

– Yeah, it doesn't have to look pretty but it has a job. (laughter) – that's the whole
point of this entire video. We've partnered with
the Arbor Day Foundation because they are the experts. They understand the silvics, they know exactly what tree
to plant in what location, and the goal is simple. We want to raise $20 million
for 20 million trees by 2020. And to do that we're gonna need your help. And I would encourage you to
consider going to and donating or right
here on the YouTube page, there's a donate button below. If you use that, YouTube's gonna pay for the transaction fees.

This is a huge thing that
we're all doing together. It is rare to have the opportunity to plant one tree for one dollar so I'm gonna take advantage of that. I don't know if you've
ever planted a tree. It's kind of expensive to
go buy an individual tree and put it in the ground
but at this kind of scale you can literally plant a thousand trees for a thousand dollars or a hundred trees for a hundred dollars or 10 trees for 10 dollars.

Your money goes a really long
way to help the environment. So if you're interested in
doing that, or click the button below
to donate here on YouTube. In fact, the sponsor for
this video, Hello Fresh, they've agreed to donate
$5000 to plant 5000 trees. (beep) This episode of Smarter Every Day and my donation to
is sponsored by Hello Fresh and you're gonna help today, Dad? – I'm gonna try. – [Destin] I don't ever think
you've cooked in front of me. Maybe–
– Hot dogs and eggs is all I know. – [Destin] All right okay, there we go. Today we're gonna do
pineapple poblano beef tacos and we're gonna cook for Mom. You think we can do this? You've assemble spacecraft. – I have. – [Destin] We can do this. Got our meats, got our ingredients. Let's get to chopping. Hello Fresh is a home
meal kit delivery system that sends you fresh
ingredients to your house. You can cook it, it's really simple. Just follow the instructions and you can make a delicious
meal for your family.

– Poblano. – [Destin Voiceover] If you
want to make Hello Fresh at your house, you can get
it by going to and using the promo code
smarter80 at checkout. That gets you 80 bucks off the
first month of Hello Fresh, which is like eight free meals. That is a lot of food
and a lot of savings. – Drizzle? Oh. – [Destin] Oh?
– Oh? (laughter) – [Destin] You're the one I got it from. (Darryl laughs) Hello Fresh is now from $5.66 per serving so you can feed your family delicious food at an affordable price. All right, moment of truth. What do you think? – It's good. – Big thanks to Hello
Fresh for sponsoring this.

Big portion of this sponsorship
is gonna go towards trees at (beep) Please consider going to and joining Team Trees. Also go check out all these other videos these other creators are making. We're all in this together. We are trying to do this
huge movement together and we need you on Team Trees. So that's it! I'm Destin, you're
getting smarter every day. Have a good one. Bye..

As found on YouTube