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See also Rewilding

Creating or re-creating forests and woodlands has many beneficial effects. Growing trees absorb CO
and sequester it in their trunks, branches, roots, leaves, and in the soil on which they grow. Some of it can remain locked up for centuries under ideal conditions, for example in wood used for construction, furniture, etc, or in soils built up over time. (Indeed some has been sequestered for millions of years until recently being unearthed and released as fossil fuels.) Many forest ecosystems support wide biodiversity. Trees can stabilise soils, reducing or preventing erosion and desertification. Trees can extract water from mist and fog, and their roots can encourage rainfall to penetrate deep into the ground and replenish underground aquifers rather than running off the land, and thus reduce or prevent flooding downstream. Trees provide shade, allowing the growth of less hardy plants. Bodies of trees create their own microclimate, even their own rainfall, as in the Amazon. Forests also provide direct benefits to humans, through recreation, and exploitation of wood and other forest products providing livelihoods for people. Trees in cities can also moderate climate and provide health benefits to people.

How to plant a trillion trees Rachel Cernansky; Nature news feature; 29 Aug 2018

As projects to restore woodlands accelerate, researchers are looking for ways to avoid repeating past failures.

When the Philippines opened its first school of forestry in 1910, the institute’s leaders hatched a plan to restore degraded woodlands surrounding the campus outside Manila. They planted dozens of tree varieties, both native and exotic. In 1913, the school received 1,012 mahogany (Swietenia macrophylla) seeds from a botanical garden in Calcutta, India, and started growing them around the grounds. The American hardwood became such a staple of reforestation efforts in the country that it spread throughout natural areas, so much so that it eventually proved a nuisance. The trees create veritable green deserts: their tannin-rich leaves are unpalatable to local animals and seem to stifle the growth of other plants where they fall. They also produce seeds annually, giving them an advantage over native hardwoods, which do so at intervals of five years or more.

It’s hardly history’s only forestry folly. “The whole notion of what species should be used in restoration tends not to receive, I would say, adequate attention,” says Douglas McGuire, coordinator of the Forest and Landscape Restoration Mechanism at the Food and Agriculture Organization of the United Nations in Rome.

Many projects fail because they choose the wrong trees, use too few species or are not managed for the long term. Foresters and ecologists are realizing that for restoration efforts to succeed, they need to think more broadly — about matching trees to their location, about the effects on nearby insects and other animals and about relationships with soil and the changing climate. In other words: the ecosystem.

Scientists are now testing and comparing strategies that range from letting nature take its course, to forest-management approaches that look a lot like farming. There is no one-size-fits-all solution, but the work exposes some philosophical friction. Ecologists seeking to increase biodiversity might champion a broad range of species, whereas sustainable-development advocates could back exotic fruit-bearing trees that benefit local people. And researchers seeking to mitigate climate change might push for a single fast-growing variety.

However forests,and their sequestration potential, are also threatened by climate change: Climate-driven risks to the climate mitigation potential of forests William R. L. Anderegg, Anna T. Trugman, Grayson Badgley, Christa M. Anderson, Ann Bartuska, Philippe Ciais, Danny Cullenward, Christopher B. Field, Jeremy Freeman, Scott J. Goetz, Jeffrey A. Hicke, Deborah Huntzinger, Robert B. Jackson, John Nickerson, Stephen Pacala, James T. Randerson; Science; 19 Jun 2020

BACKGROUND Forests have considerable potential to help mitigate human-caused climate change and provide society with a broad range of cobenefits. Local, national, and international efforts have developed policies and economic incentives to protect and enhance forest carbon sinks—ranging from the Bonn Challenge to restore deforested areas to the development of forest carbon offset projects around the world. However, these policies do not always account for important ecological and climate-related risks and limits to forest stability (i.e., permanence). Widespread climate-induced forest die-off has been observed in forests globally and creates a dangerous carbon cycle feedback, both by releasing large amounts of carbon stored in forest ecosystems to the atmosphere and by reducing the size of the future forest carbon sink. Climate-driven risks may fundamentally compromise forest carbon stocks and sinks in the 21st century. Understanding and quantifying climate-driven risks to forest stability are crucial components needed to forecast the integrity of forest carbon sinks and the extent to which they can contribute toward the Paris Agreement goal to limit warming well below 2°C. Thus, rigorous scientific assessment of the risks and limitations to widespread deployment of forests as natural climate solutions is urgently needed.


Many forest-based natural climate solutions do not yet rely on the best available scientific information and ecological tools to assess the risks to forest stability from climate-driven forest dieback caused by fire, drought, biotic agents, and other disturbances. Crucially, many of these permanence risks are projected to increase in the 21st century because of climate change, and thus estimates based on historical data will underestimate the true risks that forests face. Forest climate policy needs to fully account for the permanence risks because they could fundamentally undermine the effectiveness of forest-based climate solutions.

Here, we synthesize current scientific understanding of the climate-driven risks to forests and highlight key issues for maximizing the effectiveness of forests as natural climate solutions. We lay out a roadmap for quantifying current and forecasting future risks to forest stability using recent advances in vegetation physiology, disturbance ecology, mechanistic vegetation modeling, large-scale ecological observation networks, and remote sensing. Finally, we review current efforts to use forests as natural climate solutions and discuss how these programs and policies presently consider and could more fully embrace physiological, climatic, and permanence uncertainty about the future of forest carbon stores and the terrestrial carbon sink.


The scientific community agrees that forests can contribute to global efforts to mitigate human-caused climate change. The community also recognizes that using forests as natural climate solutions must not distract from rapid reductions in emissions from fossil fuel combustion. Furthermore, responsibly using forests as natural climate solutions requires rigorous quantification of risks to forest stability, forests’ carbon storage potential, cobenefits for species conservation and ecosystem services, and full climate feedbacks from albedo and other effects. Combining long-term satellite records with forest plot data can provide rigorous, spatially explicit estimates of climate change–driven stresses and disturbances that decrease productivity and increase mortality. Current vegetation models also hold substantial promise to quantify forest risks and inform forest management and policies, which currently rely predominantly on historical data.

A more-holistic understanding and quantification of risks to forest stability will help policy-makers effectively use forests as natural climate solutions. Scientific advances have increased our ability to characterize risks associated with a number of biotic and abiotic factors, including risks associated with fire, drought, and biotic agent outbreaks. While the models that are used to predict disturbance risks of these types represent the cutting edge in ecology and Earth system science to date, relatively little infrastructure and few tools have been developed to interface between scientists and foresters, land managers, and policy-makers to ensure that science-based risks and opportunities are fully accounted for in policy and management contexts. To enable effective policy and management decisions, these tools must be openly accessible, transparent, modular, applicable across scales, and usable by a wide range of stakeholders. Strengthening this science-policy link is a critical next step in moving forward with leveraging forests in climate change mitigation efforts.

Risks to forests -- Anderegg et al.jpg

Effective use of forests as natural climate solutions depends on accounting for climate-driven risks, such as fire and drought.

Leveraging cutting-edge scientific tools holds great promise for improving and guiding the use of forests as natural climate solutions, both in estimating the potential of carbon storage and in estimating the risks to forest carbon storage.


Global potential

Bastin et al

Massive Forest Restoration Could Greatly Slow Global Warming Mark Fischetti; Scientific American; 4 Jul 2019

We have heard for years that planting trees can help save the world from global warming. That mantra was mostly a statement of faith, however. Now the data finally exist to show that if the right species of trees are planted in the right soil types across the planet, the emerging forests could capture 205 gigatons of carbon dioxide in the next 40 to 100 years. That's two thirds of all the CO2 humans have generated since the industrial revolution. "Forest restoration is by far our most powerful planetary solution today," says Tom Crowther, a professor of global ecosystem ecology at the Swiss Federal Institute of Technology in Zurich, and an author of a study published Thursday in Science that generated the eye-opening number.

The study team analyzed almost 80,000 satellite photo measurements of tree cover worldwide and combined them with enormous global databases about soil and climate conditions, evaluating one hectare at a time. The exercise generated a detailed map of how many trees the earth could naturally support—where forests grow now and where they could grow, outside of areas such as deserts and savannahs that support very few or no trees. The team then subtracted existing forests and also urban areas and land used for agriculture. That left 0.9 billion hectares that could be forested but have not been. If those spaces were filled with trees that already flourish nearby, the new growth could store 205 gigatons of carbon by the time the forests mature.

After 40 to 100 years, of course, the storage rate would flatten as forest growth levels off—but the researchers say the 205 gigatons would be maintained as old trees die and new ones grow. There would be "a bank of excess carbon that is no longer in the atmosphere," Crowther says.

The global tree restoration potential Jean-Francois Bastin, Yelena Finegold, Claude Garcia, Danilo Mollicone, Marcelo Rezende, Devin Routh, Constantin M. Zohner, Thomas W. Crowther; AAAS Science; 5 Jul 2019


The restoration of trees remains among the most effective strategies for climate change mitigation. We mapped the global potential tree coverage to show that 4.4 billion hectares of canopy cover could exist under the current climate. Excluding existing trees and agricultural and urban areas, we found that there is room for an extra 0.9 billion hectares of canopy cover, which could store 205 gigatonnes of carbon in areas that would naturally support woodlands and forests. This highlights global tree restoration as our most effective climate change solution to date. However, climate change will alter this potential tree coverage. We estimate that if we cannot deviate from the current trajectory, the global potential canopy cover may shrink by ~223 million hectares by 2050, with the vast majority of losses occurring in the tropics. Our results highlight the opportunity of climate change mitigation through global tree restoration but also the urgent need for action.


Zeke Hausfather Twitter

The new Nature piece on reforestation has resulted in quite a bit of confusion. They suggest a sequestration potential of 200 GtC, but (incorrectly) suggest it would represent two-thirds of all emissions from human activities so far. This is incorrect.

Cumulative emissions to-date from land use and fossil fuels are ~640 GtC (via the @gcarbonproject), so removing 200 GtC would represent one third of historic emissions.

Similarly, sucking 200 GtC out of the atmosphere doesn't reduce atmospheric concentrations by 200 GtC, just like emitting 200 GtC doesn't increase concentrations by that much. An airborne fraction of ~50% applies to both, as both similarly affect land/ocean carbon sink behavior.

Finally, 200 GtC is a technical potential assuming every hectare of forestland on earth is increased to 100% forest cover. In practice, the economic potential will be substantially smaller, and fragmentation of ownership would make coordinated global efforts challenging.

That's not to say that reforestation is not an important mitigation strategy, just to caution that like every other climate solution its part of a larger portfolio of strategies rather than a silver bullet.

(Correction: the paper was in Science, not Nature)

Pep Canadell Twitter

I am disappointed that Science has allowed an abstract of a, otherwise good, paper to say that planting trees is "our most effective climate change solution to date". This is factually wrong and certainly a distraction. 1/2

Planting trees is certainly an important part of the climate change mitigation portfolio, but are neither cheaper nor easier to implement than other options. Most importantly, it won't fix the climate problem, albeit it should be part of the solution. 2/2

it is also important to recognise that trees come with litter and soils, so a tree-only focus will always report a partial carbon balance of the true effect on climate, eg, more trees in a future warmer Russia and Canada can also have higher emissions from C-rich soils.

Bastin et al. Science paper provides a very welcome analysis with sound and robust methods; a new database with great new applications to explore C sequestration. However, authors need to be more careful in crafting top conclusions and not going beyond what the data supports.

Finally, the reader is left with the impression (final paragraph) that out of 300 Gt of anthropogenic C, 200 Gt can be removed by tree planting. Unfortunately, the carbon cycle doesn't quite work this way. See next.

When we emit 1 tonne of C, half of it is removed by the land and ocean sinks; the other half is accumulated in the atmosphere. Well, the same applies when you remove 1 tonne of C from the atmosphere, half tonne of C is released by the natural CO2 sinks. So, take half of 200 GtC.


Sikhs aim to plant million trees as 'gift to the planet' Isabella Kaminski; The Guardian; 5 Apr 2019

Sikhs around the world are taking part in a scheme to plant a million new trees as a “gift to the entire planet”. The project aims to reverse environmental decline and help people reconnect with nature as part of celebrations marking 550 years since the birth of the founder of Sikhism, Guru Nanak. Rajwant Singh, the president of the Washington DC-based environmental organisation EcoSikh, which is coordinating the Million Tree Project, said he wanted to mark the anniversary in a significant way.


Why is Africa building a Great Green Wall? A film by Amelia Martyn-Hemphill for BBC World Hacks


Eleven countries are planting a wall of trees from east to west across Africa, just under the southern edge of the Sahara desert. The goal is to bring the dry lands back to life.

8,000km Green Wall of Trees and Plants Will Provide Food Security for Millions of People Interesting Engineering


The Great Green Wall is an initiative of the African Union to combat climate change and desertification by planting millions of trees across the entire African continent. The project started as the idea to build a green wall stretching from East to West across Africa. It has since evolved into a giant project consisting of a mosaic of vegetation being planted throughout the Sahara desert, increasing biodiversity and contributing to the well-being of local inhabitants. Once the wall is completed it will be the largest living structure on earth.

The wall will start in the Sahel region of Africa on the Southern edge of the Sahara desert. The area suffers severe, ongoing drought, a lack of food and is involved in conflicts over how to best manage natural resources. The green wall will provide the local population with jobs, food security and hope. The wall isn’t just a physical manifestation of the future, its organizers hope that it will serve as a symbol of the ability to overcome struggle and adversity for many generations to come.

David Milsom, Creative Strategist at venturethree, describes the project saying, "The Great Green Wall is a hugely progressive and ambitious project, not just for Africa, for the whole world. It’s more than just an environmental initiative; it’s a symbol of hope that humanity can reverse the effects of climate change. ‘Growing a World Wonder’ lets people experience this for themselves, in incredible Virtual Reality.”

Kaduna NGO embarked on fighting Deforestation, Desertification & climate change through planting 50,000 Tress Annually, and training of youth from Nigeria and some part of Africa to protect environment African Climate Reporters; 25 Feb 2018

The founder of “Teko Farm international” Mallam salihu Ibrahim has reiterated his committed over the fight against deforestation ,desertification ,and climate change though continuous training of youth and school students from various part of Africa on the importance of trees planting in the entire 19 northern state of Nigeria and Africa ,in other to halt the increasing speed of our forestry turning to sahara

Reforesting the world: the Australian farmer with 240m trees to his name Ben Doherty; Guardian; 13 Dec 2018

Tony Rinaudo’s regeneration technique, developed in west Africa 30 years ago, has helped bring back forest over 6m hectares


What Makes a Church? A Tiny, Leafy Forest By Jeremy Seifert; New York Times; 3 Dec 2019

In Ethiopia, church forests are withstanding environmental destruction — but just barely.

With video


How a 2 hectare forest in Bangalore’s heart has lowered temperature and raised its water table Maya Kilpadi; earthamag; 18 May 2016 pdf The Better India; 5 Jun 2016

The summer temperatures in Bangalore this year have been cause for particularly high concern among its residents, with some claiming that daytime temperature shot up to 41 degrees Celsius one day in April. This summer has surely felt hotter than most old Bangaloreans remember them ever being. But, there are some parts of the city that have kept the unrelenting heat away. Walk around the lush Indian Institute of Science (IISc) Campus and you will encounter several species of trees, native and exotic. The 400 acre campus is home to 112 species of trees and 45 species of grasses. There are gulmohar lined avenues, large, raintree-shaded bowers, and colourful bursts of laburnum, jacaranda, and tabebuia. And then you walk past the Centre for Ecological Sciences department (CES) and you stop short! The vegetation here is unlike anything you’ve encountered on the rest of the campus so far. Gigantic, woody vines weave endlessly like lace through a lush canopy, the trees are thick and dense, letting only a modicum of sunlight through, and all around you, in the cool air, is the hum of insects and birds. If you feel like you are in the rainforests of Agumbe, you’re not alone. You are in IISc’s mini-forest, a forest planted by a team of researchers led by senior faculty member Dr. T.V. Ramachandra (Energy and Wetlands Research Group).

Man single-handedly grows a forest larger than Central Park


China restores great swaths of denuded forests with exemplary conservation program Lacy Cooke; inhabit; 21 Mar 2016

For years China was notorious for denuding its forests of vegetation to expand their economy. The economy grew, but water sources were tainted, air polluted, and animal habitats demolished. Only a few years ago, just 2 percent of China’s forests were undisturbed, and to make matters worse, the destruction of forests leads to one fifth of climate change-inducing emissions. Horrendous floods in 1998 that stemmed from the lack of trees prompted the government to finally take action. They implemented the National Forest Conservation Program, and a new study reveals it’s working. [...] they banned logging in many areas and then paid farmers, who were accustomed to earning money by cutting down trees for wood, to plant trees instead. Some local citizens were even paid to monitor forests and report any illegal logging. After several years of this, the Chinese government claimed their conservation project had begun to show signs of progress, a claim confirmed in a new independent analysis.

China’s eco-civilization plan calls for 23% forest cover by 2020 Josh Marks; inhabit; 30 May 2016

Besides the United States, China has done more than any other country to contribute to climate change. But while China’s greenhouse gas emissions are rapidly warming the planet, the Asian nation is quickly shifting its focus to climate change mitigation to ensure a sustainable biosphere for future generations. According to a new United Nations report, China plans to build an “ecological civilization” that could be a model for the rest of the world. The project includes an initiative to cover nearly one quarter of the country with forests by 2020. The report, titled “Green is gold: The strategy and actions of China’s ecological civilization,” was launched at the UN Environmental Assembly in Nairobi, Kenya. Zhu Guangyao, executive vice president of the Chinese Ecological Civilization Research and Promotion Association, called ecological civilization a new concept in the development of human civilization that requires respect for nature. “The outdated view that man can conquer nature and ignore the bearing capacity of resources and the environment should be completely abandoned,” said Guangyao. “Conscientious efforts should be made to live in harmony with nature, allowing for a new approach to modernization characterized by such co-existence.”

Green is gold: The strategy and actions of China’s ecological civilization REPORTfrom UN Environment Programme; refiefweb; 26 May 2016

The Chinese government has been paying close attention to ecological and environmental issues for many years. It has highlighted Ecological Civilization (or Eco-civilization for short) and environmental protection as a long-term strategy vital to the country’s modernization and its people’s well-being. China started framing environmental protection as a fundamental national policy in the 1980s and established sustainable development as a national strategy in the 1990s. At the beginning of the 21st century, the government proposed a “Scientific Outlook on Development” that is people-centered, fully coordinated, and environmentally sustainable. In particularly, since late 2012, the government has incorporated Eco-civilization into the “Five-in-One” blueprint of socialism with Chinese characteristics, which outlines a commitment to “innovative, coordinated, green, open and shared development”.


Watch: How Europe is greener now than 100 years ago Washinton Post

Animated graphics


UK National Forest

How millions of trees brought a broken landscape back to life John Vidal; Guardian; 7 Aug 2016

Twenty-five years ago, the Midlands villages of Moira, Donisthorpe and Overseal overlooked a gruesome landscape. The communities were surrounded by opencast mines, old clay quarries, spoil heaps, derelict coal workings, polluted waterways and all the other ecological wreckage of heavy industry. The air smelt and tasted unpleasant and the land was poisoned. There were next to no trees, not many jobs and little wildlife. Following the closure of the pits, people were deserting the area for Midlands cities such as Birmingham, Derby and Leicester. The future looked bleak. Today, a pastoral renaissance is taking place. Around dozens of former mining and industrial communities, in what was the broken heart of the old Midlands coalfield, a vast, splendid forest of native oak, ash and birch trees is emerging, attracting cyclists, walkers, birdwatchers, canoeists, campers and horse-riders.

The National Forest 25 Years of Transformation thenationalforest; YouTube; 19 Jul 2016

Showcasing the transformation of The National Forest over 25 Years.

National Trust - Thorneythwaite

I’m sorry if rewilding hurts farmers, but we need it Nick Cohen; The Guardian; 3 Sept 2016

The National Trust’s purchase of Thorneythwaite sheep farm is part of a plan to reshape the landscape to meet the threat of global warming

Reforestation in Norway: showing what’s possible in Scotland and beyond Rewilding Britain; 20 Jan 2016

Scotland and Norway suffered large-scale deforestation over centuries but over the last 100 years the trees have been returning to Norway. It could be happening in Scotland too

Monks Wood

Monks Wood Wilderness: 60 years ago, scientists let a farm field rewild – here’s what happened Richard K Broughton; The Conversation; 22 July 2021

In the archive of the UK Centre for Ecology & Hydrology there is a typed note from the 1960s that planted the seed of an idea.

Written by Kenneth Mellanby, director of the Monks Wood Experimental Station, a former research centre in Cambridgeshire, UK, the note describes a four-hectare arable field that lies next to the station and the ancient woodland of the Monks Wood National Nature Reserve. After harvesting a final barley crop, the field was ploughed and then abandoned in 1961.

The note reads:

It might be interesting to watch what happens to this area if man does not interfere. Will it become a wood again, how long will it take, which species will be in it?

So began the Monks Wood Wilderness experiment, which is now 60 years old. A rewilding study before the term existed, it shows how allowing land to naturally regenerate can expand native woodland and help tackle climate change and biodiversity loss.

How new woodland generates itself

A shrubland of thorn thickets emerged after the first ten to 15 years. Dominated by bramble and hawthorn, its seeds were dropped by thrushes and other berry-eating birds. This thicket protected seedlings of wind-blown common ash and field maple, but especially English oak, whose acorns were planted by Eurasian jays (and maybe grey squirrels too) as forgotten food caches. It’s thought that jays were particularly busy in the Monks Wood Wilderness, as 52% of the trees are oaks.

The intermediate shrubland stage was a suntrap of blossom and wildflowers. Rabbits, brown hares, muntjac deer and roe deer were all common, but the protective thicket meant there was no need for fencing to prevent them eating the emerging trees. Those trees eventually rose up and closed their canopy above the thicket, which became the woodland understorey.

The result is a structurally complex woodland with multiple layers of tree and shrub vegetation, and accumulating deadwood as the habitat ages. This complexity offers niches for a wide variety of woodland wildlife, from fungi and invertebrates in the dead logs and branches, to song thrushes, garden warblers and nuthatches which nest in the ground layer, understorey and tree canopy.

The Monks Wood experiment benefited from the field lying close to an ancient woodland, which meant an ample supply of seeds and agents for their dispersal – jays, rodents, and the wind. Such rapid colonisation of the land would be unlikely in more remote places, or where deer are superabundant.

But there are many woods in the UK that could expand by allowing adjacent fields to return to nature. This would eventually add up to a significant increase in total woodland cover.

Tree planting or natural regeneration?

The UK is one of the least forested places in Europe, with just 13% forest cover compared to an average of 38% across the EU. Only half of the UK’s forest is native woodland, which sustains a wide variety of indigenous species. The rest is dominated by non-native conifer plantations grown for timber.

This situation is gradually changing. The UK government aims to create 30,000 hectares of new woodland each year until 2025, providing new habitat for wildlife and helping reach net zero emissions, as woodland stores more carbon than any other habitat except peatlands.

With the climate and biodiversity crises getting worse each day, there’s an urgent need to expand woodland fast. But how? Tree planting is the usual approach, but it’s costly. Saplings also have to be grown, transported, planted and protected with fencing and plastic tubes – that’s a lot of carbon emissions and potential plastic pollution, as tubes break down into the soil.

What about doing virtually nothing instead? Natural regeneration involves creating woodlands by allowing trees and shrubs to plant themselves under natural processes. It’s free and involves no plastic or nursery-grown saplings, which can introduce diseases. The result is woodland that’s well adapted to local conditions.

Allowing the land to naturally regenerate sounds exciting, but planners and ecologists need to know where this approach is likely to work best. How abandoned land turns into woodland is rarely documented, as it usually happens where people have walked away.

The Monks Wood Wilderness fills in this gap in our knowledge as an example of planned natural regeneration that has been monitored over decades, with a second two-hectare field (named the New Wilderness) added in 1996 to expand the experiment.

Since the 1990s, the two Wildernesses have been regularly surveyed by scientists counting and measuring trees on foot and tracking tree cover from planes and drones. These surveys documented the development of woodland over 60 years in our recently published study, revealing the patterns of habitat regeneration.

We can now finally answer Mellanby’s 60-year old questions. Within 40 to 50 years, the ploughed field became a closed canopy woodland with almost 400 trees per hectare. And as the canopy grows taller, more plant and animal species are arriving, such as marsh tits and purple hairstreak butterflies – mature woodland specialists that have made a home here as the habitat gradually converges with the ancient woodland nearby.

The Wilderness experiment shows what’s possible when nature is allowed to create rich, native woodland for free. I think Mellanby would be pleased with how it all turned out.

See article for pictures and links.


Paris Plans a Suburban Forest Five Times the Size of Central Park FEARGUS O'SULLIVAN; CityLab; 14 Feb 2018

With its car bans, huge transit expansion, and radical pedestrianization plans, Paris has been developing quite a name for itself recently as an aggressive fighter against urban air pollution. For its next major assault on bad air, however, the metro area is proposing to deploy an ancient weapon: trees. In fact, it would be using one million of them.

These trees would be planted as part of what could yet be this century’s grandest urban and suburban re-greening projects: the creation of a new forest north of the city limits that, at its final 1,350 hectare (5.2 square mile) extent, will be five times the size of New York’s Central Park.

France’s Biggest Forest Was Planted by People Pauline Chardin; Meridian;

At the southern end of France’s Atlantic coast lies the vast Landes de Gascogne forest and its seemingly infinite sea of maritime pines.

That’s one million square meters of forest planted by humans with the goal of halting the progression of the dunes, moderating the cold-front influence on Bordeaux vineyards, and creating farmland where there were only marshlands and swamps. The project began in the 19th century, with planting continuing through the 1950s, when half of the forest had to be resown after a devastating fire. Landes de Gascogne is now the largest forest in France and the largest "artificial" forest in Western Europe.

The mid-century approach to planting was remarkable insofar as it was a rational take on forest-building, with trees perfectly aligned in alleyways allotted to keep future fires contained.

That’s how the landscape as it is today was born, from pines that weren’t supposed to be there, arranged in a way that nature surely hadn’t intended.

Landes may not sound like a dreamlike place, but its beauty is undeniably striking.

The slim and spaced out silhouettes of the trees make the forest surprisingly luminous. Dark trunks contrast against feathery ferns on the ground.

At the end of summer, near the village of Castets, the southern end of the forest has surprises at every turn, like carpets of pink and violet heather over white sand.

A bike lane built in 2010 takes cyclists as far as the ocean. The 23-kilometer path — called Lo Camin de Hé from the Gascon term for train tracks — indeed runs along old locomotive tracks from Vielle-Saint-Girons to Taller by the sea.

Blackberries, pine nuts, and other edibles can be found and foraged along the way.


Vikings Razed the Forests. Can Iceland Regrow Them? Henry Fountain; New York Times; 20 Oct 2017

The country lost most of its trees long ago. Despite years of replanting, it isn’t making much progress.

"When Iceland was first settled at the end of the ninth century, much of the land on or near the coast was covered in birch woodlands. "'The people that came here were Iron Age culture,' Dr. Halldorsson said. 'And they did what Iron Age culture did.' "The settlers slashed and burned the forests to grow hay and barley, and to create grazing land. They used the timber for building and for charcoal for their forges. By most accounts, the island was largely deforested within three centuries. "'They removed the pillar out of the ecosystem,' Dr. Halldorsson said. "Eruptions over the ensuing centuries from some of Iceland’s many volcanoes deposited thick layers of volcanic material. The ash, while rich in nutrients, made for very fragile, poor soil that couldn’t hold water and moved around as the wind blew. "As a result, Iceland is a case study in desertification, with little or no vegetation, though the problem is not heat or drought. About 40 percent of the country is desert, Dr. Halldorsson said. 'But there’s plenty of rainfall — we call it "wet desert."' The situation is so bad that students from countries that are undergoing desertification come here to study the process."

South America


This technique could restore a big chunk of Amazon rainforest Bruce Lieberman; Yale Climate Connections; 12 Mar 2018

The Amazon rainforest is home to frogs, birds, and monkeys, and to hundreds of billions of trees. Those trees absorb and store carbon, helping to counter climate change. But over the past 50 years, nearly a fifth of the Amazon forest in Brazil has been cut down for farming, ranching, and logging. That’s an area larger than the state of Texas. Rodrigo Medeiros is with the nonprofit Conservation International. Medeiros: “We are working together with several organizations to restore the Amazon rainforest and thereby return to the planet and the people the forest that had been destroyed.” The group plans to spread seeds from over 200 native species, including grasses and trees, across 70,000 acres. Medeiros says this method is less expensive and time-intensive than planting individual saplings. And, he says, it will create a dense, diverse ecosystem. Medeiros: “And in five years, we have a well-established forest that continues to develop and become mature for the next 15, 20 years.” Medeiros says this is just the beginning of reforestation efforts in Brazil. The country aims to restore nearly 30 million acres by 2030.


Photographer And His Wife Plant 2 Million Trees In 20 Years To Restore A Destroyed Forest And Even The Animals Have Returned Ilona Baliūnaitė; Bored Panda; 2019

According to the United Nations’ Food and Agriculture Organization, 129 million hectares of forest, an area almost equivalent in size to South Africa, have been lost from the Earth forever since 1990 due to deforestation. An area roughly the size of the country of Panama is being lost every year.

With some 15 percent of all greenhouse gas emissions come from deforestation, and countless species of plants and animals losing their habitats every single day. These are absolutely devastating figures for the health of our planet, and this rate of natural habitat destruction simply cannot be allowed to continue.

... Brazilian photographer Sebastião Salgado and his wife Lélia Deluiz Wanick Salgado decided to show what a small group of passionate, dedicated people can do by turning deforestation on its head, and begin the process of reforestation.

... Back in the 1990s, exhausted physically and emotionally after documenting the horrific barbarity of the Rwandan genocide, he returned home to his native area of Brazil, which was once covered in a lush tropical rainforest. He was shocked and devastated to find that the area was now barren from forest trees and devoid of wildlife, but his wife Lélia believed that it could be restored to its former glory.

“The land was as sick as I was – everything was destroyed,” Salgado said in The Guardian back in 2015. “Only about 0.5% of the land was covered in trees. Then my wife had a fabulous idea to replant this forest. And when we began to do that, then all the insects and birds and fish returned and, thanks to this increase of the trees I, too, was reborn – this was the most important moment.”

Together, Sebastião and Lélia founded Instituto Terra, a small organization that has since planted 4 million saplings and has brought the forest back from the dead. “Perhaps we have a solution,” Salgado said. “There is a single being which can transform CO2 into oxygen, which is the tree. We need to start tree planting on a massive scale. You need forest with native trees, and you need to gather the seeds in the same region you plant them or the serpents, and the termites won’t come. And if you plant forests that don’t belong, the animal population won’t grow, and the forest will be silent.”

And so, after taking utmost care to ensure that everything planted is native to the land, the area has flourished remarkably in the ensuing 20 years. Wildlife has returned, where there was a deathly silence, there is now a cacophony of birdcalls and insects buzzing around.

In all, some 172 bird species have returned, as well as 33 species of mammals, 293 species of plants, 15 species of reptiles and 15 species of amphibians, an entire ecosystem rebuilt from scratch.

Aerial reforestation

Planes Can Plant 900,000 Trees A Day With Seed Bombs Culture of Awareness; 10 Apr 2016

Old military planes are now being reconditioned and refitted with new mechanics. Using these planes, we can drop tree bombs instead of landmines.

Aerial bombardment to reforest the earth Paul Brown, Environment Correspondent; Guradian; 2 Sep 1999

Old Military Planes Could Drop 900,000 Tree-Bombs a Day Brian Merchant; TreeHugger; 19 Oct 2010

NASA scientist is using drones to plant 1 billion trees per year Joe McCarthy; Global Citizen; May 24, 2016


Thailand seed bombs: aerial reforestation to foster new growth on damaged land by 2017 TomoNews US; 5 Jul 2013

The Thai government has initiated a five-year pilot project that uses aerial reforestation to boost forest regeneration. Aerial reforestation is a technique used to quickly plant large numbers of new trees. Local tree seeds are mixed with soil and shaped into small balls called seed bombs. The seed bombs are dropped from airplanes over deteriorated forests.

These bombs don’t kill, they give life.