Tag Archives: forest

We can’t “plant our way” out of the climate crisis, researchers argue

We won’t solve the climate crisis by planting a large number of trees around the world. Instead, countries should focus on keeping the existing forest healthy, so they can continue to act as carbon sinks and remove greenhouse gases from the atmosphere through photosynthesis, according to a new commentary piece.

Image credit: Flickr / Walkers

University of Arizona’s researcher David Breshears and his colleague from the University of Michigan Jonathan Overpeck said the world can’t “plant its way out of the climate crisis.” According to the two researchers, the idea of planting trees as a substitute for the direct reduction of greenhouse gas emissions is simply a pipe dream.

“Policymakers need to enable new science, policy and finance mechanisms optimized for the disturbance and vegetation change that is unstoppable, and also to ensure that the trees and forests we wish to plant or preserve for the carbon they sequester survive in the face of climate change and other human threats,” they wrote.

“Tree-planting has great appeal to some climate activists because it is easy and not that expensive,” Breshears said. “But it’s like bailing water with a big hole in the bucket: While adding more trees can help slow ongoing warming, we’re simultaneously losing trees because of that ongoing warming.”

The idea of planting trees as a low-cost and high-impact solution to climate change increasingly pops up time and time again. Previous studies have highlighted the potential of trees to soak up and store carbon, with countries like the US and the UK starting massive tree-planting campaigns as part of their climate plans.

But it’s not that simple. There are many tree-planting initiatives underway across the globe, all of which aim to capture carbon to compensate for the huge carbon dioxide emissions that are a major cause of rising global temperatures. But in some cases, they don’t actually increase carbon capture and instead have negative consequences.

Breshears and Overpeck said policymakers and land managers have to acknowledge that additional vegetation changes are inevitable. Climate change has recently been linked to record-setting wildfires in the United States and Australia, for example. These trends are expected to accelerate as the climate warms, the researchers argued. 

“Even in a world where climate change is soon halted, global temperature rise will likely reach between 1.5 and 2 C above pre-industrial levels, with all the associated extreme heat waves that brings, and thus global vegetation will face up to double the climate change already experienced,” they wrote.

While climate change is accelerating, deforestation continues to expand globally and is especially damaging in tropical forests, which hold vast amounts of biodiversity and sequestered carbon, Breshears and Overpeck said. Last year, at least 42,000 squared kilometers of tree cover were lost in key tropical regions such as the Amazon basin.

Two-thirds of global forest cover loss is occurring in the tropic and subtropic regions of the world, where vast clusters of deforestation hot spots are destroying the important ecosystem services forests provide. There are 24 of these hot spots that are spread across Latin America, sub-Saharan Africa, Southeast Asia, and Oceania.

The researchers advise countries to manage forests proactively for the vegetation changes that can be anticipated, instead of trying to maintain forests as they were decades ago. This means more aggressive thinning of forests to reduce the buildup of fuels that increase wildfires and replacing trees that aren’t in optimal climate zones. 

While these actions will increase the cost of forest management, Breshears and Overpeck described it as a prudent investment, helping to preserve the service of carbon capture provided by forests. Capturing carbon should rank high on the list of invaluable services that forests provide, and efforts to preserve it should be funded. 

“Thinning of forests, conversion of the removed wood to biochar and burial of the biochar in forest soils is a way to bring new jobs to forested rural areas while allowing forests to play a bigger role in keeping carbon out of the atmosphere and thus fighting climate change. Forest carbon management could be a boon for rural areas in need of new economic engines,” the researchers wrote.

The commentary was published in Science. 

The bedrock under forests also affects carbon storage

The species of trees in a forest, their growth, and their capacity to store carbon are greatly influenced by the bedrock underneath the trees. This could have implications for forest management and carbon models.

Geology often gets left out of the environmental debate, although it provides the support for the entire ecosystem — both figuratively and literally. The bedrock and soil direct the entire chemical profile of the ecosystem and provide the necessary nutrients that ultimately support every living creature in the ecosystem. According to a new study, the influence of the bedrock might be even greater than previously thought.

A team of researchers led by Margot Kaye, associate professor of forest ecology at Penn State University, found that forests growing on shale bedrock store 25% more carbon and grow faster, taking up about 55% more carbon each year than forests growing on sandstone bedrock.

The findings show that forests lying on shale may provide more ecosystem services, and should perhaps be prioritized by forestry management when it comes to conservation.

“As forests grow and respond to warming, shifts in precipitation and invasive species, managers will benefit from incorporating lithological influences and considerations on forest composition and productivity,” she said. “For example, conserving forests growing on shale with higher species diversity will likely lead to forests that are resilient to stressors and can grow more vigorously.”

To reach this conclusion, researchers surveyed forest inventory from 565 plots in Pennsylvania. They analyzed the topography and soil features of the area, as well as the age and species of trees in the forests.

The study covered more than 23,000 trees, ranging from 20 to 200 years old, with most being around 100 years old. Most forests were dominated by different types of oak. Some 800,000 acres of forests were on sandstone, compared to only 262,000 acres on shale.

“That is an eye-opening number,” said lead researcher Warren Reed, a doctoral student in ecology.

If forest productivity is related to bedrock, it means that we would be getting much more environmental services if there were more forests on shale. Oaks seem to grow faster and be more expansively on shale — and the reason for this has to do with chemistry.

Forest soil (and soil, in general) forms as the underlying bedrock breaks down and decays. Over millions of years, rocks are slowly eroded and transformed, but because of their composition, shale breaks down into finer soils than sandstone, which is coarser.

This affects the trees’ capacity to absorb and store water and nutrients. It’s not entirely surprising that shale makes for better forests, but the scale of the difference was surprising.

Researchers were also surprised to see just how much more carbon these shale forests store — which could be an important consideration for climate objectives, researchers conclude.

Journal Reference: Warren P. Reed et al, Bedrock type drives forest carbon storage and uptake across the mid-Atlantic Appalachian Ridge and Valley, U.S.A., Forest Ecology and Management (2020). DOI: 10.1016/j.foreco.2020.117881 Journal information:Forest Ecology 

The Bosco Verticale In Milan in spring, West side. Credit: Wikimedia Commons.

The urban forest of the future: how to turn our cities into Treetopias

The Bosco Verticale In Milan in spring, West side. Credit: Wikimedia Commons.

The Bosco Verticale In Milan in spring, West side. Credit: Wikimedia Commons.

The 21st century is the urban century. It has been forecast that urban areas across the world will have expanded by more than 2.5 billion people by 2050.

The scale and speed of urbanisation has created significant environmental and health problems for urban dwellers. These problems are often made worse by a lack of contact with the natural world.

With research group the Tree Urbanistas, I have been considering and debating how to solve these problems. By 2119, it is only through re-establishing contact with the natural world, particularly trees, that cities will be able to function, be viable and able to support their populations.

Future cities

The creation of urban forests will make cities worth living in, able to function and support their populations: Treetopias.

This re-design will include the planting of many more urban trees and other vegetation – and making use of new, more creative methods. Although we didn’t fully realise it at the time, the 1986 Hundertwasserhaus in Vienna, a building that incorporated 200 trees in its design, was the start of more creative urban forestry thinking.

The Hundertwasserhaus in Vienna, designed by Friedensreich Hundertwasser. Credit: Wikimedia Commons.

This has been carried on in Stefano Boeri’s Bosco Verticale apartments in downtown Milan, which incorporates over 800 trees as part of the building. Similar structures are being developed around the world, such as in Nanjing in China and Utrecht in The Netherlands.

The urban forest needs to be designed as a first principle, part of the critical infrastructure of the whole city, not just as a cosmetic afterthought. We know for example that in 2015, urban forest in the UK saved the NHS over £1 billion by helping to reduce the impact of air pollutants. In 2119, we may well look back on this present time as the equivalent of the Victorian slum.

Trees can create places which can greatly improve our health and well-being. Our urban forest can give us the spaces and places to help manage our mental health and improve our physical health. Research has indicated for example that increasing the canopy cover of a neighbourhood by 10% and creating safe, walkable places can reduce obesity by as much as 18%.

Cities built on trees

As rural areas become less productive as a result of climate change, cities – which previously consumed goods and services from a large hinterland – will have to become internally productive. Trees will be at the centre of that, contributing to the city energy balance through cooling, regulating and cleaning our air and water flows, and ensuring that our previously neglected urban soils function healthily.

Urban forests could also provide timber for building. We have a history of productive woodlands in the UK, yet alternative construction materials and a growth in an urban population with less knowledge of forest management means that the urban forest is rarely viewed as productive. We are now recognising the potential productivity of the urban forest, as campaigns to stimulate homegrown timber markets and achieve more efficient management efficiencies are proving to be successful.

Furthermore, economic growth is still deemed to be the prime symbol of the effectiveness of a city, but we need to be equally aware of other invisible values. This will open up new approaches to governance. Governance needs to embrace all forms of value in a balanced way and facilitate a new vision, considering how trees can help create liveable cities.

New opportunities

As the urban population rises, we need to get better at understanding the breadth and diversity of the values held about our urban forest. Individual people can hold several distinct values at once, as urban forests may contribute to their wellbeing in different ways.

The current guardians of our urban forest, mainly local authority tree officers, spend much of their time managing risks rather than maximising the opportunities of trees. They often receive complaints about trees and tree management, and it can sometimes be difficult to remember that people do care about trees. We need to develop viable partnerships between tree managers, community members and businesses to support trees in our cities.

Although the canopy cover of cities worldwide is currently falling, this is not the case in Europe, where it is increasing. Many European countries are acknowledging the fact that we have over-designed our towns and cities to accommodate the car, and now it is time to reclaim the public realm for our people – either pedestrians on foot or on bicycles.

Creative developments like the Hundertwasserhaus are not the only answer to creating Treetopia. We are and will continue to plant more street trees, urban groves and informal clusters of trees in our parks and green spaces. Treetopia has begun.


Alan Simson, Professor of Landscape Architecture and Urban Forestry, Leeds Beckett University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Researchers develop new tool to help regrow burned-down forests

New research at the University of California, Davis with support from U.S. Geological Survey (USGS), Cal Fire, and the U.S. Forest Service aims to understand how forests regenerate after wildfires.

Image via Pixabay.

The team has managed to create a predictive mapping tool that showcases where forests may have trouble regrowing after burning down. This tool can be used to nurture those areas that could have trouble recovering on their own, an especially important task in the wake of the massive wildfires we’ve seen in Australia and the USA this year.

After the flame

“Huge fires are converting forested areas to landscapes devoid of living trees,” said lead author Joseph Stewart, a postdoctoral researcher at UC Davis and with USGS.

“Managers need timely and accurate information on where reforestation efforts are needed most.”

Wildfires might char whole forests down to the ground, but there will always be saplings to start anew — at least, that’s what we like to think. There are, in fact, multiple factors that influence whether, and how fast, a forest can regrow after such an event; understanding what these are and how they interact in the real world can thus help preserve forests even after they have burned down.

The new tool, known as the Post-fire Spatial Conifer Regeneration Prediction Tool (POSCRPT), aims to give forest managers a way of estimating which areas will regrow naturally after a fire, and which are likely to need some help to do so. It produces results within weeks of a fire, too, meaning steps can be taken quickly to prevent long-lasting forest losses.

POSCRPT was developed from data recorded in the USA in the wake of the massive wildfires that swept through California. The team found that conifers (which dominate North America’s forests) are less likely to recover after a fire if seedlings have to face drier conditions. This is especially pronounced in low-lying forests that already experience frequent periods of drought, the team explains.

Fewer conifers are expected to regrow in California’s lower elevation forests due to climate change and its associated drought conditions, the team adds.

“We found that when forest fires are followed by drought, tree seedlings have a harder time, and the forest is less likely to come back,” said Stewart.

The study recorded post-fire recovery data from more than 1,200 study plots in 19 wildfires that burned between 2004 and 2012, and 18 years’ worth of forest seed production data. This was put together with multispectral satellite imagery, forest structure maps, as well as data pertaining to climate and other environmental factors. The end result was a model of how seed availability and forests’ regeneration probabilities vary for different groups of conifers.

A prototype has been used over the last few years by forest managers, the authors explain — the latest update includes more in-depth information on post-fire climate and seed production and also has an improved web interface.

“This work is a great example of how multiple partners can come together to solve major resource management problems that are arising from California’s climate and fire trends,” said co-author Hugh Safford, regional ecologist for the USDA Forest Service’s Pacific Southwest Region and a member of the research faculty at UC Davis.

The paper “Effects of postfire climate and seed availability on postfire conifer regeneration” has been published in the journal Ecological Applications.

Humanity is making trees grow less and live shorter lives

Forests around the world are feeling the shifts in global climate and atmospheric chemistry, a new paper reports. Trees are growing shorter, and there are fewer and fewer older ones around, as tree mortality is on the rise due to a conflux of factors.

Image credits Ilona Ilyés.

These changes have a profound effect on the overall makeup of forest ecosystems, and can potentially have ramifications for all other ecosystems on the planet.

Tree troubles

“This trend is likely to continue with climate warming,” said Nate McDowell, the study’s lead author and a researcher at the U.S. Department of Energy’s Pacific Northwest National Laboratory.

“A future planet with fewer large, old forests will be very different than what we have grown accustomed to. Older forests often host much higher biodiversity than young forests and they store more carbon than young forests.”

They used satellite imagery and available research on forests to conclude that the average size of trees has been declining over the last century. The changes in trees’ lifecycles are being driven by rising average temperatures and growing concentrations of atmospheric CO2 gases.

Greater availability of carbon in the air makes for more fertile times, as plants use this element to develop and grow. However, higher average temperatures are placing increased stress on the plants and increasing the frequency of damaging events such as wildfires, droughts, and damaging winds — which increase tree mortality. Deforestation also factors in here, further increasing tree mortality and inducing changes in the age and structure of forests.

According to the team, these elements have already induced a noticeable change in the makeup and average age of forests. Such human-induced changes will most likely continue in the foreseeable future, they add, leading to ever-shrinking old-growth forests globally.

Forest life

The makeup and age of individual forests are closely interlinked characteristics, and they’re primarily the product of three different factors: recruitment, which is the addition of seedlings to a community, growth rates, as determined by the net increase in biomass/carbon, and mortality rates.

“Mortality is rising in most areas, while recruitment and growth are variable over time, leading to a net decline in the stature of forests,” said McDowell. “Unfortunately, mortality drivers like rising temperature and disturbances such as wildfire and insect outbreaks are on the rise and are expected to continue increasing in frequency and severity over the next century.”

“So, reductions in average forest age and height are already happening and they’re likely to continue to happen.”

Old-growth forests have different characteristics compared to young ones. They’re different ecosystems, harboring a greater diversity of plants and animals, as well as more biomass overall. They have a greater ability to process atmospheric carbon, and they store more of it. The shift from old- to young-growth forests around the world “has consequences on biodiversity, climate mitigation, and forestry,” McDowell adds.

The problem is further exacerbated by the fact that large areas of old-growth forests lost over the last century weren’t replaced by young forests, but by completely different landscapes and ecosystems, such as agricultural, pastoral, or industrial areas.

Humanity takes a toll

Image via Pixabay.

As our effects on global ecological mechanisms increases, the toll these changes take on forests will increase as well. The team explains that higher concentrations of CO2 only seem to benefit young forests that have abundant nutrients and water. Given that many fertile areas of the world have issues with the supply of either or both of those essential elements, the increase in atmospheric CO2 only brings a modest benefit to forests.

At the same time, higher temperatures promote freak, damaging weather events, and reduce plants’ ability to photosynthesize. The team explains that this temperature-induced impairment is one of the leading causes of the trees’ reduced size. Droughts associated with climatic shifts further impact forest mortality.

Finally, wood harvesting has one of the most profound effects on global forest age seen in the study. Where forests are re-established on harvested land, the trees are smaller and biomass is reduced.

All in all, the findings make it loud and clear that trees are struggling around the world. Forests are seen as an important part of our current global warming mitigation strategies (which are far from sufficient as it is), and the findings showcase that we may have overestimated how much they can help given their current, damaged state.

The paper “Pervasive shifts in forest dynamics in a changing world” has been published in the journal Science.

Cut down half the forest and the rest quickly follows suit

Researchers at the University of Cincinnati (UoC) report finding a ‘tipping point’ for deforestation past which rapid forest loss occurs.

Landscapes are constantly in flux due to natural processes and human activity. The latter can either cause changes directly, think clear-cutting, or indirectly, such as climate change.

Image via Pixabay.

In order to better understand how landscapes react to direct causes of human-driven change, a team at the UoC tracked deforestation dynamics across the planet between 1992 and 2015. They found that, at least on a 9-kilometer-wide scale, deforestation occurs slowly until about half of the forest is gone — then the remaining trees disappear quickly. Mixed landscapes such as a forest together with agriculture are comparatively few, the authors explain, and tend to homogenize relatively quickly.

The findings provide new insight into landscape change dynamics, and the team hopes they will be used to guide conservation efforts in the future.

Don’t half-forest it

“I think it’s very intuitive. It corresponds to the different climatic zones,” says Professor Tomasz Stepinski, the paper’s corresponding author. “The Earth before people was certainly like that. You had forests and mountains and wetlands and deserts.”

“You would expect people would create more fragmentation, but as it turns out, people never stop. They convert the entire block on a large scale.”

In his previous research, Stepinski investigated the scale of landscape change, showing that around 22% of the Earth’s surface was measurably altered between 1992 and 2015. The single largest transition he found was from woodlands to agricultural fields. The same dataset was used for this study, which aimed to understand the dynamics of how one landscape changes into another. To this end, the team divided up the Earth’s landmasses into (roughly 1.8 million) 81-square-kilometer blocks. These blocks corresponded to 64 different combinations of landscape types.

All in all, the researchers report, some 15% of these blocks transitioned from predominantly one type to predominantly another between 1992 and 2015. Deforestation was the leading cause of man-made landscape change, they add.

Land-use map shows changing landscapes in North and South America between 1992 and 2015. White indicates little or no change. Darker shades indicate the highest rate of change in each category.
Image credits Tomasz Stepinski/UC.

Next, it was time to get to the meat of the matter. Using a class of modeling algorithms known as the Monte Carlo (MC) methods, they looked at how likely different types of landscape changes are to occur over longer periods of time (centuries, in this case).

“The data we have covers 23 years. That’s a relatively short period of time. But from that we can calculate change in the future,” Stepinski said.

Landscapes, they found, tend to shift from one homogenous state to another. In other words, they tend to move towards (predominantly) the same state across all their surface, at least on the 81-sq-km scale the team used. The authors didn’t look into why they behave like this, but Stepinski says it’s likely that as human developments are introduced into an area — such as the construction of logging roads and drainage systems — subsequent change of the landscape becomes easier and happens faster.

“Planet Earth wants to be homogeneous. The land wants to be the same in all these patches. And when they start to change, they don’t stop until they convert everything into another homogeneous block,” he explains.

“I can only speculate [why] because that was not part of the study, but I would imagine two things are happening. If you are cutting forest, you have the infrastructure to finish it. It’s so much easier to cut the rest. Second, the forest is more vulnerable to change when there has been a disturbance.”

The findings largely align with what we know of landscape conservation so far. Wildlife managers will try to preserve larger intact blocks of a certain habitat or landscape as this improves their resilience to virtually every pressure, including climate change and invasive species. Large swathes of wildland are also difficult and expensive to exploit, reducing their attractiveness as sources of raw material or land. Small parcels are just easier to transform, for nature and humans both.

“I think it is interesting that this property applies both to natural and human landscapes,” said co-author Nowosad, a former UC postdoctoral researcher who now works as an assistant professor at the Adam Mickiewicz University in Poland. “This model can be used to help understand how landscapes evolved and are going to evolve in the future,” Nowosad said.

“It’s thought-provoking. My hope is that people will criticize it and come up with different ideas,” Stepinski adds.

The study helps us better understand long-term landscape change, Nowosad explains, adding that it would be interesting to see if the dynamic applies to other types of transitions since the study focused on shifts between forest and agricultural land.

The paper “Stochastic, Empirically Informed Model of Landscape Dynamics and Its Application to Deforestation Scenarios” has been published in the journal Geophysical Research Letters.

Cutting down trees and planting new ones is wrecking the soil

It’s always a good idea to plant new trees after you cut some old ones. But that’s not exactly sustainable, a new analysis shows.

Image in public domain.

Forests still cover about 30% of the world’s land area, but their coverage are decreasing fast. Logging has always been an issue in modern times, with 1.3 million square kilometers of forest being lost between 1990 and 2016. Since humans have started cutting forests, 46% of trees have been felled, according to a 2015 study in the journal Nature. After a few encouraging signs, deforestation is once again on the rise.

Of course, forests have a natural replenishment rate, and humans also plant new tree areas. These efforts have put a dent in overall deforestation figures, although the net effect still heavily leans towards deforestation.

But even cutting trees and planting an equal amount is problematic, a new study suggests. Trees of recovering tropical forests were found to be different from those of old-growth forests. They had tougher leaves, with lower concentrations of the nutrients phosphorus and nitrogen — both essential for plant and tree growth. This is because constantly cutting trees and planting new ones depletes the soils of crucial nutrients, a new study concludes.

Essentially, multiple cycles of logging and replanting irreversibly remove phosphorus from the forest system — pushing the forest to its very limit.

“Old-growth tropical forests that have been the same for millions of years are now changing irreversibly due to repeated logging,” said Dr Tom Swinfield, a plant scientist at the University of Cambridge Conservation Research Institute, and first author of the paper published in the journal Global Change Biology.

Nutrients like phosphorus come from rocks, which are slowly incorporated into soil, from where they are absorbed by roots. When a tree is cut, these nutrients are lost. Swinfield and colleagues calculated that as much as 30% of the phosphorus in the soil is removed by repeated logging.

In order to do this, they used LIDAR measurements to create high-definition images of forests in north-eastern Borneo. This method uses high-precision laser scanners to take numerous measurements across the entire light spectrum to create a very detailed, 3D image of the forests. They then combined this data with nutrient measurements from 700 individual trees in the same forest — this allowed them to map the concentrations of nutrients in tree leaves over natural growth areas and areas with repeated logging.

The researchers found that differences from old-growth forest become more pronounced as logged forests grow larger over time, suggesting exacerbated phosphorus limitation as forests recover.

Each consecutive logging harvest reduces the levels of nutrients in the soil, the team adds. So far, trees seem to be coping, but they are being stressed more and more.

“We see that as the logged forests start recovering, they’re actually diverging from the old growth forests in terms of their leaf chemistry and possibly also species composition, as the amount of available nutrients goes down,” said Swinfield. “At the moment the trees can cope, but the fact that they’re changing indicates phosphorus levels in the soil are dropping. This could affect the speed at which forests recover from future disturbances.”

This matter has been severely understudied, the researchers also emphasize. Globally, we tend to think of forests as a zero-sum game: if we plant as much as we cut, then everything’s alright. But that’s not really the case.

Soils are often ignored in the conversation, and this can have devastating consequences for forest conservation. Also, it’s not just that the trees are there — not all trees are alike, and natural-growth, stress-free trees provide much better environmental services.

Lastly, while the study focused on Borneo, it is very likely that this issue affects forests worldwide.

“Phosphorus limitation is a really serious global issue: it’s one of the areas where humans are using a vital resource beyond sustainable levels,” concludes Professor David Coomes, Director of the University of Cambridge Conservation Research Institute, who led the project.

Journal Reference: Swinfield, T. et al: ‘Imaging spectroscopy reveals the effects of topography and logging on the leaf chemistry of tropical forest canopy trees.’ Global Change Biology, Dec 2019. DOI: 10.1111/GCB.14903

In 2019, Brazil cut down twice as much of the Amazon as it did in the previous year

Deforestation in Brazil’s Amazon forest has risen by 104% compared to November of 2018, according to data released by Brazil‘s National Institute for Space Research (INPE) on Saturday.

Image credits Rosina Kaiser.

All in all, some 563 square kilometers (217 square miles) of forest were cut down in November, the largest area ever felled since November of 2015. It’s not only the sheer scale of deforestation that’s worrying, but also that it took part during the rainy season — when, traditionally, deforestation efforts slowed down.

A terrible toll

INPE’s report explains that between January and November of this year — which were the first 11 months in office for Jair Bolsonaro, a far-right leader who has eased restrictions on exploiting the Amazon — a total of 8,973.3 square kilometers (3464.6 sq mi) of the forest have been cut down.

That is almost double the total recorded over the first 11 months of 2018 (4,878.7 sq km).

The data was recorded by the DETER (Detecção de Desmatamento em Tempo Real), a satellite-based real-time deforestation detection system employed by INPE. The system uses data from the MODIS sensor aboard the Terra and Aqua NASA satellites. The system is mostly used as an indicator of the rate of deforestation but does not represent the whole area cut down, which is measured by the PRODES project.

According to PRODES readings — the system is more reliable but slower to compile data than DETER — between August 2018 and August 2019, the total deforested area in the Brazilian Amazon exceeded the 10,000 square kilometer threshold for the first time since 2008. It would represent a 43% increase over the preceding 12 month period (when the total was 7,033 sq km).

Areas of the Amazon that see indigenous habitation have experienced some of the fastest-rising rates of deforestation (74.5%) over the preceding period, INPE adds.

Ricardo Galvao, INPE’s former president, was sacked by the Bolsonaro government in early August under accusations of exaggerating the report on deforestation. On Friday, Galvao was named one of the 10 most important scientists of the year by the journal Nature.

The full report (link in Portuguese) can be read here.

Even a little extra CO2 is triggering big changes in forests

While there’s a lot of talk about how forests can help mitigate climate change thanks to their net-positive CO2 absorption, not nearly enough attention has been given to how climate change will affect forests. A new study found that as the concentration of atmospheric carbon dioxide increases, plants adapt by changing the way they utilize water. The results suggest that evergreen plants are at an advantage, potentially replacing deciduous or leaf-shedding trees in many areas of the globe.

Credit: Pixabay.

Jennifer McElwain, a paleobotanist at Trinity College Dublin, has in the past analyzed how plants adapted to changes in atmospheric oxygen and carbon dioxide millions of years ago. This time, McElwain and colleagues didn’t look at the fossil record but rather studied relatively recent data and records on forest growth.

The work of Jack Wolfe at the Smithsonian Institute in Chicago proved paramount. During the 1980s and 1990s, he kept meticulous records of changes in forests around the world, from tropical ecosystems like Fiji to desert landscapes in Arizona. When this data was recorded, CO2 levels in the atmosphere were about 50 parts per million (ppm) lower than they are today.

The team led by McElwain traveled to 21 forest sites that Wolfe had first surveyed decades earlier, comparing what they found to the old records.

What they found was very surprising. In the span of only 30 years, the way the forests responded to CO2 was significantly different at the physiological level.

“We looked at how the woody plants handle water, which they release through the leaves as water vapour, and we could see plants had become more efficient at holding on to water,”said Dr. Wuu Kuang Soh, a research associate at Trinity College and lead author of the new study. “They were losing less water for every molecule of carbon they were taking up from the atmosphere.”

The findings suggest that increasing CO2 in the atmosphere is affecting the forests’ capacity to retain water, and this may have important consequences. For example, when forests recycle less water, floods became more common.

Evergreen trees and shrubs are more efficient in using water than their leaf-shedding counterparts in cooler climates. By the end of the century, the amount of carbon dioxide in the atmosphere could double, dramatically altering the ecology of forests globally.

“Our results indicate that future increases in atmospheric carbon dioxide may confer a competitive advantage to woody evergreen trees in cooler parts of the world, and this insight will improve our ability to build models on vegetation response to future climate change,” McElwain said in a statement.

The findings appeared in the journal Science Advances.

Trees and water: don’t underestimate the connection

Trees have extraordinary powers. They provide shade, cool the local climate, draw carbon dioxide from the air, and can repair and replicate themselves while running on little more than sunlight and rainwater (Pokorný 2018). They also contribute numerous goods and services like fruit, wood and soil improvement with a wide choice of species and varieties suitable for different needs and conditions. But such powers should be wielded with care.

Credit: Pixabay.

On the 5th of July 2019 Science published an article by Jean-François Bastin and colleagues titled “The global tree restoration potential”. In it, they explain how, without displacing agriculture or settlements, there is enough space to expand the world’s tree cover by one-third or around one billion hectares. Such increased forest would eventually reduce atmospheric carbon by about a quarter. A lot could be said about this proposition, much of it supportive. But in a brief comment piece just published in Science, colleagues and I highlight some reservations along with some even bigger opportunities. We focus on water.

The idea that the protection and restoration of tree cover could improve the climate while providing other benefits is well established. Indeed, there have been numerous international programs based on this including REDD “Reducing Emissions from Deforestation and Degradation”, the Bonn Challenge, which seeks to reforest and restore degraded land, as well as various related programs.

So what is new here?

Well, what Bastin et al. have done is estimate the scale of this opportunity and the contribution that restoring tree cover could make. For example, they list such estimates country by country as a “scientific evaluation” with relation to restoration targets specified under the Bonn Challenge. Under these targets, and those specified by the New York Declaration on Forests, an impressive list of countries (59) have undertaken to end deforestation and to restore 350 million hectares of land by 2030. They note that several of these countries have committed to restoring an area that “exceeds the total area that is available for restoration”. They note how these results “reinforce the need for better country-level forest accounting”.

Yet there is a paradox lurking within these claims. The authors state that their estimates are not “future projections of potential forest extent”. So what are they?

Credit: Pixabay.

In brief, their assessment represents an estimate of potential tree cover assuming current environmental conditions and no influence or modifications arising from the trees themselves. But large-scale changes in tree cover would modify these conditions.

Trees and forests influence the availability of water and water influences the degree to which a landscape can support trees. While current tree cover reflects current conditions, any assessment of the prospects for large-scale changes in tree cover must account for how these changes will influence those conditions. Potential tree cover should reflect the conditions that would exist with that tree cover.

This may seem esoteric, which may explain why it was not raised in the extensive media coverage, but these details matter. They matter a lot.

Access to adequate fresh water is a key development challenge and is central to the United Nations Sustainable Development Goals. Around half a billion people suffer insufficient fresh water year-round while many more face seasonal scarcity. Such shortages cause hardship and are widely believed to play an increasing role in the complex of issues that increase the likelihood of conflict and migration. With relatively fixed fresh water resources and a growing population, the global fresh water resources per person are declining.

As we highlight in our comment, trees influence the availability of water both locally and regionally. Neglecting these influences undermines the value of the estimates and renders them near meaningless. This affects both the technical aspects of the estimates—the variables used to predict tree cover would change, and more importantly, the wider implications for people and life on the planet.

Tree cover influences water availability through a range of processes and mechanisms. Only some of these are well understood. But we know enough to know there will be impacts.

Impacts can be negative. Where trees use a lot of water this can accentuate local water scarcity. There are many examples where dense plantations have caused a decline in local stream flows and depleted groundwater when compared to open lands. This is crucial, but far from being the whole story.

Impacts can also be positive. This has been shown by studies in Burkina Faso where landscapes with some tree cover captured several times more water than otherwise comparable tree-free landscapes. In this case, the costs of increased water use are more than compensated by the increased soil infiltration and moisture storage. Trees and forest also provide water vapour and condensation nuclei (the particles that promote cloud formation) that can contribute to rainfall elsewhere. Thus, it is clear that tree cover supports rainfall downwind—and many people depend on such rainfall.

The power of such recycling suggests that if tree cover in drylands can be expanded in the right manner, it can generate increased rainfall, thus opening the opportunity to increase regional moisture and land able to support trees and forests. In addition, an exciting new theory, the Biotic Pump, suggests that forest cover plays a fundamental role in generating the winds that carry moisture into continents. This theory conforms with observations in the Amazon region concerning how rainfall relates to changes in air pressure, and how forest derived moisture controls the monsoon. In effect, we could develop a system that waters itself and thereby regreens the world’s deserts. We could, for example, imagine returning a much wetter climate to the Sahel of Africa or to Western Australia.

So how can we avoid the negatives and promote the positives of increased tree cover? We don’t yet know the optimal way. Likely we may not even agree what “optimal” implies. My personal view is that, if we emphasise the protection, expansion and restoration of natural vegetation that can regenerate and maintain itself (rather than industrial plantations), the positives are generally more likely. The rationale is that nature has evolved effective systems for distributing and maintaining water. These are the systems that kept the world green and productive long before people got involved. (Such restoration is what Bastin and colleagues are suggesting, though much of the media attention discussed “tree planting” more generally as if this is equivalent—it isn’t).

Credit: Pixabay.

But there are plenty of good reasons to promote tree cover even in productive landscapes and to identify how we might green large areas of our planet. The potential to bring more water into currently arid regions seems a real opportunity. We can also look for ways to ensure that plantations, where justified, are developed without wider environmental costs. Natural systems can provide both template and inspiration.

But it remains true that negative impacts can still result, especially as what may be optimal at a continental scale may not be ideal at more restricted scales, and patches of regenerating forest may deplete local water even if it boosts rain downwind. When tree cover does boost groundwater in arid regions there can be additional challenges if this raises salt within the soil profile.

Looking beyond water there is no shortage of additional concerns. For example, we need to ensure people benefit, we need to protect key grasslands and we need to ask why the tree cover was depleted in the first place.

There are many good reasons to protect and restore tree cover and other natural vegetation—wherever and to the degree that that is possible. There are also plenty of good reasons to promote agroforestry and to encourage even scattered tree cover where that is possible within productive landscapes.

Our point is that there will be wider impacts than those on atmospheric carbon alone. Many impacts are likely to be positive, increasing greenness, stabilising rainfall, and reducing biodiversity losses. But widespread tree planting can also cause harm, displacing people and biodiversity and contributing to water scarcity.

The power of trees is often underestimated—it is a transformative power with capacity to achieve great good and great harm. Please use it wisely.

This article was originally published by the Center for International Forestry Research (CIFOR)’s Forest News website and was re-published here under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0).

Forest fires put the Amazon close to its tipping point

In just two years, the Amazon rainforest could reach a tipping point in which it would stop producing enough rain to sustain itself and start slowly converting into a savannah, releasing billions of tons of carbon emissions to the atmosphere, a Brazilian economist warned.

Credit Wikipedia Commons

Usually described as the “lungs of the planet,” the Amazon has been severely affected by a set of forest fires during its latest dry season. The policies of President Jair Bolsonaro were linked to the unusual number of fires, as farmers clear out land for their crops.

Monica de Bolle, a senior fellow at the Peterson Institute for International Economics in Washington DC, issued the tipping point warning in a policy brief, which created controversy. Some believe the tipping point is still 15 to 20 years away, while others agree with de Bolle.

“It’s a stock, so like any stock you run it down, run it down – then suddenly you don’t have any more of it,” de Bolle, whose brief also recommended solutions to the current crisis, told The Guardian.

Brazil’s space research institute, INPE, reported that deforestation in August was 222% higher than in August 2018. Maintaining the current rate of increase INPE reported between January and August this year would bring the Amazon close to the estimated tipping point as soon as 2021, de Bolle said.

“If Bolsonaro is serious about developing the Amazon without paying any attention to sustainability or maintaining the forest’s standing, these rates would happen within his mandate,” she added.

One of Brazil’s leading climate scientists and a senior researcher at the University of São Paulo’s, Carlos Nobre questioned her calculation that estimated deforestation would quadruple from an estimate of nearly 18,000 km2 this year to nearly 70,000 km2 by 2021.

“It seems very improbable to me – the projected deforestation increase is more an economic calculation than ecological,” he said. However, he added: “We are seeing an increase in deforestation, I am not questioning this.”

Last year, Nobre argued in an article written with celebrated American conservation biologist Thomas Lovejoy that the Amazon tipping point could happen in eastern, southern and central Amazonia when 20% to 25% of the rainforest has been felled – not expected for 20 to 25 years. He has since brought forward his prediction by about five years.

“The Amazon is already 17% deforested, so when you calculate at the current rate of deforestation, this 20% to 25% is reached in 15 to 20 years,” he said. “I hope she is wrong. If she is right, it is the end of the world.”

Lovejoy, a professor at George Mason University in Fairfax, Virginia, said that de Bolle’s projection could come true because global heating, soaring deforestation and an increase in Amazon fires have created a “negative synergy” that is accelerating its destruction – citing droughts in recent years as a warning sign.

“We are seeing the first flickering of that tipping,” he told The Guardian. “It’s sort of like a seal trying to balance a rubber ball on its nose … the only sensible thing to do is to do some reforestation and build back that margin of safety.”

Among other commitments under the Paris climate deal, Brazil agreed to reforest 12m hectares and end illegal deforestation by 2030. Mongabay reported last month that Brazil looks increasingly unlikely to meet its Paris targets. Deforestation began rising under Rousseff in 2013 after nine years of decline and has accelerated under Bolsonaro.

What is happening in the Amazon? Key questions and answers

Wildfires are raging throughout the Amazon forest, making headlines worldwide and pushing the world’s largest forest closer and closer to an ecological “tipping point” at which the forest could irretrievably degrade into drylands.

But is be a complex story, and online discussion has been riddled with misinformation, misleading photos, and outright errors. To fill in the gaps and bust some common myths, we answered some of the key questions regarding the forest fires.

Credit: Flickr

What is happening in the Amazon now?

Fires are burning in Brazil and Bolivia, many of them in the world’s llargest rainforest, the Amazon, sending clouds of smoke across the region and pumping alarming quantities of carbon into the world’s atmosphere.

So far this year, almost 73,000 fires have been detected, which marks an 83% increase from 2018 and the highest number on record since 2013. In several states across Brazil, the amount of ash and other particulates in August has hit the highest level since 2010.

Is all the Amazon forest under fire?

No, images of an entire forest ablaze are exaggerated. There has been misinformation spread in social media, using images of previous years’ burning seasons. There are larger fires in Colombia and eastern Brazil than in the Amazon. While there are fires in protected areas, most of them are in already deforested ones.

What’s causing the forest fires?

The fires are mostly caused by farmers clearing forest for cropland or burning stubble after the harvest season. Illegal land-grabbers are also responsible, destroying trees to raise the value of the property they seize. They are manmade and, in many cases, deliberate. Unlike the recent forest fires in Siberia and Alaska, the Amazon fires are very unlikely to have been caused by lightning. Many of the fires can be linked to deforestation for soy crops, which is used to feed cattle and pigs to support the ever-growing demand for meat.

Why is the Amazon so important?

The Amazon rainforest is known as the “planet’s lungs,” because it provides a large part of the Earth’s atmospheric oxygen. The rainforest also removes vast amounts of carbon from the atmosphere and stores it, which can help slow down global warming. Additionally, the rainforest is home to more than 3 million species of plants and animals, representing the most biodiversity in the world. Millions of indigenous people also live in the Amazon rainforest.

If the Amazon is the planet’s lungs, should we worry about oxygen?

No. The crops being planted in the cleared forest areas would also produce oxygen, quite likely at higher levels. So, although the burning of the rainforest is worrying for many reasons, there is no need to worry about an oxygen shortage.

If it’s not oxygen, what are the consequences of the forest fires?

It’s mostly CO2 and ecosystem destruction. Mostly illegal, the forest fires are degrading the world’s biggest terrestrial carbon sink and most important home for biodiversity. They also contribute to a rise in deforestation in the region. Scientists argue the Amazon is approaching a tipping point, after which it will irreversibly degrade into a dry savannah. This is happening at a time when the world needs billions of more trees to absorb carbon and stabilize the climate.

How much forest is being lost?

Deforestation spiked in July to a level not seen in more than a decade. Trees were being cleared at the rate of five football pitches every minute, according to Brazil’s space agency. Over the single month, 2,254 sq km (870 sq miles) were lost, a rise of 278% in the same month last year. This year could be the first for 10 years in which 10,000 sq km of Amazon are lost.

Brazil had been able to slow down deforestation by 80% between 2005 and 2014. This was done with strict monitoring, better policing and stiffer penalties. But that system has been eroded in recent years and many fear a return to the alarming levels of forest loss that occurred two decades ago.

Is the Brazilian national government the one to blame?

Yes, at least in part. Brazilian president Jair Bolsonaro weakened the country’s environment agency, attacking conservation NGOs and promoting the opening of the Amazon to mining, farming, and logging. He also dismissed satellite data on deforestation and fired the head of the space agency. Alongside Bolsonaro, the agricultural lobby is powerful in Brazil and it has steadily eroded the protection system that was so successful from 2005-2014.

How is Brazil being helped by the rest of the world?

The United Nations Secretary-General Antonio Guterres, world leaders, and celebrities have expressed their concern about the situation in Brazil. The issue was one of the main topics in the G7 leaders’ summit in France, with countries committing to release US$22 million to help stop the fires. Brazil’s neighboring countries Argentina and Uruguay have also offered help to Brazil.

If the fires are stopped, could the Amazon be fully restored?

Yes. The areas in the Amazon that are currently being burned have a high restoration potential because the Amazonian ecosystem is incredibly resilient, and also because so many areas that are degraded are in close proximity to the intact forest. Nevertheless, it will take time and effective efforts to leave the forest alone. Naturally regenerating tropical forests take about 20 years for forest cover to come back.

What can individuals do?

No matter how far you live from the Amazon rainforest, you are probably benefiting from all that it gives to the Earth.

There are a few things you can do to show your support, such as donating to donating highly-rated charities that are fighting to protect the Amazon, such as Amazon Watch. Also, you can reduce your beef and dairy consumption, activities that can lead to deforestation — this is probably the most important and significant thing you can do. Lastly, pushing your politicians to take action on these issues, both locally and globally. At the very least, being aware (and spreading awareness) can also amount to something.

Change diets to save the tropical forests, researchers say

If the consumption of meat and dairy doesn’t fall, at least one-quarter of the world’s tropical lands could disappear by the end of the century, according to new research which studied the impacts of consumption trends on biodiverse regions across the globe.

Credit: Flickr

Researchers at the University of Edinburgh and Karlsruhe Institute of Technology estimate that large swathes of natural land could potentially vanish if the demand for animal products continues to grow. The study was published in the Global Environmental Change journal.

About 9% of natural land — 95% of which is in the tropics — could go within 80 years unless global dietary habits change, the scientists said, looking at consumption and agriculture patterns.

“Reducing meat and dairy consumption will have positive effects on greenhouse gas emissions and human health. It will also help biodiversity, which must be conserved to ensure the world’s growing population is fed. Changing our diets will lead to a more sustainable future and complement food security goals while addressing global food inequalities,” lead author Dr Roslyn Henry said.

As incomes increase across the globe, consumption has shifted from staples such as starchy roots and pulses to meat, milk, and refined sugars. Meat and dairy products are associated with higher land and water use and higher greenhouse gas emissions than any other foods.

By replacing animal products with plant-based alternatives, the researchers predict that the global demand for agricultural land could be reduced by 11%. Industrial feed systems also reduce agricultural expansion but may increase environmental degradation due to agricultural pollutants such as fertilizer, they said.

The study comes only a week after a report on land use by the Intergovernmental Panel on Climate Change (IPCC), which identified reducing meat consumption and changing diets to plant-based as an important focus for climate change mitigation.

Fossil Friday: Oldest fossil forest discovered in Asia

The so-called “age of the fishes”, from 419 million to 359 million ago, is the period in which ancient fish took over the sea. But, despite initial beliefs, they weren’t the single species to quickly evolve in that period, according to a new study.

Reconstructions of lycopsid trees (Guangdedendron micrum). Left: juvenile plant. Right: adult plant. Image credits: Zhenzhen Deng.

In the journal Current Biology, researchers described the largest example of a forest from back then, made up of 250,000 square meters of fossilized lycopsid trees, which was recently discovered near Xinhang in China’s Anhui province. The fossil forest, which is larger than Grand Central Station, is the earliest example of a forest in Asia.

The fossilized trees found in the forest are similar to palm trees, with branchless trunks and leafy crowns, and grew in a coastal environment prone to flooding. These trees were normally less than 3.2 meters tall, but the tallest was estimated at 7.7 meters, taller than the average giraffe.

Giant lycopsids trees would later define the Carboniferous period, which followed the “age of fishes”, and become much of the coal that is mined today. The Xinhang forest depicts the early root systems that made their height possible. Two other Devonian fossil forests have been found: one in the United States, and one in Norway.

“The large density as well as the small size of the trees could make Xinhang forest very similar to a sugarcane field, although the plants in Xinhang forest are distributed in patches,” sid Deming Wang, a professor in the School of Earth and Space Sciences at Peking University, co-first author on the paper.

The fossilized trees are visible in the walls of the Jianchuan and Yongchuan clay quarries, below and above a four-meter thick sandstone bed. Some fossils included pinecone-like structures with megaspores, and the diameters of fossilized trunks were used to estimate the trees’ heights. The authors remarked that it was difficult to mark and count all the trees without missing anything.

“Jianchuan quarry has been mined for several years and there were always some excavators working at the section. The excavations in quarries benefit our finding and research. When the excavators stop or left, we come close to the highwalls and look for exposed erect lycopsid trunks,” said Wang, who found the first collection of fossil trunks in the mine in 2016.

Forest Fire.

Wildfires lock away a ‘considerable amount of carbon’ for centuries, or even millennia

Wildfires could, surprisingly, act as net carbon traps.

Forest Fire.

Image via Pixabay.

The charcoal produced by wildfires can keep carbon out of the atmosphere for hundreds of years, new research from the Swansea University suggests.. The findings will help us better model changes in climate, especially as warmer mean temperatures in the arctic are leading to an unprecedented outbreak of wildfires and CO2 release in the area.

Burned and buried

Wildfires generate a large quantity of CO2. Generally, however, the gas is re-captured as vegetation grows back, so wildfires are considered to be more or less carbon-neutral once this regrowth process is complete.

“However, in a fire some of the vegetation is not consumed by burning, but instead transformed to charcoal,” explains Dr. Matthew Jones, lead author of the paper who recently joined the University of East Anglia’s (UEA) School of Environmental Sciences from Swansea University.

“This carbon-rich material can be stored in soils and oceans over very long time periods. We have combined field studies, satellite data, and modelling to better quantify the amount of carbon that is placed into storage by fires at the global scale.”

On average, wildfires burn an area roughly equivalent to the size of India every year and emit more carbon dioxide than global road, rail, shipping, and air transport combined, the team explains. Given the increased occurrence of wildfires in the past few years, a trend which will likely pick up in our warmer, drier future, the team set out to quantify how much carbon this charcoal can sequester from the air. All in all, the team says that this charcoal could lock away a considerable amount of carbon for years to come.

Vegetation growing back in burned areas draws on atmospheric CO2 to grow (through photosynthesis). This stage of the fire-recovery cycle takes just a bit under a year for grasslands, up to several decades in fire-adapted forests. In extreme cases, such as we’re seeing today in the arctic or tropical peatlands, full recovery may not occur for centuries. The timing of this recovery is important because the carbon that is emitted during the fire stays in the atmosphere and contributes to climate heating. Plants recapture it as they mature.

Overall, grassland fires don’t have that great of an impact; deforestation fires, however, are a particularly important contributor to climate change. Forests produce a lot of emissions as they burn, and take a long time to regrow, resulting in a long-term injection of carbon to the atmosphere.

The team explains that the charcoal resulting from forest fires — known as pyrogenic carbon — plays a larger part in mitigating these emissions than we’ve assumed. While they do emit CO2 to the atmosphere, landscape fires also transfer a significant fraction of the carbon locked in the affected vegetation to charcoal and other charred materials. The researchers say the quantity of this pyrogenic carbon is significant enough that it needs to be considered in global fire emission models.

As this material gets covered in soil, it locks carbon in place. Given time for flora to recover, the process actually leads to a net loss of carbon in the atmosphere — which is what we want.

“Our results show that, globally, the production of pyrogenic carbon is equivalent to 12 % of CO2 emissions from fires and can be considered a significant buffer for landscape fire emissions,” Dr. Jones said.

“Climate warming is expected to increase the prevalence of wildfires in many regions, particularly in forests. This may lead to an overall increase in atmospheric CO2 emissions from wildfires, but also an increase in pyrogenic carbon storage. If vegetation is allowed to recover naturally then the emitted CO2 will be recaptured by regrowth in future decades, leaving behind an additional stock of pyrogenic carbon in soils, lakes and oceans.”

The pyrogenic carbon will eventually find its way back into the atmosphere as the charcoal degrades, but it takes centuries or even millennia to do so. In the meantime, all the carbon it contains doesn’t influence the climate. It isn’t enough to offset man-made emissions, but every bit helps.

“This brings some good news, although rising CO2 emissions caused by human activity, including deforestation and some peatland fires, continue to pose a serious threat to global climate,” Dr. Jones adds.

The findings showcase the importance of factoring in pyrogenic carbon production in future climate models and in the global carbon cycle. The team plans to continue researching how the warmer more drought-prone climate of the future is going to impact the global extent of wildfires and to more accurately estimate the proportion of CO2 emissions recaptured by future vegetation regrowth.

The paper “Global fire emissions buffered by the production of pyrogenic carbon” has been published in the journal Nature Geoscience.

Iceland.

Vikings cut down all of Iceland’s forests — the country is planting them anew

Iceland is trying to heal its Viking-induced wounds — by reforesting.

Iceland.

The Icelandic countryside; soon to also feature trees.
Image credits Monica Volpin.

Iceland is currently considered the least forested country in all of Europe, but this wasn’t always the case. At the end of the ninth century, as Vikings from Norway first set foot on the island, a quarter of it was covered in lush birch forests. The Vikings, however, cut down almost 97% of these trees to obtain building materials and make room for crops and pastures.

Today, less than 0.5% of Iceland is forested, according to the United Nations Food and Agriculture Organization (FAO). Locals joke that, because the forests here are so rare and so young, all you need to do to find your way around them is to stand up. Partly as a way to address climate change, partly as a way to prevent environmental degradation, and partly out of a desire to simply see the island blanketed in forests again, Iceland is now trying to reforest itself, according to AFP.

Forestland

Iceland, sadly, isn’t a very welcoming place for trees. Its harsh climate and active volcanoes (which periodically cover the soil in layers of lava and ash) make it hard for trees to take root and grow here. However, the lack of trees is particularly bad news for Iceland; without their roots to support it, the soil here erodes quickly and can’t store water very well. All in all, this means Iceland is experiencing extensive desertification despite its northern latitude

The country has made reforesting one of the priorities in its 2018 climate action plan, citing carbon uptake by trees as an important avenue for Iceland to mitigate climate change.

Reforestation efforts that began in the 1950s and the 1990s have helped replant some of these forests, but there is still much to do. For example, the Icelandic Forest Service (IFS) has been tasked to turn the alien landscape of Hafnarsandur, an 8,000-hectare area of basalt and black sand in Iceland’s southwest, into a forest. This is meant both as a way to increase forest cover in Iceland as well as a method to protect the nearby town of Thorlakshofn from recurring dust storms. The IFS is now busy planting lodgepole pines and Sitka spruces in the area

“This is one of the worst examples of soil erosion in Iceland on low land,” Hreinn Oskarsson, the IFS head of strategy, explains about Hafnarsandur. “We are planning an afforestation project to stabilise the soil,” Oskarsson added.

Iceland’s only domestic tree is the birch. However, the IFS focuses its afforestation efforts on other species. The problem with the native birch, according to Adalsteinn Sigurgeirsson, deputy director of the IFS, is that it isn’t a “productive species”. For objectives such as fast carbon sequestrations or timber production, it just doesn’t cut it — so the IFS is branching out from monocultures using this single native species.

Iceland is now peppered with nursery gardens that feed the country’s afforestation efforts with young poplars and pines. These are grown indoors for three months and are afterward moved outside.

“Originally, they come from Alaska but now we have 30, 40, 50 year-old trees giving us seeds, so we collect that and we use that for forest seedlings production,” Holmfridur Geirsdottir, a 56-year-old horticulturist and greenhouse owner, told AFP.

Once in the wild, these trees have an uphill battle to fight. Iceland’s soils are very poor in nitrogen, an essential element for plants, limiting the average growth rate of trees here to around one-tenth the rate observed in the Amazon rainforests. However, climate change might offer an unexpected boost in these trees’ growth rates.

“What has mainly been hampering growth of forest here has been the low temperatures and the coolness of the summers, but we are realising changes in that because of climate change,” said forest service deputy director Sigurgeirsson.

“Warming appears to be elevating tree growth in Iceland, and therefore also the carbon sequestration rate,” he continued.

Since 2015, Iceland has planted around 1,000 hectares of forest (between three and four million trees).

Credit: Pixabay.

The Earth has room for a trillion more trees — which might be our best bet against climate change

Credit: Pixabay.

Credit: Pixabay.

In order to stave off potentially catastrophic climate change, not only does the world have to urgently stop emitting carbon dioxide, but it also has to find a way to absorb a good portion of it from the atmosphere. Luckily nature has evolved just the right technology that can achieve this goal: good old trees. According to a new study, although humans have massively expanded their reach across the planet, there is still enough room to accommodate 0.9 billion hectares of forest.

Nature’s CO2 removal tool

The study, which didn’t include areas currently occupied by agriculture, cities, and existing forests, estimates that there’s enough room for 1-1.5 trillion trees. Currently, there are an estimated 3 trillion trees sucking CO2 from the atmosphere all around the globe. Forests in the United States absorb and store about 750 million metric tons of carbon dioxide each year, an amount equivalent to 10% of the country’s CO2 emissions.

If allowed to mature, these extra forests would store 205 gigatons of carbon, roughly equal to two-thirds of all the carbon humans have added to the atmosphere since the Industrial Age. This would bring down heat-trapping greenhouse gases to levels not seen for nearly 100 years, according to the authors from the Swiss Federal Institute of Technology, Zurich (ETH Zurich).

“We all knew restoring forests could play a part in tackling climate change, but we had no scientific understanding of what impact this could make,” said study senior author Thomas Crowther, an assistant professor of ecology at ETH Zurich.

During photosynthesis, trees use carbon dioxide (CO2) from the atmosphere with water from rain or irrigation and nutrients from the soil to form carbohydrates, which make up the tree’s biomass. The amount of carbon stored by a tree will depend on its size, which in turn is influenced by the species and local environmental conditions.

Tree biomass percentages (approximate). Credit: Ecometrica.

Previously, the Intergovernmental Panel on Climate Change’s (IPCC) issued a report advising that planting 1 billion hectares of forest is necessary in order to prevent global temperatures from rising over 1.5°C by 2050. This figure inspired Crowther and colleagues to see whether there even was enough room left on the planet’s surface for this many trees.

The researchers analyzed more than 80,000 satellite images, from which they subtracted existing forests, crop fields, and urban areas. Russia has the most space available to accommodate new forests at 583,000 square miles (1.5 million square km), followed by the United States with 397,700 square miles (1 million square km), Canada with 302,700 square miles (784,000 square km), Australia with 223,900 square miles (578,900 square km), Brazil with 191,900 square miles (497,000 square km), and China with 155,200 square miles (402,000 square km).

The reasons why trees are such an appealing solution to tackling climate change is that they’re cheap and do not necessarily require government permission or oversight — anyone can do it, basically. Indeed, various NGOs have so far planted millions of trees. Meanwhile, some government-led projects have also proven highly successful. China has spent more than $100 billion on trees in the last decade alone. Nearly 22 percent of the country is now covered in forest, compared to 19 percent in 2000, according to the Ministry of Environmental Protection.

Meanwhile, the Bonn Challenge, signed and backed by 48 nations, pledged to restore 350 million hectares of forest by 2030. The new study, which was published in the journal Sciencenow offers these countries evidence that they could be even more ambitious. There is, after all, plenty of room to spare!

Tree.

The birth of forests helped drive two massive, ancient extinctions

The first forests on Earth may have caused massive extinctions of shallow marine life, a new study finds.

Tree.

Image via Pixabay.

An international team of researchers led by members from The University of Alabama finds that the oldest forests in today’s southeastern North America popped up millions of years earlier than previously believed. At the time, North America was part of a minor supercontinent, which suggests that forests spread across all big land masses today at that time.

They also found evidence that this event happened around the same time as a massive extinction event of shallow marine life about 370 million years ago.

Wooden weapons

“This story is, I think, ironic because today trees are the symbol of eco-friendly green life,” said Dr. Takehito Ikejiri, a paleontologist with UA’s Alabama Museum of Natural History and one of the study’s co-authors.

“But, when they first appeared in Earth’s history, they seemed to be harmful and caused big trouble for other life.”

The work offer insight into the global extinctions 370 to 360 million years ago. It also lends some weight to the theory that these events were caused by a lack of oxygen in the ancient waters, as early forests dumped massive quantities of nutrient-rich soils into the oceans, leading to eutrophication.

We call this period in Earth’s history 393 to 382 million years ago the Devonian era. At the time, Earth’s surface was dominated by supercontinents. Present-day North America was meshed with Greenland and much of Europe into a minor supercontinent known as Euramerica. Here, to the best of our knowledge, the first trees (defined as plants with wood tissues) appeared near today’s New York 393 to 382 million years ago and spread across the continent.

Not long after this (in geological time), almost all of the day’s shallow-water species (such as trilobites, corals, and plankton) experienced two massive die-offs. The reason why was unknown, but our running theories included global cooling, extensive volcanism, asteroid impacts, and marine anoxia — the rapid drop of oxygen levels in the seas.

The team believed that this anoxia could be caused by the newly-spawned forests eroding soils with their deep roots, which would then wash into the sea and create an overabundance of nutrients.

They tested their theory by analyzing an outcrop of black shale from the period from northeastern Alabama. This outcrop lay on the southernmost margin of the Appalachian Basin. Geochemical and microscopic data show that forests first appeared in the region 370 million years ago, then spreading to the southern Euramerica landmass. Man Lu, a UA doctoral student in geological sciences and lead author on the paper, analyzed the samples from these shales and reports finding tiny wood fragments in this Devonian formation where no macro-fossils were reported previously.

Further geochemical data also suggest that these forests became an important carbon source to these black shales during the Late Devonian, providing a rough timeline of how fast these forests evolved during the era.

“Our data show the global forestation occurred in a relatively short time,” Ikejiri said. “Trees spread rapidly in very large areas across the Euramerica continent and likely caused a series of drastic environmental changes.”

It’s not a smoking gun, but the evidence does seem to point to a link between the extinctions and these early forests. Dr. YueHan Lu, UA associate professor of geological sciences and corresponding author of the paper, believes the timing of this rapid forestation is interesting considering it occurs near the time of the marine life extinctions.

The paper “Geochemical Evidence of First Forestation in the Southernmost Euramerica from Upper Devonian (Famennian) Black Shales” has been published in the journal Scientific Reports.

Forest.

Old forests are better at dealing with climate change, study finds

Older forests are less vulnerable to climate change than their younger counterparts — particularly in regards to carbon storage, timber production, and biodiversity levels.

Forest.

Image via Pixabay.

The study, led by members from the University of Vermont, looked at how climate change is expected in alter forests across Canada and the United States. All in all, they report, forests are less sensitive to higher temperatures and precipitation levels as they age, being better able to retain biodiversity, timber production, and the ability to store carbon.

The old that is strong does not wither

“This study shows that older forests in the Upper Midwest to New England are uniquely resilient to climate,” says Dominik Thom, lead author and postdoctoral researcher in UVM’s Rubenstein School of Environment and Natural Resources and Gund Institute for Environment.

“Our finding that essential services are better protected against climate change by older forests is a milestone in the debate on how to prepare our forests for the uncertain environmental conditions ahead.”

In short, the study found that age helps protect forests from the effects of climate change.

The team worked with a huge body of data recorded from over 18,500 forest plots from Minnesota to Maine, and Manitoba to Nova Scotia. One of their main focuses was to identify which areas should take priority in regards to forest climate adaptation efforts. Younger forests east and southeast of the Great Lakes were less resilient to climate change, showing declines in carbon storage, timber, and biodiversity compared to older ones.

“Our study identifies opportunities to make forest management more adaptive to global change,” says William Keeton, forestry professor in UVM’s Rubenstein School and Gund Institute.

“This could include enhancing older forest conditions on landscapes within reserves, for example, and using extended cutting cycles and restorative forestry practices in working forests.”

The authors found that forests’ climate resiliency increased with age; older forests are more structurally-complex, they explain, with trees growing at multiple heights and larger canopy gaps, which free up growing space and increase light availability for a mix of species. Scientists usually count forests as ‘old’ over the age of around 150 years.

“This research presents new and entirely novel findings that are sure to push the needle in our understanding of forest dynamics,” says Keeton.

“The types of ecosystem services and biodiversity provided on forested landscapes today are likely to change dramatically into the future, both as forests age and our climate changes — a message relevant to anyone interested in forests.”

The paper “The climate sensitivity of carbon, timber, and species richness covaries with forest age in boreal–temperate North America” has been published in the journal Global Change Biology.

Credit: Pixabay.

World’s biggest terrestrial carbon sinks are young forests

Credit: Pixabay.

Credit: Pixabay.

Trees have an important role to play in mitigating climate change thanks to their ability to absorb carbon from the atmosphere. During photosynthesis, this atmospheric carbon is used to generate new leaves, shoots, and roots.

You’d think that dense tropical forests, with their tall and lush canopies, are the most important terrestrial carbon sinks in the world — meaning they take in more carbon than they release. However, a landmark 2017 study found that tropical forests, from Congo to Indonesia, are actually net emitters of carbon. This release is through natural processes such as plant respiration, droughts, and wildfires, but also emissions from human activities like deforestation.

According to new research at the University of Birmingham, the largest terrestrial carbon sinks are actually young forests. This is rather counterintuitive but it makes sense once you hear the findings.

Young forests are defined as those comprised of trees younger than 140 years. These trees have typically reforested areas previously used for agriculture or cleared by fires. For instance, this includes forests in the USA’s eastern states, where settlers established farmlands but then abandoned them to move west in the 19th century. Other areas that have seen significant forest regrowth include boreal forests in Canada, Russia, and Europe, which have seen a lot of forest fires. Meanwhile, China’s $100-billion large-scale reforestation program is also making an important contribution to the carbon sink.

Drawing on data sets of forest ages, the researchers calculated the carbon balance between 2001 and 2010. According to the findings, areas of forest regrowth absorbed large amounts of carbon due to the fertilization of tree growth but also as a result of their young age, which accounted for 25% of carbon uptake. Interestingly, age-driven carbon uptake was most concentrated in the middle and high latitude, and not in the tropics.

“It’s important to get a clear sense of where and why this carbon uptake is happening, because this helps us to make targeted and informed decisions about forest management,” Dr Tom Pugh, of the Birmingham Institute of Forest Research, said in a statement.

One important takeaway is that this carbon uptake effect will be diminished as these forests age, meaning the carbon sink will disappear unless further reforestation occurs.

“The amount of CO2 that can be taken up by forests is a finite amount: ultimately reforestation programmes will only be effective if we simultaneously work to reduce our emissions,” explains Dr Pugh.