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Forest-based agroforestry

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Tree plantings have become a go-to climate solution for governments and conservation groups due to the carbon-storing potential of trees.  While planting new trees on open farmland would help capture additional carbon, a new study led by scientists from Yale School of the Environment suggests a powerful alternative: forest-based agroforestry.

Instead of clearing land for crops or starting fresh with new trees, forest-based agroforestry (or FAF) brings agriculture into existing forests.  Think fruits, nuts, and medicinal plants, for example, grown sustainably under a forest canopy – all while maintaining biodiversity and storing carbon.

According to the researchers, human activity in forests is often seen as harmful. But for thousands of years, Indigenous and local communities have managed forests in ways that actually strengthen them.

The study, which was recently published in the journal Nature Climate Change, found that FAF not only rivals tree planting in terms of climate benefits, but it can also generate income and support cultural practices tied to the land.

Despite these benefits, forest-based agroforestry receives far less funding and policy support due to two key misconceptions. It’s frequently confused with industrial systems focused on global commodity crops, and results from tropical regions are wrongly assumed to apply to temperate and boreal forests.

The researchers recommend including FAF in agroforestry policies, clearly distinguishing it from harmful industrial practices, and expanding research on FAF in temperate and boreal regions to guide better land management.

Forest-based agroforestry appears to be a natural climate solution hiding in plain sight.

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Agriculture in Forests Can Provide Climate and Economic Dividends

Photo, posted May 8, 2023, courtesy of Preston Keres / USDA Forest Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Planting trees to cool the planet

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Planting lots of trees is one of many strategies being pursued to combat climate change. Forests absorb carbon dioxide, provide shade, and help regulate temperatures. They also support biodiversity and improve air and water quality.

According to a new study by researchers from the University of California – Riverside, restoring forests to their pre-industrial extent could reduce global average temperatures by 0.34 degrees Celsius. That’s equivalent to about 25% of the warming the Earth has already experienced.

The study models restoring 4.6 million square miles of forest.  While previous studies have focused on the role trees play in removing carbon, this research adds that trees also alter atmospheric chemistry in ways that boost their cooling impact.

Trees release natural chemicals called BVOCs – biogenic volatile organic compounds – which interact in the atmosphere to form particles that reflect sunlight and promote cloud formation. These effects enhance the cooling impact of forests, especially in climate models that take these chemical reactions into account.

But not all reforestation is created equal. The benefits of reforestation vary by region, with tropical forests offering stronger cooling and fewer drawbacks.  Importantly, the researchers emphasize that meaningful climate benefits don’t require restoring every lost forest. Small, localized efforts can still shift regional climates.

While forest restoration can meaningfully aid climate efforts, the researchers stress that it must complement – not replace – fossil fuel reductions.

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Does planting trees really help cool the planet?

Photo, posted May 20, 2005, courtesy of Ben Britten via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Record forest loss

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The world lost a record amount of forests last year.  The biggest factor for the unprecedented losses were wildfires that raged around the world.

According to the annual update by the University of Maryland and the World Resources Institute, pristine rainforests alone lost 17 million acres, which was nearly twice as much as in the previous year.  Overall, the world lost the equivalent of 18 soccer fields of forested land every minute last year.

Over time, agriculture has been the primary cause of forest losses, but last year, for the first time since record-keeping began, fires were the leading cause, accounting for nearly half of all the destruction.

With respect to the climate, wildfires emitted over 4 billion tons of greenhouse gasses, which is more than four times the amount generated by air travel in 2023.

Land clearing for agriculture, cattle farming, and other purposes was by no means in decline last year.  In fact, it rose by 14%, which was the sharpest increase in almost a decade.  This trend could permanently transform critical natural areas, unleashing large amounts of carbon, intensifying climate change, and fueling even more extreme fires.

Forests are a major contributor to the natural storing of carbon dioxide.  Intact tropical forests are especially effective at storing carbon.

Brazil has the largest area of tropical forest and it accounted for 42% of all tropical primary forest loss in 2024.  Fires fueled by the worst drought on record caused two thirds of that loss, more than a sixfold increase over the previous year.

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Global Forest Loss Hit a Record Last Year as Fires Raged

Photo, posted September 12, 2024, courtesy of the USDA Forest Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The warmer, greener Arctic and greenhouse gas

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About 15% of the Northern Hemisphere is covered by permafrost.  Permafrost is soil and sediment that has remained frozen for long periods of time, in some cases as much as 700,000 years.  It contains large amounts of dead biomass that has accumulated over millennia and hasn’t fully decomposed.  Therefore, permafrost is an immense carbon sink.

The Arctic is warming four times faster than the rest of the planet and, as a result, thawing permafrost is becoming a carbon source.  As warming continues, ice is melting, and vegetation is spreading.    A new study, published in Nature Climate Change, looked at the state of the Arctic and boreal north from the period 1990 until 2020.  The study found that although half of the Arctic region has been growing greener, only 12% of those green areas are actually taking up more carbon.  For one thing, the growth of forests means that there is more fuel for wildfires which are increasingly common.

A study of lakes in West Greenland found that thousands of crystal blue lakes have turned brown during record heat spells.  Runoff from melting permafrost made the lakes opaque killing off plankton that absorb carbon dioxide.  Meanwhile, plankton that release carbon dioxide multiplied.  So, these lakes went from being carbon sinks to being carbon sources.

As the northern latitudes warm, ice and permafrost are melting, vegetation is spreading, and the region is becoming a source of heat-trapping gas after having been a place where carbon has been locked away for thousands of years.  According to the Nature Climate Change study, roughly 40% of the Arctic is now a source of carbon dioxide.

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Warmer, Greener Arctic Becoming a Source of Heat-Trapping Gas

Photo, posted October 14, 2024, courtesy of Christoph Strässler via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Threats to the Amazon Rainforest

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Brazil has made great progress in reducing deforestation in its Amazon Rainforest.  In 2023, the rate of deforestation in Brazil dropped by 50% over the previous year. This was the result of the efforts by conservation-minded President Luiz da Silva, who replaced Jair Bolsonaro, a big proponent of deforestation.  Da Silva’s government has cracked down on land clearing by farmers and ranchers.

In the first quarter of this year, deforestation decreased by 40% over the previous year’s quarter.   Deforestation levels are the lowest they’ve been in six years, although the amount of forest cleared in the period was still nearly 200 square miles.

Unfortunately, the Amazon Rainforest is facing another growing threat:  climate change.  Because of pervasive drought and increasing temperatures, the number of wildfires in the region have hit a 20-year high.

According to satellite data from the national space agency, from January through June, Brazil recorded 13,489 wildfires in the Amazon.  That is 61% more fires than during the same period last year.  And the wildfire season has yet to reach its peak, which usually is in August or September.

Many of these fires begin in pastures or recently cleared rainforest, but then spread into the surrounding rainforest areas.  Many are huge fires.  Hundreds of square miles of rainforest have been consumed by fire, comparable in size to the areas deforested by farmers and ranchers.

Going forward, worsening wildfires could reverse the gains being made by the government’s deforestation policies.  This could not only threaten forest protection, but also weaken public support for the government’s commitment to protecting the region.

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Brazil Is Seeing a Record Number of Wildfires This Year

Photo, posted January 26, 2018, courtesy of Chris Parker via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Biofuel refineries and toxic pollution

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There have been decades of government support for renewable, crop-based fuels – primarily corn ethanol.  In fact, it is a required component of gasoline sold in this country.  The biofuels industry has long claimed ethanol to be a clean, greener alternative to petroleum. 

There have been arguments all along that the environmental benefits of corn ethanol are dubious at best because of the energy required to produce the stuff.  There are also issues related to burning a food crop instead of feeding it to people and that the conversion of grasslands and forests to produce it releases massive amounts of carbon.

Recently, another serious concern has emerged.  A new review of industry data has found that the country’s biofuel refineries, mostly located in the Midwest, produce large amounts of toxic air pollutants, in some cases ever more than from their petroleum counterparts.

Emissions data from the country’s 275 ethanol, biodiesel, and renewable diesel plants revealed that they release carcinogenic formaldehyde as well as other potentially dangerous substances including acetaldehyde, hexane, and acrolein.  In 2022, biofuel refineries released 12.9 million pounds of hazardous air pollutants, compared to 14.9 million pounds emitted by oil refineries, and the biofuel plants actually emitted more of the four chemicals just mentioned than petroleum refineries did.

The broad use of crop ethanol is the result of intensive industry lobbying.  Ethanol plants are even exempt from some air pollution permitting requirements.  Perhaps the time has come to revisit its pervasive and mandated use.

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Biofuel Refineries Are Releasing Toxic Air Pollutants in Farm Communities Across the US

Photo, posted February 27, 2021, courtesy of Sue Thompson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Where not to plant trees

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Planting huge numbers of trees is often proposed as a way to reduce the severity of climate change.  Studies have looked at the potential for Earth‘s ecosystems to support large additional areas of forest and have found that it would be possible to have at least 25% more forested area than we do now.  This in turn could capture large amounts of carbon and substantially reduce the amount in the atmosphere.

A recent study by researchers at Clark University in Massachusetts and The Nature Conservancy mapped the climate impact of tree planting across the globe, identifying where it would be most and also least beneficial.  The study, published in Nature Communications, found that trees planted in arid, desert regions or in snowy places like the Arctic would, on balance, worsen warming rather than reduce it.

Trees take up carbon dioxide from the atmosphere, which helps to keep warming in check.  But trees with dark, green leaves also absorb heat from sunlight.   Snow and desert sand, on the other hand, are light-colored and reflect more sunlight back into space.  For this reason, trees planted in snowy areas or in the desert will absorb more sunlight than their surroundings.  This can negate the climate benefits of soaking up carbon dioxide.

Previous studies only looked at how much carbon dioxide would be removed by planting trees in order to determine how much warming would be prevented.  The new study finds that it matters where the trees are planted.

Fortunately, the new study also shows that tree planting projects that are currently underway or that are in the pipeline are largely concentrated in regions where they will indeed help slow global warming.

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This Map Shows Where Planting Trees Would Make Climate Change Worse

Photo, posted April 5, 2022, courtesy of UC Davis Arboretum and Public Garden via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Adirondack lakes becoming inhospitable for trout

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A combination of the warming climate and the phenomenon of lake browning are making the bottom of most lakes in New York’s Adirondack Mountains unlivable for cold water fish – such as trout, salmon, and whitefish – in the summer.

Lake browning occurs when dissolved organic matter from forests turns the water tea-brown.  Browning is the legacy of a century of acid rain and subsequently the fact that forest soils have suffered reduced capacity to absorb weak organic acids, leading to more dissolved plant matter flowing into lakes.  Climate change has increased the frequency of extreme precipitation events and the length of growing seasons, leading to more runoff of organic matter.

Browner water traps more of the sun’s heat at the top of the lake and blocks the sun’s rays from reaching deeper.  The result of the browning is lakes that are either too warm or too deoxygenated to support trout populations.

A study of 1,467 Adirondack lakes by Cornell University researchers found that only about 5% of them may continue to maintain water that is cold and oxygenated enough to support cold-water fish.

Deeper lakes fare much better because they have so much water that their oxygen is hard to deplete, but only 1% of all Adirondack lakes are deeper than 30 meters.  Another 4% are very clear because the influx of cold water outpaces the expansion of low-oxygen zones and limits the effects of browning.

The study urges the protection of as many lakes as possible from species invasions, nutrient and salt pollution, and other forms of environmental degradation. 

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Most Adirondack lakes will likely become unsuitable for trout

Photo, posted July 17, 2011, courtesy of Lida via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Cutting Deforestation | Earth Wise

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Deforestation is a major contributor to climate change because the destruction of tropical rainforests worldwide eliminates a crucial natural sink for carbon.  Between 2015 and 2020, roughly 39,000 square miles of forest were cut down, an area about 70% the size of the entire state of New York.  In many places, such as the Amazon and Congo Basins, deforestation continues to accelerate.  In Bolivia, deforestation rose 59% over the past five years; in Ghana, the rise was 71%.

A new report from the World Resources Institute revealed one bright spot in the deforestation story:  both Indonesia and Malaysia have cut deforestation by more than half in recent years.  The two countries have managed to keep rates of primary forest loss to near record-low levels.

Over the past five years, Indonesia saw a 64% decline and Malaysia a 57% decline in deforestation.  Indonesia is the second largest source of deforestation with only Brazil removing more trees.

Indonesia has a national goal of having its forests absorb more carbon than they release by 2030.  They have moved to curb logging and limit the clearing of land for palm oil plantations.  They have also ramped up efforts to suppress forest fires.

It is good that Indonesia and Malaysia and some other countries have shown progress in reducing forest loss.  However, too many other countries have seen continued activities and policies that are causing acceleration of deforestation in critical areas.  Protecting forests is an important part of the effort to mitigate the effects of climate change.  Preserving forests also is essential for protecting the people and the biodiversity that depend on them.

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Indonesia, Malaysia Have Cut Deforestation in Half in Last Half-Decade

Photo, posted March 22, 2021, courtesy EPJT Tours via of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Reducing Cattle-Driven Deforestation | Earth Wise

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The Amazon rainforest is the biggest rainforest in the world, larger than the next two biggest combined.  It covers more than three million square miles, roughly the size of the lower 48 states.  The Amazon functions as a critical sink for carbon in the atmosphere.

However, human activity has removed more than 10% of the vegetation from the Amazon rainforest since the 1960s.  Cattle ranching accounts for roughly 70% of Amazon deforestation – much of which is illegal.   

According to a study recently published in the journal Global Environmental Change, companies’ ‘zero-deforestation’ commitments could reduce cattle-driven deforestation in the Brazilian Amazon by 50%.   Better adoption and implementation of company supply chain policies for Brazilian beef and leather could significantly reduce carbon emissions. 

Between 2010 and 2018, some of the world’s largest slaughterhouses reduced cattle-driven deforestation by 15% through their commitment to zero-deforestation policies.  If these policies were fully implemented and adopted across all cattle companies operating in the Amazon, more than 9,200 square miles of forest could have been spared over the same time period, effectively halving the cattle-driven deforestation in Brazil.  

Zero-deforestation commitments currently cover 82% of beef exported from the Brazilian Amazon for trade internationally.  However, a large amount of beef production destined for Brazil’s domestic markets is not covered.

The researchers say a mix of interventions by both the private and public sector is needed to improve cattle-rearing practices and help reduce deforestation in countries like Brazil.

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Companies’ zero-deforestation commitments have potential to halve cattle-driven deforestation in Brazilian Amazon

Photo, posted January 17, 2011, courtesy of Kelly Sato via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Here Come The Lanternflies | Earth Wise

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The spotted lanternfly is an invasive pest from Asia that primarily feeds on tree of heaven, which is itself an invasive species that has become widespread.  The real problem is that the lanternfly can also feed on some 70 other plants such as grapevines, maples, fruit trees, and more.

The lanternfly was first discovered in the US in Pennsylvania in 2014 and has since spread to 14 states including New York, Massachusetts, Connecticut, and Rhode Island.  (It was first spotted in New York in Staten Island in 2020 and has continued to spread).

The insect poses a significant threat to New York’s agricultural and forest health. Both the adults and nymphs feed on the sap of plants which stresses them making them vulnerable to diseases and other insect attacks.  They also secrete a sticky substance that attracts molds and interferes with photosynthesis.

Lanternflies are not strong fliers.  They mostly spread through human activity by laying their eggs on vehicles, firewood, outdoor furniture, and other objects that people transport.

The bout of unusually warm weather that the Northeast experienced in early spring is likely to have jumpstarted the spotted lanternfly timeline and hatching could be bumped up to as early as May.

Agriculture officials are asking for people to look for spotted lanternfly egg masses and scrape them off with implements with a sharp edge.  Adult insects should be reported to local authorities and should be killed if at all possible.  There is lots of information online about how to recognize the egg masses and the insects.  Spotted lanternflies are not a direct threat to humans, but they have the potential to cause great harm to vineyards, orchards, and forests.

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Spotted Lanternfly

Photo, posted September 12, 2018, courtesy of the U.S. Department of Agriculture via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Caterpillars And Light Pollution | Earth Wise

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Most of us are familiar with air pollution, water pollution, soil pollution, and even noise pollution.  But it turns out that light can be a pollutant as well, and it’s a consequence of industrial civilization.  In fact, nighttime light pollution now covers approximately 23% of the globe and over 80% of inhabited regions. 

Light pollution affects more than just our view of the stars.  For example, light pollution can alter our circadian rhythm, disrupting our sleep cycle.  In nature, light pollution can kill baby turtles by causing them to head inland instead of into the ocean, can cause birds to migrate during the wrong season, and can deter nighttime pollinators like bats.  And those are just a few of the examples.    

According to new research from scientists at Cornell University, moderate levels of artificial light at night – like a porch light – attract caterpillar predators and reduce the chance that caterpillars grow up to become moths. 

In the study, which was recently published in the journal Proceedings of the Royal Society B: Biological Sciences, the researchers placed 552 lifelike caterpillar replicas made of soft clay in a forest to measure predation rates compared to a control group.  They found that predation rates on clay caterpillars and the abundance of arthropod predators were significantly higher on the artificial light at night treatment plots.  In fact, of the 552 clay caterpillars deployed and glued to leaves to look authentic, 521 models were recovered and 249 of them- or 47.8% – showed predatory marks from arthropods during the summer-long nighttime study.

In addition to light pollution, caterpillars also face major threats from habitat loss, pollution, invasive species, and climate change.

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Artificial light at night aids caterpillar predators

Photo, posted July 23, 2020, courtesy of Judy Gallagher via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

An Accelerating Rate Of Mountain Forest Loss | Earth Wise

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Mountains contribute disproportionately to the Earth’s diversity of life.  While mountains account for about 25% of the land area on Earth, they are home to more than 85% of the mammal, bird, and amphibian species.  But alarmingly, forested mountain habitats in which these species live are disappearing, and they appear to be disappearing at an accelerating rate.

According to a new study recently published in the journal One Earth, more than 300,000 square miles of mountain forest has been lost globally since 2000, which is an area larger than the state of Texas. 

A research team led by scientists from Leeds University in the United Kingdom and the Southern University of Science and Technology in China tracked changes in mountain forests on an annual basis from 2001 to 2018.  The researchers found logging to be the biggest driver of mountain forest loss, responsible for 42% of the overall decline.  This is followed by wildfires at 29%, so-called “slash-and-burn” cultivation at 15%, and permanent or semi-permanent agriculture at 10%.  Significant losses occurred in Asia, Africa, Europe, Australia, and South America, but not in Oceania or North America.

The research team also found that the rate of mountain forest loss seems to be accelerating: in fact, the annual rate of loss increased 50% from 2010-2018 when compared with 2001-2009.

While developing additional forest protection strategies and interventions is critical, the researchers emphasize the importance of also considering food production, livelihoods, and human wellbeing in any new measures.

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Mountain forests are being lost at an accelerating rate, putting biodiversity at risk

Photo, posted December 6, 2018, courtesy of Lance Cheung / USDA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Elephants And Global Warming | Earth Wise

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A study by researchers at Saint Louis University has found that elephants play a key role in creating forests that store large amounts of atmospheric carbon and in maintaining the biodiversity of forests in Africa.  Since elephants are endangered, their status represents a significant threat to an ecosystem that is very important to the Earth’s climate.

The African rainforest contains trees with both low carbon density (light wood) and high carbon density (heavy wood).  High carbon density trees grow more slowly and can be crowded out by the faster growing low carbon density trees rising above them.  Elephants affect the relative abundance of these trees by feeding more on the low carbon density trees which are more palatable and nutritious.  This thinning of the forest allows the trees that sequester the most carbon to flourish.

Elephants are also excellent dispersers of the seeds of high carbon density trees.  Essentially, elephants are the gardeners of the forest.  They plant the forest with high carbon density trees and get rid of the weeds – in this case, the low carbon density trees.  According to the study, if elephants were to become extinct, the African rainforest – the second largest on earth – would gradually lose between six and nine percent of its ability to capture atmospheric carbon.

Elephants have been hunted by humans for millennia.   Gaining support for protecting them has mostly been driven by the argument that everybody loves elephants.  Focusing on their role in maintaining forest diversity has not driven much more action.  The hope is that the evidence of how important elephants are for climate mitigation will be taken seriously by policy makers to generate the support needed for improved elephant conservation.

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Can Elephants Save the Planet?

Photo, posted March 15, 2008, courtesy of Michelle Gadd/USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Tracking Global Forest Changes | Earth Wise

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India is one of the most biodiverse countries in the world.  An estimated 47,000 plant species and 89,000 animal species can be found in India, with more than 10% of each thought to be on the list of threatened species.

India is also one of the 10 most forest-rich countries in the world.  Trees cover approximately 25% of the nation.  But this is still a significant decline from years past.  In fact, between the 1890s and 1990s, a combination of rapid development and resource overexploitation caused India to lose nearly 80% of its native forest area.  Today, as India’s forests continue to disappear, researchers are trying to help preserve what forest remains. 

Using satellite-monitoring data, researchers from The Ohio State University have developed a deep learning algorithm that could provide real-time land use and land cover maps for parts of India. 

The land use monitoring system was trained using satellite data from Norway’s International Climate and Forests Initiative.  By combining this data with a global land cover map produced by Tsinghua University in China, the researcher team’s deep learning model was able to acquire a more detailed type of base map of the area.  Using their model, the researchers were able to process 10 monthly maps.  Their research was recently  presented at the annual meeting of the American Geophysical Union.   

Using these maps, the researchers were able to detect seasonal shifts across india.  These include changes to barren land, how crop land was affected by monsoons, and the distribution of forests in mountainous regions. 

Understanding the impact of these seasonal changes will help scientists better predict the effects of climate change on forests.

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Using deep learning to monitor India’s disappearing forest cover

Photo, posted January 20, 2013, courtesy of Frontier Official via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Saving Giant Sequoias | Earth Wise

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Last year, the KNP Complex Fire burning in Sequoia National Park drew global attention as the General Sherman, the world’s largest tree, was wrapped in tinfoil-like material in order to repel the flames from the fire.  Hundreds of firefighters labored for weeks trying to save giant redwood trees.  Despite these efforts, the U.S. Forest Service estimates that wildfires killed 13% to 19% of the world’s giant sequoias in 2020 and 2021.

This past July, the Washburn Fire burned through part of Yosemite’s Mariposa Grove and the giant sequoias there were surrounded by automated sprinklers trying to shelter them from the flames.

For a century, government agencies have worked to extinguish all natural wildfires and prohibited Native people in the region from lighting the fires they traditionally used to manage their lands.  As a result, forests have grown far thicker with trees that can fuel fires.  The Sierras are now home to more than three times as many trees as when they were managed by indigenous communities.  But more than 100 million of those trees had died by 2016 because of drought.

Add to this massive amount of kindling the effects of climate change – a hotter and drier environment – and there is the perfect storm for megafires among the giant sequoias.

There is federal legislation pending that would provide resources for prescribed burning and other forms of active forest management.  It is controversial.  It has attracted support from the Nature Conservancy, the Save The Redwoods League, and others, but also opposition from more than 80 environmental groups.

What is not controversial is that the Giant Sequoias are in the midst of a crisis and urgent action is needed.

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In California, a Race to Save the World’s Largest Trees From Megafires

Photo, posted December 10, 2014, courtesy of Laura Camp via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Decreasing Forest Area Per Capita | Earth Wise

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Over the past 60 years, global forest area has decreased by 315,000 square miles, an area about twice the size of California. Combined with global population growth over that period, this has resulted in more than a 60% decline in global forest area per capita.

The continuous loss as well as degradation of forest affects the integrity of forest ecosystems and reduces their ability to generate and provide essential services and sustain biodiversity.  It impacts the lives of at least 1.6 billion people worldwide – primarily in developing countries – who depend upon forests in multiple ways.

According to the new study published in the journal Environmental Research Letters, forest losses have been occurring primarily in lower-income countries in the tropics while forest gains have occurred in higher-income countries in the mid-latitudes or extratropics. 

More than half of the world’s forest losses were in Brazil, home to the Amazon rainforest.  In the past 60 years, that country has had a net loss of 170,000 square miles of forest.  While most high-income countries had net forest gains, Canada actually had a net loss of about 11,000 square miles of forest.

Economic growth has a stronger association with net forest gain than with net forest loss.  Therefore, the study highlights the need to strengthen the support given to lower income countries, especially in the tropics, to help improve their capacity to minimize or curtail their forest losses.  To help address this ongoing displacement of forest losses to lower income countries, higher-income nations need to reduce their dependence on imported tropic forest products.

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New study finds global forest area per capita has decreased by over 60%

Photo, posted April 19, 2011, courtesy of ©2011CIAT/NeilPalmer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

California Trees Are Dying | Earth Wise

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California relies on extensive forests to help reduce the amount of carbon dioxide entering the atmosphere.  But extensive drought and increasingly frequent wildfires have been reducing the state’s tree population for the past three decades.

A comprehensive study by a team of scientists from the University of California Irvine used satellite data to study vegetation changes between 1985 and 2021.  Across the entire state, tree cover area has declined 6.7% over that time period.  The results varied from region to region across the state.

Southern California exhibited the sharpest decline, where 14% of the tree population in local mountain ranges vanished, potentially permanently.  In the Sierra Nevada mountains, tree populations were relatively stable until about 2010.  After that, a severe drought followed by historically large wildfires resulted in a 8.8% die-off of trees.  The northern parts of the state, with higher rainfall and cooler temperatures, fared better, being able to more easily recover from wildfires.

The study goes beyond measuring the tree population of the state and its effects on carbon storage.  The data is also important for understanding how changes in forest cover affects water resources and fire behavior in the state.

The decline of trees in California is affecting the carbon storage abilities of the state.  The satellite survey showed that as the tree populations have dropped, the state’s coverage of shrubs and grasses has risen, possibly indicating that permanent ecosystem shifts are occurring.  The forces contributing to the decline of trees in California are not going away any time soon.  As a result, the threat to California’s ability to mitigate the effects of climate change continues to grow.

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UCI study: California’s trees are dying, and might not be coming back

Photo, posted March 24, 2016, courtesy of David Fulmer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Some Good Monarch News | Earth Wise

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Eastern monarch butterflies spend their winter months in central Mexico.   Every spring, they embark on a lengthy, multigenerational migration that takes them into the United States and even into southern Canada, where they breed.  The butterflies go through several generations before they eventually migrate back to Mexico.

Twenty-five years ago, overwintering monarchs in Mexico blanketed nearly 45 acres of forest.  The acreage covered, which has been surveyed annually since 1993, is a rough indicator for the actual number of butterflies that survive the difficult migration process. In 2013, the monarchs occupied only 1.6 acres of Mexican forest.  The butterflies were deemed to be on the edge of extinction.

Last December, the monarch survey found 7 acres covered by the butterflies, an increase of 35% over the previous winter.  The population appears to be steadily rebounding, although the numbers are still substantially lower than the levels seen in the 1990s.

The butterflies are struggling with multiple problems.  There continues to be a lack of milkweed, the only food source for the caterpillars, in their breeding grounds along their migratory route.  More extreme weather driven by climate change is another challenge, and illegal logging in their overwintering habitat in Mexico has also become a threat.

After the butterfly population crashed in 2013, conservation efforts shifted into high gear with lots of milkweed planting in the US and Canada, and crackdowns on timber poachers in Mexico.

The remarkable multigenerational migration of monarchs is a delicate phenomenon that can be disrupted by many different things.  Eastern monarchs are still in serious danger, but the current trend seems to be positive.

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Warming Trends: Butterflies Bounce Back, Growing Up Gay Amid High Plains Oil, Art Focuses on Plastic Production

Photo, posted August 12, 2021, courtesy of Paul VanDerWerf via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Forest Loss | Earth Wise

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India is one of the most biodiverse countries in the world.  An estimated 47,000 plant species and 89,000 animal species can be found in India, with more than 10% of each thought to be on the list of threatened species. 

India is also among the top ten countries in the world in terms of total forest coverage.  According to Indian government data, the total forest and tree cover in India is 312,000 square miles, which is 24.62% of the geographical area of the country.

However, forest loss in India has been a problem for many decades driven largely (researchers thought) by land use change.  But it turns out that climate change may also have been contributing to forest loss, and its impact is projected to become an even bigger problem in the coming years. 

In the first ever national-scale study of the relationship between forest loss and rainfall and temperature trends in India, researchers from the University of Reading in the U.K. found that climate change may have contributed to large declines in forest since the turn of the century.

The study, which was recently published in the journal Global Change Biology, found far greater forest losses were observed where and when the climate was changing most rapidly.  Decreases in rainfall had the strongest impact on forest loss. 

These findings exacerbate concerns about the already-worrying levels of deforestation in the country, and contradict official reports that have shown relatively small decreases in forest coverage in recent years. 

The research team warns that rapid changes to the climate in some regions will require targeted preservation action to reduce the risk to biodiversity in India. 

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Indian forest loss ‘worse than feared’ due to climate change

Photo, posted January 20, 2013, courtesy of Dicky Broadhurst / Frontier Official via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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