Tall and old or dense and young: Which kind of forest is better for the climate? (2022)

  • Scientists say reforestation and better forest management can provide 18 percent of climate change mitigation through 2030. But studies appear to be divided about whether it’s better to prioritize the conservation of old forests or the replanting of young ones.
  • A closer look, however, reconciles these two viewpoints. While young forests tend to absorb more carbon overall because trees can be crowded together when they’re small, a tree’s carbon absorption rate accelerates as it ages. This means that forests comprised of tall, old trees – like the temperate rainforests of North America’s Pacific coast – are some of the planet’s biggest carbon storehouses.
  • But when forests are logged, their immense stores of carbon are quickly released. A study found the logging of forests in the U.S. state of Oregon emitted 33 million tons of CO2 – almost as much as the world’s dirtiest coal plant.
  • Researchers are calling on industry to help buffer climate change by doubling tree harvest rotations to 80 years, and urge government agencies managing forests to impose their own harvest restrictions.

In 2007, Richard Branson, the British business magnate, offered a $25 million prize to anyone who can invent a device capable of removing significant volumes of carbon dioxide from the atmosphere.

Andy Kerr, a noted Oregon environmentalist, drew a picture of a tree and sent it in. After all, a tree performs the job of sucking carbon out of the air far better than any technology yet devised by humans. But Kerr didn’t win, foiled by contest rules specifying the winner must be the inventor of such a device, and it’s certain neither Kerr nor anyone else invented the tree. An artificial tree might win if it could perform the implausible feat of inhaling CO2.

Kerr’s idea, however, was rooted more in the climate benefits provided by an entire forest rather than just a single tree. These benefits can be enormous, according to “Natural Climate Solutions,” a paper published in 2017 in the Proceedings of the National Academy of Sciences.

The paper asserts better management of forests, wetlands and farmland can provide 37 percent of the cost-effective climate mitigation needed through 2030. Forests alone can provide 18 percent of the mitigation, according to a statement published last year by the Climate and Land Alliance and signed by an international group of 40 scientists.

“The ‘natural technology’ of forests is currently the only proven means of removing and storing atmospheric CO2 at a scale that can meaningfully contribute to achieving carbon balance,” the 40 scientists said. “The world’s forests contain more carbon than exploitable oil, gas, and coal deposits, hence avoiding forest carbon emissions is just as urgent as halting fossil fuel use.”

Tall and old or dense and young: Which kind of forest is better for the climate? (1)

Last year, the United Nations’ Intergovernmental Panel on Climate Change (IPCC) warned we have only until 2030 to act if we hope to limit global warming to moderate levels.

Forests cool the atmosphere by inhaling CO2 through the process of photosynthesis and storing or sequestering it in roots, trunks, branches, needles and leaves. Half a tree’s weight is carbon. Although every backyard vegetable garden absorbs some amount of carbon, a rainforest takes in exponentially more. For this reason, rainforests and other large terrestrial ecosystems made up of dense vegetation are known as “carbon sinks.”

(Video) Old-Growth Forests vs. Second-Growth Plantations

Kerr lives at the edge of a temperate rainforest straddling the west coast of North America from the redwoods of Northern California into Alaska, the largest contiguous temperate rainforest in the world. Few ecosystems anywhere match its capacity to absorb and store carbon. Trees in the temperate rainforest, among the tallest in the world, live for 800 years or more.

The expansive Amazon tropical rainforest of South America is one of the world’s largest carbon sinks. But on a per-acre basis, the Amazon is not nearly as efficient at absorbing carbon as the coastal temperate rainforest. The Douglas fir forests of Oregon and the hemlock and cedar forests of Alaska store about twice as much carbon per acre as the Amazon. The giant redwoods of Northern California, which store seven times as much, are regarded as the most carbon dense forests in the world.

The temperate rainforest is a “carbon storage powerhouse,” says John Talberth of the Portland, Ore.-based advocacy group Center for a Sustainable Economy (CSE). “If allowed to mature, Pacific Northwest forests can capture and store more carbon than almost any terrestrial ecosystem on Earth.”

Tall and old or dense and young: Which kind of forest is better for the climate? (2)

The problem is most mature trees in the rainforest have been cut down and young ones are not allowed to mature. Outside conservation areas like national parks and wilderness, ancient groves are converted to industrial tree farms by the timber industry.

After cutting down every old growth tree it can get its hands on, the industry typically plants a young sapling in its place. The saplings grow for about 40 years on average until the next harvest. Then the cycle repeats again and again.

This business model might be good for timber industry profits, but what does it do to the climate?

Sara Duncan, a spokeswoman for the Oregon Forest Industry Council, a lobbying group, claims this business model is good for both profits and the climate. She says old growth trees store a lot of carbon, but like everything else, old growth trees eventually die. If they aren’t harvested and converted into wood products, they will fall down in a windstorm, burn up in a wildfire or meet their fate some other way. Eventually they will release all their stored carbon content back to the atmosphere.

The industry’s solution to the climate crisis is to log the trees, truck them to the mill, and store the carbon in 2-by-4s, plywood boards and toilet paper. Eventually, however, the carbon in these products will still return to the atmosphere one day.

But is there a more climate-friendly way to manage our forests? Can we get more climate mitigation from a forest if we don’t cut it down every 40 years? The science suggests we can.

(Video) 10 year old food forest - Feral, Dense and Productive

In 2014, a study published in Nature by a team an international team of researchers led Nathan Stephenson, a forest ecologist with the United States Geographical Survey, found that a typical tree’s growth continues to accelerate throughout its lifetime, which in the coastal temperate rainforest can be 800 years of more.

Stephenson and his team compiled growth measurements of 673,046 trees belonging to 403 tree species from tropical, subtropical and temperate regions across six continents. They found that the growth rate for most species “increased continuously” as they aged.

“This finding contradicts the usual assumption that tree growth eventually declines as trees get older and bigger,” Stephenson says. “It also means that big, old trees are better at absorbing carbon from the atmosphere than has been commonly assumed.”

But the science, as usual, is muddy. As Mongabay reported in February, a study published in the Proceedings of the National Academy of Sciences in 2019 by Thomas Pugh of the Birmingham Institute of Forest Research in the UK found young forests sequester more carbon per year than old-growth forests.

“These findings upend conventional wisdom that old-growth tropical rainforests are the planet’s biggest carbon sinks,” Pugh’s study said. It defined old-growth forests as any stand over 140 years of age.

It would appear the two studies contradict each other. But both scientists say they are consistent.

“The difference is that Stephenson et al. looked at biomass of individual trees, whereas our study looks at biomass of whole stands of trees,” Pugh said in an email. “Whilst a single tree might continue to pile on more and more biomass, there will be less of such trees in a stand, simply because of their size and as tree stands age, gaps tend to appear due to tree mortality.”

“So, our conclusion is actually that young forests are responsible for more of the terrestrial carbon sink than old growth forests,” Pugh said.

“Both things are true,” Stephenson said in an email. “Individual tree mass growth rate increases with tree size, but old forests usually absorb carbon more slowly than young forests.”

(Video) No Space? Super Dense Tropical Food Forest Tour (Front Yard)

However, the relative growth rates of young and old trees do not tell the entire story.

“Older forests store a lot more carbon than young forests and much of it is returned to the atmosphere quickly when harvested and planted with young trees,” says Beverly Law, a professor of global change biology at Oregon State University.

By the time it becomes a desk, table or 2-by-4, a log will lose about 70 percent of its carbon, according to Dominick DellaSala, director of the GEOS Institute, an environmental think tank based in Oregon.

About 45 percent of the carbon is left on the forest floor, said DellaSala, a member of the Oregon Global Warming Commission Task Force on Forest Carbon. “This includes decomposition of root wads, branches, and tops remaining on site and a little soil carbon. Logging takes nearly half the carbon and puts it into the atmosphere within years.”

Tall and old or dense and young: Which kind of forest is better for the climate? (4)

Another 25 percent is lost during manufacturing, he said. And as the finished wood products decay over time, he said, they emit even more.

And that doesn’t include carbon emitted by chainsaws, logging trucks and lathes. In 2018, Law led a team of researchers who quantified these and all other carbon emissions as logs move from forest to sawmill. Their paper, published in the Proceedings of the National Academy of Sciences, said logging operations in Oregon contribute an average of 33 million tons of CO2 to the air. This equates to almost as much as the world’s dirtiest coal plant, Taichung Coal Plant in Taiwan, which emits about 36 million tons per year.

Moreover, the climate impacts of logging are even greater if you factor in a harvested log’s lost future growth opportunities, Law says. Although her paper makes no attempt to quantify a logged tree’s foregone climate mitigation potential, she acknowledges it could be significant.

Law called on the industry to help buffer climate change by doubling harvest rotations to 80 years and urged government agencies managing forests to impose their own harvest restrictions. These and other actions could increase the amount of carbon absorbed by Oregon forests by 56 percent by the year 2100, as well as improve water quality and biodiversity, her paper said. She is conducting a similar analysis for forests in California and Washington.

Even after the wood is converted into a wood product, the carbon will likely return to the atmosphere sooner than people might think, Law said.

(Video) (ENG SUB)인류 원형 탐험 - 아마존 활의 전사 볼리비아 유끼족ㅣBow Warriors of the Amazon Yuqui of Bolivia

“Old growth trees in the coastal temperate rainforest can sequester carbon for hundreds of years,” she said, “which is much longer than is expected for buildings that are generally assumed to outlive their usefulness or be replaced within several decades.”

Paul Koberstein and Jessica Applegate are editors of Cascadia Times, an environmental journal based in Portland, Oregon.

Feedback:Use this formto send a message to the editorof this post. If you want to post a public comment, you can do that at the bottom of the page.

Article published by Morgan Erickson-Davis

carbon, Carbon Sequestration, Climate Change, Environment, Forest Destruction, Forests, Global Warming, Global Warming Mitigation, Green, Logging, Rainforest Destruction, Rainforests, Research, Temperate Forests, Tropical Forests

Print

FAQs

Are young trees better for the environment? ›

Those young patches of trees may take up CO₂ more strongly than the older patches they replace, but this is more than countered by the increased rate of death. The capacity of the forest to store carbon has been reduced.

Are old-growth forests good for the environment? ›

Old-Growth Forests Often Have Incredible Biodiversity

These include functions like protecting nearby water systems, encouraging the formation of healthy soil, and breaking down ambient air pollution. Untouched old-growth forests exhibit a number of important properties that younger, disturbed forests may not.

Are old-growth forests good? ›

Old growth forests are awe-inspiring and highly diverse ecosystems that can be found all around the world. They play essential roles in wildlife habitat, species diversity, hydrological regimes, nutrient cycles, carbon storage, and numerous other ecological processes.

How do old-growth forests help climate change? ›

Forests full of big, old trees are highly effective at trapping climate-warming greenhouse gases like carbon dioxide from the atmosphere and storing it away.

Why old trees are important? ›

Conclusion. Large old trees are organisms of great importance in the field of forest ecosystems as they are able to fix large quantities of atmosphere gases, produce oxygen and create local habitats which are unique and are not comparable to younger stands of trees.

Do older or younger trees produce more oxygen? ›

Photosynthesis occurs across the surface of a leaf, and the total oxygen production of a tree depends upon its total leaf area. This changes with the age and size of a tree. Old trees produce more oxygen and young trees. Leaf area also changes dramatically from season to season.

Are old-growth forests good for biodiversity? ›

government used to regard protection of old growth as one of the most effective ways of conserving biodiversity at the landscape level; and old-growth forests are very important to the public, for ecological, spiritual, aesthetic, and other intrinsic values.

Why do old-growth forests matter? ›

The scientists noted that old-growth forests “store and gradually release clean drinking water for millions of Americans while mitigating flood and fire impacts resulting from climate-driven increases in erratic and severe weather events.

What is an old forest? ›

The DNR defines old growth forests as forests that have developed over a long period of time, essentially free from catastrophic disturbances. They contain large, old trees of long-lived species that are beyond traditional rotation (harvest) age.

What are old-growth forests used for? ›

Old growth ecosystems support diverse flora and fauna, from mosses and liverworts to large mammals and species at risk. These forests also provide habitat for many birds, mammals, and amphibians. Government has protected old growth forests in areas throughout the province to support species that depend on them.

Why are old-growth forests often more ecologically valuable than second growth forests? ›

Old-growth forests have more fallen and standing dead trees known as “woody debris” which provide food, shelter, and moisture for more biodiversity. Second-growth forests have less and smaller woody debris.

Why do older trees store more carbon? ›

As trees get older, they absorb more carbon every year, and because they are bigger they store more carbon.

What do old-growth forests look like? ›

Typical characteristics of old-growth forest include presence of older trees, minimal signs of human disturbance, mixed-age stands, presence of canopy openings due to tree falls, pit-and-mound topography, down wood in various stages of decay, standing snags (dead trees), multilayered canopies, intact soils, a healthy ...

Where is the old-growth forest? ›

Biggest Old Growth Forests In The United States
RankLocationVirgin Old Growth Area
1Tongass National Forest, Alaska5.4 million acres
2Ouachita National Forest, Arkansas800,000 acres
3Winema National Forest, Oregon712,000 acres
4Mount Baker-Snoqualmie National Forest, Washington644,000 acres
6 more rows

Why are old-growth forests irreplaceable? ›

The reason is simple: these forests are irreplaceable and we need them to sustain life on earth. Systems that have been in place for hundreds or thousands of years are disrupted and this causes a ripple effect that impacts flora and fauna, and even the mineral content in the soil and the flow of rivers and streams.

Which stores more carbon old or new forests? ›

Old forests have accumulated more carbon than younger forests; however, young forests grow rapidly, removing much more CO2 each year from the atmosphere than an older forest covering the same area.

Why should we protect old trees? ›

They provide shelter and resources for humans. They hold important cultural value to First Nations People. They speak to our hearts, and in forests, they even communicate with each other. And the older they are, the more valuable they are.

Why should we protect ancient forests? ›

Ancient forests, also known as old-growth forests, serve as the lungs of our nation. These forests naturally sequester enormous amounts of carbon, reduce wildfire risk, supply clean drinking water, and provide refuge to threatened and endangered species.

Which kind of forest are more important for slowing climate change? ›

Both old and young forest plays significant role in slowing climate change, although old forest May seems to play more significant role because of the rich in its biodiversity especially the large volume of the tree canopy, also the young forest could also do so depending on it's structure, components and the age of ...

Do bigger trees produce more oxygen? ›

A larger or faster-growing plant or one with a high photosynthetic rate will produce more oxygen than a smaller or slower growing one.

At what age do trees produce the most oxygen? ›

An actively growing tree will emit more oxygen than one that is near the end of maturity, is elderly or dying.

Are old-growth forests renewable or nonrenewable? ›

Old-growth forests are an extremely valuable natural resource, because of their considerable standing crops of large-dimension timber of desirable tree species. Old-growth stands are rarely, however, managed by foresters as a renewable, natural ecosystem.

What kind of trees are in old-growth forests? ›

Tree species found in these stands typically include western hemlock (Tsuga heterophylla), Sitka spruce (Picea sitchensis), and sometimes red or yellow cedar (Thuja plicata and Cupressus nootkatensis, respec- tively). Western hemlock tends to dominate in the oldest stands, as it is the more shade-tolerant species.

What is the difference between old-growth and second growth forest? ›

In contrast to dense second-growth forest, old-growth forest has fewer and larger trees, many large snags and logs, and abundant understory plants, providing habitat for many more wildlife species and individuals of each species.

What are two important facts about primary old-growth forests? ›

Old-growth forests are more structurally intact than secondary forests and provide superior ecosystem services. As forests age, plants grow and die to fill available space, so old-growth forests are more filled with carbon-storing plant matter than secondary forests.

What do we mean by closed canopy forest and old-growth forest? ›

Closed-canopy forests are forests where tree crowns cover most of the ground. Old-growth forests, or frontier forests, are those that are large enough and have been undisturbed by human activities for long enough for the trees to live out a natural life cycle and for ecological processes to happen normally.

What age is old-growth forest? ›

Old-growth stands are past the economic optimum for harvesting – usually between 80-150 years, depending on the species.

How old does an old-growth forest have to be? ›

In the 1970s, researchers started using the term “old growth” to describe complex, biodiverse forests at least 150 years old. Environmentalists prefer using the term to describe forests with large, old trees undisturbed by human impact.

How tall are old-growth trees? ›

Old growth trees vary in size and age, but the most common image is of a massive tree erupting from the earth stretching 60 metres or more into the sky.

Why are tree plantations not as ecologically valuable as old-growth forests? ›

Biologically simplified tree plantations can reduce overall forest biodiversity and it can disrupt important ecosystem services. How serious is tropical deforestation? Tropical deforestation hasten climate change and increased drier climate risk of more forest fires.

Do younger or older trees grow faster? ›

In fact, scientists have discovered that trees grow faster the older they get. Once trees reach a certain height, they do stop getting taller. So many foresters figured that tree growth — and girth — also slowed with age.

Do trees grow faster when older? ›

Trees do not slow in their growth rate as they get older and larger — instead, their growth keeps accelerating, according to a study published today in the journal Nature.

Do old-growth trees release carbon? ›

Old-growth forests accumulate carbon for centuries and contain large quantities of it. We expect, however, that much of this carbon, even soil carbon9, will move back to the atmosphere if these forests are disturbed.

What's the oldest forest in the world? ›

Scientists have discovered the world's oldest forest in an abandoned quarry near Cairo, New York. The 385-million-year-old rocks contain the fossilized woody roots of dozens of ancient trees. The find marks a turning point in Earth's history.

Where is the largest old-growth forest? ›

Tongass National Forest in southeast Alaska is the world's largest remaining intact coastal temperate rain forest. At almost 17 million acres, this unique area houses some of the oldest trees in the nation—many over 800 years old—and provides essential habitat for the largest population of Bald Eagles in the world.

How do you determine the age of a forest? ›

Forest age can be determined based on stem cores taken at individual reference trees (Grissino-Mayer 2003). Counting the number of year rings in the stem core extracted close to the ground leads to a good estimate of tree age.

What animals live in old-growth forests? ›

Some well-known, North American examples of species considered substantially dependent on old-growth forests are birds such as the northern spotted owl (Strix occidentalis caurina), marbled murrelet (Brachyramphus marmoratus), and red-cockaded woodpecker (Picoides borealis), and mammals such as marten (Martes americana ...

How can we protect old-growth forests? ›

Protect old-growth forests from logging and development by establishing a system of permanent old-growth forest reserves on state lands. Require an inventory of the forests on state-owned land to determine the extent and condition of old-growth forest stands and their surrounding landscapes.

What is an old-growth rainforest? ›

Old-growth forests (PDF 392KB) are ecologically mature forests. They often have a diverse structure and mix of species, with relatively large old trees which may contain hollows. The protection and management of old growth forests is extremely important in maintaining biodiversity.

Do young trees absorb more carbon than old trees? ›

While young forests tend to absorb more carbon overall because trees can be crowded together when they're small, a tree's carbon absorption rate accelerates as it ages.

Do mature trees capture more carbon than young trees? ›

A sweeping study of forests around the world finds that the older the tree, the greater its potential to store carbon and slow climate change. The 38 researchers from 15 countries found that 97 percent of trees from more than 400 species studied grew more quickly as they aged, thus absorbing more carbon.

How much CO2 does a young tree absorb? ›

A young tree absorbs about 5900 gram CO2 per year, while a 10 year old tree absorbs almost 22.000 gram per year. By taking these numbers we can calculate the average CO2 that is absorbed by a tree during his lifetime. To make this more tangible we convert the absorption per tree, to the CO2 capture per acre.

Does the age of a tree affect carbon storage? ›

Trees play an important role in the fight against climate change. They capture and store carbon in their biomass — their roots, stumps and branches. According to new European research, when it comes to a tree's climate benefit, as a tree get older it also stores more carbon.

Do young trees store more carbon? ›

SEQUESTRATION RATE AND CARBON STORAGE OVER AGE*

Old forests store more carbon but sequester it much more slowly than younger managed forests. As old trees die or are lost to insects, storms, or fire, they release their carbon back to the atmosphere.

Which kind of forest are more important for slowing climate change? ›

Both old and young forest plays significant role in slowing climate change, although old forest May seems to play more significant role because of the rich in its biodiversity especially the large volume of the tree canopy, also the young forest could also do so depending on it's structure, components and the age of ...

How much carbon does an old-growth forest absorb? ›

The original research article concluded that old-growth forests more than 200 years old bind an average of 2.4 tonnes of carbon per hectare, per year, and that 1.3 tonnes of this amount is bound in forest soil.

Which young forest types accumulate the most carbon? ›

Kristina and Susan used ForC to investigate global carbon capture by young regrowing forests. Based on their previous research, they thought that, since tropical forests regrow fastest due to a year-round warm and wet climate, they would have the highest rate of carbon accumulation.

Are old mature forests are carbon sinks? ›

They found that far from being carbon neutral, the majority of forests between 15 and 800 years old are carbon sinks, absorbing more carbon than they release. Old-growth forests in the northern hemisphere account for 15% of the world's total forested area.

Do bigger trees produce more oxygen? ›

A larger or faster-growing plant or one with a high photosynthetic rate will produce more oxygen than a smaller or slower growing one.

What is the best tree to plant for climate change? ›

Broadleaved species – such as oak, beech and maple – are best because they have a larger surface area of leaves which generates more photosynthesis, whereas conifers absorb more heat.

Which tree removes most CO2? ›

All trees filter impurities from the air but some trees are better than others at removing greenhouse gases. The most efficient carbon absorbing trees are East Palatka holly, slash pine, live oak, southern magnolia and bald cypress. Palms are the least effective at carbon sequestration.

Does grass produce more oxygen than trees? ›

Scientists say figures show grass produces around three times more the amount of oxygen than trees. However, if you want grass to be at its most green (and we're talking about in the climate sense rather than its pigment sense, here), don't mow it.

Do mature forests absorb CO2? ›

However, new evidence suggests that mature forests have limited ability to absorb additional carbon as atmospheric CO2 emissions increase. Growing trees absorb carbon and can use additional carbon in the atmosphere to grow faster which is known as CO2 fertilisation.

Which trees absorb the most carbon? ›

The live oak is the most efficient carbon capturing tree, which is able to sequester some 10,994 CO2 equivalent over its lifetime.

Which one is the most dense forest in the world? ›

Amazon basin in South America is dwelling to the planet's biggest and most dense contiguous tropical rain forest. The Amazon is the planet's second-longest and the greatly voluminous river flowing across nine nations.

Videos

1. The Underwater Forest
(This Is Alabama)
2. Scientists Terrifying New Discovery Under Sahara Desert Changes Everything!
(Tech Space)
3. This is What an OLD GROWTH FOREST in the Northeast Looks Like — Ep. 026
(Flock Finger Lakes)
4. Never Pull Weeds Again! Weed Whacker Trick
(Ambro's Landscaping Inc.)
5. Bow Warriors of the Amazon Yuqui of BoliviaㅣExploring the Origin of Humanity
(EBS WORLD)
6. Western White Pine Forests: Past, present, and future by Dr. Terrie Jain
(Whitepine chapter INPS)

Top Articles

Latest Posts

Article information

Author: Francesca Jacobs Ret

Last Updated: 10/01/2022

Views: 6211

Rating: 4.8 / 5 (48 voted)

Reviews: 87% of readers found this page helpful

Author information

Name: Francesca Jacobs Ret

Birthday: 1996-12-09

Address: Apt. 141 1406 Mitch Summit, New Teganshire, UT 82655-0699

Phone: +2296092334654

Job: Technology Architect

Hobby: Snowboarding, Scouting, Foreign language learning, Dowsing, Baton twirling, Sculpting, Cabaret

Introduction: My name is Francesca Jacobs Ret, I am a innocent, super, beautiful, charming, lucky, gentle, clever person who loves writing and wants to share my knowledge and understanding with you.