Quantcast

Mixed Forests Are Healthier, But Can They Survive Climate Change?

Climate
Autumnal mixed forest in Germany. Christian Hueller

By Tim Radford

German researchers have confirmed once again that a good forest is a mixed forest, a natural one, with a diversity of species. The more diverse the forest, the better it becomes at doing what forests do.

Forests with a greater number of species grow at a faster rate, store more carbon, and are more resistant to pests and diseases, according to a six-nation study of European woodlands.


But this safety-in-species-numbers approach may not offer quite the protection against climate change and its consequences that such a finding should predict. A second study by European researchers suggests that when conditions become extremely wet, or extremely dry, diversity may not confer automatic resilience.

The message is that healthy, diverse, natural forest systems remain important buffers against climate change—but also that climate extremes could diminish the capacity of the forest to absorb carbon and limit global warming.

At the heart of both studies is a deeper concern about the response of the natural world to human-induced change, in the destruction of habitat, the loss of the plants, birds, insects, mammals, amphibians and reptiles that depend on habitat, and in the steady increase in atmospheric levels of greenhouse gases, as a consequence of profligate combustion of fossil fuels.

Repeated studies have confirmed that the world's forests are under threat. Repeated studies have confirmed that in overall rewards for humanity, undisturbed natural forests deliver a greater economic return. And repeated studies have confirmed that rising global temperatures offer a threat to plant diversity around the planet in general and to Europe in particular.

Researchers at the Centre for Integrative Biodiversity Research in Germany reported in the journal Ecology Letters that they selected plots of forest in Germany, Finland, Poland, Romania, Italy and Spain.

Within these plots the numbers of species varied: there might be one species, or five. The German plot, for example was home to beech, oak, Norway spruce, birch and hornbeam.

The scientists then measured 26 functions in these plots that could answer questions about nutrients, carbon cycles, growth and resilience and forest regeneration. Those stands of timber with more species grew faster and withstood pests and disease assault better than those with fewer.

"Our summers will be drier and longer as a result of climate change," said Christian Wirth, who directs the Cenre for Integrative Biodiversity Research and heads the department for systematic botany at Leipzig University. "We are therefore presuming that in future, it will be even more important to manage forests in a way that they have a high diversity of tree species."

Mixed answer

But a study in the Journal of Ecology suggests that the answer may not be so simple.

Researchers led by Hans de Boeck from the University of Antwerp reported that they looked at a wide range of studies of what scientists call ecosystem stability and biodiversity during climate extremes—that is, unusual heat, drought or flooding.

The answer, they found, was mixed. A greater range of diversity in an ecosystem seemed to speed up recovery after an extreme climatic event, but if the event was extreme enough biodiversity alone might not offer much protection.

The relationship between diversity and resistance wasn't always obvious. Researchers, the scientists suggested, have more questions to resolve.

In the stilted language of sciencespeak, the researchers concluded that "there are numerous and non-trivial exceptions to the purported general rule that biodiversity increases stability. This raises the question of whether existing concepts of biodiversity-stability derived from the context of mild fluctuations are readily transposable to extreme events."

Reposted with permission from our media associate Climate News Network.

EcoWatch Daily Newsletter

Tuna auctions are a tourist spectacle in Tokyo. Outside the city's most famous fish market, long queues of visitors hoping for a glimpse of the action begin to form at 5 a.m. The attraction is so popular that last October the Tsukiji fish market, in operation since 1935, moved out from the city center to the district of Toyosu to cope with the crowds.

Read More Show Less

gmnicholas / E+ / Getty Images

By Nicole Greenfield

Kristan Porter grew up in a fishing family in the fishing community of Cutler, Maine, where he says all roads lead to one career path: fishing. (Porter's father was the family's lone exception. He suffered from terrible seasickness, and so became a carpenter.) The 49-year-old, who has been working on boats since he was a kid and fishing on his own since 1991, says that the recent warming of Maine's cool coastal waters has yielded unprecedented lobster landings.

Read More Show Less
Sponsored
TeamDAF / Getty Images Plus

The climate crisis is getting costly. Some of the world's largest companies expect to take over one trillion in losses due to climate change. Insurers are increasingly jittery and the world's largest firm has warned that the cost of premiums may soon be unaffordable for most people. Historic flooding has wiped out farmers in the Midwest.

Read More Show Less
Aerial view of lava flows from the eruption of volcano Kilauea on Hawaii, May 2018. Frizi / iStock / Getty Images

Hawaii's Kilauea volcano could be gearing up for an eruption after a pond of water was discovered inside its summit crater for the first time in recorded history, according to the AP.

Read More Show Less
The Eqip Sermia Glacier is seen behind a moraine left exposed by the glacier's retreat during unseasonably warm weather on Aug. 1 at Eqip Sermia, Greenland. Sean Gallup / Getty Images

Andrew Yang's assertion that people move away from the coast at the last Democratic debate is the completely rational and correct choice for NASA scientists in Greenland.

Read More Show Less
Sponsored
hadynyah / E+ / Getty Images

By Johnny Wood

The Ganges is a lifeline for the people of India, spiritually and economically. On its journey from the Himalayas to the Bay of Bengal, it supports fishermen, farmers and an abundance of wildlife.

The river and its tributaries touch the lives of roughly 500 million people. But having flowed for millennia, today it is reaching its capacity for human and industrial waste, while simultaneously being drained for agriculture and municipal use.

Here are some of the challenges the river faces.

Read More Show Less

Fibonacci Blue / CC BY 2.0

By Jake Johnson

As a growing number of states move to pass laws that would criminalize pipeline protests and hit demonstrators with years in prison, an audio recording obtained by The Intercept showed a representative of a powerful oil and gas lobbying group bragging about the industry's success in crafting anti-protest legislation behind closed doors.


Speaking during a conference in Washington, DC in June, Derrick Morgan, senior vice president for federal and regulatory affairs at the American Fuel & Petrochemical Manufacturers (AFPM), touted "model legislation" that states across the nation have passed in recent months.

AFPM represents a number of major fossil fuel giants, including Chevron, Koch Industries and ExxonMobil.

"We've seen a lot of success at the state level, particularly starting with Oklahoma in 2017," said Morgan, citing Dakota Access Pipeline protests as the motivation behind the aggressive lobbying effort. "We're up to nine states that have passed laws that are substantially close to the model policy that you have in your packet."


The audio recording comes just months after Texas Gov. Greg Abbott signed into law legislation that would punish anti-pipeline demonstrators with up to 10 years in prison, a move environmentalists condemned as a flagrant attack on free expression.

"Big Oil is hijacking our legislative system," Dallas Goldtooth of the Indigenous Environmental Network said after the Texas Senate passed the bill in May.

As The Intercept's Lee Fang reported Monday, the model legislation Morgan cited in his remarks "has been introduced in various forms in 22 states and passed in ... Texas, Louisiana, Oklahoma, Tennessee, Missouri, Indiana, Iowa, South Dakota, and North Dakota."

"The AFPM lobbyist also boasted that the template legislation has enjoyed bipartisan support," according to Fang. "In Louisiana, Democratic Gov. John Bel Edwards signed the version of the bill there, which is being challenged by the Center for Constitutional Rights. Even in Illinois, Morgan noted, 'We almost got that across the finish line in a very Democratic-dominated legislature.' The bill did not pass as it got pushed aside over time constraints at the end of the legislative session."

Reposted with permission from our media associate Common Dreams.

DESIREE MARTIN / AFP / Getty Images

Wildfires raging on Gran Canaria, the second most populous of Spain's Canary Islands, have forced around 9,000 people to evacuate.

Read More Show Less