Rapid ʻŌhiʻa Death

The ʻŌhiʻa tree, with its companion lehua blossom, is found only in Hawaiʻi, and is the most common of our Islands’ native trees. It is the keystone of the Hawaiʻi forest, critical to the ecology of our watersheds and sacred in Hawaiian culture. And now it is under attack, with new species of fungi killing trees on two islands.

Source: Rapid ʻŌhiʻa Death | Insights on PBS Hawaiʻ‘i, 2019-04-04

Sacred Hawaiian tree is under threat as tourists are asked to help save it

By Lucy Sherriff
The native ʻōhiʻa is sacred to Hawaiians as a cultural touchstone and ecological underpinning for the state’s lush forests and abundant wildlife.

HONOLULU — A deadly fungus threatens one of Hawaii’s most beloved and important species, the ʻōhiʻa tree, and those believed responsible for introducing the threat to the tree in the first place are now being asked to help save it — tourists.

The native ʻōhiʻa is sacred to Hawaiians as a cultural touchstone and ecological underpinning for the state’s lush forests and abundant wildlife. The flowering evergreens that can tower to 85 feet comprise 80 percent of the state’s canopy, covering 1 million acres, and its nectar sustains birds and insects found nowhere else on Earth.

Now, public agencies and private citizens are trying to avoid biological and economic catastrophe by proclaiming war against a deadly fungal disease coined “rapid ʻōhiʻa death,” or ROD, that is swiftly destroying the trees. What’s more, invasive species like the miconia tree, native to North and South America and called the “green cancer” of Hawaii’s forests, are choking out the ʻōhiʻa.

The federal government has attempted to stop the fungus and tackle invasive species by imposing a quarantine on Hawaii Island and carrying out extensive tests to learn how the fungus spreads, but it has yet to find a solution. Hawaiian organizations, communities and scientists are now stepping in.

Gunstock Ranch, a horse riding stable and tourist destination on Oahu, is replanting native trees, although not the ʻōhi‘a yet. After conducting a survey on 80 acres of its land in 2016, and finding just two native species, owner Greg Smith established a Hawaiian “legacy forest,” where visitors can plant trees and monitor their growth online.

“Our hope is that as our guests plant and dedicate a tree they will form a new connection to the land and Hawaii and leave knowing that they made a difference,” Smith said.

Source: Sacred Hawaiian tree is under threat as tourists are asked to help save it – NBC News, 2019-06-30

Trees talk to each other and scientists have mapped the network

By Robert Dalheim
Scientists discovered that trees talk to each other through the Wood Wide Web. And now, they’ve mapped it.

Do trees actually talk to each other? And if so, how do they do it?

Just over 20 years ago, ecologist Suzanne Simard discovered that trees do communicate with each other, and it’s through a fungal network scientists have nicknamed the Wood Wide Web.

And now, an international team of scientists has created the first global map of the vast underground network. They did this by creating a computer algorithm to analyze a database from the Global Forest Inititiave, which includes 1.2 million trees in more than 70 countries.

The algorithm takes into account the different fungal species that associate with each tree species. It also takes into account local climate factors – which the scientists say has the biggest role to play.

“It’s the first time that we’ve been able to understand the world beneath our feet, but at a global scale,” Thomas Crowther, an author of the study from ETH Zurich, told the BBC. “Just like an MRI scan of the brain helps us to understand how the brain works, this global map of the fungi beneath the soil helps us to understand how global ecosystems work.

“What we find is that certain types of microorganisms live in certain parts of the world, and by understanding that we can figure out how to restore different types of ecosystems and also how the climate is changing,” he said.

Source: Trees talk to each other and scientists have mapped the network – Woodworking News, 2019-05-16

Researchers map symbiotic relationships between trees and microbes worldwide

by Taylor Kubota, Stanford University
In and around the tangled roots of the forest floor, fungi and bacteria grow with trees, exchanging nutrients for carbon in a vast, global marketplace. A new effort to map the most abundant of these symbiotic relationships—involving more than 1.1 million forest sites and 28,000 tree species—has revealed factors that determine where different types of symbionts will flourish. The work could help scientists understand how symbiotic partnerships structure the world’s forests and how they could be affected by a warming climate.

In and around the tangled roots of the forest floor, fungi and bacteria grow with trees, exchanging nutrients for carbon in a vast, global marketplace. A new effort to map the most abundant of these symbiotic relationships—involving more than 1.1 million forest sites and 28,000 tree species—has revealed factors that determine where different types of symbionts will flourish. The work could help scientists understand how symbiotic partnerships structure the world’s forests and how they could be affected by a warming climate.

Source: Researchers map symbiotic relationships between trees and microbes worldwide – Phys.org, 2019-05-15

Tree disease leaving ‘zombie forest’ in its wake, expert warns

A forester from Bancroft, Ont., says the province could be doing much more to deal with an insidious disease that’s killing beech trees across Ontario.

Svetlana Zeran called in to CBC’s Ontario Today Monday to say beech bark disease is a major concern on the nearly 400,000 hectares of forest her company manages.

“We have been dealing with beech bark disease for about a decade,” Zeran said. “Now that it is here on the [Canadian] Shield, it is moving very rapidly and we are seeing the disease come in and infect the trees and they are dead within two to five years.”

The disease begins when an insect bores holes in the bark, allowing a red fungus to invade the tree and slowly weaken it from the inside out.

Source: Tree disease leaving ‘zombie forest’ in its wake, expert warns – CBC News, 2018-11-14

Termite gut holds a secret to breaking down plant biomass

In the Microbial Sciences Building at the University of Wisconsin-Madison, the incredibly efficient eating habits of a fungus-cultivating termite are surprising even to those well acquainted with the insect’s natural gift for turning wood to dust.

According to a study published today (April 17, 2017) in the journal Proceedings of the National Academy of Sciences, when poplar wood undergoes a short, 3.5-hour transit through the gut of the termite, the emerging feces is almost devoid of lignin, the hard and abundant polymer that gives plant cells walls their sturdiness. As lignin is notorious for being difficult to degrade, and remains a costly obstacle for wood processing industries such as biofuels and paper, the termite is the keeper of a highly sought after secret: a natural system for fully breaking down biomass.

“The speed and efficiency with which the termite is breaking down the lignin polymer is totally unexpected,” says John Ralph, a UW-Madison professor of biochemistry, researcher at the Great Lakes Bioenergy Research Center (GLBRC) and lignin expert. “The tantalizing implication is that this gut system holds keys to breaking down lignin using processes that are completely unknown.”

Source: Termite gut holds a secret to breaking down plant biomass – EurekAlert! Science News, 2017-04-17

Suzanne Simard: How Do Trees Collaborate?

Ecologist Suzanne Simard shares how she discovered that trees use underground fungi networks to communicate and share resources, uprooting the idea that nature constantly competes for survival.

About Suzanne Simard:
Suzanne Simard is a professor of forest ecology at the University of British Columbia. Her work demonstrated that these complex, symbiotic networks in our forests mimic our own neural and social networks. She has thirty years of experience studying the forests of Canada.

Source: Suzanne Simard: How Do Trees Collaborate? : NPR, 2017-01-13

Soil fungi help tree seedlings survive, influence forest diversity

A new paper published Jan. 13 in Science reveals that the relationship between soil fungi and tree seedlings is more complicated than previously known. The paper was co-written by Ylva Lekberg, an assistant professor of soil community ecology at the University of Montana.

Lekberg and her collaborators studied 55 species and 550 populations of North American trees. Scientists have long known that plants and soil biota can regulate one another, but the new findings highlight the complexity of the feedback loop.

“Fungi differ in their ability to protect tree seedlings from pathogens, and this has implications for seedling recruitment and therefore forest community patterns,” Lekberg said.

Most plant roots are colonized by mycorrhizal fungi, but tree species associate with different fungal groups. The researchers showed that ectomycorrhizal fungi that form a thick sheet around root tips are better able to protect trees from pathogens than arbuscular mycorrhizal fungi.

Thus, while ectomycorrhizal tree seedlings actually prefer growing next to parent trees, arbuscular mycorrhizal tree seedlings can only establish outside the control of parents’ enemies. This can have consequences for how temperate forests are structured and their overall diversity.

Source: Soil fungi help tree seedlings survive, influence forest diversity — ScienceDaily, 2017-01-13

Ash dieback: Insect threat to fungus-resistant trees

Release by University of Exeter
Ash trees which can resist the killer dieback fungus may be more vulnerable to attacks by insects, according to new research.

Scientists from the universities of Exeter and Warwick examined trees which are resistant to ash dieback and – unexpectedly – found they had very low levels of chemicals which defend against insects.

With efforts under way to protect ash trees from dieback, the scientists warn that selecting trees for fungal resistance could put them at risk from insects.

Aside from ash dieback, the other major threat to European ash trees is the Emerald Ash Borer beetle, which has already devastated vast tracts of ash in the USA and is currently spreading westwards across Europe.

Source: Ash dieback: Insect threat to fungus-resistant trees | EurekAlert! Science News