By Kat Kerlin
CCalifornia’s drought and bark-beetle infestation killed more than 129 million trees between 2012 and 2016 in the Sierra Nevada. But amid the devastation stood some survivors.
At the time, UC Davis biologist Patricia Maloney and a team of researchers entered the forest to collect seeds from 100 surviving sugar pine trees. Alongside other parched sugar pines etched with the tell-tale tunnel marks of bark beetles, were green, healthy trees. The researchers spent the past two years raising 10,000 seedlings from 100 surviving mother trees around the Lake Tahoe Basin. They were first cultivated at the USDA Forest Service’s Placerville Nursery and then moved to the UC Davis Tahoe City Field Station.
This week, between 4,000 and 5,000 of the seedlings are being planted around Lake Tahoe’s North Shore as part of a restoration project funded by the Tahoe Fund and the California Tahoe Conservancy. About 1,500 will be used to study and identify important adaptive traits, and the remainder will be given to private landowners to plant.
f the seedlings turn out to be as genetically resilient as Maloney thinks and hopes they will be, these trees could represent the future forest, one better able to withstand the threats of climate change, including more droughts and bark beetle outbreaks.
“These survivors matter,” said Maloney, a scientist in the UC Davis Department of Plant Pathology and Tahoe Environmental Research Center. “Essentially, these are the offspring of drought survivors. This is hopefully the genetic stock of the future.”
By Peter Fimrite
It is the forgotten killer when compared to our increasingly frequent climate calamities, but the virulent pathogen known as sudden oak death remains active and is spreading death so fast it could destroy California’s coastal forest ecosystem, UC Berkeley scientists reported Thursday.
The deadly microbe has now established itself throughout the Bay Area and has spread along the coast from Monterey to Humboldt County, according to a study of 16,227 trees in 16 counties in Northern California.
Millions of coast live oak and tan oak trees have withered and died over the past quarter century, leaving acres of kindling for wildfires, but the outbreak this year was one of the worst. Oak trees have historically been abundant in California and southwestern Oregon, with hundreds of millions of them stretching all the way to Baja California.
The rate of trees infected almost doubled in 2019 — from 3.5% to 5.9% — and was 10 times higher in some places compared with the 2018 survey, said Matteo Garbelotto, the director of the UC Berkeley Forest Pathology and Mycology Laboratory, which tested leaf samples taken by 422 volunteers.
Infections were found in all the well-known hotbeds, like Marin and Sonoma counties, the East Bay, Big Sur and the Santa Cruz mountains. But the 12th annual survey detected more of the pathogen this year in virtually every location. That’s mainly because the disease spreads faster in the kind of wet weather that hit California last winter, Garbelotto said.
“There was a significant increase in infection rates over last year, but that’s not totally surprising because we had a lot more rainfall,” Garbelotto said. “But it was a surprise to see them all at once. It’s telling us we are entering a different phase of the disease, where the organism isn’t really establishing itself in new areas, but is showing itself more when weather conditions are favorable.”
Sudden oak death is an exotic disease that was discovered in Mill Valley in 1995. It now exists in forests and wildlands in 14 California counties and in Curry County, Ore., just across the state border.
It kills oak trees, including California’s signature tree — the live oak — and there are 107 susceptible host plants, including such common garden ornamentals as camellias and rhododendrons. Although some hosts are sickened, they do not always die from the fungus-like ailment. Instead, these plants, bushes and trees help spread the deadly spores.
They are iconic to Florida, but palm trees offer little shade to urban heat islands and capture very small amounts of carbon, a greenhouse gas contributing to global warming.
South Florida’s palm trees are postcard promises of sighing sea breezes and sandy beaches, but the icon of the tropics may be an impractical adornment in an era of climate change.
From the regal royal palm to the sometimes shabby cabbage, the perennial symbol of the Sunshine State offers little shade to baking urban heat islands and captures minimal amounts of carbon — a greenhouse gas contributing to global warming.
As city officials look for more ways to cool concrete jungles and balance carbon emissions, the priority for new plantings is often broadleaf hardwood trees, not the idyllic palm.
Live oaks can absorb and store 92 pounds of carbon a year with a mature tree’s canopy spanning more than 100 feet. That’s compared to less than one pound of carbon for a royal palm and its compact crown of 15 to 20 fronds.
“People coming from up north or other parts of the country are expecting to see palm trees, so I don’t see them disappearing entirely from the landscape,” said Charles Marcus, a certified arborist who wrote an urban tree management plan for West Palm Beach. “But it would benefit most communities if they increased the percentage of hardwoods and I think it’s something cities will have to consider.”
Palms aren’t even an option at City of West Palm Beach community tree giveaways, and a 2018 city ordinance puts an emphasis on using more shade trees in new construction, especially parking lots where 75 percent of the required trees must now be shade trees.
“We’re not trying to seek out and replace palm trees with canopy trees, but we are looking at if we have to do a replacement, would a canopy tree fit,” said Penni Redford, resilience and climate change manager for West Palm Beach.
Three years of studies in cities including Baltimore, Richmond, Va., and Washington by the National Oceanic and Atmospheric Administration found that areas covered in concrete with few trees could be 17 degrees warmer than shaded areas.
The same study conducted in West Palm Beach this past August found a heat-index temperature of 122 degrees near downtown, compared to 92 degrees taken during the same time period near the wetlands area of Grassy Waters Preserve.
“These are samples taken in one time period and one day out of the year, but given the conditions, the difference is staggering,” said Michael Rittehouse, sustainability project coordinator for West Palm Beach.
By Laura Lundquist
Federal and state leaders laud not only the ability of Montanans to hash out tough issues but also the way collaboration has gotten several timber projects into production.
That was evident from the speeches of Lt. Gov. Mike Cooney and Jim Hubbard, U.S. Department of Agriculture undersecretary, who kicked off the Montana Forest Collaboration Network’s annual two-day workshop in Missoula.
The two men praised the efforts of Montana’s collaborative groups, represented by the 120 participants in the audience, that have put many hours into finding agreement on which forest tracts have “the right acres in the right places” to sustain commercial timber projects.
“In an age where political polarization often threatens the progress of important policy, you all quietly keep coming back to the table, year after year,” Cooney said. “You find sensible paths forward by engaging diverse local perspectives, treating one another like neighbors in advancing plans that ultimately can achieve durable returns for our forests and our communities.”
Cooney said that kind of cooperation was one reason Gov. Steve Bullock was able to make Montana the first state to sign a stewardship agreement with the U.S. Forest Service, allowing the state to negotiate with federal, tribal and private partners to thin trees or use prescribed burns regardless of who manages the area. Thus, foresters can focus on any region that might be important for reducing wildfire risk near communities. Yet, only seven other states have signed shared stewardship agreements.
Hubbard said being able to work across multiple jurisdictions is necessary to do work at a large enough scale to be effective at slowing a potential wildfire. But when it comes to wildfire, thinning projects go only so far.
“There’s no way in the world we’re going to protect all the communities that are at risk of fire in the West. There’s no way in the world we’re going to treat all the acres that need treatment. So which ones are we going to go for? That’s the shared priority, to decide what we want to do together,” Hubbard said. “Also, the community has to be engaged, because if the community isn’t paying attention, all that land treatment is not necessarily going to reduce their risk very much.”
Bullock was also among the first to sign a Good Neighbor agreement. The 2014 Farm Bill created the Good Neighbor Authority to allow states to log timber on federal land adjacent to state or private land undergoing thinning operations. The 2018 Farm Bill broadened that authority.
Cutting down trees inevitably leads to more carbon in the environment, but deforestation’s contributions to climate change are vastly overestimated, according to a new study.
Deforestation for timber and farmland is responsible for about 92 billion tons of carbon emissions into the environment since 1900, found a study led by researchers at The Ohio State University and Yale University.
“Our estimate is about a fifth of what was found in previous work showing that deforestation has contributed 484 billion tons of carbon – a third of all manmade emissions – since 1900,” said Brent Sohngen, a professor of environmental and resource economics at Ohio State.He said that widely accepted estimate didn’t take into account the planting of new trees and other forest management techniques that lessen the environmental burden. The model used in this study did take those factors into account, which made a significant difference considering the intensive forest management happening in many parts of the world and the less-intensive, but not inconsequential, management that is happening elsewhere.
The study appears today (Nov. 4, 2019) in the Journal of Forest Economics.
“There was a significant shift toward treating forests as a renewable, rather than nonrenewable, resource in the last century, and we estimate that those reforestation and forest management efforts have led to a far smaller carbon burden on the environment,” Sohngen said, adding that the previous estimate was based on trees’ natural regrowth without any human intervention.
The Nature Conservancy has begun using a drone to aid its reforestation efforts in northeast Minnesota.
By Cody Nelson and Jiwon Choi
To understand the health of a forest, conservation workers typically hit the ground and survey the land acre by acre.
It can involve trudging through the woods with hiking boots or snowshoes, looking for gaps in the forest canopy that need restoring.
But this summer, the Nature Conservancy’s Minnesota branch found an easier way to survey the large swaths of forest that comprise some of the over 60,000 acres it manages in the state.
The conservancy began using a drone to aid its reforestation efforts in northeast Minnesota. It has helped in several ways from making highly detailed maps to providing flyover video in key areas.
“It’s almost like another staff member,” said Chris Dunham, the nonprofit’s forestry manager. “We’re a small, small forest team here and we can use every advantage we can get.”
While the forest may look quite thick from the bird’s-eye view, the vantage point can be misleading. The nonprofit has estimated hundreds of thousands of acres of North Shore forest is in need of some help.
One of the Nature Conservancy’s focuses in Minnesota is on restoring riparian gaps — or places along rivers and streams in the forest where trees have died or been cut down.
Restoring these gaps is good for preventing erosion into the river, sequestering more carbon in the forest and creating better wildlife habitat.
There’s still ground-truthing to do once the drone footage in hand, Dunham said, “but you can be way more efficient if you’ve already taken a cruise above the trees and know where you’re headed.”
By Theresa Davis
BANDELIER NATIONAL MONUMENT – Pinecones hang from tree branches and scatter the forest floor near Los Alamos. At first glance, they are nothing special. But inside those cones are seeds that can help bring a forest back to life.
This year, ponderosa pine trees in New Mexico are producing more pinecones than they will for the next 10 to 15 years – an event scientists call a “mast seeding.”
The Nature Conservancy, Santa Clara Pueblo, the National Parks Service, the Institute for Applied Ecology, the New Mexico Department of Game and Fish and Highlands University are collecting the abundant seeds to plant in areas that have burned in severe wildfires.
The groups set a goal of gathering 1 million seeds in New Mexico and Colorado this fall, according to Sarah Hurteau, urban conservation director for the Nature Conservancy.
“Mast seeding is an evolutionary process,” she said. “In these years, trees will produce enough seeds that animals can’t eat them all, so more seeds get the chance to germinate.”
Last winter’s above-average precipitation helped make this year ideal for a mast seeding. Ponderosa pines currently have more viable seeds per cone, which means the groups get a better selection of potential trees for reforestation.
Wildfire is a natural part of the life cycle in northern New Mexico forests. Many trees need fire to germinate. But the size and severity of recent forest fires is unusual, said Kay Beeley, a natural resource manager with the National Park Service. She referenced the forest damage done by Los Conchas Fire in 2011. The blaze consumed 156,000 acres and burned for more than a month in northern New Mexico.
By Michelle Ma
About 450 nonnative, plant-eating insect species live in North American forests. Most of these critters are harmless, but a handful wreak havoc on their new environment, attacking trees and each year causing more than $70 billion in damage.
The problem is, scientists often don’t know which insect will emerge as the next harmful invader.
A team led by the University of Washington, drawing largely on the evolutionary history of insect-plant interactions, has developed a way to understand how nonnative insects might behave in their new environments. The team’s model, described in a paper appearing Oct. 17 in the journal Ecology and Evolution, could help foresters predict which insect invasions will be problematic, and help managers decide where to allocate resources to avoid widespread tree death.
“What makes the bad invaders so special? That has been the million-dollar question, for decades,” said Patrick Tobin, an associate professor in the UW School of Environmental and Forest Sciences and one of the project leaders. “This has the potential to profoundly change how we predict the impact of nonnative species and prioritize limited resources used to mitigate these impacts.”
The new model can quickly evaluate whether a newcomer insect, even before it gets here, has a high probability of killing a population of North American trees. To use the model, all that’s needed is information about the insect’s feeding method (wood, sap or leaf feeder, for example) and what trees it feeds on in its native range. The model will then determine whether any North American trees are at risk of dying from it.
Whether a nonnative insect takes hold and becomes destructive has more to do with the evolutionary history between the new (North American) host tree and the insect’s native host tree from its home region, Mech explained. Molecular tools that allow scientists to construct comprehensive phylogenies (or maps) of how tree species evolved was key to the team’s breakthrough.
For example, if a pine tree in Asia and another in North America diverged tens of millions of years ago, the North American pine likely wouldn’t have retained defenses against an insect that only lives with the pine in Asia. Alternatively, two pines on both continents that share more evolutionary history and diverged more recently might still share similar defenses.
The new model helps identify the evolutionary “perfect storm” for conifers, where the invasive insect still recognizes the new tree as a food source, but the tree hasn’t retained adequate defenses to keep the invader in check.
By Aaron Labaree
The biggest wildfire in 20 years in Spain’s Catalonia region began on June 26, when a pile of chicken manure, baking in record high temperatures, burst into flames.
Fed by strong winds, the flames spread quickly, igniting dry brush and pine forest. In three days the fire burned more than 16,000 acres, and it took more than 500 firefighters to put it out.
Fires in California and the Amazon rainforest have grabbed attention, but large areas of Europe’s forests also were consumed this summer. Blazes nearly the size of the one in Catalonia tore through Spain’s Canary Islands, the south of France and the Greek islands of Evia and Samos.
From January to mid-October, the European Union has had almost triple the average number of wildfires for the same period over the past decade, with more than 800,000 acres burned so far this year, according to the European Forest Fire Information System.
Heat waves like the ones Europe experienced in 2019 are far more likely to happen because of the changing climate. And hot, dry conditions contribute to making massive fires no longer just a southern European problem: Last year Sweden saw its biggest fires in modern history, and this year the United Kingdom had a record number of them.
Now, like in the United States, firefighters and ecologists in Europe are starting to realize that putting out each fire isn’t possible or desirable. To prevent megafires, experts say, the authorities have to let forests burn naturally — and sometimes even set fires on purpose.
“We need to learn to live with fire, the same way we do with tornadoes or snowstorms,” says Marc Castellnou, chief analyst for a special forest unit of Catalonia’s fire services, known by its Catalan initials GRAF.
The wildfire problem is partly a result of decades of prevention. Fire plays a natural role in a healthy forest, burning away brush, dead trees and plant debris, while leaving many mature trees alive. But to protect human habitation, officials have tried to allow almost no fires to burn. The result is forests that are packed with undergrowth providing kindling and enormous unbroken stocks of trees to burn — megafires waiting to happen.
Europe’s forests have reached this dangerous state for another reason not seen in the U.S.: rural abandonment.
“When I was growing up, all of this was harvest — hazelnuts and olives,” says Rut Domènech, a forest expert who lives in Ribera d’Ebre, the county in Catalonia’s Tarragona province where the recent fires took place, pointing at what is now continuous forest. In the 1950s, the price of these and other crops plummeted with international competition and farmers were forced to move to cities.
Over much of Europe, rural abandonment has led to once-cultivated fields being given back to nature. In the 50 years after World War II, Western Europe’s forest area increased almost 30%. The continent’s land is now more than 40% forested.
Mediterranean shepherds and farmers have been using fire to manage the landscape for thousands of years. But most techniques used by firefighters today were developed in the United States, where the record-setting blazes of the past 10 years have shown the limits of suppression alone. In the U.S. as well as Europe, the change in approach toward fire is just beginning.
“In the scientific community, it’s understood we need to get fire back on the landscape,” says Rod Linn, a climate modeler at Los Alamos National Laboratory in New Mexico. “And most fire practitioners have come to grips with fire having a lot of benefits. But with the public, there’s work to do to get it socialized, to get people aware that just because you see smoke, it’s not necessarily bad.”
By Will Brendza
Jeremy Altdorfer’s day of delivery was hectic, but successful. All day on Saturday, Oct. 5 he was zipping around Boulder in his car, which was loaded to the brim with white pine saplings; making one delivery after the next, dropping off the baby trees wherever they’d been requested. Meanwhile, his brother and other partners from Experience Dental, opening Oct. 30, were doling out more trees at several different locations throughout the county.
Their goal: to plant 1,000 trees in Boulder County in a day. Or, at least, to give out 1,000 ready-to-plant trees to individuals, businesses and schools that wanted and needed them. In part, Altdorfer wants to reduce his own business’ carbon footprint, and in part, he wants to help save Boulder’s threatened canopy of trees.
“I thought we were crazy, trying to do 1,000 in a single day,” Altdorfer says. But by the end of the day, they’d met their goal — all 1,000 trees had been distributed.
Altdorfer’s 1,000 white pines are going to help offset what the City of Boulder is calling the “Tree Crisis of 2019.” Boulder’s trees are currently under threat, and while the City’s forestry department plants about 500 new ash trees a year, Altdorfer’s contribution of 1,000 white pines in a single day is a welcome offering and a much-needed addition.
“Planting new trees is crucial to maintaining our urban tree canopy,” says Kathleen Alexander, a forestry worker with the City of Boulder’s forestry department.
According to Alexander, Boulder is projected to lose some 70,000 ash trees to the emerald ash tree borer (EAB), an invasive insect from Asia, over the next 10 years. By 2035, she says, the EAB could destroy 25 percent of Boulder’s urban tree canopy.
It’s why the City is urging residents and the community to take action and plant trees to replace those being killed, and to protect existing trees. It’s why the City has planted more than 2,500 trees on public property since 2013, and why it’s provided more than 3,900 trees to residents for planting on private property.
Having an assorted mix of tree species around the City and throughout Boulder County means the urban canopy is less vulnerable to any one stressor.
“A diversity of tree species is going to help make the urban forest more resilient long-term,” Alexander says.
White pines are good options because they grow fast, they grow large (so they sequester a lot of carbon) and they aren’t at risk from EAB.