College of Natural Resources, UC Berkeley

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March 30, 2004

U.S. Military Indavertently Introduced Tree Pathogen to Italian Forest During World War II

by Sarah Yang

BERKELEY - During World War II, soldiers from the Fifth U.S. Army set up camp at an exclusive hunting estate in Italy, regrouping between military drives north against German troops and fascist leader Benito Mussolini. Sixty years later, forest pathologists are pointing to huge gaps of dead trees in the estate as the visible reminders of that brief stay.

In a new study published in the April issue of Mycological Research, researchers at the University of California, Berkeley, and in Italy, have unlocked the mystery of how the destructive Heterobasidion annosum pathogen could have spread to the Presidential Estate of Castelporziano, which has been sealed off from the public for centuries.

They were able to trace the origins of the pathogen back to eastern North America, where U.S. troops departed for Europe during World War II. The researchers say the pathogen likely hitched a ride in transport crates, pallets or other military equipment made from untreated lumber from infected trees. It took decades for the pathogen to establish itself, but since symptoms were first noticed in the 1980s, the root fungus has wiped out large swaths of stone pine trees in the Castelporziano estate less than 15 miles southwest of Rome.

"The spread of exotic plant and tree diseases is not new, but this is the first evidence of a pathogen being introduced into a different continent through military activity," said Matteo Garbelotto, an adjunct assistant professor of ecosystem sciences at UC Berkeley's College of Natural Resources and co-author of the study.

"Quarantines and regulations already exist to guard against the introduction of pests and pathogens from lumber brought in through commercial and other sources, but there is no equivalent standard for lumber brought in by the military," said Garbelotto, who is also a UC cooperative extension specialist in forest pathology. "This study suggests that when planning military operations abroad, there is a need, and a responsibility, to check for potential micro-organisms that could be introduced to foreign lands, and to take measures to prevent them from spreading."

Control of the nearly 15,000-acre estate has passed through the hands of various leaders in Italy's history. For centuries it was used as a hunting ground favored by the popes before becoming the exclusive property of the king by 1870. After World War II, when Italy voted to dissolve the monarchy to become a republic, the estate was turned over to the president, but public access remained restricted.

"The estate is of naturalistic importance because it is a pristine example of a Mediterranean forest," said senior author Paolo Gonthier, assistant professor at the University of Torino's Department of Exploitation and Protection of the Agricultural and Forestry Resources. "Except for a few eucalyptus trees, the estate contains exclusively native Italian flora."

In the mid-1980s, estate staff started noticing symptoms of infection in the stone pines. They did not know what was causing the die-off at the time, but the disease spread quickly, killing several hundred trees throughout the forest.

"There is a gap in the forest of about 100 meters from where trees were cut down because they were dead from infection by the fungus," said Gonthier. "There are now just a few isolated stone pine trees that remain in the gap."

In an effort to find the culprit, the investigators combined cutting-edge DNA analysis an extensive search through historical documents and interviews with staff members at the preserve.

Gonthier and his colleagues collected samples of the pathogen from fertile fruiting bodies, allowing researchers to obtain pure cultures for analysis.

But when the researchers analyzed the genetic material, they unexpectedly found a telltale insertion of a piece of DNA in the mitochondria known to be present in North America, but not in Europe.

Researchers in Garbelotto's lab had just finished constructing a genetic database for H. annosum, enabling them to narrow down the region where the samples taken from Castelporziano originated. They sequenced four different genes, all of which matched the DNA of North American species. Two of the four matched eastern North American species, and one matched a species in the Southeast region of the United States.

Further genetic analysis revealed that the samples they collected from the woodlands each had different genotypes, indicating that the population was several generations removed from the "founding" pathogens that originally settled the estate.

"At this point, the H. annosum population at Castelporziano is indistinguishable from a natural population in the eastern United States, which indicates that it has become well-established," said Garbelotto. "DNA analysis also indicates that the Castelporziano population is diversified and is made up of many different individuals, as it is normally seen in the wild in the United States. This process takes decades, so we know the infection was not a recent occurrence."

What the researchers did not know at the time, however, was how the non-European pathogen could have ended up in an Italian estate that saw very few visitors, both foreign and domestic. They ruled out the introduction of an infected plant since exotic species had not been planted in the forest, except for a small group of eucalyptus trees that are far from the areas of infection.

"The only other possible mode of transport is through untreated lumber," said Garbelotto. "This pathogen is not that easy to move. It doesn't move through soil, and its airborne spores are short-lived. And until now, the only documented transport of this pathogen was on the scale of a few kilometers, certainly not thousands of miles."

The connection to military activity came when researchers learned from interviews with estate staff that the U.S. Army had set up an encampment on the grounds during World War II. A search through accounts of military history confirmed that, for at least one month in the summer of 1944, the 85th Infantry Division, part of the Fifth U.S. Army, stayed on the grounds shortly after capturing Rome.

"There is little doubt in my mind that the source of the pathogen was the U.S. Army," said Garbelotto. "Everything matches - the timeline and location of infection, plus the region of origin of the fungus."

Garbelotto said the findings support a common suspicion among plant pathologists in Europe that certain diseases in that region are linked to U.S. Army bases. "The sources of tree diseases that have afflicted Europe this past century, including Chestnut blight, often seem to be near U.S. military bases, but they had no way of proving the link," said Garbelotto. "This study is as close to a link as we've gotten."

He said the lesson in this is that when there is an organized mass movement of people and equipment through unregulated military channels, the introduction of microbes is a real risk.

"This study suggests that self-imposed regulations may be a useful implementation by the military," said Garbelotto. "The effects of the introduction of exotic microbes may not be evident for decades, and by then eradication of the exotic organism may be impossible."

The researchers are not sure how they can protect the remaining stone pine trees in Castelporziano, but they are watching to see if the pathogen manages to spread beyond the estate. While the pathogen infects a number of plants, it does the most damage to pine, juniper and cedar trees.

"Right now we know that this pathogen is virulent on Italian stone pines, but we don't yet know if it has affected other pines or broad-leaf species in Europe," said Gonthier. "When tourists visit the region, they expect to see these stone pines. It's the landmark tree for the Mediterranean coast. We need to ensure that this exotic pathogen does not spread to regions outside the estate."

The other authors of this study are Rachel Warner of the UC Berkeley Department of Environmental Science, Policy and Management; and in Italy, Giovanni Nicolotti of the University of Torino Department of Exploitation and Protection of the Agricultural and Forestry Resources, and Angelo Mazzaglia of the University of Studies of Tuscia Department of Plant Protection.

This research was conducted with the cooperation of the Technical and Scientific Commission of the Presidential Estate of Castelporziano.

NOTE: To reach Matteo Garbelotto, call (510) 643-4282 or e-mail

Print-quality images are available for download here

March 18, 2004

Research Questions Efficacy of Fire Management Strategies in California Shrublands

by Sarah Yang

BERKELEY - The age of vegetation in California's shrublands does not strongly influence the probability of wildfires, finds a new study led by a researcher at the University of California, Berkeley. The findings challenge a basic assumption underlying fire management strategies used to prevent wildfires like the ones that swept through southern California in October 2003.

"If the goal is to save people's homes and avoid loss of life, then treating extensive portions of the landscape to create a mixture of young and old vegetation is not money well spent," said lead author Max A. Moritz, wildland fire specialist at the UC Center for Forestry's Fire Program. The center is based at UC Berkeley's College of Natural Resources.

Conventional wisdom has been that older shrubs have a higher percentage of dry, dead biomass that can more easily fuel intense wildfires, said Moritz. In addition, decades of fire suppression are believed to have allowed extensive stands of older vegetation to accumulate. As a result, fire management strategies have focused on various techniques to create an "age-patch mosaic" on the landscape because it is assumed that fire will not spread through younger stands of regenerating shrublands.

The findings of the study, reported in the March issue of Frontiers in Ecology and the Environment, break from a school of thought in fire management that incorporates treatments of extensive portions of the landscape, such as prescribed burns, to reduce fire risk.

In forested ecosystems that prehistorically experienced frequent, low-intensity surface fires, decades of successful fire suppression are typically blamed for allowing the accumulation of underbrush and medium-sized trees, particularly in the ponderosa pine forests of the southwestern United States. Many researchers believe that fire suppression has led to the formation of "ladder fuels" that now allow high-intensity fires to climb into the canopies of taller trees.

This view of a direct link in an ecosystem between fire hazard and the time since the last fire appears to have been adopted in shrubland fire management without really being tested, said Moritz. The rationale for shrublands was that suppressing smaller fires promoted the accumulation of older, contiguous stands of more flammable vegetation. Fire management strategies therefore included methods such as small, prescribed fires as a way to initiate the growth of new vegetation that, theoretically, is less prone to burning.

"One problem is that the model of fire hazard for some forests is not necessarily appropriate for the shrublands of southern California, which are characterized by periodic, high-intensity fires," said Moritz. "There has been ongoing debate in fire management about whether the age and spatial patterns of fuels are really an important constraint on the development of large shrubland fires. Our study provides evidence that different strategies should be used for the different ecosystems."

The authors analyzed data from several hundred wildfires over the past century in an area from northern Baja, just south of the United States-Mexico border, up to Monterey Country. Areas of the study include Los Padres National Forest and the Santa Monica Mountains National Recreation Area. They used various sources of data to determine how frequently the fires occurred and how much vegetation burned in different age classes.

"If age had a strong effect on the frequency and extent of wildfires in shrublands, we would have seen minimal burning in younger vegetation and a significant increase in burning with older vegetation," said Moritz. "Instead, we found that for almost all of the regions studied, vegetation age was not a clear driver of fire hazard."

The authors conclude that an accumulation of older shrublands due to fire suppression would not play a major role in causing large wildfires. Rather, the impact of the hot, dry Santa Ana winds, which blow through California's southern and central coast regions every fall, is the more dominant factor.

The one exception where the age of the vegetation was linked to a lower hazard of burning was in the western end of the Santa Ynez Mountains, a region in the backcountry behind Santa Barbara. The authors note, however, that the area is relatively sheltered from the effects of the Santa Ana winds.

"It's not that the age of the vegetation is irrelevant," said Moritz. "But for fires that occur during extreme weather conditions of southern California, vegetation age simply becomes much less important."

Moritz said the findings from this study indicate that treatments of extensive portions of the landscape in California's shrublands to create a mixture of young and old vegetation patches will not have the fire hazard reduction impact people are expecting. The authors note that large wildfires occurred throughout the region's history, even before modern fire suppression methods were introduced, and that we may need to accept them as natural and inevitable events for the area.

"Fire management strategies should focus on more effective use of resources, like creating defensible space immediately around people's homes and communities, attempting to fire-proof structures, and developing better evacuation procedures," said Moritz. "We also have to ask ourselves whether it makes sense to build homes in areas at risk for fire or natural hazards in the first place. Doing so is inherently dangerous, and it is at least in part an urban planning problem."

Co-authors of the paper are Jon Keeley of the U.S. Geological Survey's Western Ecological Research Center; Edward Johnson of the University of Calgary's Department of Biological Sciences; and Andrew Schaffner of Cal Poly State University's Statistics Department.

Environmental Protections Weakened Under Bush Administration


by Kelly Hill

Former U.S. Environmental Protection Agency Administrator Carol Browner believes the Bush administration is gutting the agency she led for eight years.

Browner spoke at Boalt Hall on Thursday afternoon. The lecture was sponsored by the College of Natural Resources’ Department of Environmental Science, Policy and Management as part of an ongoing colloquium series.

Browner had the longest tenure of any EPA administrator, heading up a $7 billion-dollar-a-year, 18,000-employee agency under former President Bill Clinton. Among other accomplishments, she was responsible for coordinating a $1 billion program to clean up the nation’s Brownfields sites.

Browner said that with the country focused on issues such as the war in Iraq, homeland security and the economy, not much press coverage or public attention is focused on the changes that the Bush administration is making to environmental rules.

“It is not simply a question of benign neglect – rather, it is actual destruction,” Browner told the crowd. “They are systematically dismantling the system that has brought us progress.”

Among the examples she cited:
* Withdrawing the U.S. from the Kyoto protocol on greenhouse gas emissions.
* Allowing national monuments to be open to oil and gas exploration.
* Allowing EPA lawsuits against some of the nation’s dirtiest, oldest power plants to stagnate in the court system.
* Proposing a weaker mercury emissions standard than a plan by EPA under Clinton; the Bush plan, Browner said, would allow polluters to release mercury at higher levels for a longer period of time than the previous plan.

In discussing the role of the private sector in environmental progress, Browner said that one of America’s strengths was being “willing to set standards, even if we don’t know how we’ll meet them” because it encourages the private sector to invest in discovering new technologies that are effective, often cheaper than first expected and which create jobs.

Browner also said that the Bush administration has weakened the agency’s enforcement. During her tenure, the agency took a “sector approach” that encouraged many companies with similar violations to clean up voluntarily, Browner said. Now enforcers work at the older, slower method of building each case separately without taking industry-wide problems into account.

“It’s not fair to those who do comply, if their competitors are allowed to not comply,” she said, adding that the Bush administration has “taken the environmental cop off the beat.”

She also noted the importance of informing the public about environmental hazards in order to gain support for widespread change, such as cutting down on greenhouse gasses.
Browner is currently chair of the board of directors of the National Audubon Society and a board member of Environment2004, a partisan group that opposes the Bush administration’s environment-related policies.


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U.S. Military Indavertently Introduced Tree Pathogen to Italian Forest During World War II
Research Questions Efficacy of Fire Management Strategies in California Shrublands
Environmental Protections Weakened Under Bush Administration


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