In severely burned areas, nearly all lichen were gone, even 16 years after a fire.
As increasingly hot and severe wildfires scorch the West, some lichen communities integral to conifer forests aren't returning, even years after the flames have been extinguished, according to a study from scientists at the University of California, Davis.
Lichen, an often overlooked organism that forms fuzzy, leaflike layers over tree bark and rocks, is an unsung hero in forest ecosystems. It provides food for deer, caribou and elk, and is sometimes the only food source for flying squirrels, which are key prey for threatened spotted owls. Birds and insects use it to eat and nest. An important contributor to the nutrient cycle, it also helps fix nitrogen in forest soils.
“Lichen are beautiful, ecologically important, are all around us and tell us important things about the environment,” said lead author Jesse Miller, a postdoctoral scholar in the Department of Environmental Science and Policy at UC Davis. “But even if you don't notice lichens, you would notice the consequences in ecosystems when they are lost.”
Lichen loss and fire severity
For the study, published Aug. 9 in the journal Global Change Biology, researchers sampled lichen communities in about 100 study plots across California's Sierra Nevada region. Five wildfires had burned, at varying levels of severity, in and around the plots between four and 16 years before the study's sampling.
The results show that lichen communities were largely unaffected by low-severity fires. This suggests that prescribed fires and natural wildfires under moderate weather and fuels conditions are compatible with lichen diversity.
But areas that experienced higher severity wildfires had significantly lower abundance and diversity of lichen.
In severely burned areas where most of the trees died, nearly all the lichen were gone, even 16 years after the fire.
The lichens' recovery is likely held back by the loss of tree canopy after the fire, the researchers said. The hot, dry microclimate left in the forest post-fire is not conducive to lichen growth. This indicates that lichen communities burned in Sierra Nevada forests likely won't recolonize until mature trees regrow and the forest canopy is restored. This may exacerbate the effects of climate change that already threaten lichens.
“If the species could keep pace with the rate of climate change, the effects of fire might not be so bad,” Miller said. “But the concern is they might not. These fires happen so quickly and in such a large area, they could cause species ranges to contract faster than they are expanding.”
The study also indicates that the trend of increasingly dry forests and hotter, bigger and more severe wildfires could cause broad impacts to lichen diversity across the landscape, which could impact nutrient cycling and multiple food-chain interactions among wildlife.
The study areas included:
Yosemite, in areas burned by the Rim (2013) and Grouse (2009) fires
Greater Lake Tahoe Basin, in areas burned by the Showers (2002) and Long (2009) fires
Warner Mountains, in northeastern California, in areas burned by the Blue Fire (2001).
The study's co-authors are Hugh Safford of UC Davis and the USDA Forest Service, Pacific Southwest Region; and Heather Root from Weber State University in Utah.
The research was funded by the USDA Forest Service, Pacific Southwest Region.
Jesse Miller, Environmental Science and Policy, firstname.lastname@example.org
Kimberly Hale, UC Davis News and Media Relations, 530-752-9838, email@example.com
Kat Kerlin, UC Davis News and Media Relations, 530-752-7704, 530-750-9195 (cell), firstname.lastname@example.org, Kerlin will be out of the office Aug 9-13.
The news that Americans are getting about California's devasting fires is not being hyped up by the media, said UC Cooperative Extension area fire advisor Lenya Quinn-Davidson on the nationally broadcast NPR program On Point.
Host Eric Westervelt of WBUR in Boston got a Northern California perspective from Quinn-Davidson, who works with communities in Siskiyou, Trinity and Mendocino counties on managing the threat of wildfires and is the Northern California coordinator of the California Fire Science Consortium.
"I definitely don't think the situation is being hyped up," Quinn-Davidson said. "I'm in Ukiah and there's a thick blanket of smoke. Everyone can feel the tension of the Mendocino Complex Fire."
Quinn-Davidson said she grew up in the vicinity and, back then, major fires like those burning today only happened every few years. Lately, such super fire seasons are happening every year. She said it's time for Californians to take a different approach when thinking about fire.
"Fire is the only natural disaster that we fight against," Quinn-Davidson said. "With hurricanes and earthquakes, we adapt and try to identify vulnerabilities and change our behavior. We haven't treated fire like that. We need to learn how to adapt and make changes that make us more resilient to fire."
On Point is NPR's only call-in program. One caller asked whether climate change has reached an irreversible tipping point at which little can be done to reverse the damage that is causing extreme flooding, heat, hurricanes and wildfires.
Quinn-Davidson said she offers hope to the people in communities she serves.
"They're not powerless," she said. "I don't want people to feel that we are beyond some tipping point and they should just throw in the towel. I think we need to feel empowered to make the changes we can make - whether on a personal scale, at at the mid-grade community scale, or if it is taking political action to make larger change ... We still have some place to make a difference. I really believe that."
Michael Mann, professor of atmospheric science and director of the Earth System Science Center at Pennsylvania State University, was also a guest on the On Point program. He said that, as a nation, we may have breached a different tipping point - a tipping point in public consciousness. Recent news reports have informed the public about extreme flooding in Japan, record-breaking heat in Europe and catastrophic wildfires in California.
"This summer has made a difference in the public perception of how profound the threat of climate change already is," Mann said. "And I like to think that when they go to the voting booths in less than 100 days, they're going to be thinking about climate change and the need to act on this problem. I think we will see progress."
Reposted from the Confluence, blog of the California Water Resources Institute
California National Guard members wade through mud to people trapped inside a Montecito home. Air National Guard photo by Senior Airman C. Housman.
Maryam Kia-Keating, Ph.D. is an Associate Professor of Clinical Psychology at UC Santa Barbara and a Licensed Clinical Psychologist. Her work focuses on coping and resilience in the context of adverse childhood experiences, trauma, and stress, particularly for vulnerable and understudied populations. She is on Twitter @drkiakeating.
You have done research related to resilience and trauma in the wake of disasters in California. What have you learned?
It's important to pay attention to the psychological impact of disasters. Oftentimes, there is an initial, understandable focus on basic needs and stabilization in the aftermath of disasters. But neglecting psychosocial well-being is short-sighted. There is a lot of empirical evidence demonstrating its impact on other elements of individual and community health and resilience, both initially and over the long-term.
What I have learned in my own research, as well as from work by many others in disaster mental health, is that recovery takes time and has many phases. It can be different for different people who experienced the same disaster, and it is important not to judge one person's experiences and reactions by another's.
For example, after a wildfire, one family described enjoying a newfound sense of cohesion and camaraderie with their neighbors. At the same time, they experienced conflicts and tensions because of the differences in what people needed, and the fact that their reactions that were sometimes poles apart. Part of the issue was that the impact the fires had on homes was sometimes vastly different; some were still standing and others right next door were burnt to the ground.
It's also clear from empirical data that secondary stressors play a major role. The trauma experienced during the disaster is important, but what you face as a result -- financial stress, displacement, and other burdens -- adds another component that predicts overall well-being in the long-term.
A California Air National Guard rescue helicopter with air crews provides search and rescue operations during mudslides in southern California, January 2018. Photo by Staff Sgt. Cristian Meyers.
Can you describe the kinds of issues that face people after they deal with disasters? You've written about both trauma and more positive outcomes, like prosocial behaviors, that emerge.
A traumatic event shakes your core assumptions about the world as a safe place. That feeling of deep uncertainty and disruption to your own safety and the safety of those you love can be terrifying. The added intensity of personal and material losses can lead to complete and utter disorientation. Some people I worked with described a period of time when they just couldn't focus on anything, walking around with glazed expressions, not recognizing familiar people and places. At the same time, well-meaning people and organizations tried to provide them with assistance, but they were challenged to receive the benefits.
Following that initial period, they described disrupted relationships. This led to a sense of isolation and disconnection because they were still struggling even though the disaster itself was long past, and they felt ashamed or that others couldn't understand. Several families I spoke with after losing their homes to a wildfire just fell apart over time. They stopped speaking and went their separate ways. They didn't have any resources left within themselves to deal with the losses they had experienced. In the case of a husband and wife, they coped with the disaster very differently and found they didn't know where their common ground had gone or how to find it again.
It is also important to recognize that, yes, there are positive outcomes that people and communities can experience, including finding new meaning and increasing their altruistic and prosocial behaviors towards others. This kind of resilience, or even what's called post-traumatic growth, can happen for anyone. But, no one should feel flawed in how they respond. It takes time to build the capacity for resilience, and it's especially helpful to take a trauma-informed lens to help support people and communities in developing it, rather than judging those who don't show it right away. We do a lot to encourage people and communities to have their emergency preparedness plans and kits ready, but not enough to equip themselves with psychosocial “resilience readiness” in the face of disasters.
How might people working from more of a natural science background become more trauma informed as they work with individuals and communities affected by disaster?
In Santa Barbara, after experiencing the massive Thomas Fire in December 2017 and hazardous air quality for weeks, we were then pummeled by the horrible tragedy of the Montecito debris flow that took the lives of many beloved members of the community. In the aftermath, there has been a surge of connection between scientists, particularly geologists, and the community. People are extremely anxious to understand the science and engage with researchers to comprehend not only what happened, but the potential dangers ahead.
A Santa Barbara County firefighter searches through a home destroyed by a deadly mudflow. Photo courtesy of Mike Eliason/Santa Barbara County Fire.
The kind of scientific information that tends to be helpful, productive, and protective for communities in the immediate aftermath of disasters typically focuses on what's most important for immediate safety and stabilization. These are primary goals that approaches like Psychological First Aid articulate in order to reestablish calm and order and reduce distress. In the longer term, of course scientific information can and should be shared, but it's good to continue to be thoughtful and intentional about how and when to disseminate that knowledge to support community change and resilience. Another great resource comes from journalists who report on disasters and other tragedies, and have thought carefully about how to approach these issues.
I've been fortunate enough to spend time with interdisciplinary groups at conferences focused on climate change and disasters. These conferences have also opened my eyes to the personal distress that natural science researchers and professionals have been experiencing, in part because they are so attuned to the potential risks in our natural environment. This knowledge can heighten their fear and sense of urgency. Those who help communities respond to disaster can experience secondary trauma, or what's called vicarious trauma, which is where people who are responding to disasters or are otherwise exposed to traumatic material can experience the same kinds of post-traumatic stress symptoms.
Oftentimes, people are told to monitor and reduce their exposure to traumatic material, but professionals like first responders and natural scientists who continue to study these issues, don't have that luxury. They can't just turn it off because it comes with the territory. But they would be wise to attend to the role of trauma in their work, to minimize its potential negative consequences. One repository of evidence-informed tools is the Vicarious Trauma Toolkit, which is free and easy to access. I'm hopeful that as we raise awareness about these issues across disciplines that we'll see more energy and commitment towards trauma-informed practices and preparations.
During periods of "extreme fire conditions," PG&E will shut off electric power lines to prevent wildfires, reported Dale Kasler in the Sacramento Bee.
The reporter spoke to Lenya Quinn-Davidson, UC Cooperative Extension area fire advisor in Northern California, about the utility's proposed actions. She said PG&E will have to give communities plenty of advance warning before turning off power so residents aren't left without a means of receiving emergency information.
"They're going to have to do a lot of good community outreach so people will be prepared," she said. Still, she called it "a reasonable short-term solution while they're figuring out other things" to reduce fire risks.
Lenya Quinn-Davidson, the UC Cooperative Extension area farm advisor who serves Humboldt, Siskiyou, Trinity and Mendocino counties. (Photo: Larry Luckham)
To see dwarf mistletoe seeds is to experience them. These are not typical seeds that gently drop from a mature plant. Rather, they are explosive — forcibly ejected from their fruits at high rates of speed. I remember learning about this in college: that dwarf mistletoe seeds can travel up to 60 mph and fly more than 60 feet from their hosts (Hinds et al., 1963). This process is triggered by internal heat production (called thermogenesis) within the mistletoe fruit — something that's never been observed in another plant (Rolena et al., 2015). It wasn't until many years after college that I actually experienced the phenomenon for myself. I remember driving along the Trinity River here in northern California and seeing a sudden splattering of little gelatinous green balls all over my windshield. I still remember how excited I was when I realized what they were: seeds that had flown as fast as I was driving.
Dwarf mistletoe fruits. Credit: Thompson Rivers University shared via Flickr Creative Commons.
It turns out that the seeds are only one of many intriguing things about mistletoe. There are more than 1,300 species of mistletoe; they grow all over the world (on all continents except Antarctica!); they support and interact with wildlife in all kinds of neat ways (Watson, 2001); and they are part of human culture and tradition (even evoking a kissing response in some!). And yet they're parasitic — not usually our favorite type of organism. More specifically, they're hemi-parasitic, meaning that they obtain all of their water and minerals from their host plant, but have some ability to provide for themselves. For example, leafy mistletoe, which is common in oaks where I live, is fully photosynthetic and therefore has a limited impact on its host trees. Dwarf mistletoe is a more demanding guest, requiring water, minerals and other nutrients, and taking a much greater toll on the many species of plants that it inhabits.
Leafy mistletoe is fully photosynthetic and therefore has a limited impact on its host trees. Credit: Dan Kidwell shared via Flickr Creative Commons.
As a major forest pathogen, dwarf mistletoe has a strong and well-studied connection to fire. Studies conducted in the 1970s clearly noted the relationship, pointing to fire suppression as the primary driver of increasing dwarf mistletoe abundance in many North American forests (Alexander and Hawksworth, 1975). At that time, dwarf mistletoe was recognized as one of the most damaging pathogens in many important forest types, and its impacts on the timber industry — with estimated losses of 3.2 billion board feet annually (Shea and Howard, 1969) — spurred quite a bit of research into its ecology and potential control tactics. Wildfire and prescribed fire naturally emerged as focal points for research, and those topics have continued to lure researchers, just as dwarf mistletoe has continued to wreak havoc. In a 2008 paper, Paul Hessburg and others argued that due to its wide distribution and habitat versatility, “dwarf mistletoes are probably responsible for more tree growth and mortality losses each year than all other forest pathogens combined.”
Like most forest pests and diseases, the relationship between fire and dwarf mistletoe is a two-way street: mistletoe affects fire, and fire affects mistletoe. For example, research has shown that mistletoe-infested stands of ponderosa pine have higher snag densities and higher fuel loads than uninfested stands, and that infested stands have higher crown fire potential (Hoffman et al., 2007). Mistletoe also has a number of tree-level effects that increase flammability and fire behavior potential, including the establishment of witches' brooms (dense, twiggy growth around areas of infection) and resinous stem cankers (Alexander and Hawksworth, 1975). Other research has documented reduced self-pruning and stunted growth in infected trees, both of which effectively lower the height of the live crown and thereby increase the potential for torching and canopy fire (Conklin and Geils, 2008).
The effects of mistletoe on fire behavior are fairly intuitive, but I find the effects of fire on mistletoe to be a little more intriguing. For instance, a study by Zimmerman and Laven tested the effect of smoke on the seed germination of three species of dwarf mistletoe, and they found that smoke exposure can reduce germination or prevent it altogether (when exposure exceeds 60 minutes) (1987). Earlier work by Koonce and Roth had also indicated that heat and smoke might have a disproportionate effect on dwarf mistletoe compared with their effects on the host plant (1980). Other studies have looked at the sanitizing effect that fire can have on mistletoe-infected trees. Conklin and Geils studied ponderosa pine stands in New Mexico, and they observed reductions in the dwarf mistletoe rating (DMR) — a categorical system for assessing infection (Hawksworth, 1977) — in 12 of 14 frequently burned plots (2008). This sanitizing effect was associated with average tree scorch above 25 percent, and it points to the potential utility of prescribed fire for dwarf mistletoe management, assuming that fire intensity is able to meet these minimum “scorch pruning” thresholds. Hessburg et al. also found that thinning and burning could be effective treatments for dwarf mistletoe in ponderosa and Douglas-fir forests, but that treatments would have to be implemented on regular intervals, as effects diminished after 20 years (2008).
Foresters using prescribed fire to treat mistletoe infestations in the 1970s. Credit: U.S. Department of Agriculture shared via Flickr Creative Commons.
Of course, the relationship between fire and mistletoe — and the approach to fire-based treatments — is highly dependent on the fire regime of the specific forest type in question. Much of the literature on dwarf mistletoe and fire comes out of frequent-fire forests like ponderosa pine and western mixed conifer, but lodgepole pine and black spruce are also common hosts, and their fire regimes are much different. In those types of forests, which are adapted to less frequent, more severe fire regimes, stand-replacing fire may be important for protecting future cohorts of trees from infection. Research in Rocky Mountain lodgepole pine forests showed that the time elapsed since the last stand-replacing fire was a good predictor of mistletoe infestation, and that the presence of remnant infected trees increased rates of infestation in younger, post-fire stands (Kipfmueller and Baker, 1998). In these forest types, the authors suggest that effective prescribed fire treatments would need to be intense and stand replacing.
I've always thought that mistletoe was interesting, but working on this blog opened a whole can of unexpected worms. Who knew that it was mistletoe, with its many interesting wildlife synergies, that inspired Charles Darwin to study evolution (Watson 2001)? Or that the term “mistletoe” is an ancient reference to some mistletoe species' reliance on seed dispersal by birds, who eat the seeds then deposit them on tree branches — the name comes from “misteltan,” an Anglo-Saxon word meaning “dung twig” (!!). Mistletoe has also been used by humans to bait deer for hunting (the foliage is quite tasty!); to treat infertility, syphilis, bubonic plague, epilepsy and other ailments; and to celebrate the return of summer, which mistletoe hints at with its evergreen foliage (Paine and Harrison, 1992). So with this blog, I celebrate mistletoe — i.e., dung twig, kissing plant, ballistic seeder, fire friend and foe — as quite possibly the coolest plant ever!
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Alexander, M. E., & Hawksworth, F. G. (1975). Wildland fires and dwarf mistletoes: a literature review of ecology and prescribed burning (Vol. 14). Rocky Mountain Forest and Range Experiment Station, Forest Service, US Department of Agriculture.
Hawksworth, F. G. (1977). The 6-class dwarf mistletoe rating system. The 6-class dwarf mistletoe rating system., (RM-48).
Hinds, T., Hawksworth, F. & McGinnies, W. Seed discharge in Arceuthobium: a photographic study. Science140, 1236–1238 (1963).
Hoffman, C., Mathiasen, R., & Sieg, C. H. Dwarf mistletoe effects on fuel loadings in ponderosa pine forests in northern Arizona. Canadian Journal of Forest Research, 37, 662-670.
Kipfmueller, K. F., & Baker, W. L. (1998). Fires and dwarf mistletoe in a Rocky Mountain lodgepole pine ecosystem. Forest ecology and management, 108(1-2), 77-84.
Koonce, A. L., & Roth, L. F. (1980, April). The effects of prescribed burning on dwarf mistletoe in ponderosa pine. In Proceedings of the Sixth Conference on Fire and Forest Meteorology, Seattle, Wash (pp. 22-24).
Paine, L. K., & Harrison, H. C. (1992). Mistletoe: its role in horticulture and human life. HortTechnology, 2(3), 324-330.
Rolena, A. J., Paetkau, M., Ross, K. A., Godfrey, D. V., & Friedman, C. R. (2015). Thermogenesis-triggered seed dispersal in dwarf mistletoe. Nature communications, 6, 6262.
Shea, K. R., & Howard, B. (1969). Dwarf mistletoe control; a program for research and development in the West. West Forest Conserv Assoc West Reforest Coord Comm Proc.
Watson, D. M. (2001). Mistletoe—a keystone resource in forests and woodlands worldwide. Annual Review of Ecology and Systematics, 32(1), 219-249.
Zimmerman, G. T., & Laven, R. D. (1987). Effects of forest fuel smoke on dwarf mistletoe seed germination. The Great Basin Naturalist, 652-659.