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Forest management can help giant sequoias and coastal redwoods survive
In 2020, 9,000 fires scorched more than 4 million acres of California, a record-breaking year, reported Alejandra Borunda in National Geographic. Fires burned through homes and oak forests, grasslands and pines — and also through patches of giant sequoias and coast redwoods, respectively the most massive and the tallest trees on earth.
Giant sequoias are not the oldest living trees, but some have been growing in Sierra Nevada forests for more than 3,200 years. They are found in 68 groves on the Sierra's western flank. The state's redwood forests grow in a narrow strip along the coast of Northern California and Southern Oregon.
The 2020 fires burned through about 16,000 acres of sequoia groves, about a third of their total area. In redwood forests of the Santa Cruz Mountains, 40,000 acres burned.
But because redwoods are well-adapted to fire, they'll likely recover pretty quickly, said Scott Stephens, a UC Berkeley fire scientist. “In some ways, this fire could make redwoods more dominant in the landscape," he said, because other trees — like the hardwoods or Douglas firs that crowded the local forests — died outright in the burns.
However, scientists are concerned one cause of the fires, climate change, could have additional impacts on these natural treasures.
Since the mid-1800s, temperatures in the western U.S. have increased by 1.6 degrees Fahrenheit. Fog banks are fading in coast redwood territory, and snows are less consistent in the Sierras. The changes leave redwoods and sequoias without their preferred climate conditions.
The most responsible thing to do now, Stephens said, is to “take the opportunity that has been handed to us,” and make a plan to go back in and burn again—soon, within the next few years.
UC Cooperative Extension forestry advisor Lenya Quinn-Davidson agrees that California must manage fire to help the trees survive. Tree-ring records show that humans have influenced the fire regime for better and worse as long as they've been in these forests.
“The empowering message there is, human management can actually override the effects of climate in a fire contest,” Quinn-Davidson said. “It's not just a climate story. We can't just throw in the towel, feel overwhelmed, and tell ourselves these trees are done for. That's not true!”
Climate change is converting cities into 21st century ghost towns
In California, most ghost towns were created when a local industry collapsed. Now, climate change is more often to blame when booming communities whither and die, reported Daniel Cusick in E&E News.
In an eerie horror story released just before Halloween, Cusick wrote about five towns around the nation that have died or are dying from climate-related disasters. Historic Shasta and Helena, Calif., are featured in one of the vignettes.
"Those are two towns that are getting more ghostly," said Yana Valochovich, UC Cooperative Extension forestry advisor in Humboldt and Del Norte counties.
A 19th-century mining town, Shasta City had been a preserved tourist destination in Shasta State Historic Park since 1937 when it was burned in the 2018 Carr Fire, the seventh most destructive wildfire in California history. Helena, a 170-year-old pioneer mining settlement, burned in the Helena Fire of 2017.
There almost certainly will be more "dead towns" as fires consume more of Northern California, Valochovic added.
North Coast forests are more dense and dry, fueling fires
Five of California's six largest fires have occurred in 2020, reported Julie Cart in CalMatters.
Quinn-Davidson is based in Humboldt County, with typically rainy, foggy redwood forests. However, she said, the forests don't resemble their former state.
"They are suffering from the same things that the rest of the state forests are. They are poorly managed and have fuels buildup," Quinn-Davidson said.
Redwood and pine forests are many times more dense than at any time in their history.
"We are now entering a new regime, the climate is changing and we are seeing drier conditions and we are seeing a longer fire season. We are not getting that fall precipitation," she said.
The state's 2018 Fourth Climate Assessment included dire predictions for the North Coast: “Future wildfire projections suggest a longer fire season, an increase in wildfire frequency, and an expansion of the area susceptible to fire.”
Average annual maximum temperatures in Mendocino, Humboldt, Del Norte, Lake, Trinity and Siskiyou Counties could increase by as much as 9 degrees through the end of the century, the report concluded.
The fog that reliably blankets the North Coast is dissipating. Research from UC Berkeley found that fog frequency has declined by a third compared with a century ago.
“Even here in Humboldt County — we are right on the ocean, basically in a rainforest — people are starting to look around and say, ‘Is my house ready for a wildfire?' I'm hearing those conversations,” Quinn-Davidson said.
Climate-change research provides tools for farmers to adapt
This is one of a series of stories featuring a sampling of UC ANR academics whose work exemplifies the public value UC ANR brings to California.
Farmers are already seeing the effects of warmer winter nights and hotter summer days on their crops. Climate change is gradual, but increasing overall temperatures affect many aspects of farming, including where and how crops are grown. Tapan Pathak, University of California Cooperative Extension specialist based at UC Merced, is doing applied research that farmers and ranchers can use to adapt to new conditions created by a variable and changing climate.
“You don't have to shift your practice tomorrow, but if you are thinking of making a 30-year investment, it's important to know what risks there are for planting different crops,” said Pathak, who is based in the Sierra Nevada Research Institute at UC Merced.
Pathak co-chairs the UC Cooperative Extension Climate Change Program Team, whose mission is to increase the capacity among UCCE academics to address climate change concerns with science-based information. Pathak also collaborates with extension professionals from across the western U.S. to do extension events related to climate change adaptation. He works closely with state and federal agencies statewide and growers to identify changes occurring as a result of climate change that affect agriculture. Pathak's research will inform growers' decisions, such as crop variety, planting and harvest dates, extreme heat and frost protection and pest management.
“We are seeing impacts of climate change, that's evident. We have some solutions that are available, but we also need to do more locally relevant crop specific research to make agriculture resilient to climate risks,” Pathak said.
The UCCE scientist was the lead author on an important paper that synthesized the impacts of climate change on California agriculture and offers directions for future research and implementation. The authors concluded that almost all of California's crops, collectively valued at more than $50 billion a year, will be endangered to some degree by rising temperatures and variable weather patterns. The study “Climate Change Trends and Impacts on California Agriculture” was published in Agronomy in 2018.
“I think there's a lot of solutions available and there is also a clear need for adaptation research that include growers' perspectives,” said Pathak, who received a Climate Leadership Award for research from the California Climate & Agriculture Network.
Pathak is also collaborating very closely with UC Davis-based UCCE specialist Daniele Zaccaria, who is leading an international project on evaluating bioclimatic indices and developing the index that is more relevant to irrigated agriculture, which includes scientists from the U.S., Italy, Brazil and Chile.
“A bioclimatic index specific to irrigated agriculture can provide more accurate and valuable agricultural drought information that could be helpful for water resources planning and management decisions,” Pathak said.
Cal AgroClimate
Pathak is developing a web-based decision support system called Cal AgroClimate to help growers make decisions, in partnership with the USDA California Climate Hub director Steven Ostoja. It is being built on the same platform as AgroClimate, which is popular with growers in the Southeast.
Cal AgroClimate translates historical climate data and future projections into a useful decision support system for growers. For example, growers can get extreme heat and frost advisories for the next 10 to 14 days in their region and relevant resources to mitigate risks for their selected crop. It is in the early phase of development and will include a suite of tools based on the needs and priorities identified by UCCE colleagues, growers and the agricultural community in general.
In addition to his work on Cal AgroClimate, Pathak has been conducting research on specific crops.
Tomatoes
In a study looking at processing tomato production in the Central Valley, Pathak and UCCE advisor Scott Stoddard found that changing temperatures will likely change the tomato growing season. The scientists looked at processing tomato data starting from 1950 and projections for 2030-2040 to see how the time to maturity is changing.
“In general, the time from emergence to maturity, the timeframe for processing tomatoes in that region is going to shrink by two to three weeks,” said Pathak. “A lot of processors have their timeline for when they need the tomatoes for processing and so when you have this shift in the phenology, that alters the timeframe for when they mature and are ready for the processors. So, there's a whole shift in the management that growers might have to think about in the future.”
Almonds
To identify the climate information almond growers need to take adaptation action, UC Berkeley postdoctoral researcher Kripa Jagannathan, former UCCE advisor David Doll and Pathak interviewed almond growers in the Central Valley. During their conversations with farmers, the researchers clarified that long-term climate projections are not seasonal forecasts or weather forecasts for the next 20 to 30 years. The projections provide information on trends or potential of shifts from historical conditions for making long-term planning decisions.
Pest control is one area where growers will need to make changes. Research by UCCE advisor Jhalendra Rijal and Pathak shows the almond pest navel orangeworm is already extending its life to a fifth generation during a season.
Strawberries
For strawberries, Pathak, UCCE entomology and biologicals advisor Surendra Dara and postdoctoral researcher Mahesh Maskey have developed a model to forecast weekly crop yields based on weather data. “The model was pretty accurate for the Santa Maria region,” Pathak said. “A crop-specific model can be used for labor management not just crop management.”
Because California produces more than 400 agricultural products, adapting to climate change will be more complex than in other states.
Protected areas needed across climates to safeguard biodiversity
Around the world, countries have established protected areas as the primary defense to reduce widespread biodiversity loss and guard vulnerable habitats. However, species and ecosystems are adapted to particular climates—as those climates shift across and outside of protected area boundaries, species may track them into unprotected landscapes where human land uses degrade conservation potential.
In a new study published in Science Advances today, Berkeley researchers offer a broad analysis of how protected areas will continue to capture the climates suitable for species into the future. The study was led by Paul Elsen, a climate adaptation scientist at the Wildlife Conservation Society and former postdoctoral researcher in the Department of Environmental Science, Policy and Management, and it was co-authored with Cooperative Extension specialist Adina Merenlender, recent Ph.D. graduate Eric Dougherty, and Bill Monahan, currently with the U.S. Forest Service.
The authors first determined how climate is expected to change within all terrestrial protected areas globally by utilizing data from several major global climate models and maps of protected areas. They found that over the next 50 to 80 years, the total amount of protected land situated in both warm and cold climates, over a wide range of annual precipitations, is expected to decline significantly.
“We calculate that most countries will fail to protect over 90% of their available climate at current levels, forcing many species to shift into unprotected lands,” says Merenlender.
Species or ecosystems adapted to specific climatic conditions would disproportionately be impacted, such as those in tropical and subtropical moist broadleaf forests, boreal forests, tundra, savannas, grasslands and shrublands.
The authors then tested how different mitigation and adaptation strategies might work to limit the amount of change species may experience in protected areas within countries, thereby reducing species' vulnerability. For example, they investigated whether greenhouse gas mitigation or the addition of new protected areas were more effective for building resilience to climate change.
“Protected areas are invaluable to conserving biodiversity, but where those protected areas are positioned in relation to available climates can have a huge influence on their ability to reduce species' vulnerability to climate change,” says Elsen.
If countries were to expand protected areas to double the diversity of climates under protection, the authors find, they would retain 118% more land area of today's protected climates into the future. By contrast, reducing greenhouse gas emissions in accordance with global targets would increase retention of currently protected climates by 102%.
“If we adopt a strategy for increasing protection that seeks to maximize the diversity of climate types represented within protected areas—for example, cold, warm, hot, wet, temperate, arid, etc.—we stand a much better chance that protected areas will continue to encompass the climatic conditions that support currently protected biodiversity,” says Elsen, lead author of the study.
The authors were surprised to find that simply establishing more protected areas wasn't the solution to building resilience. “Whether it's ‘half-earth' or a more modest target, we need more protected areas but they must be climate smart,” says Merenlender. “This means protecting a full range of climate types, or parks will not protect biodiversity as intended into the future.”
The long-term conservation potential of protected areas depends on careful maintenance of appropriate biotic and abiotic conditions that promote biodiversity. The authors stress that decisions about land use, which are socio-economic in nature, need to also account for conservation and ecosystem health. “Species that track climate into unprotected landscapes may face landscapes that are highly modified by agriculture, infrastructure, development, and other human activities, so it is still critical that we work to increase the suitability of unprotected lands for biodiversity, too,” says Elsen.
The study includes recommendations for planning for future reserves that stand to better protect biodiversity and will be more resilient to climate change over the long term.
Read the study on the Science Advances website.
