About 70 million years ago, the tectonic plates underlying the Pacific Ocean plunged beneath the North American Plate and began to form the row of volcanoes known as the Cascade Range. Lassen Volcanic National Park crowns the southernmost part of the range in a remote region of northeastern California. The Park is most famous for its spectacular geology, the result of active vulcanism from the ongoing creation of the Cascade Range. The vast majority of the Park's rock formed within the past three million years as a series of volcanoes rose up and eroded away. Lassen Peak, the Park's tallest mountain, formed about 27,000 years ago, near the end of the last Ice Age. The Peak hosted the Park's most recent eruptions from 1914 to 1917. The Park also boasts 17 smaller volcanoes and four mountains remaining along the rim of an enormous eroded volcano. In nine hydrothermal areas, subterranean molten rock heats bodies of water at the Earth's surface and enriches the soil with otherworldly yellows and reds. The steam and sulfuric stench reminds us that the Park's history of eruptions is far from over.

Lassen also hosts a remarkable diversity of plants, including over 900 vascular and 170 nonvascular species. To put those numbers in perspective, only about 1,200 vascular plants grow in the entire state of North Dakota, which covers an area more than 400 times the size of the Park. Lassen sits near the junction of three relatively distinct floristic provinces and shares plants with all three: the Vancouverian Province to the north, the Great Basin Province to the east, and the particularly diverse California Province to the west and south. The Park's plant diversity also benefits from its considerable habitat diversity, including variations in elevation (5,000 to 10,457 ft/1,520 to 3,187 m), slope incline, precipitation, sun exposure, disturbance history, and the depth, composition, and chemistry of soils. The interactions of all these factors create a mosaic of habitats where a wide variety of plants can flourish.

Lassen's native plant communities also benefit from an unusually low abundance of invasives. Invasive plants are non-native species that outcompete natives. They have the potential to replace unique local diversity with a handful of cosmopolitan species. This process has occurred and continues to occur all over the world, mainly as the result of humans moving plants around during this era of globalization. Conservation scientists consider invasive species to be one of the greatest threats to biodiversity worldwide. Lassen is lucky. Modern human disturbance has been low enough that in many areas of the Park very few invasive plants, if any, can be found. That said, some parts of the Park do have problems with invasives, especially cheatgrass (Bromus tectorum), bull thistle (Cirsium vulgare), woolly mullein (Verbascum thapsus), Canada thistle (C. arvense), and oxeye daisy (Leucanthemum vulgare). Preventing these species from spreading is crucial for protecting Lassen's plant diversity.

Lassen's ecosystems are mostly forests interspersed with shrublands and meadows. Below about 6,500 feet (2,000 m), ponderosa pines (Pinus ponderosa), Jeffrey pines (P. jeffreyi), sugar pines (P. lambertiana), and white firs (Abies concolor) dominate mixed conifer forests. Red firs (A. magnifica) dominate forest from 6,500 to 8,000 feet (2,000 to 2,400 m), along with white firs, western white pines (P. monticola), and lodgepole pines (P. contorta var. murrayana). Mountain hemlocks (Tsuga mertensiana) begin to take over above 8,000 feet (2,400 m), and whitebark pines (P. albicaulis) dominate at timberline. Forest understories often feature the low-growing shrubs pinemat manzanita (Arctostaphylos nevadensis) and mahala mat (Ceanothus prostratus), along with herbs such as mountain coyote mint (Monardella odoratissima), narrowflower lupin (Lupinus angustiflorus), goosefoot violet (Viola purpurea), and spotted coralroot (Corallorhiza maculata). Greenleaf manzanita (Arctostaphylos patula), whitethorn (Ceanothus cordulatus), and Sierra gooseberry (Ribes roezlii) are among the larger shrubs. Small wildflowers like Mount Hood pussypaws (Calyptridium umbellatum), Jepson's monkeyflower (Diplacus jepsonii), and Torrey's blue-eyed Mary (Collinsia torreyi) often grace the surface of dry soils in full sun.

Wetlands cover only about 0.8% of the Park, but they host more than half of Lassen's plant species, as well as a great deal of insect and bird diversity. Plant communities can vary broadly from wetland to wetland. At stream margins, gray alders (Alnus incana var. tenuifolia) or willows (Salix spp.) often dominate the overstory, with understory plants including stream violet (Viola glabella), musk monkeyflower (Erythranthe moschatus), and Pacific bleeding heart (Dicentra formosa). Wet meadows are often filled with graminoids such as inflated sedge (Carex vesicaria), Sierra rush (Juncus nevadensis), and mountain bentgrass (Agrostis thurberiana). Moist meadows often feature corn lilies (Veratrum californicum) along with herbs like arrowleaf senecio (Senecio triangularis), large-leaved lupin (Lupinus polyphyllus), plantain-leaf buttercup (Ranunculus alismifolius), and various sedges (Carex spp.).

Lassen also hosts probably the only acid geothermal fens documented in the Cascade Range or Sierra Nevada. Masses of peat moss, abundant groundwater, and very acidic soils (pH 3.0-4.5) characterize this wetland type, one of the rarest in the world. The acidity results from underground vents emitting sulfide gas, which forms sulfuric acid when it mixes with water near the surface of the soil. Lassen's acid geothermal fens feature various mosses, especially sphagnum (Sphagnum spp.), as well as short ericaceous shrubs such as western bog laurel (Kalmia microphylla) and purple mountain heath (Phyllodoce breweri). You can also find the small carnivorous herb round-leaved sundew (Drosera rotundifolia).

All of Lassen's ecosystems evolved in the midst of wildfire. Before the 20th century, low-to-moderate-severity fires often burned through the forest. Fires of this kind only killed a small or moderate amount of vegetation.

They consumed dead plant debris and killed above-ground parts of herbs, shrubs, and tree saplings while generally sparing below-ground plant parts and large trees. They usually burned in patches rather than sweeping through entire landscapes. Frequent burning kept the amount of flammable material low, generally preventing high-severity fires strong enough to kill entire stands of large trees.

Fire regimes began to change around the turn of the 20th century after Europeans and their descendants took control of the land. These newcomers tended to see fire as a threat to their land and property. Native Americans often used fire as a land management tool, but Euro-Americans put a stop to that whenever they could. I'm not aware of any evidence that Lassen's native tribes (the Atsugewi, Mountain Maidu, and Yana) intentionally burned the area now included in the Park, but indigenous people used fire to drive game and maintain oak savannas at lower elevations. Some of those fires might have made their way up to Lassen.

For much of the 20th century, the United States government had a strict fire suppression policy. Firefighters put out every wildfire as quickly as possible, and no intentional burning was allowed. Tree density increased, closing forest canopies. Unburned plant debris accumulated in the understory, providing ample fuel for high-severity fires. Intense understory fires easily spread to living trees, and fires spread easily from tree to tree in a dense forest. Many forests that burned at low to moderate severity before European settlement began to burn at high severity during the era of fire suppression.

Anthropogenic climate change also contributes to the risk of high-severity fire. Warm temperatures occur earlier in the spring, so precipitation that used to fall as snow now falls as rain. The slow melting of snow keeps the ground moist for a long time. Rain runs off quickly, so plants run out of soil moisture earlier in the year. Drought years are predicted to become more frequent and intense, leading to increased tree mortality. These factors together result in more fuel, and drier fuel, for high-severity fires.

High-severity fires can sweep through entire landscapes, reducing a diversity of habitats into a homogeneous expanse. Rain erodes the unprotected soil and washes sediment downstream in warm streams that harms fish populations. Modern high-severity fires also facilitate the spread of invasive plants, which tend to thrive in recently disturbed soils. Although high-severity fires consume an enormous amount of fuel, they also make fuels available for future fires as standing dead trees fall and underbrush grows back. So, once a forest starts to burn at high severity, it's likely to continue to burn at high severity.

Frequent high-severity fires have converted segments of conifer forest to chaparral all across the Cascade Range and Sierra Nevada. Chaparral ecosystems are shrublands dominated by species like manzanita (Arctostaphylos spp.) and ceanothus (Ceanothus spp.) that resprout quickly following fires and reach maturity much more quickly than trees. The conversion of conifer forest to chaparral is expected to continue in the coming decades.

The methods used to suppress fires can also harm ecosystems, especially the extreme methods used to stop high-severity fires. These can include clearing huge swaths of vegetation with heavy machinery and dropping chemical flame retardants from aircraft, as well as using hand crews to fell trees and scrape organic material from the soil. Hand crews and machinery inadvertently introduce invasive plant seeds from other areas. Firefighting thus creates the perfect conditions for invasives to establish and flourish. All these methods might be necessary to prevent wildfires from destroying human settlements, but the less they have to be used the better.

Fortunately, forest managers have begun to learn from the fire management mistakes of the past. It's now common knowledge that indiscriminate fire suppression is a bad idea. Firefighters often let low-to-moderate-severity fires burn when it's safe to do so. They also conduct prescribed burns to reduce fuel for high-severity wildfires and restore fire-adapted ecosystems. These burns have the potential to reintroduce low-to-moderate-severity fire to the landscape, prevent high-severity fires from taking over, and minimize the use of fire suppression.

In 2019, Lassen Volcanic National Park started a project aiming to reintroduce low-to-moderate-severity fire to the heart of the headwaters of the North Fork of the Feather River. This area is a crucial source of water for the Park, the town of Chester, Lake Almanor, and Lake Oroville. The proposed burn area consists of 4,033 acres in the southeastern corner of the Park, including Flatiron Ridge and land bounded by Horseshoe Lake, Juniper Lake, the Crystal Cliffs, and Inspiration Ridge. Managers chose to focus on this area because of the importance of its water supply, as well as its location between existing fuel breaks. Successful prescribed burns would complete a landscape-scale fuel break that could slow or stop the spread of high-severity wildfires.

Another goal of the burns was to restore Lassen's fire-adapted ecosystems. For example, lodgepole pines encroached on the margins of many of Lassen's montane meadows during the era of fuel suppression. I've even seen small meadows completely taken over by lodgepole saplings. These trees are a problem for meadows mainly because they suck up large amounts of water, stealing habitat from plant species adapted to wet conditions. Letting fire burn around meadows would kill many of the lodgepoles, allowing wetland plants to reclaim their territory.

Implementing a prescribed burn isn't as simple as just starting a forest fire. Conditions must be controlled to let the fire burn a substantial amount of fuel over a broad area, but not too much fuel or too broad of an area. The Park proposed establishing fuel breaks (a.k.a. the fireline) around the perimeter of the intended burns. This would entail felling trees and clearing vegetation to connect and enhance pre-existing fuel breaks like roads, trails, rocky areas, and bodies of water. Firefighters would burn piles of fuel constructed from many of the felled trees and later conduct broadcast burns over broad areas. They would ignite the fires on cool fall days with calm winds after precipitation had moderated some of the summer's dryness, but before that dryness had fully disappeared. During the burns, they would patrol the fireline to make sure the fire didn't escape and extinguish any embers that crossed over the line.

The Park's plan for the headwaters was unusual in one regard: it called for the use of hand tools instead of chainsaws to cut trees around the fireline. The vast majority of the proposed burn area is managed as wilderness, where power tools are rarely used. The Wilderness Act of 1964 defines wilderness as "an area where the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain." The Act's goal is to protect wilderness areas in perpetuity from "expanding settlement and growing mechanization." It bans all commercial enterprises and permanent roads from wilderness areas and prohibits the use of mechanized equipment, except when such equipment is necessary to protect human safety or preserve "wilderness character." Firefighters still use chainsaws in wilderness to suppress fires (protecting human safety), and sometimes to prepare for prescribed burns, but the Park decided to prepare for the headwater burns with hand tools to maintain the spirit of the Wilderness Act.

The primary tools for felling trees in wilderness are axes and crosscut saws. These were the tools loggers used to cut down trees from the 1880s until after World War II. Each crosscut felling saw is operated by two sawyers, one on each side of the tree. They start the felling process by making a horizontal cut with the saw, usually about a third of the way into the tree, in the direction they want the tree to fall. Then one of them uses an ax to chop a sloping cut that meets the horizontal cut and opens the face of the tree like a gaping mouth. Finally, they saw a horizontal cut from the back of the tree to slightly above and behind the initial cut, and the tree falls. Complex trees with compromised wood or inconvenient leans complicate this process, but that's the basic outline the sawyers follow.

People unfamiliar with crosscut saws often have a sense of them as simple, brute-force tools, but that's far from the truth. The advanced crosscuts of the early 20th century were the result of hundreds of years of technological development from the simple saws used in medieval Europe. The best crosscuts are vintage tools precisely engineered for maximum efficiency and crafted by hand from high-quality steel. Crosscut sharpening is a delicate art with few living experts. Cutting with a crosscut is a deeply social process, where being in tune with your partner and pulling the saw with just the right pressure and rhythm are much more important than brute force. When you cut through good wood with a high-quality, wellsharpened crosscut, staying in sync with your partner, the saw rings out with a pure, beautiful tone, earning the tool its old nickname "the singing saw." But if the saw isn't good, or it's sharpened poorly, or you and your partner aren't cutting well, using a crosscut is a real pain, and the tool earns its other old name: "the misery whip."

The Park's nonprofit partner the Sierra Institute hired me in 2019 as a crosscut sawyer with the wilderness fuels reduction crew preparing for prescribed burns. Felling trees with axes and crosscut saws isn't as fast as felling them with chainsaws (of course), but it's more effective than you might expect. In 2019, our six- to seven-person crew felled an average of 120 larger trees (over eight inches/20 cm dbh, a.k.a. diameter at breast height) and 1129 smaller trees (less than eight inches/20 cm dbh) during each eight-day work week. We worked at a similar pace in subsequent years. Most of the larger trees we felled were dead and often complex, and the largest was five feet eleven inches (1.8 m) in diameter at the height of the cut. We finished prepping the fireline around Flatiron Ridge, finished much of the area near Horseshoe and Juniper Lakes, and created fuel breaks around the Mount Harkness Fire Lookout and the Ranger Stations Firefighters completed pile burns in some parts of the project area, but logistics and weather conditions prevented them from conducting any broadcast burns. I worked happily on the crew until the Dixie Fire ended the field season abruptly during the summer of 2021.

On July 13th, 2021, a Douglas-fir (Pseudotsuga menziesii) fell on a power line near Dixie Road, between the towns of Paradise and Belden, about 40 miles (64 km) south of the Park. The fallen tree formed a bridge between the still-active power line and the dry conifer needles covering the ground. Over the next ten hours, the stray electric current slowly heated the needles to the point of ignition. One hundred and four days later, after burning through 963,309 acres, the Dixie Fire was finally fully contained. It was the largest single-source wildfire in the recorded history of California.

About a week after the fire started, my crew and I evacuated from Lassen to the Sierra Institute's headquarters in Taylorsville, about 35 miles (56 km) to the southeast. We had been living at Juniper Lake Ranger Station, in the southeastern corner of the Park, and working near Horseshoe Lake. The fire wasn't threatening to enter the Park, but it was filling our project area with smoke. The air quality was too low for us to safely work outdoors. I brought all my possessions with me when I left the Ranger Station, but most of my crew didn't. They assumed they'd have a chance to return and get their things later. I wasn't so sure, but, unfortunately, I didn't speak up. I didn't want to scare anyone or spoil their optimism. I figured I was probably just being paranoid.

There wasn't much for us to do in Taylorsville. Sierra Institute gave us some busy work, but mostly we just sat around and worried. We could see from online satellite heat maps that the fire was burning toward the Park more quickly than expected. It was also spreading toward us in Taylorsville. Wecould see a wall of smoke advancing from the west. After a couple of days, the fire crested a nearby hill, and the whole town evacuated. Sierra Institute had nothing else for us to do. The rest of my crew spent the night in Genesee, a few miles to the southeast, but I was tired of living in constant expectation of another evacuation. I drove northeast of Genesee for half an hour and spent the night on a hill overlooking Antelope Lake. The rest of my crew dispersed within the next few days. No one knew what was next.

I spent the next month drifting from one friend's couch to another. First I moved to Reno, far east of the fire but still drenched in smoke. I checked fire maps every 15 minutes or so (a pointless, nervous tic) and started looking for jobs. I assumed correctly that field season at Sierra Institute was over, and I felt useless twiddling my thumbs while my home and years of work were on the verge of going up in flames. Our fuel breaks

were designed to hold back controlled, low-to-moderate-severity fires, not uncontrolled, high-severity fires, so I expected our work to be mostly useless in the face of the Dixie Fire. I expected our project area to burn with exactly the kind of fire we'd been working for years to prevent.

I left Reno after a few days and moved in with a couple of friends in Chico, about 25 miles (40 km) southwest of the fire, in the opposite direction of its spread. I wanted to escape the smoke, and hopefully keep myself from sinking into depression. There was still some smoke in Chico, but I had just enough physical and mental space from the fire to start getting a handle on my emotions. Meanwhile, the fire kept getting worse. On August 4th, it destroyed most of Greenville, a town about five miles (8 km) northwest of Taylorsville, including the homes of some of the Sierra Institute's employees. On August 5th, it entered the southeast corner of the Park. Satellite heat maps showed the fire sweep over Juniper Lake Ranger Station and into our project area. Then the winds shifted, and the fire burned over the Ranger Station again from the opposite direction. I assumed the Ranger Station was gone, along with everything my crew left behind.

I left Chico to stay with a friend in Oakland and escape the smoke entirely. I interviewed for a chainsaw fuels reduction job in Idaho from the comfort of my friend's couch. Then I spent a couple of days living out of my Subaru along the coast, south of the Bay Area. A homeless Vietnam veteran tried to fight me outside of Davenport because he thought I was watching him sleep in his car. I motioned toward the bedding in the back of my vehicle, and he realized I was sleeping there too. He calmed down abruptly, apologized, and told me his PTSD made him crazy.

A couple of days later, my crew reunited from all across northern California on a beach in Monterey, then dispersed yet again. It was bittersweet knowing this would probably be the last time I would see everyone all in the same place. I moved back to Chico and stayed in the empty apartment of a different friend, who'd recently moved out but still paid rent. I put my sleeping pad in the corner of the living room where the couch used to be.

Firefighters fully contained the Dixie Fire on August 26th, a few days before I left Chico for the job in Idaho. The bulk of firefighting efforts in the Park focused on reinforcing and connecting existing fuel breaks along roads, trails, and sites of previous fuels reduction. Bulldozers cleared strategic swaths of land. Heavy machinery masticated logs. Hand crews felled trees with chainsaws, scraped organic material from the soil, and conducted quick controlled burns along fuel breaks. Aircraft dropped chemical flame retardants into the midst of the blaze. These efforts, along with changes in the weather, stopped the fire at around where Highway 89 winds through the Park's western extent.

The Dixie Fire ultimately burned through about 69% of the Park. About 32% of the land within the fire perimeter burned at high severity, but fortunately, 23% burned at moderate severity, 24% burned at low severity, and 18% was unaffected by the flames. Most of the high-severity burns occurred in the southern part of the Park, including our project area. The fire also destroyed four buildings at Drakesbad Guest Ranch, seven of eight cabins at Juniper Lake, and the beautiful Mount Harkness Fire Lookout. It spared most of the Park's buildings, including two of the buildings we protected with fuel breaks: Horseshoe Lake Ranger Station and, surprisingly, Juniper Lake Ranger Station. My crew recovered all their possessions.

I visited Lassen for the first time since the fire in June of 2022. I expected to find vast expanses of land where all above-ground plant life had been killed, and I did. But I also found regeneration well underway in many areas, as well as many areas rich with surviving trees. In general, meadows and wetlands were thriving, with the usual extravagant plant diversity and plenty of butterflies and birds, including a pair of magnificent sandhill cranes. I expected the trip to be upsetting, but I felt great.

That's the end of my story for now, but no story about ecology is ever truly finished. We have some idea of what the future holds, but we don't know for sure. The forests that burned at high-severity in the Dixie Fire might continue to burn at high severity, converting those forests to chaparral. High severity fires and the methods used to suppress them might spread invasive plants through the chaparral and beyond, reducing plant diversity. Or, land managers might successfully reintroduce a frequent, low to moderate severity fire regime and prevent both of those outcomes. Already, the Park is building off my crew's work to prepare for prescribed burns in its southeastern corner, as well as working on fire mitigation projects elsewhere. It won't be easy to increase the scale and frequency of prescribed burns enough to keep up with the pace of wildfire, but it is possible, and it's a crucial goal to pursue.

References

Adamus, P. R., & Bartlett, C. L. (2008). Wetlands of Lassen Volcanic National Park: An assessment of vegetation, ecological services, and condition. U.S. Department of the Interior, National Park Service. http://npshistory.com/ publications/lavo/nrtr-2008-113.pdf

Associated Press. (2021, August 5). The Dixie Fire has destroyed most of a historic northern California town. National Public Radio. https://www.npr. org/2021/08/05/1025087402/the-dixie-fire-has-destroyed-most-of-a-historicnorthern-california-town

Buckley, S. (2018). Improving landscape and watershed health through restoring fire regimes in Lassen Volcanic National Park [Unpublished grant proposal]. U.S. Department of the Interior, National Park Service.

Clynne, M. A., Janik, C. J., & Muffler, L. J. P. (2009, December 4). "Hot

Water" in Lassen Volcanic National Park - Fumaroles, Steaming Ground, and

Boiling Mudpots. U.S. Geological Survey. https://pubs.usgs.gov/fs/2002/fs10102

Egger, J. M., & Malaby, S. (2015). Castilleja collegiorum (Orobanchaceae), a new species from the Cascade Mountains of southern Oregon, and the status of Castilleja lassenensis Eastw. Phytoneuron, 2015(33): 1-13. https://www. phytoneuron.net/2015Phytoneuron/33PhytoN-Castillejacollegiorum.pdf

Gonzalez, P., & Reiner, W. B. (2017). Climate change in Lassen Volcanic

National Park, California, USA. U.S. Department of the Interior, National Park Service. http://www.patrickgonzalez.net/images/Gonzalez_Reiner_climate_ change_Lassen_Volcanic_NP.pdf

Hansen, L. C. (2023). Remotely sensing the effects of managed wildfire programs on Sierra Nevada meadows [Master's thesis, San Francisco State University]. California State University ScholarWorks. https://scholarworks. calstate.edu/downloads/6m311w879

Lassen Volcanic National Park Resource Management Division. (n.d.). Lassen Volcanic National Park. Consortium of Bryophyte Herbaria. https:// bryophyteportal.org/portal/checklists/checklist.php?clid=75&pid=12

Lassen Volcanic National Park Resource Management Division. (n.d.). Lassen Volcanic National Park. Consortium of California Herbaria. https://cch2.org/ portal/checklists/checklist.php?clid=14&pid=1

Lauvaux, C. A., Skinner, C. N., & Taylor, A. H. (2016). High severity fire and mixed conifer forest-chaparral dynamics in the southern Cascade Range, USA. Forest Ecology and Management, 363: 74-85. https://doi.org/10.1016/j.

foreco.2015.12.016

Michael, D. E. (2004). Saws That Sing, A Guide to Using Crosscut Saws. U.S. Department of Agriculture, U.S. Forest Service. https://www.fs.usda.gov/t-d/ pubs/htmlpubs/htm04232822/toc.htm

National Park Service. (n.d.). Lassen geology. U.S. Department of the Interior,

National Park Service. https://www.nps.gov/lavo/learn/kidsyouth/upload/ Lassen-Geology.pdf

National Park Service. (2017, February 1). Wilderness. U.S. Department of the Interior, National Park Service. https://www.nps.gov/lavo/learn/nature/ wilderness.htm

National Park Service. (2019, February 1). Volcanoes of Lassen. U.S. Department of the Interior, National Park Service. https://www.nps.gov/lavo/ learn/kidsyouth/upload/Volcanoes-site-bulletin.pdf

National Park Service. (2019, March 19). Non-native invasives. U.S. Department of the Interior, National Park Service. https://www.nps.gov/lavo/ learn/nature/non-native-invasive-plants.htm

National Park Service. (2020, November 4). Plants. U.S. Department of the Interior, National Park Service. https://www.nps.gov/lavo/learn/nature/plants. htm

National Park Service. (2020, November 4). Whitebark Pine. U.S. Department of the Interior, National Park Service. https://www.nps.gov/lavo/learn/nature/ wbp.htm

National Park Service. (2022, May 16). Effects of the 2021 Dixie Fire. U.S.

Department of the Interior, National Park Service. https://www.nps.gov/lavo/ learn/nature/dixie-fire-effects.htm

National Park Service. (2023, August 22). Dixie Fire. U.S. Department of the Interior, National Park Service. https://www.nps.gov/lavo/learn/nature/dixiefire.htm

Ogle, H., & McCullough, K. (2009). Archeological inventory of fuel treatment units at Lassen Volcanic National Park. U.S. Department of the Interior, National Park Service. https://www.academia.edu/2043902/Archeological_

Inventory_of_Fuel_Treatment_Units_at_Lassen_Volcanic_National_Park_2009

Palade, M., & Berry, L. (2021). Dixie Fire Investigation Report. California Department of Forestry and Fire Protection. https://s1.q4cdn.com/880135780/ files/doc_downloads/2022/06/DIXIE_FINAL_Redacted_PGE-ProposedRedactions-Statement-49411384.pdf

Schlising, R. A., & Mackey, H. E. (2020). Biology of the ephemeral geophyte, steer's head (Dicentra uniflora, Papaveraceae) in the southernmost Cascade Range, Butte County, California. Madroño, 66(4): 148-163. https://doi.

org/10.3120/0024-9637-66.4.148

Stein, B. A. (2002). States of the Union: Ranking America's biodiversity. NatureServe. https://www.natureserve.org/sites/default/files/publications/files/ stateofunions.pdf

Thorne, R. F. (2007). Phytogeography of North America North of Mexico.

Flora of North America Association. http://flora.huh.harvard.edu/FNA/Volume/ V01/OldV01/Chapter06_bak.html

Tutella, F. (2022, June 27). California's Dixie Fire shows impact of legacy effects, prescribed burns. Pennsylvania State University. https://www.psu.edu/ news/earth-and-mineral-sciences/story/californias-dixie-fire-shows-impactlegacy-effects-prescribed/

Wilderness Act, 16 U.S.C. § 1131 (1964). https://parkplanning.nps.gov/ showFile