Castle Lake is a glacial

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

(''

cirque A (; from the Latin word ') is an amphitheatre-like valley formed by glacial erosion. Alternative names for this landform are corrie (from Scottish Gaelic , meaning a pot or cauldron) and (; ). A cirque may also be a similarly shaped landform ...

'' lake or tarn) located in the

Trinity Mountains The Trinity Mountains are a subrange of the Klamath Mountains, one of the ranges within the California Coast Ranges and part the greater Pacific Coast Ranges, the coastal mountain system extending from Mexico to Alaska. The Trinity Mountains subran ...

, in

Siskiyou County Siskiyou County (, ) is a county in the northernmost part of the U.S. state of California. As of the 2020 census, the population was 44,076. Its county seat is Yreka and its highest point is Mount Shasta. It falls within the Cascadia bioregion ...

of northern

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

. It is west of Mount Shasta City and

Mount Shasta Mount Shasta ( Shasta: ''Waka-nunee-Tuki-wuki''; Karuk: ''Úytaahkoo'') is a potentially active volcano at the southern end of the Cascade Range in Siskiyou County, California. At an elevation of , it is the second-highest peak in the Cascades ...

peak. The outlet of the lake drains into Castle Lake Creek, and then into

Lake Siskiyou Lake Siskiyou is a reservoir formed by Box Canyon DamBox Canyon Dam
NPDP Da ...

reservoir, part of the headwaters of the

Sacramento River The Sacramento River ( es, Río Sacramento) is the principal river of Northern California in the United States and is the largest river in California. Rising in the Klamath Mountains, the river flows south for before reaching the Sacramento–S ...

. Nearly all of the lake's are within the Shasta-Trinity National Forest. Trails lead from Castle Lake into the adjacent Castle Crags Wilderness area, and on to

Castle Crags State Park Castle Crags is a dramatic and well-known rock formation in Northern California. Elevations range from along the Sacramento River near the base of the crags, to over at the summit of the tallest crag. Located just west of Interstate 5, betwe ...

, including trails to Little Castle Lake and Heart Lake.

Fishing Fishing is the activity of trying to catch fish. Fish are often caught as wildlife from the natural environment, but may also be caught from stocked bodies of water such as ponds, canals, park wetlands and reservoirs. Fishing techniques inclu ...

camping Camping is an outdoor activity involving overnight stays away from home, either without shelter or using basic shelter such as a tent, or a recreational vehicle. Typically, participants leave developed areas to spend time outdoors in more nat ...

, and

hiking Hiking is a long, vigorous walk, usually on trails or footpaths in the countryside. Walking for pleasure developed in Europe during the eighteenth century.AMATO, JOSEPH A. "Mind over Foot: Romantic Walking and Rambling." In ''On Foot: A Histor ...

are also available at or near the lake.

Natural history

Castle Lake and the surrounding area contain a wide variety of animals and plants including trout, bears, deer, otters, frogs, and osprey. The area is also well-known for early summer displays of flowers, including red Columbine (''Aquilegia truncata''), fawn lily (''Erythronium sp.''), and Shasta pentstemon (''Pentstemon laetus''). Castle Lake is home as well to the Castle Lake Limnological Research Station affiliated with the

University of California at Davis The University of California, Davis (UC Davis, UCD, or Davis) is a public land-grant research university near Davis, California. Named a Public Ivy, it is the northernmost of the ten campuses of the University of California system. The institut ...

(UC Davis), which uses the site for study and to teach

limnology Limnology ( ; from Greek λίμνη, ''limne'', "lake" and λόγος, ''logos'', "knowledge") is the study of inland aquatic ecosystems. The study of limnology includes aspects of the biological, chemical, physical, and geological characteristi ...

courses (in conjunction with the

University of Nevada, Reno The University of Nevada, Reno (Nevada, the University of Nevada, or UNR) is a public land-grant research university in Reno, Nevada. It is the state's flagship public university and primary land grant institution. It was founded on October 12, ...

Recreation

The lake is usually reached by driving along an approximately road from

Lake Siskiyou Lake Siskiyou is a reservoir formed by Box Canyon DamBox Canyon Dam
NPDP Da ...

. elev. About from the lake, along this road, are Ney Springs elev. and Faery Falls. elev. Ney Springs is the site of the historic Ney Springs Resort, a late 19th-century resort based on the mineral springs there; this resort was one of a number of such popular resorts in Siskiyou County, including

Upper Soda Springs Upper Soda Springs is on the banks of the Sacramento River in Dunsmuir, California, USA. It consists of approximately ten acres (40,000 m²) of level ground on both sides of the River, the surrounding hillsides, and continues north along the eas ...

, and Shasta Springs. A short hiking trail leads to nearby Faery Falls, where Ney Springs Creek falls nearly down a granite cliff face, forming a clear pool at the bottom. About one-quarter mile (400 m) north of Castle Lake is a campground with 6 first-come, first-served campsites. At the lake itself, fishing and picnicking, as well as viewing the local plant life, wildlife and scenery, are common activities. The lake waters can be cool, so

swimming Swimming is the self-propulsion of a person through water, or other liquid, usually for recreation, sport, exercise, or survival. Locomotion is achieved through coordinated movement of the limbs and the body to achieve hydrodynamic thrust that r ...

is generally limited to summer months.

Kayaking Kayaking is the use of a kayak for moving over water. It is distinguished from canoeing by the sitting position of the paddler and the number of blades on the paddle. A kayak is a low-to-the-water, canoe-like boat in which the paddler sits fac ...

, rowboating and

raft A raft is any flat structure for support or transportation over water. It is usually of basic design, characterized by the absence of a hull. Rafts are usually kept afloat by using any combination of buoyant materials such as wood, sealed barrel ...

ing are available on the lake. In the winter, in addition to

cross-country skiing Cross-country skiing is a form of skiing where skiers rely on their own locomotion to move across snow-covered terrain, rather than using ski lifts or other forms of assistance. Cross-country skiing is widely practiced as a sport and recreation ...

and snow-shoeing along the trails in the area, the lake will ice over and

ice fishing Ice fishing is the practice of catching fish with lines and fish hooks or spears through an opening in the ice on a frozen body of water. Ice fishers may fish in the open or in heated enclosures, some with bunks and amenities. Shelters Longer ...

is a common activity. From the parking area at the lake, a half-mile (1 km) trail winds along the northern and western shore of the lake, ending at the granite face of the

headwall In physical geography and geology the headwall of a glacial cirque is its highest cliff. The term has been more broadly used to describe similar geomorphic features of non-glacial origin consisting of a concave depression with convergent slopes ty ...

, which forms the southern shore. Along the way, hikers will pass the Castle Lake Limnological Research Station. Following the eastern shore, the Little Castle Lake Trail leaves the parking area, and then climbs the adjoining ridge; about along this trail is Little Castle Lake, elev. a small glacial tarn reached by passing through meadows of wild flowers in the early summer. Little Castle Lake is within the Castle Crags Wilderness Area. Heart Lake, elev. another small tarn, located above the headwall of Castle Lake, may also be reached via an informal cut-off from the Little Castle Lake Trail. At this point, the well-known

Pacific Crest National Scenic Trail The Pacific Crest Trail (PCT), officially designated as the Pacific Crest National Scenic Trail, is a long-distance hiking and equestrian trail closely aligned with the highest portion of the Cascade and Sierra Nevada mountain ranges, which lie ...

is one-half mile (1 km) away, just over the Trinity Divide. The Pacific Crest National Scenic Trail stretches from

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

to Canada, following the highest portion of the

Sierra Nevada The Sierra Nevada () is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primarily ...

, Klamath Mountains, and

Cascade Range The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, ...

and paralleling the Pacific Ocean by . The Little Castle Lake Trail continues on to Mt. Bradley, elev. a locally prominent mountain with views of

, overlooking

Dunsmuir, California Dunsmuir is a city in Siskiyou County, northern California. It is on the upper Sacramento River in the Trinity Mountains. Its population is 1,707 as of the 2020 census, up from 1,650 from the 2010 census. Dunsmuir is currently a hub for tourism ...

and the canyon of the Upper

. Along the way, the trail joins with a network of connections leading into Castle Crags State Park.

Formation

The lake's origins date to the

Pleistocene Era The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...

(more than 10,000 years ago) when a

glacier A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its Ablation#Glaciology, ablation over many years, often Century, centuries. It acquires dis ...

carved a basin in the location of the current lake. During that era, much of North America was glaciated. Castle Lake is a typical glacier ''

'' lake (or tarn), reaching depths of up to near the southern,

granitic A granitoid is a generic term for a diverse category of coarse-grained igneous rocks that consist predominantly of quartz, plagioclase, and alkali feldspar. Granitoids range from plagioclase-rich tonalites to alkali-rich syenites and from quart ...

part of the lakeshore (the ''cirque face''). There is a

terminal moraine A terminal moraine, also called end moraine, is a type of moraine that forms at the terminal (edge) of a glacier, marking its maximum advance. At this point, debris that has accumulated by plucking and abrasion, has been pushed by the front edge ...

boulders In geology, a boulder (or rarely bowlder) is a rock fragment with size greater than in diameter. Smaller pieces are called cobbles and pebbles. While a boulder may be small enough to move or roll manually, others are extremely massive. In co ...

and

gravel Gravel is a loose aggregation of rock fragments. Gravel occurs naturally throughout the world as a result of sedimentary and erosive geologic processes; it is also produced in large quantities commercially as crushed stone. Gravel is classifi ...

forming a natural

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use ...

opposite the cirque face along the northeastern shore of the lake, where there is an outlet, and the lake is deep. The cirque where Castle Lake is found is a classic

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...

cirque. The ''cirque headwall'' (the highest part of the mountain where the glacier began to form) was in the south or southwest, and the part of the mountain that sloped downward to the northeast was away from the prevailing winds. The resulting shaded area was sheltered from direct sun, and from the

evaporating Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidi ...

effects of wind. These conditions encouraged snow which had fallen in the winter to remain throughout the summer and fall, creating a year-round snow pack which grew deeper each year. Glacial Tarn Formation EN

During initial glacial formation, snow changed into glacial ice as this year-round snow pack increased and deepened. The process of

nivation Nivation is the set of geomorphic processes associated with snow patches. The primary processes are mass wasting and the freeze and thaw cycle, in which fallen snow gets compacted into firn or névé. The importance of the processes covered by the ...

followed (where a hollow in a slope was enlarged by

freeze-thaw Frost weathering is a collective term for several mechanical weathering processes induced by stresses created by the freezing of water into ice. The term serves as an umbrella term for a variety of processes such as frost shattering, frost wedg ...

weathering and glacial erosion). As the hollow enlarged and filled with snow and ice, rock debris (or till) contained within the glacial ice also began to abrade the

bedrock In geology, bedrock is solid Rock (geology), rock that lies under loose material (regolith) within the crust (geology), crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface mater ...

surface – as the glacial ice moved down the slope, it had a "sandpaper effect" on the bedrock which it scraped. Eventually the hollow took the shape of a large bowl in the side of the mountain, with the headwall being weathered by constant freezing and thawing, and eroded by plucking. The basin became deeper (especially at the base of the headwall) as it continued to be eroded by abrasion. When the current warming period began, the glacier retreated and finally melted completely. It left behind a bowl shape, deepest at the base of the headwall where the glacial ice had been the deepest and most abrasive. The bowl shape extended to its northeast edge, where there was a terminal moraine of smaller rocks and debris which had been deposited by the glacier. When the bowl-shaped crater filled with water, this terminal moraine acted as a natural dam, helping to contain the water in the newly formed cirque lake.

History

Castle Lake was within the range of the

Okwanuchu The Okwanuchu were one of a number of small Shastan-speaking tribes of Native Americans in Northern California, who were closely related to the adjacent larger Shasta tribe. Geography The Okwanuchu occupied territory south, southwest, and south ...

tribe, one of a number of small Shastan-speaking tribes of Native Americans who were closely related to the adjacent larger Shasta tribe. (Dover Publications (New York) reprint ed., , p. 284) The Okwanuchu occupied territory near

, including the nearby present-day cities of

and

, and the upper

canyon (among other areas). The Okwanuchu were speakers of the older

Hokan The Hokan language family is a hypothetical grouping of a dozen small language families that were spoken mainly in California, Arizona and Baja California. Etymology The name ''Hokan'' is loosely based on the word for "two" in the various Hokan ...

-speaking family of languages, with archaeological sites associated with their range dating back more than 5000 years. However, members of a tribe of the

Penutian Penutian is a proposed grouping of language families that includes many Native American languages of western North America, predominantly spoken at one time in British Columbia, Washington, Oregon, and California. The existence of a Penutian s ...

-speaking family of languages, the

Wintu The Wintu (also Northern Wintun) are Native Americans who live in what is now Northern California. They are part of a loose association of peoples known collectively as the Wintun (or Wintuan). Others are the Nomlaki and the Patwin. The Wintu ...

, who arrived in central Northern California about 1200 years ago, were out-competing their Hokan-language family neighbors, and were expanding Wintu territory. It is unclear at the time of first contact with non-Native Americans in the 1820s which tribe was living nearest to Castle Lake. Little or no information is available about Native American use or beliefs regarding Castle Lake; for example, Castle Lake is not mentioned in a published collection of Wintu tales and legends. The first non-Native Americans to pass through the area of Castle Lake were hunters and trappers of the

Hudson's Bay Company The Hudson's Bay Company (HBC; french: Compagnie de la Baie d'Hudson) is a Canadian retail business group. A fur trading business for much of its existence, HBC now owns and operates retail stores in Canada. The company's namesake business div ...

, who began to come down the

Siskiyou Trail The Siskiyou Trail stretched from California's Central Valley to Oregon's Willamette Valley; modern-day Interstate 5 follows this pioneer path. Originally based on existing Native American foot trails winding their way through river valleys, t ...

from present-day

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

into Mexican-controlled California, in the late 1820s and early 1830s, in search of beaver and other pelt-bearing animals. At about this same time,

Ewing Young Ewing Young (1799-February 9, 1841) was an American fur trapper and trader from Tennessee who traveled in what was then the northern Mexico frontier territories of Santa Fe de Nuevo México and Alta California before settling in the Oregon Country. ...

led the first group of Americans up the Siskiyou Trail, passing near Castle Lake. In 1841, an overland party of the

United States Exploring Expedition The United States Exploring Expedition of 1838–1842 was an exploring and surveying expedition of the Pacific Ocean and surrounding lands conducted by the United States. The original appointed commanding officer was Commodore Thomas ap Catesby ...

, the first cartographers and scientists came through the area. Following the annexation of California by the United States in 1848 as a result of the

Mexican–American War The Mexican–American War, also known in the United States as the Mexican War and in Mexico as the (''United States intervention in Mexico''), was an armed conflict between the United States and Mexico from 1846 to 1848. It followed the 1 ...

, Castle Lake came under the control of the U.S. Federal Government as

public land In all modern states, a portion of land is held by central or local governments. This is called public land, state land, or Crown land (Australia, and Canada). The system of tenure of public land, and the terminology used, varies between countrie ...

. In 1855, an area near Castle Lake, now known as Battle Rock, was the site of a battle between Native Americans and

California Gold Rush The California Gold Rush (1848–1855) was a gold rush that began on January 24, 1848, when gold was found by James W. Marshall at Sutter's Mill in Coloma, California. The news of gold brought approximately 300,000 people to California fro ...

-era settlers. The poet

Joaquin Miller Cincinnatus Heine Miller (; September 8, 1837 – February 17, 1913), better known by his pen name Joaquin Miller (), was an American poet, author, and frontiersman. He is nicknamed the "Poet of the Sierras" after the Sierra Nevada, about which h ...

wrote a first-hand account of this battle, ''The Battle of Castle Crags,'' in which Miller took part in the fight, and received an arrow wound through the cheek and jaw. This battle was reportedly the last battle between Native Americans and settlers in which the Native Americans fought exclusively with bow and arrow. With the development, first, of the U.S. "Forest Reserve" system in the late 19th century, and then the organization of the U.S. National Forests in the early 20th century, Castle Lake came under the stewardship of the

U.S. Forest Service The United States Forest Service (USFS) is an agency of the U.S. Department of Agriculture that administers the nation's 154 national forests and 20 national grasslands. The Forest Service manages of land. Major divisions of the agency in ...

. The association between U.C. Davis and Castle Lake began in 1957, with the first extensive study done of the lake, followed by the construction of the itself.

Animal life

Humans introduced

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

into the lake in the 1930s for

sport fishing Recreational fishing, also called sport fishing or game fishing, is fishing for leisure, exercise or competition. It can be contrasted with commercial fishing, which is professional fishing for profit; or subsistence fishing, which is fishing ...

, including

rainbow trout The rainbow trout (''Oncorhynchus mykiss'') is a species of trout native to cold-water tributaries of the Pacific Ocean in Asia and North America. The steelhead (sometimes called "steelhead trout") is an anadromous (sea-run) form of the coasta ...

(''Oncorhynchus mykiss''),

brook trout The brook trout (''Salvelinus fontinalis'') is a species of freshwater fish in the char genus ''Salvelinus'' of the salmon family Salmonidae. It is native to Eastern North America in the United States and Canada, but has been introduced elsewhere ...

(''Salvelinus fontinalis''), and golden shiner (''Notemigonus crysoliecas''). Trout were last released into Castle Lake in 2008 by the California Department of Fish and Wildlife but recreational fish stocking has since ceased due to concern for other species (i.e., threatened or endangered). The brook char was also originally stocked but now has become self-sustaining, and reproduces naturally in springs found on the eastern side of the lake. Golden shiner is a bait fish

minnow Minnow is the common name for a number of species of small freshwater fish, belonging to several genera of the families Cyprinidae and Leuciscidae. They are also known in Ireland as pinkeens. Smaller fish in the subfamily Leusciscidae are co ...

that was likely placed in the lake by anglers who left their remaining bait behind in the lake. The fish feed on

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

and

insects Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of j ...

; the fish are then eaten by

predators Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

around the lake, especially

osprey The osprey (''Pandion haliaetus''), , also called sea hawk, river hawk, and fish hawk, is a diurnal, fish-eating bird of prey with a cosmopolitan range. It is a large raptor reaching more than in length and across the wings. It is brown o ...

(''Pandion haliaetus''). Other birds in the area include

bald eagle The bald eagle (''Haliaeetus leucocephalus'') is a bird of prey found in North America. A sea eagle, it has two known subspecies and forms a species pair with the white-tailed eagle (''Haliaeetus albicilla''), which occupies the same niche as ...

(''Haliaectus leucoephalus''),

golden eagle The golden eagle (''Aquila chrysaetos'') is a bird of prey living in the Northern Hemisphere. It is the most widely distributed species of eagle. Like all eagles, it belongs to the family Accipitridae. They are one of the best-known bird of p ...

(''Aquila chrysaetos''),

peregrine falcon The peregrine falcon (''Falco peregrinus''), also known as the peregrine, and historically as the duck hawk in North America, is a Cosmopolitan distribution, cosmopolitan bird of prey (Bird of prey, raptor) in the family (biology), family Falco ...

(''Falco peregrinus''),

wood duck The wood duck or Carolina duck (''Aix sponsa'') is a species of perching duck found in North America. The drake wood duck is one of the most colorful North American waterfowl. Description The wood duck is a medium-sized perching duck. A typi ...

(''Aix sponsa''), belted kingfisher (''Megaceryle alcyon''),

Steller's jay Steller's jay (''Cyanocitta stelleri'') is a bird native to western North America and the mountains of Central America, closely related to the blue jay found in eastern North America. It is also known as the long-crested jay, mountain jay, and pin ...

(''Cyanocitta stellere''), and

sooty grouse The sooty grouse (''Dendragapus fuliginosus'') is a species of forest-dwelling grouse native to North America's Pacific Coast Ranges.del Hoyo, J., Elliott, A., & Sargatal, J., eds. (1994). ''Handbook of the Birds of the World'' 2: 401-402. Lynx ...

(''Dendragapus fuliginosus'').

Reptiles Reptiles, as most commonly defined are the animals in the Class (biology), class Reptilia ( ), a paraphyletic grouping comprising all sauropsid, sauropsids except birds. Living reptiles comprise turtles, crocodilians, Squamata, squamates (lizar ...

and

amphibians Amphibians are four-limbed and ectothermic vertebrates of the class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial, fossorial, arbore ...

around the lake, including the

rough-skinned newt The rough-skinned newt or roughskin newt (''Taricha granulosa'') is a North American newt known for the strong toxin exuded from its skin. Appearance A stocky newt with rounded snout, it ranges from light brown to olive or brownish-black on t ...

(''Taricha granulosa''), the

Cascades frog The Cascades frog (''Rana cascadae'') is a species of frog in the family Ranidae found in the Pacific Northwest, mainly in the Cascade Range and Olympic Mountains. Description Appearance The Cascades frog has a green to brown color on its b ...

(''Rana cascadae'') and the

garter snake Garter snake is a common name for generally harmless, small to medium-sized snakes belonging to the genus ''Thamnophis'' in the family Colubridae. Native to North and Central America, species in the genus ''Thamnophis'' can be found from the sub ...

(''Thamnophis sirtalis''), feed as well on insects and young fish (among other prey). Many mammals can be found around the lake and in the adjacent

wilderness area Wilderness or wildlands (usually in the plural), are natural environments on Earth that have not been significantly modified by human activity or any nonurbanized land not under extensive agricultural cultivation. The term has traditionally re ...

, national forest, and parklands. These include

black bear Black bear or Blackbear may refer to: Animals * American black bear (''Ursus americanus''), a North American bear species * Asian black bear (''Ursus thibetanus''), an Asian bear species Music * Black Bear (band), a Canadian First Nations group ...

(''Ursus americanus''),

blacktail deer Two forms of black-tailed deer or blacktail deer that occupy coastal woodlands in the Pacific Northwest of North America are subspecies of the mule deer (''Odocoileus hemionus''). They have sometimes been treated as a species, but virtually all ...

(''Odocoileus hemionus''), river otter (''Lutra canadensis''),

black-tailed jackrabbit The black-tailed jackrabbit (''Lepus californicus''), also known as the American desert hare, is a common hare of the western United States and Mexico, where it is found at elevations from sea level up to . Reaching a length around , and a ...

(''Lepus californicus''), and

mountain lion The cougar (''Puma concolor'') is a large cat native to the Americas. Its range spans from the Canadian Yukon to the southern Andes in South America and is the most widespread of any large wild terrestrial mammal in the Western Hemisphere. I ...

(also known as "cougars" or "puma") (''Puma concolor''). Castle lake cougars have on occasion been known to crouch in the bushes and watch humans, their eyes shining in the moonlight. No attacks have been noted.

Plant life

Although the lake (at elevation ) and surrounding areas are well below local

tree line The tree line is the edge of the habitat at which trees are capable of growing. It is found at high elevations and high latitudes. Beyond the tree line, trees cannot tolerate the environmental conditions (usually cold temperatures, extreme snowp ...

(for example, on nearby Mount Shasta, the tree line is at about ), because of the high concentration of granite and the often exposed steep, rocky slopes, the vegetation at the lake and in the area can vary widely, from dense mixed forest near and below the lake to the appearance of near-alpine conditions above the lake. At and in the area below the lake, mixed forests of

ponderosa pine ''Pinus ponderosa'', commonly known as the ponderosa pine, bull pine, blackjack pine, western yellow-pine, or filipinus pine is a very large pine tree species of variable habitat native to mountainous regions of western North America. It is the ...

(''Pinus ponderosa''),

red fir ''Abies magnifica'', the red fir or silvertip fir, is a western North American fir, native to the mountains of southwest Oregon and California in the United States. It is a high-elevation tree, typically occurring at elevation, though only rare ...

(''Abies Magnifica''),

white fir ''Abies concolor'', the white fir, is a coniferous tree in the pine family Pinaceae. This tree is native to the mountains of western North America, including the Cascade Range and southern Rocky Mountains, and into the isolated mountain range ...

(''Abies Concolor''),

lodgepole pine ''Pinus contorta'', with the common names lodgepole pine and shore pine, and also known as twisted pine, and contorta pine, is a common tree in western North America. It is common near the ocean shore and in dry montane forests to the subalpine, ...

(''Pinus Contorda''),

incense cedar ''Calocedrus'', the incense cedar (alternatively spelled incense-cedar), is a genus of coniferous trees in the cypress family Cupressaceae first described as a genus in 1873. It is native to eastern Asia and western North America. The generi ...

(''Libocedrus decurrens''), and

alder Alders are trees comprising the genus ''Alnus'' in the birch family Betulaceae. The genus comprises about 35 species of monoecious trees and shrubs, a few reaching a large size, distributed throughout the north temperate zone with a few sp ...

can be found. Alders play a particularly important role, as alders establish symbioses with the

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

-fixing

Actinomycetota The ''Actinomycetota'' (or ''Actinobacteria'') are a phylum of all gram-positive bacteria. They can be terrestrial or aquatic. They are of great economic importance to humans because agriculture and forests depend on their contributions to soi ...

(''Frankiella alni''). This bacteria converts atmospheric nitrogen into soil-soluble

nitrate Nitrate is a polyatomic ion A polyatomic ion, also known as a molecular ion, is a covalent bonded set of two or more atoms, or of a metal complex, that can be considered to behave as a single unit and that has a net charge that is not zer ...

s which can be utilised by the alder, and favorably enhances the soil fertility generally. Alders benefit other plants growing near them by taking nitrogen out of the air and depositing it in the soil in usable form; fallen alder leaves make very rich

compost Compost is a mixture of ingredients used as plant fertilizer and to improve soil's physical, chemical and biological properties. It is commonly prepared by decomposing plant, food waste, recycling organic materials and manure. The resulting m ...

. The rarely-seen

Brewer spruce ''Picea breweriana'', known as Brewer spruce, Brewer's weeping spruce, or weeping spruce, is a species of spruce native to western North America, where it is one of the rarest on the continent. The specific epithet ''breweriana'' is in honor of ...

(''Picea breweriana'') exists in a few small locations on the igneous slopes behind the lake. Other deciduous trees at lower elevations in the area may include such species as

bigleaf maple ''Acer macrophyllum'', the bigleaf maple or Oregon maple, is a large deciduous tree in the genus '' Acer''. It is native to western North America, mostly near the Pacific coast, from southernmost Alaska to southern California. Some stands are al ...

vine maple ''Acer circinatum'', the vine maple, is a species of maple native to western North America. Description It most commonly grows as a large shrub growing to around tall, but it will occasionally form a small to medium-sized tree, exceptionall ...

black oak Black Oak may refer to: Places in the United States * Black Oak, Arkansas * Black Oak, Daviess County, Indiana * Black Oak, Lake County, Indiana, a neighborhood of Gary, Indiana * Black Oak, Missouri Other * Black Oak Arkansas Black Oak Ar ...

and

Pacific dogwood ''Cornus nuttallii'', the Pacific dogwood, western dogwood, or mountain dogwood, is a species of dogwood tree native to western North America. Description It is a small to medium-sized deciduous tree, reaching tall, often with a canopy spre ...

. At higher elevations above the lake (especially in rocky or exposed locations), the pine and fir tree forests are thinner, and the trees grow in a more stunted fashion; instead, shrubs and bushes, such as green manzanita (''Arctostaphylos patula''), dwarf mountain manzanita (''Arctostaphylos nevadensis''), and

tan oak ''Notholithocarpus densiflorus'', commonly known as the tanoak or tanbark-oak, is a broadleaf tree in the family Fagaceae, and the type species of the genus ''Notholithocarpus''. It is native to the far western United States, particularly Oregon ...

(''Lithocarpus densiflorus'') find areas and niches to grow. Other shrubs found around the lake are Sierra laurel (''Leucothoe davisiae''), and the lake is ringed with western azaleas (''Rhododendron occidentale''), which bloom mostly in June. Western azalea Castle Lake CA

The best-known plant life in the area, however, are the lakeside and nearby meadow displays of alpine and sub-alpine flowers in the early summer. These can include wood rose (''Rosa gymnocarpa''), Shasta lupine (''Lupinus albicaulis''), red/crimson/scarlet columbine (''Aquilegia formosa''), tiger lily (''Lilium pardalinum''), fawn lily (''Erythronium sp.''), pine-drops (''Pterospora andromedea''), douglas spiraea (''Spiraea douglasii''), scarlet paintbrush (''Castilleja pinetorum''), alpine paintbrush (''Castilleja arachnoidea''), dwarf paintbrush (''Castilleja miniata''), alpine saxifrage (''Saxifraga nidifica''), Shasta penstemon (''Penstemon laetus''), alpine buckwheat (''Eriogonum pyrolifolium''), and Tofield's swamp lily (''Tofieldia occidentalis''). Also, in cool, wet spots near the lake, carnivorous

Pitcher Plants Pitcher plants are several different carnivorous plants which have modified leaves known as pitfall traps—a prey-trapping mechanism featuring a deep cavity filled with digestive liquid. The traps of what are considered to be "true" pitcher p ...

(''Darlingtonia californica'') appear.

Notes

References

* * * * * * * * (Dover Publications (New York) reprint ed., ) * * * * *

External links

* * * {{authority control Lakes of Siskiyou County, California Trinity Mountains (California) Shasta-Trinity National Forest Pleistocene California Tourist attractions in Siskiyou County, California Lakes of Northern California Lakes of California