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Difference Between Sequoia and Redwood

Nex Virox Team
Written byNex Virox Team
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Varshal Nirbhavane
Senior SEO & Organic Growth Professional · 5+ years
19 min read
Quick answer

The main difference between Sequoia and Redwood is that sequoias grow in California's Sierra Nevada with thicker trunks and fire-resistant bark, while redwoods grow along the Pacific coast and are taller. Sequoia is a massive, high-elevation tree, while Redwood is a coastal, sky-scraping tree.

Key takeaways

  • Core distinction: Sequoia is the genus for giant sequoias, while redwood refers to coast redwoods.
  • Size and location: Giant sequoias grow massive trunks inland, whereas coast redwoods reach taller heights near oceans.
  • Growth conditions: Sequoias need dry mountain climates with fire, while redwoods require foggy coastal moisture.
  • Wood properties: Redwood resists decay better for outdoor use, but sequoia wood is more brittle.
  • Best choice: Plant a redwood for fast coastal growth, or a sequoia for dramatic trunk girth.

Difference Between Sequoia and Redwood: Comparison Table

AspectSequoiaRedwood
DefinitionGiant sequoias are massive trees native only to California's western Sierra Nevada slopes.Coast redwoods are the tallest trees, native to a narrow fog belt along California's Pacific coast.
PurposeGiant sequoias dominate high-elevation groves, surviving snow, drought, and frequent natural fires.Coast redwoods thrive in cool, foggy coastal conditions, maximizing growth in mild, wet climates.
Core MechanismSequoia bark is thick, fibrous, and fire-resistant, protecting the tree from intense ground blazes.Redwood bark is tannin-rich and rot-resistant, defending against fungal decay, insects, and coastal moisture.
Maximum HeightGiant sequoias typically reach 250 to 280 feet, with the tallest known specimen around 311 feet.Coast redwoods commonly exceed 300 feet, with the tallest recorded individual standing 379.7 feet tall.
Trunk DiameterSequoias have massive trunks, often 20 to 30 feet in diameter, with the largest exceeding 37 feet.Redwoods have narrower trunks, typically 12 to 18 feet in diameter, with the widest near 27 feet.
Bark ThicknessSequoia bark can reach 3 feet thick, providing exceptional insulation against frequent, low-intensity fires.Redwood bark is thinner, usually 6 to 12 inches thick, offering less fire protection but strong decay resistance.
Growth RateGiant sequoias grow slowly, adding roughly 1 to 2 feet in height each year during early decades.Coast redwoods grow rapidly, often gaining 2 to 6 feet annually, especially in deep, moist soils.
LongevityGiant sequoias live about 3,000 to 3,200 years, with the oldest known specimen exceeding 3,200 years.Coast redwoods typically live 500 to 1,000 years, with the oldest recorded individual around 2,200 years old.
Wood DensitySequoia wood is moderately dense, brittle, and prone to shattering on impact, limiting commercial timber use.Redwood wood is lightweight, soft, and straight-grained, making it highly valued for construction and outdoor projects.
DurabilitySequoia wood resists insects and decay well but is brittle, cracking easily under heavy snow or wind loads.Redwood heartwood is naturally decay-resistant, lasting decades outdoors without chemical treatment or preservatives.
Fire ResistanceSequoias survive intense fires thanks to thick bark, high canopy, and cones that open after heat exposure.Redwoods have thinner bark and are less fire-adapted, but their tall crowns often escape low-to-moderate ground fires.
Pest ResistanceSequoias face few insect threats, but bark beetles can attack stressed trees during prolonged drought periods.Redwoods produce tannins that repel most insects, though termites may attack wood in contact with damp soil.
Root SystemGiant sequoias have shallow, wide-spreading roots extending up to 100 feet from the trunk, anchoring in rocky soil.Coast redwoods develop shallow roots that interlock with neighboring trees, enhancing stability in wet, loose coastal ground.
Climate ToleranceSequoias endure cold winters, heavy snow, and hot, dry summers typical of California's Sierra Nevada mountains.Redwoods require mild, humid coastal climates, suffering in extreme heat, frost, or prolonged dry conditions.
Water NeedsGiant sequoias rely on snowmelt and winter rain, tolerating several months of summer drought without irrigation.Coast redwoods demand abundant moisture, absorbing water from fog drip, rain, and consistently damp soil year-round.
Sunlight NeedsSequoia seedlings need full sunlight to grow, thriving in open gaps created by fire or wind disturbance.Redwood seedlings tolerate partial shade, but mature trees require full sun to maintain rapid vertical growth.
ReproductionSequoias produce serotinous cones that open only after fire, releasing thousands of seeds onto mineral soil.Redwoods reproduce via seeds and sprout vigorously from roots or stumps, forming rings of cloned trees.
Leaf ShapeSequoia leaves are scale-like, overlapping, and bluish-green, forming dense, feathery sprays along branchlets.Redwood leaves are flat, needle-like, and dark green, arranged in two rows along each side of the twig.
Cone SizeGiant sequoia cones are small, about 1 to 2 inches long, containing roughly 200 seeds each.Redwood cones are tiny, measuring only 0.5 to 1 inch, holding 10 to 60 seeds per cone.
Bark ColorSequoia bark is reddish-brown to cinnamon-colored, deeply furrowed, and fibrous, resembling a spongy texture.Redwood bark is reddish-brown to dark mahogany, with thick, soft, and deeply ridged vertical furrows.
Native RangeGiant sequoias grow naturally in about 70 groves covering roughly 35,000 acres on the Sierra Nevada's west slope.Coast redwoods span a 450-mile strip along the Pacific coast, from southern Oregon to central California.
Elevation RangeSequoias thrive at elevations between 5,000 and 8,000 feet, where winter snowpack provides essential moisture.Redwoods grow from sea level up to about 3,000 feet, staying within reach of coastal fog and mild air.
Conservation StatusGiant sequoias are listed as endangered, with only about 26,000 trees remaining in their native groves.Coast redwoods are classified as endangered, with roughly 100,000 acres of old-growth forest surviving today.
Primary ThreatsSequoias face severe threats from drought, bark beetles, and increasingly intense wildfires killing mature groves.Redwoods face threats from logging, habitat fragmentation, and climate change reducing fog frequency and moisture.
Notable SpecimensGeneral Sherman is the largest tree by volume, standing 275 feet tall with a base diameter exceeding 36 feet.Hyperion is the tallest living tree, reaching 379.7 feet, though its exact location is kept secret.
Typical UsersSequoia groves attract hikers, campers, and nature photographers seeking ancient, massive trees in mountain parks.Redwood forests draw tourists, road-trippers, and conservationists exploring coastal trails, scenic drives, and state parks.
Commercial UseSequoia wood is rarely harvested commercially due to brittleness, low availability, and full protection in national parks.Redwood timber is highly prized for decks, siding, and furniture, though old-growth logging is now restricted.
Cultural SignificanceSequoias symbolize resilience and wilderness, featured prominently in Native American lore and early conservation movements.Redwoods represent enduring natural heritage, inspiring state parks, national monuments, and environmental activism in California.
Best-Fit ScenarioChoose sequoias for high-elevation, fire-prone landscapes where massive trunk size and extreme longevity are desired.Choose redwoods for coastal, fog-rich areas where rapid vertical growth, tall canopies, and decay-resistant timber are priorities.

What Is Sequoia?

Sequoia is a genus of massive evergreen trees native to the western United States. It exists as a biological group containing the world's largest living organisms by volume. These trees thrive in specific coastal and mountain climates, growing for thousands of years.

Definition of Sequoia

Sequoia is a taxonomic genus within the cypress family Cupressaceae, comprising two surviving species: Sequoiadendron giganteum and Sequoia sempervirens. These conifers are distinguished by their immense trunk diameter, fibrous reddish bark, and exceptional longevity. They reproduce via cones containing winged seeds.

Key Characteristics of Sequoia

CharacteristicWhat It Means in Practice
Massive trunk volumeGiant sequoias hold more wood than any other single tree on Earth.
Reddish fibrous barkBark can be up to 3 feet thick, providing strong fire resistance.
Exceptional longevitySome individuals live over 3,000 years, surviving many climate shifts.
Conifer reproductionSeeds are released from woody cones, often after fire opens them.
Shallow root systemRoots spread wide, not deep, making them vulnerable to toppling.
Needle-like leavesScale-like foliage stays green year-round, reducing water loss.
High water demandThey absorb huge amounts of moisture daily from fog and soil.
Slow growth rateThey gain height steadily but take centuries to reach full size.
Fire-dependent ecologyHeat clears competing plants and prepares seedbeds for regeneration.
Limited natural rangeThey grow only in narrow bands of California and Oregon.

Common Examples of Sequoia

  • General Sherman – the largest tree by volume, located in Sequoia National Park.
  • General Grant – a giant sequoia known as the nation's Christmas tree.
  • President Tree – a massive specimen in Giant Forest with over 3,200 years of age.
  • Coast Redwood – the tallest tree species, reaching over 370 feet in height.
  • Hyperion Tree – the current tallest known living tree, found in Redwood National Park.
  • Lost Monarch – a coast redwood with enormous combined trunk volume.
  • Grizzly Giant – an ancient sequoia in Mariposa Grove, Yosemite.
  • Stagg Tree – a giant sequoia with a massive trunk, located in private land.
  • Boole Tree – the largest sequoia in Converse Basin, with a huge base.
  • Lincoln Tree – a notable giant sequoia in Sequoia National Park.

Advantages and Limitations of Sequoia

AdvantagesLimitations
Provides massive carbon storage, helping mitigate climate change effects.Requires enormous water supply, making it vulnerable to drought.
Extremely fire-resistant due to thick, protective bark layers.Shallow roots cause easy uprooting in strong winds or wet soil.
Lives for millennia, offering long-term ecosystem stability.Slow reproduction rate limits population recovery after disturbances.
Creates unique habitats for many dependent animal and plant species.Very narrow native range makes it susceptible to habitat loss.
High timber value historically, though now protected in most areas.Vulnerable to root rot and fungal diseases under stress.
Attracts millions of tourists, supporting local economies.Large size makes them difficult to manage in urban or small spaces.
Produces durable wood resistant to decay and insects.Wood is brittle, breaking easily under heavy snow or ice loads.
Supports biodiversity by offering nesting sites for birds and mammals.Requires specific foggy coastal or high-elevation climates to thrive.
Acts as a natural firebreak due to high moisture content in bark.Cannot survive prolonged flooding or waterlogged soil conditions.
Provides shade and cools local microclimates significantly.Growth is extremely slow, taking decades to reach moderate height.

What Is Redwood?

Redwood is the common name for the tallest tree species on Earth, Sequoia sempervirens. It is a conifer that grows in a narrow coastal fog belt. It exists to dominate the damp, mild climate of the Pacific Northwest.

Definition of Redwood

Redwood is a massive, evergreen coniferous tree in the family Cupressaceae. It is characterized by thick, fibrous, reddish-brown bark and flat, needle-like leaves. It is the sole living member of its genus.

Key Characteristics of Redwood

CharacteristicWhat It Means in Practice
Coastal habitatIt relies on ocean fog for moisture, limiting its range to a narrow strip of coastline.
Extreme heightIt can exceed 300 feet, making it the tallest known tree species on the planet.
Fibrous barkThe thick, spongy bark can be up to 12 inches deep, providing insulation against fire.
Rapid growthIt grows faster than most conifers, adding several feet of height each year in good conditions.
Long lifespanIndividual trees can live for over 2,000 years, though many are younger due to logging.
Shallow rootsIts root system is shallow and wide, spreading laterally to anchor the massive trunk.
No resin ductsUnlike pines, it lacks resin ducts, which reduces its flammability and fire risk.
Clonal sproutingIt can regenerate from burls at the base, allowing new trees to grow after damage or fire.
Flat needlesIts leaves are flat and arranged in two ranks, unlike the round needles of pines.
Small conesIts cones are only about one inch long, holding tiny seeds that need bare soil to germinate.

Common Examples of Redwood

  • Hyperion - The tallest known living tree, standing over 380 feet tall in Redwood National Park.
  • Lost Monarch - A massive redwood with the largest trunk volume, located in Jedediah Smith State Park.
  • Stratosphere Giant - A former record-holder for height, found in Humboldt Redwoods State Park.
  • General Sherman - A giant sequoia, not a coastal redwood, often confused with this species.
  • Redwood National Park - A protected area preserving ancient groves of coastal redwoods in California.
  • Muir Woods National Monument - A popular grove near San Francisco with accessible, ancient redwood trees.
  • Armstrong Redwoods State Reserve - A park in Sonoma County known for its old-growth redwood forest.
  • Prairie Creek Redwoods State Park - A habitat for the largest redwood grove, featuring dense, pristine stands.
  • Big Basin Redwoods State Park - California's oldest state park, established to protect a redwood watershed.
  • Sequoia sempervirens - The scientific name for the coastal redwood, distinguishing it from the giant sequoia.

Advantages and Limitations of Redwood

AdvantagesLimitations
It is naturally resistant to rot, insects, and fire, making it durable.It is highly dependent on a specific foggy climate, so it cannot survive in dry inland areas.
It grows quickly, allowing for rapid timber production in managed forests.Its wood is soft and brittle, making it prone to denting and breaking under heavy load.
It sequesters large amounts of carbon due to its massive size and long life.It requires a vast amount of water, making it vulnerable to drought and climate change.
Its thick bark protects it from most ground fires, aiding survival.It has a shallow root system, making it susceptible to being toppled by strong winds.
It regenerates easily from sprouts, allowing forests to recover after logging.It produces tiny seeds that rarely germinate, limiting natural reproduction to specific conditions.
It creates a unique, shaded ecosystem that supports diverse understory plants.It grows in a narrow coastal band, so its natural range is extremely limited.
Its straight, tall trunk yields high-quality lumber for construction.It is highly susceptible to Phytophthora, a root pathogen that causes widespread decline.
It provides habitat for endangered species like the marbled murrelet.It is slow to mature, taking decades to produce cones and seeds for reproduction.
It is a major tourist attraction, boosting local economies through parks.It is sensitive to air pollution, which can damage its foliage and reduce growth.
It has cultural significance for indigenous tribes, who used its wood and bark.It is vulnerable to logging pressure, with most old-growth forests already harvested.

Similarities Between Sequoia and Redwood

Shared AspectHow Sequoia and Redwood Are Alike
Tree CategorySequoia and redwood are both coniferous evergreen trees belonging to the cypress plant family.
Native RangeSequoia and redwood both grow naturally only in the coastal and mountain regions of California.
Long LifespanSequoia and redwood both live for over 2,000 years under ideal natural growing conditions.
Wood CompositionSequoia and redwood both produce heartwood rich in natural tannins that resist insect attacks.
Fire AdaptationSequoia and redwood both possess thick bark that protects them from frequent low-intensity wildfires.
Seed ReproductionSequoia and redwood both reproduce primarily through tiny cones that release numerous small seeds.
Growth RateSequoia and redwood both grow rapidly, adding several feet of height each single year.
Root SystemSequoia and redwood both develop shallow, wide-spreading root systems rather than deep taproots.
Climate PreferenceSequoia and redwood both thrive in mild climates with wet winters and dry summers.
Water NeedsSequoia and redwood both require substantial moisture from fog or rain to survive.
Conservation StatusSequoia and redwood both receive legal protection as vulnerable or endangered native tree species.
National Park PresenceSequoia and redwood both serve as flagship attractions within dedicated United States national parks.
Tourism ValueSequoia and redwood both draw millions of visitors annually who come to view their massive trunks.
Timber QualitySequoia and redwood both yield lightweight, straight-grained lumber that resists warping and decay.
Historical LoggingSequoia and redwood both faced intensive commercial logging during the nineteenth and twentieth centuries.
Bark ThicknessSequoia and redwood both develop fibrous bark that can measure over twelve inches in thickness.
Foliage TypeSequoia and redwood both display scale-like, overlapping leaves arranged along their branchlets.
Scientific ClassificationSequoia and redwood both belong to the subfamily Sequoioideae within the cypress family.
Shade ToleranceSequoia and redwood both tolerate partial shade during their early seedling establishment stages.
Pest ResistanceSequoia and redwood both suffer relatively few serious problems from native bark beetles.
Landscape UseSequoia and redwood both serve as ornamental specimen trees in large parks and estates.
Fungal RelationshipSequoia and redwood both form beneficial mycorrhizal associations with soil fungi for nutrient uptake.
Branch StructureSequoia and redwood both shed lower branches naturally as they mature and grow taller.
Carbon StorageSequoia and redwood both sequester massive amounts of carbon dioxide within their enormous wood volumes.
Cultural SignificanceSequoia and redwood both hold deep symbolic importance for Native American tribes and Californians.
Photography AppealSequoia and redwood both offer dramatic scale that makes them favorite subjects for landscape photographers.
Scientific StudySequoia and redwood both attract ongoing botanical research into longevity and climate resilience.
Propagation MethodSequoia and redwood both propagate successfully from seeds, cuttings, and nursery-grown saplings.
Soil PreferenceSequoia and redwood both prefer well-drained, slightly acidic soils rich in organic matter.
Ecosystem RoleSequoia and redwood both provide critical habitat for birds, mammals, and understory plants.

Sequoia or Redwood: Which Should You Choose?

Your choice comes down to one variable: available space versus fire risk. If you have acres of room and want the tallest tree on Earth, choose a Redwood. If you have limited space or live in a fire-prone zone, choose a Sequoia.

When to Use Sequoia

Choose Sequoia when your property is under half an acre, when you need a tree that tolerates drier soil, or when you live in an area with regular wildfire risk. Sequoias also suit colder climates down to -10°F and grow faster in their first decade.

When to Use Redwood

Choose Redwood when you have more than 50 feet of clearance from structures, when you want maximum height exceeding 300 feet, or when your soil stays consistently moist. Redwoods also thrive in coastal fog zones and tolerate salt spray better than Sequoias.

Common Misconceptions About Sequoia and Redwood

Common MythThe Reality
Sequoia and redwood are the exact same tree species.Sequoia is Sequoiadendron giganteum in the cypress family, while redwood is Sequoia sempervirens, a distinct genus and species.
All redwoods grow taller than every sequoia tree.Redwoods exceed 350 feet in height, but individual sequoias often surpass 250 feet, making height overlap common between mature specimens.
Sequoia trees are the largest by total volume on Earth.The General Sherman sequoia holds the volume record at 52,500 cubic feet, but redwoods grow taller and have larger individual trunks in length.
Redwood bark is thicker than sequoia bark.Sequoia bark reaches 3 feet thick, while redwood bark typically maxes out around 12 inches, making sequoia bark significantly thicker.
Sequoia and redwood trees grow naturally in the same forests.Sequoias grow only on the western Sierra Nevada slopes, while redwoods grow in coastal fog belts from Oregon to central California.
Redwood trees live longer than sequoia trees.Sequoias live over 3,000 years, while redwoods typically reach 2,000 years, giving sequoias the clear longevity advantage.
Sequoia cones are larger than redwood cones.Sequoia cones measure 1.5 to 3 inches, while redwood cones are only 0.5 to 1 inch, making sequoia cones noticeably bigger.
Redwood wood is more fire-resistant than sequoia wood.Sequoia bark contains more tannin and is thicker, giving sequoia superior fire resistance compared to redwood's thinner bark layer.
Sequoia trees require coastal fog to survive.Sequoias thrive in inland mountain snow and rain, while redwoods depend heavily on summer fog for moisture and humidity.
Redwood branches grow only at the very top of the tree.Redwoods retain branches along their upper two-thirds, while sequoias keep branches lower on the trunk and have a broader crown.
Sequoia and redwood produce identical cone shapes.Sequoia cones are egg-shaped and woody, while redwood cones are rounder and smaller, with distinctly different seed arrangements inside.
Redwood trees can regenerate only from seeds.Redwoods sprout vigorously from stumps and roots, while sequoias regenerate primarily from seeds after fire clears the forest floor.
Sequoia needles are flat like redwood needles.Sequoia needles are scale-like and awl-shaped, while redwood needles are flat, linear, and arranged in two rows along the branch.
Both sequoia and redwood grow naturally outside California.Sequoia and redwood both have native ranges restricted entirely to California, with no wild populations occurring in any other state.
Redwood trees have deeper root systems than sequoia trees.Sequoia roots spread 100 feet wide but only 6 to 12 feet deep, while redwood roots are similarly shallow and wide-spreading.
Sequoia wood is softer and weaker than redwood lumber.Sequoia wood is brittle and weak, while redwood lumber is stronger, straighter-grained, and far more valuable for construction and decking.
Redwoods grow only in national parks and protected areas.Redwoods grow on private timberlands, state parks, and federal lands, with many unprotected groves still managed for commercial harvest.
Sequoia trees produce cones every single year without fail.Sequoia cones remain green and closed for 20 years, opening only after fire or heat, while redwoods produce seeds annually.
Redwood bark is bright red like sequoia bark.Redwood bark is reddish-brown and fibrous, while sequoia bark is cinnamon-red, deeply furrowed, and spongy to the touch.
Sequoia trees grow faster than redwood trees in height.Redwoods grow 2 to 3 feet per year in height, while sequoias grow slower, adding only 1 to 2 feet annually in most conditions.
Redwood and sequoia trees have identical leaf structures.Sequoia leaves are overlapping scales, while redwood leaves are flat needles with distinct upper and lower surfaces, differing visibly.
Sequoia trees cannot survive outside their native mountain range.Sequoias grow successfully in botanical gardens worldwide, including Europe and Asia, though they rarely reach giant proportions outside California.
Redwood trees are immune to all insect pests and diseases.Redwoods suffer from root rot and canker diseases, while sequoias face fewer pathogens but are vulnerable to bark beetle attacks.
Sequoia and redwood trees have the same wood color.Redwood heartwood is deep red to mahogany, while sequoia heartwood is lighter reddish-brown and often contains more white sapwood.
Redwood trees drop all their needles every autumn.Redwoods are evergreen and drop needles gradually year-round, while sequoias also remain green and shed foliage continuously.
Sequoia trees grow only from seeds released by fire.Sequoia seeds release after fire, but they also germinate from cones opened by drought, insects, or mechanical damage over decades.
Redwood trees have thicker trunks than sequoia trees.Sequoia trunks reach 40 feet in diameter, while redwood trunks max out near 22 feet, making sequoia trunks nearly twice as wide.
Sequoia and redwood trees are both classified as true pines.Neither sequoia nor redwood is a pine; both belong to the cypress family, Cupressaceae, and are not true pines at all.
Redwood trees grow naturally in the Sierra Nevada mountains.Redwoods grow only in coastal regions, while sequoias grow exclusively in the Sierra Nevada, with no natural overlap between their ranges.
Sequoia trees are the tallest living organisms on Earth.Redwoods hold the height record, with Hyperion reaching 379.7 feet, while sequoias are the largest by volume, not by height.

Conclusion

Difference Between Sequoia and Redwood comes down to location and size: sequoias grow in California's Sierra Nevada and are more massive, while redwoods hug the coast and grow taller. Pick a sequoia for sheer bulk; pick a redwood for maximum height.

FAQs on Difference Between Sequoia and Redwood

What is the main difference between a Sequoia and a Redwood?
The main difference is location and size: giant sequoias grow only in California's Sierra Nevada and are shorter but wider, while coast redwoods grow along the Pacific coast and are the tallest trees on Earth.
Which tree is taller, a Sequoia or a Redwood?
Redwoods are taller, reaching over 380 feet, whereas giant sequoias typically max out around 311 feet, making the coast redwood the world's tallest tree species.
Which is better for a backyard, a Sequoia or a Redwood? Neither is ideal for a typical backyard because both grow over 300 feet tall, but a giant sequoia is slightly more adaptable to drier inland climates than a coast redwood. How much does a Sequoia or Redwood tree cost to plant?
A small sapling costs $30 to $100, but mature specimen trees can cost thousands, with final pricing depending on size, nursery source, and shipping logistics.
Are Sequoia trees more fire-resistant than Redwood trees?
Yes, giant sequoias are more fire-resistant due to their thick, spongy bark up to 3 feet thick, while redwoods rely on coastal fog and thinner bark for protection.
Do Sequoias and Redwoods need the same soil conditions?
No, giant sequoias prefer well-drained sandy loam in sunny, drier mountain sites, while coast redwoods demand deep, moist, acidic soil with constant fog and humidity.
What is a common beginner mistake when growing a Sequoia or Redwood?
A common mistake is overwatering a giant sequoia, which causes root rot, while underwatering a coast redwood in hot, dry summer air quickly leads to leaf scorch.
Can you use Sequoia and Redwood lumber interchangeably in construction?
Yes, both woods are soft, decay-resistant conifers used for outdoor decking and siding, but redwood is lighter and easier to work with than denser sequoia lumber.
What is a real-world use case for planting a Sequoia instead of a Redwood?
Plant a giant sequoia for a dramatic, wide-trunked landscape specimen in an inland, sunny park where coastal fog and salt spray would harm a redwood.
Can I switch from growing a Redwood to a Sequoia in the same spot?
Yes, you can switch, but only after removing all redwood roots and amending the soil, because redwoods acidify the ground and sequoias need neutral to slightly alkaline conditions.