Giant Sequoia Sequoiadendron

giganteum

Rebecca KnappENH 101

Fall Quarter 2010

What’s in a name?Sequoiadendron giganteum

Kingdom: PlantaeDivision: Pinophyta gymnospersms, cone-bearingClass: PinopsidaOrder: Pinales extant conifers (AKA Coniferales)Family: Cupressaceaecedar, cypress, juniper, redwoodSubfamily: SequoioideaeGenus: Sequoiadendron

Subfamily: Sequoioideae3 genera• Sequoia (Coast Redwood)

& Sequoiadendron– California/Oregon

• Metasequoia– China (Dawn Redwood)

• Largest and tallest trees in world

• Endangered subfamily

Genus: Sequoiadendron• Giant Sequoia=Sierra Redwood=Wellingtonia• Sole living species in genus• Largest in terms of total volume

– Avg. height: 160-279ft.– Diameter: 20-26ft.

• Record trees– 311ft tall, 56ft. Diameter– Oldest: 3,500 years

Description• Bark: fibrous, furrowed, very

thick (1-3ft)– Fire protection

• Leaves: evergreen, blue/green, scale-like, awl-shaped, arranged spirally

• Young trees retain dead branches

• Mature trees free of branches until 20-50m

Regeneration• Seed cones: 4-7mm long, mature 18-20mos.

– Remain green/closed up to 20yrs.– 30-50 scales, 230 seeds per cone

• Large cones associate w/reproductive maturity—150 or 200yrs.

• Browning/drying of cones, w/shrinkage of scalesdisperses seeds– Long-horned wood-boring beetle– Douglas squirrel– Fire

• Wind dispersal

Flowering & Fruiting• Monoecious: MF cone

buds form late summer• Pollination: April/May• Fertilization: August

(cones full-size)– Embryos develop during

next summer and reach maturity at end of 2nd

growing season

Seedling Development• Extremely tenuous—few seeds

successfully establish• Germinate in favorable conditions

– Moist mineral soil, covers seed– Partial shade to avoid desiccation– Full sunlight, free from litter– Best chance: dropped before 1st

snow or as snow melts

• Height growth relatively slow first few yrs.– Competition for light/moisture

Distribution• Western Sierra Nevada• Scattered groves, 68 total• Humid climate: dry

summer/snowy winter• Elevation: 4,600-7,000ft.• Mixed montane coniferous

forests• Popular ornamental in UK

Ecology• Shade intolerant• Require periodic wildlife

to clear competing vegetation– W/o fire, shade-loving

species crowd out young sequoia

– Fire suppression efforts of 20th Century

• Dense growth of White Fir

Danger!• Fire scars: fungi,

root disease, heart rot

• Lightning• Old giant sequoias

die by toppling• Classified as

vulnerable• 90% population

protected

Largest: General Sherman– DBH 825 cm– Crown spread 33m– Height 83.6m– 52,508 cubic ft.