Giant Sequoia Sequoiadendron giganteum Rebecca Knapp ENH 101 Fall Quarter 2010 What’s in a name? Sequoiadendron giganteum Kingdom: Plantae Division: Pinophyta gymnospersms, cone-bearing Class: Pinopsida Order: Pinales extant conifers (AKA Coniferales) Family: Cupressaceaecedar, cypress, juniper, redwood Subfamily: Sequoioideae Genus: Sequoiadendron Subfamily: Sequoioideae 3 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 • Fire scars: fungi, root disease, heart Danger! 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..