Giant sequoia (Sequoiadendron giganteum): what the agencies record

This page reports what US federal publications say about one tree. It does not identify trees from descriptions or photos and does not say what should be done with any tree. The family overview, tree species in the agency records, explains the sources and holds the comparison table.

At a glance

Item	What the source records
Scientific name	Sequoiadendron giganteum (Lindl.) Buchholz, redwood family (listed as Taxodiaceae in Silvics)
Other names	Sequoia, bigtree and Sierra redwood (Silvics)
Native status, USDA PLANTS	Native in the lower 48 states
Size, Silvics	Mature specimens commonly reach a diameter of 305 to 610 cm (120 to 240 in) above the butt swell and average about 76 m (250 ft) in height; the greatest known height is 94.5 m (310 ft)
Largest specimen, Silvics	The General Sherman tree in Sequoia National Park, with an estimated bole volume of 1486 cubic metres (52,500 cubic feet)
Green weight of the wood, NRS-38	59 lb per cubic foot, without bark

Native range

The Silvics of North America handbook (Agriculture Handbook 654, volume 1, 1990) restricts the natural range of giant sequoia to about 75 groves scattered over a belt 420 km (260 mi) long and nowhere more than about 24 km (15 mi) wide on the west slope of the Sierra Nevada in central California. Only eight widely separated groves lie in the northern two-thirds of the range, from the American River in Placer County south to the Kings River area, and the remaining groves, including all the large ones, are concentrated between there and the Deer Creek Grove in southern Tulare County. The groves range from less than 1 to 1,619 ha (1 to 4,000 acres) and occupy a total of 14,410 ha (35,607 acres). The handbook says most groves have been given protected status, and that outside its natural range, in the United States and many other countries, the species is highly regarded as an ornamental.

It describes a humid climate with dry summers, mean annual precipitation in the groves of about 900 to 1,400 mm (35 to 55 in), most of it snow between October and April, and mean annual snowfall of 366 to 500 cm (144 to 197 in).

Cones and size

Silvics describes the tree as monoecious, with pollination between the middle of April and the middle of May. Mature cones are egg-shaped, 5 to 9 cm (2.0 to 3.5 in) long, and yield an average of 200 seeds each. On size, the handbook says one tree species has a greater diameter, three grow taller and one lives longer, but that by volume giant sequoia is undisputedly the world's largest tree. The greatest mean diameter it gives is for the General Grant tree in Kings Canyon National Park, 881 cm (347 in) including a large buttress and approximately 823 cm (324 in) without it. It notes the slight taper of the bole as a feature more prominent in this species than in any other Sierra Nevada conifer.

Roots

The handbook says seedlings have a taproot with few laterals for the first few years, a habit that helps survival in dry summers, and that after 6 to 8 years lateral root growth predominates and taproot elongation practically stops. Roots of a mature tree commonly extend 30 m (100 ft) or more from the bole on well-drained soils and occupy 0.3 ha (0.7 acre) or more, while along drainage bottoms or meadow edges the radial extent may be no more than 12 to 15 m (40 to 50 ft).

Wood

The Wood Handbook (FPL-GTR-282, 2021) mentions giant sequoia in its redwood entry, calling it volumetrically larger than coast redwood and growing in a limited area in the Sierra Nevada of California, and says its wood is used in very limited quantities. The handbook gives no strength table row for the species. Silvics says the heartwood of downed sequoia logs is extremely durable, sometimes remaining largely intact for thousands of years, but that the heartwood of living trees is less resistant to decay. It lists the uses of the species as esthetic and scientific within its natural range, and as an ornamental and possibly Christmas tree outside it.

The green weight of the wood without bark is in the NRS-38 table, the same figure used in the log weight calculator.

Fire, decay and damage the handbook names

Silvics (1990) names these agents by the names it used.

Fire. Called the most universal and probably most serious damaging agent in the natural range. The handbook says larger trees, because of thick bark that carries no resin and crowns high above the ground, are more resistant than associated species, but that repeated fires over the centuries burn through the bark at the base, kill the cambium and produce an ever-enlarging scar; almost all of the larger trees have fire scars. It names fire exclusion as the most significant human impact in the groves, because fire is needed to create conditions for regeneration and its removal has allowed fuel to build up.
Decay fungi. At least nine fungi have been found with decayed wood, of which Heterobasidion annosum, Armillaria mellea, Poria incrassata and Poria albipellucida are called probably the most significant. The handbook says the first two are also serious root pathogens, that diseases generally do not kill trees past the seedling stage directly but contribute to root or stem failure, and that fire scars provide entry for fungi that cause root disease and heart rot.
Toppling. Old giant sequoias most commonly die by toppling, which the handbook attributes primarily to weakening of the roots and lower bole by fire and decay, with the weight of the tree, shallow roots, wind, water-softened soils, stream undercutting and heavy snow loads as other factors.
Lightning. It sometimes knocks out large parts of crowns or ignites dead tops, though mature trees are seldom killed by it.
Insects. Insect damage does not seriously harm trees older than about 2 years, though it may reduce vigour. Carpenter ant galleries in decayed wood at tree bases are not seen as a direct cause of failure.
Outside the natural range. The handbook says that in nurseries and when planted outside its range giant sequoia is highly susceptible to a number of organisms, and sometimes rapidly killed, from seedlings to mature trees.

The guide on reporting a pest in the United States and the Canada reporting page give the offices that take sightings of regulated pests. Who may apply pesticides is in pesticide licences by country.