Physiognomy and Structure: Tall conifer trees (>70 m tall) dominate the canopy. Mixed conifers are often interspersed within groves forming a subcanopy. Shrubs are infrequent to common; the herbaceous layer is sparse to abundant.

Floristics: This forest alliance is characterized by the presence of Sequoiadendron giganteum. Other dominant trees include Quercus kelloggii, Pseudotsuga menziesii, Calocedrus decurrens (= Libocedrus decurrens), Pinus jeffreyi, Pinus contorta var. murrayana, Pinus ponderosa, Abies magnifica, Pinus lambertiana, and Abies lowiana (= Abies concolor var. lowiana). Groves can have a canopy of Abies lowiana with emergent individuals of Sequoiadendron giganteum. At lower elevations Calocedrus decurrens may dominate and at higher elevations Abies magnifica may dominate. Shrubs may be infrequent to common, and may include Chrysolepis sempervirens (= Castanopsis sempervirens), Chamaebatia foliolosa, Ceanothus cordulatus, Ceanothus parvifolius, Ceanothus integerrimus, Ceanothus velutinus, Arctostaphylos patula, Rhododendron occidentale, Ribes spp., Rosa spp., and Rubus spp. Stand structure varies considerably with elevation, latitude, exposure, soil moisture, and time since most recent fire or disturbance.

Dynamics:  Fire is the most important agent in the maintenance of this forest alliance. As a species, sequoias are very shade-intolerant and require openings within the forest canopy to establish. The species'' optimal habitat is mesic sites with good soils, and disturbance is required to open up areas with such favorable conditions. Fire reduces light competition, and increases the friability and the wetability of the exposed surface mineral soils. These are exactly the conditions most conducive to germination and establishment of sequoia seedlings. The survival rate for sequoia seedlings has been found to be 27% following a hot fire. No seedlings survived in adjacent, undisturbed areas. Fires within established groves are the single largest agent of seed drop. Heat from the fire convects into the canopy, drying and opening the mature seed cones. This allows up to 8,000,000 seeds/acre to drop. This seed drop corresponds to the favorable seed bed conditions created by the fire. Sequoia seeds are very light (91,000/lb) and winged. The updrafts caused by fire or the winds typical of the Sierra Nevada can disperse seeds more than a 1/2 mile. Once established, sequoias maintain dominance by rapid growth. Young sequoias are very susceptible to injury or death by fire, but because they usually germinate in areas recently burned, they often are large enough to withstand a light fire by the time the fuel loads would allow one to occur. Large sequoias are very fire-resistant due to their thick, non-resinous bark and elevated crowns. Few mature sequoias are killed directly by fire. Repeated fires can eventually sear through the bark near the tree base, kill underlying cambium, and produce an ever-enlarging scar. These scars provide entry points for insects and fungi, which weaken the tree. Most sequoias are killed by toppling, with a significant percentage of trees failing at the point of greatest insect and/or fungi damage and falling to the fire-scarred side. Fire suppression during the 20th century has caused a massive failure in sequoia regeneration. The reduced fire frequency also allows greater litter accumulation, increasing the severity of fires when they do occur.