Physiognomy and Structure: No Data Available

Floristics: Picea engelmannii is the dominant species in late-successional stands. Although Abies lasiocarpa may be present, individual trees are normally stunted and only occupy drier microsites. Pinus contorta is a major seral associate. The only common shrubs are Vaccinium cespitosum and Vaccinium scoparium. The undergrowth is predominately herbaceous with Caltha leptosepala, Arnica spp., Pedicularis bracteosa, Pedicularis groenlandica, Polygonum bistortoides, Potentilla spp., Sibbaldia procumbens, Trifolium spp., Carex heteroneura var. epapillosa, Carex scirpoidea, Deschampsia cespitosa, Luzula spicata, and Phleum alpinum being the commonly occurring moist- or cold-site species. A number of other wet-site forbs and graminoids are present to abundant, including Calamagrostis canadensis, Mitella pentandra, Parnassia fimbriata, Saxifraga odontoloma (= Saxifraga arguta), Senecio triangularis, and species of Carex or Juncus. Other species sometimes present are Veronica wormskjoldii, Festuca ovina, and Poa alpina. On drier sites, Antennaria microphylla, Erigeron peregrinus, Danthonia intermedia, Poa nervosa, and Trisetum spicatum are found.

Dynamics:  Crane (1982) places this association into fire group sixteen, which includes very moist spruce and subalpine fir habitat types. Fire appears to play a relatively minor role on these types. Lodgepole pine''s presence indicates that they must burn occasionally, probably during a severe wind-driven fire during a particularly dry year. If they do burn, recovery to a seral forest should be rapid. Low surface fires could occur during years when the site was too moist to burn severely but when a severe fire was carried across adjacent drier sites.

Along a general successional path, an herb stage is followed by the sprouting of shrubs along with seedlings and saplings of the seral stand. A fire at this point, though unlikely, would return the site to the herb stage. In a pole-sized stand, fire is also unlikely because of the moisture and lowered fuels. A low surface fire could open the stand and expose mineral soil for regeneration. The mature forest favors a severe, stand-replacement fire under dry conditions.

In the absence of fire, a climax forest of Engelmann spruce could develop with little lodgepole pine left. This stage is, however, unlikely as springtime flooding is a common disturbance that can create openings and expose sites.