White spruce/alder scrub unstable slopes

Description

The reference state includes two plant community phases. The reference plant community (1.1) is characterized by a tall closed alder scrub community (Viereck et al., 1992) where white spruce does not exceed 25 percent, and feather mosses, bluebells, and horsetail are abundant in the shaded slopes beneath the alder canopy. Community 1.2 is an early-mid stage successional community that is dominated by herbaceous and low shrub species that colonize this ecological site after fire or following a mass movement event. Although fire is less abundant in subalpine communities, tall, closed alder scrub carries a heavy fuel load necessary for a stand-replacing fire. In addition to fire, the unstable slopes associated with this ecological site are more likely to slide than adjacent stable slopes. Either disturbance mechanism will result in exposed mineral soil that will be colonized by forbs, and low shrub species before eventually being dominated by alder once more.

Dominant plant species

1. white spruce (Picea glauca), tree

2. Siberian alder (Alnus viridis ssp. fruticosa), shrub

3. Richardson's willow (Salix richardsonii), shrub

4. grayleaf willow (Salix glauca), shrub

5. bog Labrador tea (Ledum groenlandicum), shrub

6. black crowberry (Empetrum nigrum), shrub

7. tealeaf willow (Salix pulchra), shrub

8. false toadflax (Geocaulon lividum), grass

9. tall bluebells (Mertensia paniculata), grass

10. fireweed (Chamerion angustifolium), grass

11. field horsetail (Equisetum arvense), grass

12. splendid feather moss (Hylocomium splendens), grass

13. Schreber's big red stem moss (Pleurozium schreberi), grass

Submodel