Forest Vegetation types - OW2

OW2Black spruce / Lambkill / Reindeer lichen
Picea mariana / Kalmia angustifolia / Cladina spp.

Riversdale, Colchester County

Riversdale, Colchester County

Concept: The Black spruce / Lambkill / Reindeer lichen woodland is found on acidic rock outcrops and thin glacial soils. This coniferous ecosystem is characterized by its open black spruce canopy, very poor soils, low productivity and prominent representation of reindeer lichens.

Vegetation: The open canopy is dominated by black spruce or co-dominated by black spruce and pine (white or red). Other tree species are uncommon. The well-developed woody understory is comprised of acid tolerant shrubs (e.g. lambkill, low bush blueberry and wild raisin). Species usually found on moist soils (e.g. rhodora and false holly) are supported by surface peat deposits found over mineral soil or in cracks and depressions of exposed bedrock. Herbaceous species richness and abundance is reduced. Reindeer lichens (usually grey and/or lesser green) are frequent and usually abundant. In some occurrences, bryophyte cover is higher than lichen cover.

Environmental Setting: OW2 is associated with dry to moist, nutrient very poor soils that are often shallow to bedrock and/or stony. The low elevation ecosystem is found on rocky outcrops or on shallow glacial tills. Soil moisture increases with organic accumulation, particularly where near-surface bedrock is present or cemented (orstein) soil horizons reduce drainage. Site exposure is moderate to high, while surface microtopography and stoniness is low. It occurs throughout the province but is especially common in the Eastern and Western ecoregions. OW2 is uncommon but widespread across the Maritimes. Although this Vegetation Type (VT) is similar to boreal lichen woodlands from eastern Canada, it is considered nationally distinct.

Successional Dynamics: This early successional ecosystem is largely maintained by exposure and limiting soil conditions. It will not succeed to latter successional stages (e.g. other black spruce or pine vegetation types) and is considered a type of edaphic climax. Possible disturbances include fire, windthrow and breakage. Black spruce will regenerate on OW2 sites by seed and/or layering. Most stands have uneven age class structures.

Ecological Features: The Black spruce / Lambkill / Reindeer lichen is unique to the east coast, occurring as a small patch ecosystem in each of the four Atlantic Provinces. This relatively rare woodland has strong boreal affinity, but the presence of northern temperate species (e.g. huckleberry, rhodora and chokeberry, among others) differentiates the VT from its boreal analogs in Quebec and Ontario. Limited distribution in Nova Scotia may present a conservation challenge. This ecosystem supports unique habitat conditions, but associated animal, plant and lichen species are undocumented. It typically features a very open canopy, and high shrub and lichen cover. Productivity, tree age, canopy height and old growth potential are all low.

ow2 Characteristic Plants


Reindeer lichen
Reindeer lichen

Distinguishing Features:
This woodland is characterized by scattered black spruce, and sometimes, white or red pine, exposed bedrock, stony and/or shallow soils and prominent reindeer lichen.

Site Characteristics

Slope Position:

Level5 Crest3 Other2

Surface Stoniness:

(Non - Slightly)6 (Very - Excessively)3  (Moderately)1

Bedrock Outcrop: 

(Non-Rocky)5 (Very - Excessively)4 (Slightly - Moderately)1

Elevation Range: 

9 - 327m

Slope Gradient: 

Level7 Gentle1 Moderate1 nd1


West1 None8 Other1


Moderate6 Exposed2 Other2


Level8 Slightly1 Moderately1


Imperfect3 Rapid3 Well3 Other1


Soil Characteristics

Soil Type: 

ST153 ST32 ST11 ST2-G1 ST161 Other2

Parent Material:

Glacial till6 Till/Bedrock2 Glaciofluvial1 Organic/Bedrock1

Rooting Depth (cm):

(<30)5 (30-45)2 (>45)1 nd2

Duff Thickness (cm):

(6-10)3 (11-20)4 nd3

Ow2 Map