Home/Ecosystems/ Great Lakes Sub-boreal Pine and Spruce Forest

Great Lakes Sub-boreal Pine and Spruce Forest

EVT 7240Laurentian-Acadian Hardwood Forest

CES103.425GNRTreeHardwood

Summary

This subboreal forest ecological system is found on dry-mesic nutrient-poor soils in a variety of topographic settings. It ranges from northwestern Ontario to eastern Canada, and southward into Minnesota, the Great Lakes region, and very locally into northwestern Maine. Soils are loamy to sandy, varying from nutrient-poor, thin soils over bedrock to deeper soils, sometimes sandy. Sites are typically dry-mesic. The dominant fire regime varies from 50-100 years. Pinus banksiana, Pinus resinosa, and Picea mariana are characteristic overstory species, with Pinus strobus occasionally common, over much of the range, but east of the Great Lakes, Picea mariana becomes increasingly dominant with Abies balsamea as an important associate. Canopy structure is mostly closed but can be partially open. Conifers typically dominate the canopy, but boreal hardwoods (Populus tremuloides, Betula papyrifera) may codominate. As time since fire increases, Picea mariana may dominate. Tree regeneration includes Abies balsamea, Betula papyrifera, Populus tremuloides, and Picea mariana. The shrub and field layers can be very open to somewhat dense (5-75% cover). Characteristic low-shrub and herb species include Amelanchier spp., Vaccinium angustifolium, Diervilla lonicera, Cornus canadensis, Linnaea borealis, Doellingeria umbellata, and Eurybia macrophylla. Older Picea mariana stands may be strongly dominated by feathermosses.

Source: NatureServe Explorer

Vegetation

Pinus banksiana and Picea mariana are characteristic overstory species. In the Upper Great Lakes region, Pinus banksiana may intermix with Pinus resinosa. Canopy structure is mostly closed but can be partially open. Conifers typically dominate the canopy, but boreal hardwoods (Populus tremuloides, Betula papyrifera) may codominate. As time since fire increases, Picea mariana may dominate. Tree regeneration includes Abies balsamea, Betula papyrifera, Populus tremuloides, and Picea mariana. Characteristic low-shrub and herb species include Amelanchier spp., Vaccinium angustifolium, Diervilla lonicera, Cornus canadensis, Linnaea borealis, Doellingeria umbellata (= Aster umbellatus), and Eurybia macrophylla. Older Picea mariana stands may be strongly dominated by feathermosses (Minnesota DNR 2003).

Source: NatureServe Explorer

Environment

Soils are loamy to sandy, varying from nutrient-poor, thin soil over bedrock to deeper soils, sometimes sandy. Sites are typically on dry-mesic to dry sites, but not commonly found on xeric sandplains or bedrock sites.

Source: NatureServe Explorer

Distribution

This system ranges from northwestern Ontario to eastern Canada, and southward into Minnesota, the Great Lakes region, and very locally into northwestern Maine.

Source: NatureServe Explorer

State Conservation Ranks (3)

Subnational conservation status ranks (S-ranks) assigned by Natural Heritage Programs in each state where this ecosystem occurs. S1 indicates critically imperiled at the state level, S2 imperiled, S3 vulnerable, S4 apparently secure, and S5 secure. An ecosystem may be globally secure but imperiled in specific states at the edge of its range.

State	S-Rank
MI	SNR
MN	SNR
WI	SNR

Roadless Areas (4)

Inventoried Roadless Areas where this ecosystem is present, identified from LANDFIRE 2024 Existing Vegetation Type spatial analysis. Coverage indicates the proportion of each area occupied by this ecosystem type.

Maine (1)

Area	Forest	Coverage	Hectares
Caribou - Speckled Ext	White Mountain National Forest	2.3%	55.89

New Hampshire (2)

Area	Forest	Coverage	Hectares
Presidential - Dry River Ext	White Mountain National Forest	1.2%	53.28
Carr Mountain	White Mountain National Forest	1.1%	75.69

Vermont (1)

Area	Forest	Coverage	Hectares
Griffith Lake 09084	Green Mountain and Finger Lakes National Forests	6.0%	44.73

Methodology and Data Sources

Ecosystem classification: Ecosystems are classified using the LANDFIRE 2024 Existing Vegetation Type (EVT) layer, mapped to NatureServe Terrestrial Ecological Systems via a curated crosswalk. Each EVT is linked to the USNVC (U.S. National Vegetation Classification) hierarchy through pixel-level co-occurrence analysis of LANDFIRE EVT and NatureServe IVC Group rasters across all roadless areas.

Vegetation coverage: Coverage percentages and hectares are derived from zonal statistics of the LANDFIRE 2024 EVT raster intersected with roadless area boundaries.

Ecosystem narratives and community species: Sourced from the NatureServe Explorer API, representing professional ecological assessments of vegetation composition, environmental setting, dynamics, threats, and characteristic species assemblages.

IVC hierarchy: The International Vegetation Classification hierarchy is sourced from the USNVC v3.0 Catalog, providing the full classification from Biome through Association levels.

Component associations: Plant community associations listed as components of each NatureServe Ecological System. Association data from the NatureServe Explorer API.

State ranks: Conservation status ranks assigned by NatureServe member programs in each state where the ecosystem occurs.