E-Flora BC: Electronic Atlas of the Flora of British Columbia

Tsuga mertensiana (Bong.) Carrière
mountain hemlock
Pinaceae (Pine family)

Introduction to Vascular Plants

© Dave Ingram  Email the photographer   (Photo ID #26824)

E-Flora BC Static Map
Distribution of Tsuga mertensiana
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This is an evergreen coniferous tree species that is common in western BC at high elevations.

Species Information

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Tree, seldom to 40 m tall, much shorter near tree-line; narrow crown, with slightly drooping leader (growing tip), less evident with age; twigs strongly hairy with mix of short and long hairs; bark thick, strongly furrowed and ridged, dark purplish- to reddish-brown.
Needles thickened in centre and somewhat 4-sided, round to blunt at tip, (10) 12-20 mm long, spread around branches to somewhat upturned, not forming flat sprays; yellow-green to deep blue-green, stomata on both surfaces, rarely whitish.
Seed cones maturing from green or purple to dark brown, (2.5) 3-6 (7) cm long, cylindric with narrowed ends; pollen cones bluish, 3-4 mm long.
See above for hybridization with T. heterophylla.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
Blooming Period:
Early Summer
Fruit/Seed characteristics:
Colour: Brown
Present from Summer to Fall
Source:  The USDA

Habitat / Range

Wet to dry slopes in the lowland to subalpine zones; common at high elevations along W BC and infrequent in SE BC and lower elevations of NW BC coast; N to SE AK and S to C CA, N ID and W MT.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Tsuga mertensiana

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class




Elevation (metres) 5 980 2500
Slope Gradient (%) 0 29 130
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
0 241 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
0 4 8
Modal Nutrient Regime
Number of field plots
 species was recorded in:
Modal BEC Zone Class
All BEC Zones (# of stations/zone) species was recorded in: AT(3), CMA(17), CWH(675), ESSF(427), ICH(60), IDF(4), MH(737), MS(15), SBS(3), SWB(1)

Ecological Indicator Information

A shade-tolerant/intolerant, montane to alpine, Western North American evergreen conifer distributed more in the Pacific than the Cordilleran region. Occurs in hypermaritime to submaritime subalpine boreal climates; its occurrence decreases with increasing precipitation and continentality. Most productive on fresh and nutrient-medium soils within maritime subalpine boreal climates. Characteristic of maritime subalpine forests.

SourceIndicator Plants of Coastal British Columbia (Information applies to coastal locations only)


The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is subalpine boreal & cool mesothermal.

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References