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

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

Introduction to Vascular Plants

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

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Distribution of Tsuga mertensiana
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Introduction

This is an evergreen coniferous tree species that is common in western BC at high elevations.

Species Information

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General:
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.
Leaves:
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.
Cones:
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.
Notes:
See above for hybridization with T. heterophylla.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
Yellow
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

Ecology

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

Minimum

Average

Maximum

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
Class
C
Number of field plots
 species was recorded in:
2010
Modal BEC Zone Class
MH
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, sub montane to subalpine, circumpolar forb (transcontinental in North America). Occurs on fresh to very moist, nitrogen-rich soils (Moder and Mull humus forms) within boreal, temperate, cool semiarid, and mesothermal climates; its occurrence decreases with increasing elevation. Frequent in herbaceous communities, occasional in broad-leaved forests on disturbed, water-shedding and water-receiving sites. A nitrophytic species characteristic of continuously disturbed sites.

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

Climate

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

Related Databases

General References