Western hemlock
- Latin name: Tsuga heterophylla (Raf.) Sarg.
- French name: Pruche de l'Ouest
- Synonym(s): Pacific hemlock
- Taxonomic Serial Number: 183400
Description
Leaves
Form
- Sides parallel, flat, finely toothed
- Length variable
- Blunt-tipped
- Needles clearly arranged in 2 ranks, with a few shorter ones on the upper side pressed against the twig
Length
- 5–20 mm
Colour
- Upper surface shiny dark green and grooved
- Whitened on lower surface with ill-defined lines of white dots on either side of the midvein
Buds
Form
- Globular
Length
- 2–3 mm
Twigs
Form
- Slender, hairy
Colour
- Brownish-grey
Seed cones (mature)
Form
- Ovoid, blunt-tipped
- Short-stalked
Length
- 20–25 mm
Colour
- Golden brown
Structure
- Scales rectangular
- Tip rounded
- Margin smooth or faintly toothed
Timing
- Cones open in autumn
- Seeds shed gradually
- Cones may stay on the tree for 1 or 2 years
Seedlings
Form
- Seedlings commonly found on rotten logs, or in partially decomposed forest litter
Bark
Form
- Smooth when young, becoming deeply furrowed with flat-topped scaly ridges
Colour
- Reddish-brown when young, becoming darker
Wood
Texture
- Moderately light, fairly hard and strong
Colour
- Whitish to dull light brown
Morphology
- Little contrast between sapwood and heartwood
Uses
- Wood pulp, lumber
- Siding, flooring, plywood, railway ties, boxes, and crates
Size
Height
- To 50 m
Diameter
- To 120 cm, occasionally larger
Maximum age
- 500 years
Tree form
Forest-grown
Trunk
- Lower trunk long, branch-free
Crown
- Open, conical, becoming irregular with age
- Leading shoot oblique, bending away from prevailing wind
- Principal branches coarse, spreading horizontally from the trunk
- Drooping sprays of branchlets giving a graceful appearance
Root system
- Shallow, wide-spreading
Habitat
Site
- Varied soils and in the mountains up to 1500 m
Light tolerance
- Very shade-tolerant
- Regenerates well under a closed canopy
- Thrives in full light and in shade
Associated species
- Grows in pure stands, but usually mixed with western redcedar, Douglas-fir, grand fir, black cottonwood, and red alder
Range
Pacific Coast, adjacent islands
Photos
Photos
Anthony Scullion
Anthony Scullion
Insects and mites
Insects that cause damage to this tree.
-
Douglas-fir beetle
Scientific name: Dendroctonus pseudotsugae (Hopkins)
-
Hemlock woolly adelgid
Scientific name: Adelges tsugae Annand
-
Poplar-and-willow borer
Scientific name: Cryptorhynchus lapathi (Linnaeus).
-
Western blackheaded budworm
Scientific name: Acleris gloverana (Walsingham)
Cones or seeds
- Enypia venata (Grote)
- Eupithecia placidata (Taylor)
-
Filament bearer
Scientific name: Nematocampa resistaria (Herrich-Schaffer)
-
Orange tortrix
Scientific name: Argyrotaenia citrana (Fernie)
Foliage or buds
Hemlock looper
-
Lambdina fiscellaria
(Guenée)
- Lambdina fiscellaria fiscellaria
- Lambdina fiscellaria lugubrosa
- Lambdina fiscellaria somniaria
- Archips tsugana (Powell)
- Argyrotaenia dorsalana (Dyar)
-
Brownlined looper
Scientific name: Neoalcis californiaria (Packard)
- Caripeta aequaliaria Grote
- Coleotechnites atrupictella (Dietz)
- Cosmia elisae (J.B. Smith)
-
Dioryctria moth
Scientific name: Dioryctria pseudotsugella Munroe
-
Douglas-fir bud moth
Scientific name: Zeiraphera hesperiana (Mutuura & Freeman)
- Egira hiemalis (Grote)
- Enypia griseata (Grossbeck)
- Enypia venata (Grote)
- Eupithecia longipalpata (Packard)
- Eupithecia olivacea (Taylor)
- Feralia comstocki Grote
-
Filament bearer
Scientific name: Nematocampa resistaria (Herrich-Schaffer)
- Gabriola dyari (Taylor)
-
Golden buprestid
Scientific name: Buprestis aurulenta Linnaeus
-
Gray spruce looper
Scientific name: Caripeta divisata Walker
-
Green larch looper
Scientific name: Semiothisa sexmaculata (Packard)
-
Green velvet looper
Scientific name: Epirrita autumnata (Harrison)
-
Greenstriped forest looper
Scientific name: Melanolophia imitata (Walker)
-
Greenstriped webspinning sawfly
Scientific name: Acantholyda balanata (MacGillivray)
-
Hemlock looper
Scientific names:
-
Lambdina fiscellaria
(Guenée)
- Lambdina fiscellaria fiscellaria
- Lambdina fiscellaria lugubrosa
- Lambdina fiscellaria somniaria
-
Lambdina fiscellaria
(Guenée)
-
Hemlock sawfly
Scientific name: Neodiprion tsugae Middleton
- Hydriomena irata Swett
- Hydriomena speciosata (Packard)
-
Larch pug moth
Scientific name: Eupithecia annulata (Hulst)
-
Lodgepole terminal weevil
Scientific name: Pissodes terminalis (Hopping)
- Nepytia umbrosaria nigrovenaria (Packard)
-
Northern tent caterpillar
Scientific name: Malacosoma californicum pluviale (Dyar)
-
Orange tortrix
Scientific name: Argyrotaenia citrana (Fernie)
-
Packard’s gridle moth
Scientific name: Enypia packardata (Taylor)
- Pero behrensaria (Packard)
-
Pero moth
Scientific name: Pero morrisonaria (Hy. Edwards)
-
Phantom hemlock looper
Scientific name: Nepytia phantasmaria (Strecker)
-
Pine measuringworm moth
Scientific name: Hypagyrtis piniata (Pack.)
-
Pine tussock moth
Scientific name: Dasychira grisefacta (Dyar)
-
Poplar-and-willow borer
Scientific name: Cryptorhynchus lapathi (Linnaeus).
- Promylea lunigerella Ragonot
- Protoboarmia porcelaria (Guenee)
-
Redlined conifer caterpillar
Scientific name: Feralia jocosa (Gn.)
- Sabulodes edwardsata (Hulst)
-
Saddleback looper
Scientific name: Ectropis crepuscularia (Denis and Schiffermuller)
-
Silverspotted tiger moth
Scientific name: Lophocampa argentata (Packard)
-
Small pine looper
Scientific name: Eupithecia palpata Pack.
-
Spruce fir looper
Scientific name: Macaria signaria dispuncta (Walker)
- Stenoporpia pulmonaria satisfacta (Barnes and McDunnough)
- Synaxis pallulata (Hulst)
- Syndemis afflictana Walker
- Syngrapha celsa (Henry Edwards)
- Thallophaga hyperborea (Hulst)
-
Twolined larch sawfly
Scientific name: Anoplonyx laricivorus (Rohwer et Middleton)
-
Western blackheaded budworm
Scientific name: Acleris gloverana (Walsingham)
-
Western false hemlock looper
Scientific name: Nepytia freemani (Munroe)
-
Western hemlock looper
Scientific name: Lambdina fiscellaria lugubrosa (Hulst)
-
Whitelined looper
Scientific name: Epirrita pulchraria (Taylor)
-
Whitetriangle leafroller
Scientific name: Clepsis persicana (Fitch)
- Xestia mustelina (Smith)
-
Yellowlined forest looper
Scientific name: Cladara limitaria (Walker)
- Zeiraphera vancouverana McDunnough
Roots, bark, stem or trunk, or branches
Diseases caused by pathogens
Diseases caused by pathogens that cause damage to this tree.
Black stain root disease
Pathogen name: Grosmannia wageneri (Goheen & F.W. Cobb) Zipfel, Z.W. Beer & M.J. Wingf.
-
Black stain root disease
Pathogen name: Grosmannia wageneri (Goheen & F.W. Cobb) Zipfel, Z.W. Beer & M.J. Wingf.
-
Brown cubical sap rot
Pathogen name: Gloeophyllum sepiarium (Wulfen: Fr.) P. Karst.
-
Discocaninia canker
Pathogen name: Discocainia treleasei (Sacc.) Reid & Funk
-
Fir-willow rust
Pathogen name: Melampsora abietis-capraearum Tub.
-
Nectria dieback
Pathogen name: Nectria cinnabarina (Tode:Fr.) Fr.
-
Ribes-willow rust
Pathogen name: Melampsora ribesii-purpureae
Cones or seeds
-
Brown felt blight
Pathogen name: Herpotrichia juniperi (Duby) Petr.
-
Sirococcus Shoot Blight
Pathogen name: Sirococcus conigenus (Dc.) Cannon & Minter
Foliage or buds
-
Brown felt blight
Pathogen name: Herpotrichia juniperi (Duby) Petr.
-
Hemlock - Blueberry rust
Pathogen name: Naohidemyces vaccinii (Wint.) Sato, Katsuya et Hiratsuka
-
Hemlock-willow rust
Pathogen name: Melampsora epitea Thuem.
-
Phomopsis canker of douglas-fir
Pathogen name: Diaporthe lokoyae Funk
-
Sirococcus Shoot Blight
Pathogen name: Sirococcus conigenus (Dc.) Cannon & Minter
Roots, bark, stem or trunk, or branches
Annosus root and butt rot (Heterobasidion occidentale)
Pathogen name: Heterobasidion occidentale Otrosina & Garbel
Brown pocket rot of Sitka spruce
Pathogen name: Neolentinus kaufmannii (A. H. Smith) Redhead & Ginns
Pitted sap rot
Pathogen name: Trichaptum abietinum (Dicks.) Ryvarden (Common names for this fungus: purple conk fungus, purple-toothed polypore)
Schweinitzii butt rot
Pathogen name: Phaeolus schweinitzii (Fr.) Pat. (Common names for the fungus: velvet-topped polypore, dyer’s polypore)
White butt rot - White laminated rot
Pathogen name: Ceriporiopsis rivulosa (Berk. & Curtis) Gilb. & Ryvarden
Distribution map
