Western Hemlock
Encyclopedia
Tsuga heterophylla. the Western Hemlock, is a species of hemlock
native to the west coast of North America
, with its northwestern limit on the Kenai Peninsula
, Alaska
, and its southeastern limit in northern Sonoma County
, California
.
, where it is a climax species
. It is also an important timber tree throughout the region, along with many of its large coniferous associates.
coniferous
tree
growing to 165-230 ft (50–70 m) tall, exceptionally 270 ft (82 m), and with a trunk diameter of up to 9 ft (2.7 m). It is the largest species of hemlock
, with the next largest (Mountain Hemlock
T. mertensiana) reaching a maximum of 194 ft (59 m). The bark
is brown, thin and furrowed. The crown is a very neat broad conic shape in young trees with a strongly drooping lead shoot, becoming cylindric in older trees; old trees may have no branches in the lowest 100-130 ft (30–40 m). At all ages, it is readily distinguished by the pendulous branchlet tips. The shoots are very pale buff-brown, almost white, with pale pubescence about 1 mm long. The leaves
are needle-like, 5–23 mm long and 1.5–2 mm broad, strongly flattened in cross-section, with a finely serrated margin and a bluntly acute apex. They are mid to dark green above; the underside has two distinctive white bands of stoma
ta with only a narrow green midrib between the bands. They are arranged spirally on the shoots but are twisted at the base to lie in two ranks on either side of the shoot. The cones
are small, pendulous, slender cylindrical, 14–30 mm long and 7–8 mm broad when closed, opening to 18–25 mm broad. They have 15–25 thin, flexible scales 7–13 mm long. The immature cones are green, maturing gray-brown 5–7 months after pollination. The seed
s are brown, 2–3 mm long, with a slender, 7–9 mm long pale brown wing.
. There is however an inland population in the Rocky Mountains
in southeast British Columbia
, northern Idaho
and western Montana
. It mostly grows at low altitudes, from sea level to 600 m, but up to 1800 m in the interior part of its range in Idaho.
and Pacific silver fir. Young plants typically grow up under the canopy of other conifers such as Sitka Spruce
and Douglas-fir
, where they can persist for decades waiting to exploit a gap in the canopy. They eventually replace these conifers, which are relatively shade-intolerant, in in climax forest. However, storm
s and wildfire
s will create larger openings in the forest where these other species can then regenerate.
Initial growth is slow; one year old seedlings are commonly only 3–5 cm tall, and two year old seedlings 10–20 cm tall. Once established, saplings in full light may have an average growth rate of 50–120 cm (rarely 140 cm) annually until they are 20–30 m tall, and in good conditions still 30–40 cm annually when 40–50 m tall. The tallest specimen, 82.83 m tall, is in Prairie Creek Redwoods State Park
, California
(USA). It is long-lived, with trees over 1200 years old known.
, it is exacting about soil conditions. It needs a high level of organic matter (well-rotted wood from an old log or stump is best; animal manures may have too much nitrogen
and salt
), in a moist, acidic soil.
for timber
and paper
production, and as an ornamental tree in large garden
s, in northwest Europe
and southern New Zealand
.
It has naturalised
in some parts of Britain
and New Zealand
, not so extensively as to be considered an invasive species
, but an introduced species
tree.
can be collected by scraping slabs of removed bark. The resulting shavings can be eaten immediately, or can be dried and pressed into cakes for preservation. The bark also serves as a source of tannin
for tanning
.
Tender new growth needles (leaves) can be chewed directly or made into a bitter tea, rich in vitamin C
(similar to some other hemlock and pine species).
Western Hemlock boughs are used to collect herring
eggs during the spring spawn in southeast Alaska
. The boughs provide an easily collectible surface for the eggs to attach to as well as providing a distinctive taste. This practice originates from traditional gathering methods used by Native Alaskans
from southeast Alaska, specifically the Tlingit people.
Tsuga
Tsuga is a genus of conifers in the family Pinaceae. The common name hemlock is derived from a perceived similarity in the smell of its crushed foliage to that of the unrelated plant poison hemlock....
native to the west coast of North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, with its northwestern limit on the Kenai Peninsula
Kenai Peninsula
The Kenai Peninsula is a large peninsula jutting from the southern coast of Alaska in the United States. The name Kenai is probably derived from Kenayskaya, the Russian name for Cook Inlet, which borders the peninsula to the west.-Geography:...
, Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
, and its southeastern limit in northern Sonoma County
Sonoma County, California
Sonoma County, located on the northern coast of the U.S. state of California, is the largest and northernmost of the nine San Francisco Bay Area counties. Its population at the 2010 census was 483,878. Its largest city and county seat is Santa Rosa....
, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
.
Habitat
Tsuga heterophylla is an integral component of Pacific Northwest forests west of the Coast RangesPacific Coast Ranges
The Pacific Coast Ranges and the Pacific Mountain System are the series of mountain ranges that stretch along the West Coast of North America from Alaska south to Northern and Central Mexico...
, where it is a climax species
Climax species
Climax species, also called late seral, late-successional, K-selected or equilibrium species, are plant species that will remain essentially unchanged in terms of species composition for as long as a site remains undisturbed. They are the most shade-tolerant species of tree to establish in the...
. It is also an important timber tree throughout the region, along with many of its large coniferous associates.
Description
Tsuga heterophylla is a large evergreenEvergreen
In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...
coniferous
Pinophyta
The conifers, division Pinophyta, also known as division Coniferophyta or Coniferae, are one of 13 or 14 division level taxa within the Kingdom Plantae. Pinophytes are gymnosperms. They are cone-bearing seed plants with vascular tissue; all extant conifers are woody plants, the great majority being...
tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
growing to 165-230 ft (50–70 m) tall, exceptionally 270 ft (82 m), and with a trunk diameter of up to 9 ft (2.7 m). It is the largest species of hemlock
Tsuga
Tsuga is a genus of conifers in the family Pinaceae. The common name hemlock is derived from a perceived similarity in the smell of its crushed foliage to that of the unrelated plant poison hemlock....
, with the next largest (Mountain Hemlock
Mountain Hemlock
Tsuga mertensiana, known as Mountain Hemlock, is a species of hemlock native to the west coast of North America, with its northwestern limit on the Kenai Peninsula, Alaska, and its southeastern limit in northern Tulare County, California....
T. mertensiana) reaching a maximum of 194 ft (59 m). The bark
Bark
Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines and shrubs. Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner...
is brown, thin and furrowed. The crown is a very neat broad conic shape in young trees with a strongly drooping lead shoot, becoming cylindric in older trees; old trees may have no branches in the lowest 100-130 ft (30–40 m). At all ages, it is readily distinguished by the pendulous branchlet tips. The shoots are very pale buff-brown, almost white, with pale pubescence about 1 mm long. The leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
are needle-like, 5–23 mm long and 1.5–2 mm broad, strongly flattened in cross-section, with a finely serrated margin and a bluntly acute apex. They are mid to dark green above; the underside has two distinctive white bands of stoma
Stoma
In botany, a stoma is a pore, found in the leaf and stem epidermis that is used forgas exchange. The pore is bordered by a pair of specialized parenchyma cells known as guard cells that are responsible for regulating the size of the opening...
ta with only a narrow green midrib between the bands. They are arranged spirally on the shoots but are twisted at the base to lie in two ranks on either side of the shoot. The cones
Conifer cone
A cone is an organ on plants in the division Pinophyta that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity...
are small, pendulous, slender cylindrical, 14–30 mm long and 7–8 mm broad when closed, opening to 18–25 mm broad. They have 15–25 thin, flexible scales 7–13 mm long. The immature cones are green, maturing gray-brown 5–7 months after pollination. The seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
s are brown, 2–3 mm long, with a slender, 7–9 mm long pale brown wing.
Ecology
Tsuga heterophylla is closely associated with temperate rain forests, and most of its range is less than 100 km from the Pacific OceanPacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
. There is however an inland population in the Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
in southeast British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
, northern Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....
and western Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
. It mostly grows at low altitudes, from sea level to 600 m, but up to 1800 m in the interior part of its range in Idaho.
Shade-tolerant
It is a very shade-tolerant tree; among associated species in the Pacific Northwest, it is matched or exceeded in shade tolerance only by Pacific yewTaxus brevifolia
Taxus brevifolia is a conifer native to the Pacific Northwest of North America. It ranges from southernmost Alaska south to central California, mostly in the Pacific Coast Ranges, but with an isolated disjunct population in southeast British Columbia, most notably occurring on Zuckerberg Island...
and Pacific silver fir. Young plants typically grow up under the canopy of other conifers such as Sitka Spruce
Sitka Spruce
Picea sitchensis, the Sitka Spruce, is a large coniferous evergreen tree growing to 50–70 m tall, exceptionally to 95 m tall, and with a trunk diameter of up to 5 m, exceptionally to 6–7 m diameter...
and Douglas-fir
Douglas-fir
Douglas-fir is one of the English common names for evergreen coniferous trees of the genus Pseudotsuga in the family Pinaceae. Other common names include Douglas tree, and Oregon pine. There are five species, two in western North America, one in Mexico, and two in eastern Asia...
, where they can persist for decades waiting to exploit a gap in the canopy. They eventually replace these conifers, which are relatively shade-intolerant, in in climax forest. However, storm
Storm
A storm is any disturbed state of an astronomical body's atmosphere, especially affecting its surface, and strongly implying severe weather...
s and wildfire
Wildfire
A wildfire is any uncontrolled fire in combustible vegetation that occurs in the countryside or a wilderness area. Other names such as brush fire, bushfire, forest fire, desert fire, grass fire, hill fire, squirrel fire, vegetation fire, veldfire, and wilkjjofire may be used to describe the same...
s will create larger openings in the forest where these other species can then regenerate.
Initial growth is slow; one year old seedlings are commonly only 3–5 cm tall, and two year old seedlings 10–20 cm tall. Once established, saplings in full light may have an average growth rate of 50–120 cm (rarely 140 cm) annually until they are 20–30 m tall, and in good conditions still 30–40 cm annually when 40–50 m tall. The tallest specimen, 82.83 m tall, is in Prairie Creek Redwoods State Park
Prairie Creek Redwoods State Park
Prairie Creek Redwoods State Park is a state park, located in Humboldt County, California, near the town of Orick and 50 miles north of Eureka...
, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
(USA). It is long-lived, with trees over 1200 years old known.
Uses
Tsuga heterophylla, Western Hemlock, is the state tree of Washington.Cultivation
Western Hemlock is cultivated as an ornamental tree in gardens in its native habitats and along the U.S. Pacific Coast, where its best reliability is seen in wetter regions. In relatively dry areas, as at Victoria, British ColumbiaVictoria, British Columbia
Victoria is the capital city of British Columbia, Canada and is located on the southern tip of Vancouver Island off Canada's Pacific coast. The city has a population of about 78,000 within the metropolitan area of Greater Victoria, which has a population of 360,063, the 15th most populous Canadian...
, it is exacting about soil conditions. It needs a high level of organic matter (well-rotted wood from an old log or stump is best; animal manures may have too much nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
and salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...
), in a moist, acidic soil.
Forestry
Outside of its native range, Western Hemlock is of importance in forestryForestry
Forestry is the interdisciplinary profession embracing the science, art, and craft of creating, managing, using, and conserving forests and associated resources in a sustainable manner to meet desired goals, needs, and values for human benefit. Forestry is practiced in plantations and natural stands...
for timber
Timber
Timber may refer to:* Timber, a term common in the United Kingdom and Australia for wood materials * Timber, Oregon, an unincorporated community in the U.S...
and paper
Paper
Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....
production, and as an ornamental tree in large garden
Garden
A garden is a planned space, usually outdoors, set aside for the display, cultivation, and enjoyment of plants and other forms of nature. The garden can incorporate both natural and man-made materials. The most common form today is known as a residential garden, but the term garden has...
s, in northwest Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
and southern New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
.
It has naturalised
Naturalisation (biology)
In biology, naturalisation is any process by which a non-native organism spreads into the wild and its reproduction is sufficient to maintain its population. Such populations are said to be naturalised....
in some parts of Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
and New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, not so extensively as to be considered an invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
, but an introduced species
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
tree.
Food
The edible cambiumCork cambium
Cork cambium is a tissue found in many vascular plants as part of the periderm. The cork cambium is a lateral meristem and is responsible for secondary growth that replaces the epidermis in roots and stems...
can be collected by scraping slabs of removed bark. The resulting shavings can be eaten immediately, or can be dried and pressed into cakes for preservation. The bark also serves as a source of tannin
Tannin
A tannin is an astringent, bitter plant polyphenolic compound that binds to and precipitates proteins and various other organic compounds including amino acids and alkaloids.The term tannin refers to the use of...
for tanning
Tanning
Tanning is the making of leather from the skins of animals which does not easily decompose. Traditionally, tanning used tannin, an acidic chemical compound from which the tanning process draws its name . Coloring may occur during tanning...
.
Tender new growth needles (leaves) can be chewed directly or made into a bitter tea, rich in vitamin C
Vitamin C
Vitamin C or L-ascorbic acid or L-ascorbate is an essential nutrient for humans and certain other animal species. In living organisms ascorbate acts as an antioxidant by protecting the body against oxidative stress...
(similar to some other hemlock and pine species).
Western Hemlock boughs are used to collect herring
Herring
Herring is an oily fish of the genus Clupea, found in the shallow, temperate waters of the North Pacific and the North Atlantic oceans, including the Baltic Sea. Three species of Clupea are recognized. The main taxa, the Atlantic herring and the Pacific herring may each be divided into subspecies...
eggs during the spring spawn in southeast Alaska
Alaska Panhandle
Southeast Alaska, sometimes referred to as the Alaska Panhandle, is the southeastern portion of the U.S. state of Alaska, which lies west of the northern half of the Canadian province of British Columbia. The majority of Southeast Alaska's area is part of the Tongass National Forest, the United...
. The boughs provide an easily collectible surface for the eggs to attach to as well as providing a distinctive taste. This practice originates from traditional gathering methods used by Native Alaskans
Alaska Natives
Alaska Natives are the indigenous peoples of Alaska. They include: Aleut, Inuit, Tlingit, Haida, Tsimshian, Eyak, and a number of Northern Athabaskan cultures.-History:In 1912 the Alaska Native Brotherhood was founded...
from southeast Alaska, specifically the Tlingit people.