Tsuga Canadensis
The eastern hemlock tree is a staple in the eastern North America mixed-hardwood forest. Often growing in hemlock-spruce groves, this is an evergreen tree that is native to the majority of the eastern side of Canada and the United States.
Mostly referred to as the Canadian hemlock, or “pruche du Canada” by francophones, they are a very slow-growing tree, but get super tall. The tallest hemlock on record lives in the Great Smoky Mountains National Park and is 52.8 meters tall. But they only grow about 2 inches a year!
These trees are also very long-lived. The oldest eastern hemlock on record lived in Tionesta Pennsylvania and was an estimated 554 years old.
These impressive trees also carry the title of being the largest natural evergreen conifer in the eastern United States, with the winning tree having a trunk volume of 44.8m cubed.
If you’re curious about other types of hemlock trees, we’ve got you covered with 6 Different Types of Hemlock Trees. Head on over to 101 Types of Trees if you’re still curious after that!!
Related: Mountain Hemlock Tree | Western Hemlock Tree
What do Eastern Hemlock Trees Look Like?
Root Systems
The root system of the eastern hemlock tree is known as being a very aggressive type of growth. They have very shallow and laterally spreading root systems, but they grow extremely quickly and often take nutrients from other surrounding plants.
Dimensions
Eastern hemlock trees will usually be between 28 and 31 meters tall, but when they live in ideal growing conditions they can reach an impressive height of up to 53 meters. Their trunk diameter must be large enough to support that height, and trunks are usually between 1.5 and 1.75 meters around.
Growth Pattern
Eastern hemlocks are monopodial, meaning that growth occurs from one single point — the tree will very rarely experience a forked trunk. The trunk is very straight and upright, which grows into a broadly conic crown.
Bark
The bark of the eastern hemlock on a young tree with being deeply fissured and scaly, and brown or gray color. Hemlock bark on mature trees will be extremely deeply fissured and scaly.
Foliage
A hemlock twig ranges from yellow/brown to dark red/brown and is covered in densely down hairs. Leaf buds are small and ovoid in shape and will open up to an eastern hemlock leaf, which is in the form of a needle, quite similar to balsam fir needles.
Eastern hemlock needles are just under an inch long, and they are flat and are alternately arranged in opposite rows on the twig. A hemlock Needle has a serrated margin, the bottom side of the needle is glaucous with 2 stomatal bands (which is how conifers are easily identified), and the top side of the needle is shiny and a yellow/green color.
How do Eastern Hemlock Trees Reproduce?
Seed Cone & Pollen Cone
Hemlock trees produce both sexes of cones, meaning that they are monoecious. Male cones produce pollen, and female cones are ovule producing. Trees become sexually mature around 15 years of age and will start to produce their cones in mid-spring.
Pollen is carried through wind and lands inside the seed cones on either the same hemlock or different hemlock. The female cone will then mature with the pollen inside it, and becomes fully mature in the late summer.
Fertilization takes about six weeks, and the cone will then open in mid-fall and release the seeds. Seedlings require temperatures of at least 60 degrees Fahrenheit, and shade with 70-80% vegetative cover in order for them to germinate.
What are Some Other Hemlock Cultivars?
Beehive Hemlock – the beehive hemlock is a very small dwarf shrub that is around 1 meter tall. They are specifically grown ornamentally and shaped to resemble the shape of a beehive.
Bennett Hemlock – the Bennett hemlock is a very small dwarf shrub that is around 1 meter tall. They are grown to have branchlets that have an upward ascending arch growth pattern.
Coles Prostrate Hemlock – this hemlock is cultivated as a ground cover plant. It is a dense bush that rarely exceeds 12 inches in height. They are also a popular choice for the art of bonsai.
Gentsch Hemlock – this hemlock cultivar is also a dwarf shrub and will grow to be around 1.3 meters tall. They are a popular ornamental plant because their new winter growth comes out a creamy white color, which creates an appealing contrast against the deep green growth of the previous season.
Jeddeloh Hemlock – this hemlock cultivar is a dwarf shrub that is under a meter tall. They have an arching crown shape that is concave in the middle.
Pendula Hemlock – the pendula hemlock a dwarf shrub that is under a meter tall. It is cultivated to have upright branch growth into a weeping shape, quite similar to that of the weeping willow tree.
Sargentii Hemlock – also a weeping shrub, the sargentii is a larger cultivar that can grow to be 3 meters tall with a spread that is double that length. They grew and shaped to have pendulous ascending branches.
Where do Eastern Hemlock Trees Grow?
Hemlock trees are confined to areas that have highland climates that are cool and humid. They grow prosperously on rocky ridges, hillsides, and ravines. They will usually grow at elevations of 600-1800 meters in altitude.
The hemlock forest is present in all eastern Canadian provinces except for Newfoundland and Labrador, which includes; Ontario, Quebec, New Brunswick, Nova Scotia, and Prince Edward Island. In America, hemlocks grow from Minnesota to the Appalachian Mountains, towards northern Georgia and Alabama.
The trees will often be found growing in congruence with red spruce, balsam fir, white pine, hemlock spruce, and western hemlock.
What are the Growing Conditions of Eastern Hemlock Trees?
Sun Exposure
Hemlocks are a very valuable landscape conifer because they are an evergreen tree that is very tolerant to shade, which is unusual for evergreens. They prefer partial shade but are also very tolerant of full shade.
Water Level
The main requirements for the successful growth of the eastern hemlock tree are water and humidity. They will only grow in regions that experience cold humidity, and that receive a minimum of 740mm of rain per year.
The tallest hemlock trees grow near the Atlantic coast and in the Appalachian mountains because those places receive the most amount rain.
Temperature
Though they do prefer the cold, eastern hemlocks can live in regions that experience as few as 80 days of frost in a year. They will grow in regions where the mean temperature in January is 10 degrees Fahrenheit, and the mean temperature in July is 61 degrees Fahrenheit.
Soil
The soil requirements for the eastern hemlock tree are quite specific. The soil cannot be too dry or too wet. It must be well-drained, full of nutrients, and lean more towards a high acidity level rather than alkalinity on the pH scale.
Intolerances
Hemlocks are not usually found in cities or streets because they are very intolerant of road salt and urban pollution. They will grow more successfully in parks and gardens that are away from busy roads.
What Pests Affect Eastern Hemlock Trees?
Hemlocks are a tree species that are under great threat from an invasive species. They are currently subjected to damage by the hemlock wooly adelgid (adelges tsugae). This invasive insect was introduced to North America from Asia in 1924 on a shipment of logs.
An invasive species is an insect, plant, or animal that is introduced to a foreign land. When they arrive, the ecosystem is not prepared for their impact. When that newly introduced species invades an area, the surrounding plants, insects, and animals do not know how to interact with them. This means that the invasive species has no natural predators, and essentially have free reign over the new landscape.
The hemlock wooly adelgid is a sap-sucking bug that has absolutely decimated the hemlock population over the years. Their spread is so rapid because of the cold and humid regions in which hemlock trees grow. They are able to take out thousands of hectares of trees in only a few years.
Hemlock trees are now classified as being critically endangered, though there are efforts in place to preserve groves with the largest trees. The largest and most damaging effect of this particular invasion is the large effect that high tree death has on the carbon cycle of the forest.
The trees are affected because an HWA infestation is prevalent in areas that are cold and humid. So many eggs are hatched within the canopy of an infested tree that their foliage is completely damaged by the end of the season.
How are Eastern Hemlock Trees Used?
Wood
Eastern hemlock wood is light brown and the sapwood is slightly paler. The texture is wide to average spacing. The wood is light but hard, though it splinters easily and is cross-grained.
The wood is typically used for non-aesthetic purposes, like timber and lumber, general construction, platforms, boxes, crates, and railway ties.
Ornamental
Hemlock trees are quite easy to transplant and easy to cultivate, making them a very popular ornamental cultivar. They can withstand lots of shaping and pruning and are often grown to create a dense shrub screen to help protect more delicate plants and trees.
Nutrients
Traditionally, the inner bark of the eastern hemlock tree has been eaten either boiled or raw for its medicinal and nutritious properties. The inner bark can also be dried, ground, and turned into flour!
Wildlife
Eastern hemlock trees and a wide variety of fungi species have established a very successful and symbiotic relationship (check out this article to learn what a symbiotic plant relationship is!).
They provide valuable habitat for various small and mammals and bird species, including the black-throated green warbler, the black-throated blue warbler, and the blackburnian warbler.
Black bears tend to linger around eastern hemlock trees because cubs like to climb them, and black bear cubs and their mother will never usually stray away from hemlock forests for the first few months of the cub’s life.
The seeds of the tree are eaten by small mammals and birds, and their winter foliage is an important source of food for moose, snowshoe hares, and white-tailed deer.
FAQs
What is the difference between an eastern hemlock tree and a poison hemlock tree?
There is much confusion as to whether or not hemlock trees are poisonous, but the answer is no no no! The rumor arose from the tall that the famous philosopher, Socrates, took his own life by ingesting tea made from poison hemlock leaves.
Though that species was not the hemlock tree. The poison hemlock is a herbaceous plant (conium maculatum) that is from the carrot family. It is a small plant with many branches and smooth, hollow, purple stems, and leaves similar to ferns with white clusters of flowers. The two species are not easily mistaken whatsoever.
What is the difference between eastern hemlock trees and a Carolina hemlock?
Carolina hemlock trees and eastern hemlock trees are extremely similar by their outside appearance, and so the easiest way to differentiate the two is by their root systems. Eastern hemlock trees have very shallow and wide-spreading root systems, whereas Carolina hemlock trees have taproot systems that grow very deep into the earth.
How fast do eastern hemlock trees grow?
Eastern hemlock trees are very slow-growing, and will only grow around 2 inches for the first few years of their lives! After that, it will speed up marginally before it slows down again in their senior years.
How long do eastern hemlock trees live?
Eastern hemlock trees are quite long living. They usually average to be 250-300 years old and sometimes reaching over 500 years old as long as there is no interference from logging, environmental changes, or sickness.
How tall do eastern hemlock trees get?
Eastern hemlock trees will usually grow to be between heights of 28 and 31 meters tall, though there have been some exceptional trees that sprout up to be over 53 meters tall!
Do hemlock trees have deep roots?
The root system of a hemlock tree will depend on the variety and its growing location. Trees that live in areas that experience a lot of precipitation will usually develop shallow and wide-spreading roots. Trees that live in areas that experience more dry conditions will have a taproot, which grows very deep into the earth. This is so that they can access moisture reserves deep in the soil.
Can you eat hemlock tree bark?
Traditionally, the inner bark of the eastern hemlock tree has been eaten either boiled or raw for its medicinal and nutritious properties. The inner bark can also be dried, ground, and turned into flour!
Do hemlock trees grow in the shade?
Hemlocks are a very valuable landscape conifer because they are an evergreen tree that is very tolerant to shade, which is unusual for evergreens. They prefer partial shade but are also very tolerant of full shade.
Where do hemlock trees grow best?
The main requirements for the successful growth of the eastern hemlock tree are water and humidity. They will only grow in regions that experience cold humidity, and that receive a minimum of 740mm of rain per year.
Though they do prefer the cold, eastern hemlocks can live in regions that experience as few as 80 days of frost in a year. They will grow in regions where the mean temperature in January is 10 degrees Fahrenheit, and the mean temperature in July is 61 degrees Fahrenheit.
The soil requirements for the eastern hemlock tree are quite specific. The soil cannot be too dry or too wet. It must be well-drained, full of nutrients, and lean more towards a high acidity level rather than alkalinity on the pH scale.
Do deer eat hemlock trees?
The winter foliage of the hemlock tree is an important source of nutrients for white-tailed deer in the wintertime. They won’t browse upon spring foliage nearly as much.
Does hemlock wood make for good firewood?
Hemlock wood makes for good firewood. Its density allows it to burn at a high temperature, it has a pleasant smell, and it tends to crackle more so than other types of firewood might.