Eastern Hemlock (Tsuga canadensis)

Height: A large tree. Many reach 100 feet, some grow much taller.

Evergreen/Deciduous: Evergreen

Lifespan: At least 500 years, with questionable records of trees reaching twice this age.  

Fall Foliage: Green

Range: The tree’s range basically follows the Appalachian Mountains, while extending into Canada in the north and as far west as Wisconsin.   

Typical Habitat: Cool forests with adequate moisture. In the southern end of its range, it’s usually found at some elevation.   

The Eastern Hemlock: An Icon Under Assault   

It’s difficult to discuss eastern hemlocks without focusing on their current struggle for survival.

In 1924, a small Asian insect known as the hemlock wooly adelgid (Adelges tsugae) was introduced to the United States. In its natural range, the insect’s population is kept in check from predators, so it doesn’t reach numbers large enough to threaten Asian hemlocks. But free of these predators, hemlock wooly adelgids have decimated hemlock tree populations.

Because of the hemlock’s importance to the ecosystems it helps comprise, this is expected to have significant effects on the other species living alongside them. This includes a number of amphibians – which are already under assault — in the southern portion of its range.

Scientists are currently working to stop the damage caused by this insect, in part by experimenting with predatory invertebrates.

Eastern Hemlock Identification: Tips & Tricks

If you note that the needles of the Eastern hemlock are attached singly to the twig rather than in bundles, it’s easy to distinguish this species from the pines. And if you note that the needles are all arranged in a single plane, you know you’re not looking at a spruce.

The needles of fir trees are a bit harder to distinguish from those of hemlocks, so just look for the cones: If they hang from the branches, you’re looking at a hemlock; if they sit upright and are supported by the branch from below, you’re looking at a fir tree.

The Eastern Hemock: Additional Information

It’s easy to understand why nature lovers are interested in this species: Not only is it an attractive tree, but it’s also an important conservation species. But regardless of your reasons for wanting to learn more, the following resources should help you do so:

  • WildAdirondacks.org: An excellent resource that, among other things, provides identification tips and information about the specie’s wildlife value.
  • National Park Service: A great overview, as one would expect from the NPS.
  • Conifers.org: A ton of high-level information about the eastern hemlock, including a range map and detailed photos.

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