evergreen tree
Western Hemlock: pruning, storm risk and removal
Tsuga heterophylla. Also called West Coast hemlock, Pacific hemlock.
Plain-English notes for homeowners, plus field notes for tree crews. General guidance only: for one specific tree, have a local insured pro look at it.
Western Hemlock at a glance
| Height | 70-150 ft, taller in old forests |
|---|---|
| Spread | 15-30 ft |
| Growth rate | Medium |
| USDA zones | 6-8 |
| Lifespan | Typically 300-500 years in forests, shorter in yards |
| Type | Evergreen |
| Native range | Cool, wet forests of the Pacific Northwest from southeast Alaska through British Columbia, Washington, Oregon and northern California, with a separate population in the northern Rocky Mountains |
| Roots | Shallow and spreading, with no deep taproot. The tree depends on moist, well-drained soil and is easy to uproot when soil is soggy or loosened. |
| Wood | Light, moderately strong and straight grained. It is a major lumber and pulp tree in the Pacific Northwest. It is not a favorite firewood. |
| Storm risk | mediumShallow roots and a tall crown make blowdown common in strong winter storms, especially on wet ground or where neighboring trees were cleared. Old trees often have hidden decay in the trunk. |
Typical ranges, not guarantees. Soil, water, space and care change how a tree grows. Storm risk is our general rating for the species, not an inspection.
For homeowners
Caring for a western hemlock
Best time to prune
Late fall to winter. Remove dead and broken limbs and prune lightly. Hemlocks tolerate light shearing when young, but a natural shape suits most yards.
Avoid pruning
Avoid heavy cuts into old wood, because hemlock rarely regrows from bare branches. Do not top the tree, and avoid deep cuts that leave large wounds where decay can enter.
More on timing: when to prune trees.
- Plant in cool, moist, well-drained soil with some shade. It does poorly in hot, dry, windy spots.
- Mulch the root zone and water deeply in dry summers, especially for young trees.
- Keep digging and soil compaction away from the roots. They are shallow and easy to hurt.
- After clearing nearby trees, have an arborist check for new wind exposure. Trees that were sheltered may now lean or fall.
Safety first
Do not climb a tree or use a chainsaw on storm-loaded or broken wood. If a tree or limb is touching power lines, stay away and call the utility. If someone is in danger, call 911. For anything big, hire a local insured pro: read how to hire a tree service and is my tree dangerous?
Lirevon does not do tree work. Find local pros on Google Maps and read their reviews, then get two or three written quotes.
For tree crews
Field notes: working on western hemlock
- 1Check the trunk base for conks, cavities and soil lift before climbing. Shallow roots can fail without warning.
- 2Use the right rigging for tall, dense crowns. Branches interlock and can pull other pieces during cuts.
- 3Expect wet, soft ground. Plan access and matting before bringing equipment in.
- 4Sound the trunk at several heights. Rot often hides in older trees that look healthy.
Removal notes
Mature trees are tall with shallow roots, and a leaning or wet-ground tree can be loaded with tension. Trunk rot is common in older trees, so test the wood before climbing. Hemlock wood is light, but the volume of limbs and chips is big. Plan for wet ground, which can leave ruts under trucks and grinders.
Wood
Light, moderately strong and straight grained. It is a major lumber and pulp tree in the Pacific Northwest. It is not a favorite firewood.
Pricing this job? Try the tree job estimator. Follow your own safety plan and crew training on every job.
Common problems for western hemlock
Pests and diseases to watch for. Each link explains signs and what to do.
Trees often mistaken for it
Check the leaves, bark and shape before you decide how to prune or treat.
Where western hemlock grows
Native range: Cool, wet forests of the Pacific Northwest from southeast Alaska through British Columbia, Washington, Oregon and northern California, with a separate population in the northern Rocky Mountains
Common in these US regions. Tap one to see other trees there.
Free tools for this tree
They run in your browser and nothing is sent anywhere. Results are estimates.
Western Hemlock: common questions
How can I tell western hemlock from other conifers?
Look at the top of the tree and the needles. The leader of a western hemlock droops over, and the short flat needles vary in length along the twig. Cones are small and hang down.
How tall does western hemlock grow?
In forests it often reaches well over 100 feet. In a yard, expect 50 to 100 feet, and it will keep growing for many years.
Is western hemlock affected by the woolly adelgid?
The hemlock woolly adelgid is a serious pest of eastern and Carolina hemlock. Western hemlock is not its main host, but conditions can change, so check with your state department of agriculture or extension office for current information.
Why is my western hemlock turning brown?
Common causes are drought, root rot, sun scald, compacted soil and winter injury. A tree with a browning top may have root or trunk problems. Ask an arborist if it continues.
Will western hemlock make a good hedge?
It can, in cool, moist places. It tolerates light shearing when young, but it needs shade and moisture, and it will outgrow a small space if it is not kept in check.
When should a western hemlock be removed?
When it is dead, leaning, has trunk rot, or is close to a home after nearby trees were cleared. A certified arborist can inspect it and give written advice. Get two or three written quotes.
More trees in the same regions
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