Western redcedar in Washington and Oregon yards

Size and shape

OSU’s Landscape Plants database gives western redcedar a mature height of 50–70 feet, with 200 possible, in a narrow pyramid with a buttressed base; it usually keeps its lower branches, and its horizontal, drooping limbs turn up at the tips. The USDA Forest Service silvics manual records the largest known Washington tree at 233 inches in diameter and 178 feet tall, and says ages of 800 to 1,000 years are common; the NRCS plant guide cites trees of at least 1,460 years.

The species is more shade-tolerant than almost anything it grows with; the silvics manual lists only Pacific silver fir, western hemlock and Pacific yew as more tolerant. OSU lists it for sun to partial shade on moist, well-drained, fertile soil, and notes it “can be maintained in a hedge,” which is why its cultivars show up as privacy screens from Bellingham to Eugene. Hedge-form cedar is handled on arborvitae and hedge trimming.

A tree with a longer history than the house

The NRCS plant guide calls western redcedar “the cornerstone of northwest coast Indian culture.” Its wood went into house planks, posts and roof boards, boxes and canoes; its bark into skirts, capes and dresses; its roots and limbs into baskets and rope; and its inner bark into slow matches that carried fire between camps. The silvics manual records “canoe-cedar” among its common names. None of that changes a permit, but it is worth knowing why an old cedar on a lot in Olympia, Tacoma or Astoria may matter to more people than its owner, and why a sound one is worth keeping.

Dieback: the top dies first

Across both states redcedar is thinning, flagging and losing its top in hot, dry sites, with no primary pathogen found. Washington’s 2024 aerial survey mapped 45,630 acres of redcedar crown dieback and 6,040 acres of mortality; WSU’s tree-ring study tied westside mortality to the hot, dry years of 2017–2018. The silvics manual already noted that seedlings suffer drought damage in full sunlight, and ODF now advises planting only in moist, shaded spots and watering in summer.

The symptoms, the research and the care routine (deep watering, 2–4 inches of chip mulch, no fertilizer, no heavy pruning) are on western redcedar dieback. The short version for a tree you already have: a green lower crown with a dead top is a tree to water and watch, not to top.

Pruning: never top a cedar

Topping, cutting the leader and upper crown back to stubs, is banned in Portland and can bring fines or mandatory removal and replanting (City of Portland). On redcedar it is also pointless: the tree’s drooping side branches turn up at the tips and compete to become new leaders, so a topped cedar becomes a candelabra of weak tops over a decayed stub. Portland’s limit for any pruning cycle is 20–25 percent of the canopy, and spring is the season to avoid.

What a cedar tolerates well is limbing up: because the species “usually maintains lower branches” (OSU), removing the lowest whorls to clear a roof, a path or a view is routine and low-stress when done at the branch collar. The USDA Forest Service pruning guide sets the limit: keep live branches on at least two-thirds of the tree’s height, so a 60-foot cedar keeps live crown on its upper 40 feet. Conifers can be pruned in any month, though dormant-season cuts bleed less resin.

A smaller crown is a different matter. The same USDA guide says pyramidal conifers rarely need crown thinning except to restore a single leader, and that crown reduction should never be used on a tree with a pyramidal form; when a cedar has outgrown its space, the guide’s long-term answer is removal and a replacement that fits. (This page previously suggested reducing a cedar’s crown to live laterals; that advice suits spreading hardwoods, not redcedar, and has been corrected.) Hardwood reduction is described on crown thinning and reduction; the service page is tree trimming.

Root plate and windthrow

Redcedar has an extensive root system with a taproot that is “poorly defined or nonexistent,” a dense network of fine roots, and roots that are “shallower and less extensive on wet sites” (USFS). The windthrow verdict in the silvics manual is specific: on dry sites it is “as windfirm as Douglas-fir,” but on wet ground, “the moist sites where growth and yield are highest,” it lacks windthrow resistance and is often blown over. The NRCS guide repeats the “high susceptibility to windthrow in wet environments.”

For a yard that means the big cedar in the low, wet corner, next to the seasonal creek or the drainage swale, is the one to check each winter. Look on the windward (usually south or southwest) side for lifted or cracked soil, a root plate that rocks in wind, a new lean, and conks or mushrooms at the base; the silvics manual names Poria asiatica and P. albipellucida as the important trunk rots near the coast, and butt rot is what turns a windfirm cedar into a hinge. After a tree has gone over, the job is fallen tree removal.

The wet soil and the wind arrive together. In NOAA’s Storm Events records for 2016–2026, about 79 percent of Washington and Oregon high-wind, strong-wind and ice-storm reports fell between November and March, the same months the soil is saturated; over 1951–2026, High Wind is Oregon’s most reported event type, with 3,042 reports (reports, not separate storms).

When removal is needed

A certified arborist should make the call; what the visit involves is on tree risk assessment. Permits are the easy case for a dead or dangerous cedar: Portland issues a Type A permit without public notice for dead, dying or dangerous trees (PCC 11.40), and Seattle charges no fee for a dead-tree removal under SMC 25.11, though a healthy cedar 24 inches and larger is a Tier 2 tree there with tight removal limits. City rules are in Oregon tree removal permits and Washington tree removal permits.

Cedar is the light wood of the three big westside yard trees. The USDA Forest Service’s FIA species reference table gives western redcedar a specific gravity of 0.31 against 0.45 for Douglas fir, and with its dry-to-green weight factor of 1.41 that works out to roughly 27 pounds per cubic foot of fresh-cut wood, about two-thirds the weight of the same piece of fir. Sections are lighter to lower on a rope, but the trunk on a big buttressed cedar is still measured in tons.

Modeled estimate, not quotes (method): a 50–80 ft cedar removal models at $1,700–$3,400 in Washington and $1,800–$3,600 in Oregon, and over 80 ft at $2,950–$6,300 and $3,150–$6,750, with the ×1.25 multiplier within 10 feet of a structure and $150–$450 for the stump. The full table is on tree removal cost, and the service page is tree removal. A cedar with a sound trunk and a dead top is also the classic candidate for a wildlife snag instead of a full removal; ask about it on dead tree removal.

Next steps

1. Water and mulch any cedar in a sunny or dry spot this summer, before the top goes.
2. Check the base after the first saturated-soil storm each winter for lifted soil, lean and conks.
3. Limb up, do not top. If someone offers to top it, find another crew.
4. Get a risk assessment for a dead top or root-plate movement near a target, and attach it to the permit.
5. Check the crew with L&I Verify in Washington or the CCB and LCB lookups in Oregon.

Other species pages are under trees.