Common Trees in Washington: Identification Guide

Western Red Cedar (Thuja plicata)

Western red cedar is Washington's most culturally significant tree, revered by the Coast Salish, Makah, Quinault, and many other Washington tribes who called it the 'Tree of Life.' Its rot-resistant wood was used for ocean-going canoes up to 60 feet long, totem poles, longhouses, bent-wood boxes, and clothing woven from its bark — a culture of material wealth built on a single tree species. Washington's Olympic Peninsula hosts the largest known western red cedar in the US, the Quinault Lake Cedar, with a circumference of over 60 feet. In the Hoh and Quinault rainforests, western red cedar exceeds 200 feet tall with massive buttressed trunks supporting elaborate communities of epiphytic mosses, ferns, and orchids.

Where to find it: Moist to wet forests throughout western Washington's Coast Range and Cascades, particularly abundant in the Olympic Peninsula rainforests and river valleys below 4,500 feet elevation

How to identify it:

• Flat, fan-like sprays of scale-like leaves with a distinctive pineapple or fruity scent when crushed
• Fibrous, cinnamon-red to gray bark that shreds in long vertical strips — unmistakable in Pacific Northwest forests
• Small urn-shaped cones (0.5 inch) in clusters, each with 8–12 overlapping scales
• Massive, strongly buttressed base on old trees; trunk often fluted and tapering dramatically

Douglas Fir (Pseudotsuga menziesii)

Douglas fir is the ecological backbone of Washington's west-side forests and the most commercially important timber tree in North America. Washington's Olympic Peninsula and western Cascades produce some of the largest Douglas fir trees on Earth — the Queets Fir in the Queets River valley of Olympic National Park is one of the largest known Douglas firs, at over 14 feet in diameter and 220 feet tall. Washington's old-growth Douglas fir forests are central to the habitat of the federally threatened northern spotted owl, and old-growth conservation battles in the 1980s–90s shaped US forest policy for decades. The species can live over 1,000 years, and trees over 500 years old with multi-layered, complex canopies support entirely different ecological communities than younger managed forests.

Where to find it: Western Washington forests from sea level to 5,000 feet; most productive on moist, well-drained soils west of the Cascade crest; also found east of the Cascades at higher elevations

How to identify it:

• Distinctive cones with 3-pronged mouse-tail bracts protruding between scales — no other conifer in Washington has this feature
• Soft, flat needles (0.75–1.5 inch) with a groove along the upper surface, attached on all sides of the branch
• Deeply furrowed, corky bark on old trees — often 6–12 inches thick on large old-growth specimens
• Tall, straight bole; broad, pyramidal crown with irregular branching pattern on old trees

Sitka Spruce (Picea sitchensis)

Washington's Olympic Peninsula hosts some of the world's most impressive Sitka spruce forests, with the Queets and Quinault valleys sheltering trees that rival California redwoods in sheer biomass. The Quinault Lake Spruce in Olympic National Park is one of the largest Sitka spruce trees in the world at over 17 feet in diameter. Sitka spruce can grow up to 3 feet per year in optimal conditions on Washington's rainy Olympic coast, making it among the fastest-growing conifers in North America. The species is restricted to the Pacific coastal fog belt in Washington — abundant on the Olympic Peninsula coast and in the Willapa Hills, but essentially absent from the drier Puget lowland.

Where to find it: Pacific coastal fog belt of the Olympic Peninsula and Willapa Hills, typically within 30 miles of the ocean; most abundant below 1,500 feet elevation in the wettest areas of western Washington

How to identify it:

• Extremely sharp, stiff needles that radiate in all directions — handling them is painful without gloves
• Thin, scaly, purplish-gray bark that peels off in irregular circular or oval chips
• Long pendant cones (2–4 inches) with papery scales that have irregular, wrinkled margins
• Enormous, buttressed trunks on old trees; widest flare of any Pacific Northwest conifer

Western Hemlock (Tsuga heterophylla)

Washington's state tree, western hemlock, is the most shade-tolerant of all Pacific Northwest conifers and the climax dominant in undisturbed west-side forests — without disturbance, it eventually replaces Douglas fir as the dominant canopy species over centuries. Washington's Carbon River rainforest in Mount Rainier National Park, the most inland temperate rainforest in the lower 48, is dominated by old-growth western hemlock draped in mosses. The drooping, nodding top of the hemlock is one of the most useful field identification features visible from a distance in Washington's forests. Hemlock bark was historically used by Washington tribes to tan hides, and inner bark was eaten as a famine food in spring.

Where to find it: Moist forests throughout western Washington below 5,000 feet; the most abundant tree in many old-growth stands west of the Cascades; also found in moist eastern Cascade valleys

How to identify it:

• Nodding, drooping terminal leader (the top of the tree always nods to one side)
• Flat, feathery needles of two distinct lengths arranged in a single plane along the branch
• Very small cones (0.75–1 inch) dangling from branch tips in great abundance
• Reddish-brown, deeply furrowed bark on large trees, scaly on young trees

Bigleaf Maple (Acer macrophyllum)

Washington's most spectacular native hardwood, bigleaf maple creates a lush, green, moss-draped canopy in the Olympic Peninsula rainforests where its massive branches support hundreds of pounds of epiphytic mosses, ferns, and licorice fern per tree — a hanging garden unique in North America. In fall, bigleaf maple turns brilliant gold and yellow throughout western Washington, providing vivid color contrast against the dark conifers. The Hoh Rainforest's Hall of Mosses, one of Washington's most visited natural areas, is defined by ancient bigleaf maples with branches so heavily cloaked in club moss that the trees appear otherworldly. Washington tribes used bigleaf maple for paddles, bowls, and implements, and the maple's massive paired samaras are among the most recognizable seeds in Washington's forests.

Where to find it: Moist forests, stream banks, and forest edges throughout western Washington; most spectacular in the Olympic Peninsula's rainforest valleys and along Puget Sound lowland streams

How to identify it:

• Enormous 5-lobed leaves (6–12 inches across) — the largest maple leaves in North America
• Branches typically covered in thick cushions of mosses, lichens, and licorice fern in Olympic rainforests
• Large paired samaras (helicopters) with wings at a narrow angle
• Opposite leaf arrangement; gray-brown bark with interlacing ridges on mature trunks

Red Alder (Alnus rubra)

Red alder is the most abundant hardwood in Washington and the Pacific Northwest, rapidly colonizing landslides, logging sites, and stream banks throughout western Washington and creating nitrogen-rich soil that facilitates forest succession. It is the primary hardwood timber species in Washington, producing a light, fine-grained wood used for furniture, cabinets, and smoked salmon — Washington's fishing industry relies on alder chips for the distinctive Pacific Northwest salmon smoke flavor. Red alder's smooth, pale gray bark with white lichen patches makes it one of the most recognizable trees in Washington's winter riparian zones. Its nitrogen-fixing root nodules (with Frankia bacteria) allow it to colonize infertile soils where most trees struggle.

Where to find it: Stream banks, floodplains, landslides, and disturbed forest edges throughout western Washington; also colonizes roadsides and clear-cuts aggressively in the Coast Range and western Cascades

How to identify it:

• Smooth, pale gray to whitish bark with light-colored lichen patches — distinctive from a distance
• Oval to elliptical leaves with coarsely double-toothed margins and a slightly revolute (rolled-under) edge
• Small woody, cone-like catkins (0.75–1.5 inches) persisting on bare branches through winter
• Bright orange-red inner bark visible when outer bark is scratched — the source of the 'red' in red alder

Ponderosa Pine (Pinus ponderosa)

East of the Cascades, ponderosa pine is the defining tree of Washington's Okanogan Highlands, Chelan area, and the eastern slope of the Cascades, where its open, fire-maintained parklands are among the most scenic forests in the state. Washington's dry eastern ponderosa forests historically experienced fires every 10–20 years that maintained the park-like structure with grassy understories, but modern fire suppression has resulted in dense, fire-prone stands. Riverside State Park near Spokane showcases classic eastern Washington ponderosa parkland accessible from a major city. The Columbia River Gorge's Washington side hosts the southernmost ponderosa stands in the state, transitioning to oak woodlands downslope.

Where to find it: Eastern Washington east of the Cascade crest from 2,000–5,500 feet elevation; most extensive in the Okanogan Highlands, Wenatchee area, and eastern Cascade foothills

How to identify it:

• Long needles (5–10 inches) in bundles of 3, bright yellow-green
• Mature bark forms diagnostic orange-brown puzzle-piece plates with vanilla scent when warm
• Large cones (3–6 inches) with small prickles on each scale
• Tall, straight trunk clear of branches for 30–60 feet in mature open-grown trees

Garry Oak (Oregon White Oak) (Quercus garryana)

Garry oak (the Pacific Northwest common name for Oregon white oak) is Washington's only native oak west of the Cascades and one of the most endangered tree communities in the Pacific Northwest. Washington's Garry oak ecosystems are centered in the South Puget Sound lowlands — Fort Lewis Prairie, Glacial Heritage Preserve, and the American Camp prairie on San Juan Island represent some of the last significant Garry oak savannas in the state. The Garry oak's acorns were a critical food source for Puget Sound tribal nations who managed these landscapes with fire. Washington Garry oaks support dozens of rare plant species and specialist insects, including the rare Propertius duskywing butterfly, which requires Garry oak for its larval stage.

Where to find it: South Puget Sound lowlands, San Juan Islands, and dry, south-facing slopes of the eastern Olympic foothills; also found in rain shadow areas of the Olympic Peninsula interior

How to identify it:

• Deeply lobed leaves (5–7 rounded lobes) with a thick, leathery texture and glossy dark green upper surface
• Large, stout acorns with a shallow, warty cap covering one-quarter to one-third of the nut
• Massively furrowed, grayish bark with deep, rounded ridges — more deeply textured than most oaks
• Wide, spreading crown in open savanna form; gnarly, twisted branching pattern on old trees

English Holly

Ilex aquifolium has invaded the understory of second-growth forests throughout western Washington, particularly in King, Pierce, and Snohomish counties in the Puget lowlands. It produces abundant bird-dispersed berries and tolerates deep shade, making it a serious threat to the regeneration of native Douglas fir and western hemlock understories. Washington's King County has listed it as a priority invasive species, and removal programs in Cougar Mountain Regional Wildland Park and Tiger Mountain have been ongoing for over a decade.

Black Locust

Robinia pseudoacacia has spread throughout eastern Washington's Columbia Plateau and lower Cascades foothills, colonizing roadsides, disturbed stream banks, and degraded Garry oak sites. Its aggressive nitrogen-fixing root system facilitates its own expansion by enriching soil in ways that favor it over native bunchgrass and oak understory vegetation. Washington Department of Ecology has identified it as a priority control species in the Columbia Basin.

Callery Pear

Pyrus calleryana has escaped ornamental plantings in western Washington's urban and suburban areas and is increasingly found naturalizing in forest edges, hedgerows, and disturbed lowlands in the Puget Sound basin. Its bird-dispersed small fruits and tolerance of a wide range of soils make it a rapidly emerging invasive in the Pacific Northwest. Washington State University Extension has identified it as a species of emerging concern requiring early detection and rapid response.

What makes Washington's Olympic Peninsula forests unique?

The Olympic Peninsula's temperate rainforests are the only true temperate rainforests in the continental United States, receiving 140–170 inches of rainfall annually on the windward slopes. This extraordinary moisture supports the highest biomass per acre of any forest ecosystem on Earth, with individual trees exceeding 10–15 feet in diameter and 200+ feet in height. The Hoh, Quinault, and Queets valleys are the primary rainforest valleys, accessible via Olympic National Park, and feature Sitka spruce, western red cedar, western hemlock, and bigleaf maple draped in thick mosses and ferns.

What is Washington State's state tree and where does it grow?

Washington's state tree is the western hemlock (Tsuga heterophylla), adopted in 1947. It grows throughout western Washington's Coast Range and Cascades from sea level to about 5,000 feet, and is also found in moist valleys east of the Cascades. The drooping, nodding treetop is the most reliable field identification feature visible from a distance, and its small abundant cones and feathery needles of two different sizes make it identifiable up close. It is the most abundant tree in many of Washington's undisturbed old-growth forests.

What trees grow in eastern Washington's dry climate?

Eastern Washington east of the Cascades has a semi-arid climate that supports ponderosa pine in the montane zone, grand fir and western larch in the wetter highland areas, and western juniper and sagebrush at lower elevations. The Columbia Plateau's shrub-steppe has scattered black cottonwood along rivers, and quaking aspen in the Okanogan Highlands and Blue Mountains. The transition from the wet west-side forests to eastern Washington's dry forests is visible driving over Stevens, Snoqualmie, or Loup Loup passes — one of the most dramatic ecological transitions in the Pacific Northwest.