Science · Specimen Trees
Western Red Cedar
A large Pacific Northwest arborvitae, not a true Cedrus, with flattened sprays and fibrous bark. It favors moist soil and can suffer serious canopy decline during repeated hot dry summers.
Thuja plicata · Large evergreen conifer
Profile
- Foliage
- Flattened aromatic sprays with small elongated cones.
- Roots
- Broad shallow roots need protection from compaction and heat.
- Planting
- Set the root flare at grade and protect the expanding root zone from compaction.
- Assessment
- Confirm identity, local climate suitability and drainage before prescribing care.
Water & soil targets
- Moisture (VWC)
- Site-calibrated; varies by soil and rootstock
- Salinity tolerance
- Avoid saline irrigation and deicing runoff.
- Drought tolerance
- Low to moderate; prolonged summer drought is damaging.
Optimal root measurement depth
8–18 in
Most absorbing tree roots live in the upper 12–18 inches, out toward the drip line. Typical guidance; confirm with a soil probe on site.
Water deeply during establishment and extended summer drought, checking beyond the original root ball; maintain mulch and drainage without burying the trunk.
Problems to watch
- Cedar leaf blight
- Cypress bark beetles on weakened trees
- Root disease
Stress signs
- Persistent branch browning
- Crown thinning
- Top dieback
Where you'll find it
- Large evergreen screens
- Forest restoration and timber
More specimen trees
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All Science profilesGeneral agronomic guidance and typical ranges; actual targets vary by site, soil, climate and season.