Overview

Douglas Fir is one of the most important timber trees in western North America and a dominant species in Colorado's montane forests. Despite its name, it's not a true fir (Abies). Its distinctive cones with protruding three-pointed bracts give rise to an old legend about mice hiding in the cones, with their tails and hind legs sticking out.

Identification

  • Soft, flat needles with sweet fragrance when crushed
  • Distinctive cones with three-pointed bracts ("mouse tails")
  • Needles arranged spirally, 3/4 to 1-1/4 inches long
  • Thick, deeply furrowed, corky bark on mature trees
  • Pyramidal shape when young, irregular with age
  • Grows 40-80 feet tall in landscapes, much taller in forests

Growing Conditions

  • Long-lived, can exceed 500 years
  • Moderate to fast growth rate
  • Prefers well-drained soil
  • Full sun; tolerates partial shade when young
  • Cold hardy (zones 4-6)
  • Drought tolerant once established
  • Needs afternoon shade in lower elevations
  • Deep-rooted and wind-firm

Common Pests & Diseases

Douglas Fir Beetle

Attacks stressed, downed, or recently dead trees

Western Spruce Budworm

Defoliates trees during periodic outbreaks

Cooley Spruce Gall Adelgid

Alternates between spruce (galls) and Douglas-fir

Rhabdocline Needle Cast

Causes needle yellowing and drop

Douglas Fir Tussock Moth

Causes defoliation during periodic outbreaks

Care & Maintenance

Water deeply during establishment and drought periods. Provide afternoon shade in lower elevations to reduce stress. Monitor for signs of stress and beetle activity, especially after storms that down trees nearby. Maintain good air circulation around the tree. Avoid wounding the trunk. Douglas fir is relatively low-maintenance once established in appropriate sites.

Why Choose Earth-Wise?

Our ISA Certified Arborists have extensive experience caring for douglas firs throughout Colorado's mountain communities. We understand the unique challenges these trees face and provide expert care including disease diagnosis, pest management, proper pruning, and health consultations. Whether you need help with an established tree or guidance on planting new ones, our team can help.