Diagnosis table — Douglas-fir, oak and pine

Note: These tables list commonly encountered signs and symptoms and likely causes, but not every possible symptom or potential cause is noted. 

Douglas-fir diagnosis table

Description Possible causes (not exhaustive)
  • Tree foliage is sparse, thinning
  • Tree foliage is turning light green, yellow, orange or red
  • Whole tree appears to be dying
  • Top of tree is dying or dead
  • Branches are dying
  • Scattered branches are turning red
  • Woodpeckers are feeding on trunk; tree is losing bark
  • Foliage is thinning
  • Interior needles are being shed, cast
  • Branch tips are still green
  • Needle casts

Oak diagnosis table

Description Possible causes (not exhaustive)
  • Leaves are undersized, discolored or prematurely dropping
  • Canopy foliage appears thin, unhealthy
  • Leaves have irregular spots or splotches
  • Leaves may be curled and deformed
  • Premature (mid- to late summer, before fall) leaf drop
  • Some branches have died back
  • Leaves are partially or completely eaten
  • Leaves are being eaten or skeletonized
  • Larvae are visible on leaves
  • Larvae may hang from trees on thin, white “thread”

Pine diagnosis table

Description Possible causes (not exhaustive)
  • Top of tree is dead or dying
  • Foliage is thinning
  • Interior needles are being shed, cast
  • Branch tips are still green

Needle casts/diseases

  • Whole tree is dead or dying
  • Tree foliage is turning or has turned from green to greenish yellow
  • Woodpeckers are feeding on trunk; bark is falling off
  • Pitch tubes are visible on trunk
  • Some branch tips are dead

 

Was this page helpful?

Related Content from OSU Extension

Ask an Expert

Have a question? Ask an Expert!

Ask an Expert is a way for you to get answers from the Oregon State University Extension Service. We have experts in family and health, community development, food and agriculture, coastal issues, forestry, programs for young people, and gardening.

Ask us a question