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Tree Decay Fungi
Chelsi Abbott, MSc
The Davey Tree Expert Company
Overview
• Dangers in Tree Care Industry
• What are fungi?
• Why wood decay fungi are important
• Different groups
• Specific types of decay & wood decay fungi
Why the Concern?
153 tree care related incidents in 2016 (TCIA)
Tree Failure can Harm:
• People
• Utility Lines
• Buildings
• Vehicles
Fungi
• Eukaryotic
• Non-photosynthetic
• Decompose and absorb organic
matter
• Mushrooms, mold, mildews,
rusts etc.
• Beneficial fungi
• Damaging fungi
✓Crucial to the life cycle of the
forest
Fungi
Three components of Disease
1. Host
2. Pathogen
3. Environmental
conditions
Disease Triangle
HostPathogen
Environment
Disease
Wood Decay Fungi
Two main groups:
• Basidiomycetes:
• Most common group of fungi for wood decay.
• They have mushrooms/conks as fruiting bodies
• Ascomycetes:
• Second most common group of fungi, with only a
few wood rotter's.
• Small, irregular fruiting bodies
Signs vs. Symptoms
A sign is physical
evidence of a causal
agent
• Mushroom
• Spores
A symptom is the plants
reaction/expression to the
infection
• Chlorosis
• Leaf spot
• Death of tissue
Tree Decay Fungi:
• Mushroom and conks are obvious sign
• Some trees do not show above ground
symptoms
• Significantly affect the health and structural
integrity of the tree
• Create hazardous trees- our goal is to protect
people and property
Just because you don’t see…
…doesn’t mean it’s not there!
Things to look for:
• Fungal fruiting bodies:
• Conks, mushrooms, etc.
• Canopy decline - if canopy is
declining it could be a
problem from below
• Remember! A full canopy does
not mean structurally sound!
Symptoms associated with wood
rots
• Crown dieback
• Leaf chlorosis and necrosis
• Wood rot
• Bark peeling away
• Discolouration of bark
• Eventual death
3 Types of Wood Decay
White rot
• Most common decay fungi - hardwoods
• Leave behind white residue
Brown rot
• More frequently found on conifers
• Leave behind brown residue
Soft rot
• Not visibly different than brown or white rot in
living trees
Types of Wood Decay
White rot:
• Leaves a white or bleached
appearance to wood
• Wood feels moist, soft and
spongy
• Degrade lignin (constituent of
cell walls) & erode cellulose
• Significant strength loss only in
more advanced stages of decay
• Example: Armillaria spp.
Types of Wood Decay
Brown Rot:
• More frequently found in
conifers than hardwoods
• Brown, brittle lignin
• Decays cellulose and
hemicellulose
• Significant amount of strength
loss in initial stages of decay
• Example: Chicken of the
Woods
Types of Wood Decay
Soft Rot:
• Attacks cellulose
• Attacks links between cell
walls and lignin
• Loss in wood structural
quality
• Example: Kretzschmaria
deusta
How Do Wood Rots Gain Entry?
• Stressed trees
• Construction
damage
• Soil compaction
• Mechanical
damage
• Insect/animal
damage
Important Wood Decay Fungi
• Armillaria Spp.
• Ganoderma Spp.- Artist’s conk & Varnish conk
• Laetiporus sulphureus - Chicken of the woods
• Inonotus dryadeus
• Xylaria polymorpha - Dead Man’s Fingers
• Kretzschmaria deusta
Armillaria Root Rot
Hosts: Many deciduous trees and conifers
• Also called: Shoe-string rot and Honey
mushrooms
• Multiple species
• Infects stressed trees through wounds
• Can infect roots via rhizomorphs
• Aggressive
3 Signs of Armillaria
www.gallowaywildfoods.com
Not to be confused with…
Jack o’ lantern
Velvet shank
Ganoderma applanatum
Hosts: Most hardwoods, Maples, Oaks, etc.
• Also known as “Artist’s conk”
• Perennial conk
• Infect via wounds
• Decay can extend 1-2ft
above and below conk
• White rot
• Aggressive
Ganoderma applanatum
Ganoderma applanatum- Artist’s
Conk
G. Jones
Ganoderma lucidum
Hosts: Most hardwoods, honey locust, Maples,
oaks…
• Also known as ‘Varnish Conk’
• Annual conk
• Kills cambial tissue of roots
• White rot
• Moderately aggressive
Ganoderma lucidum
Chicken of the Woods
(Laetiporus sulphureus)
Hosts: Most hardwoods, oaks,
black cherry, etc.
• Choice edible
• Fruiting body emerges from
summer to fall
• Brown rot
• Causes extensive decay
Chicken of the woods
Hen of the woods
• Hosts: Hardwoods,
predominately oaks
• Choice edible
• Fruiting body
emerges from
September to
October
• White rot
• Weak pathogen
Theforagerpress.com
Inonotus dryadeus
Hosts: Hardwoods, Oaks, etc.
• Also known as ‘weeping conk’
• Annual but persistent
• Slow progressing white rot
• Excessive decay could mean
trees are at risk for windthrow
• Found at crown (close to ground) or
on roots
Inonotus dryadeus
Dead Man’s Fingers
(Xylaria polymorpha)
Hosts: Hardwoods including Maples and beech
• Black finger-like structures (stomata) appear in
spring
• White rot of base and roots
• Can kill cambium
• Only attack stressed trees
Dead Man’s Fingers
General Wood Rot Management
• No management
available once
infected
• Destroy fungal fruiting
bodies
• Avoid wounding the
tree
• General plant health
care
Things to take home
• Always ask if you’re not sure
• Presence of a conk is (usually) a bad sign
• Just because there isn’t a fruiting body,
doesn’t mean there isn’t decay