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