Root disease

Question 1

Which layer is thicker, mor or mull?

Answer 1

Mor, because it is slower to decompose

Question 2

Where would you expect to find mors? mulls?

Answer 2

Mors - conifer overstory

Mull - deciduous overstory

Question 3

Why do needles break down slower than leaves?

Answer 3

Needles typically have a longer “shelf life” and are infused with defenses which slow the rate of decomposition.

Question 4

What are the overall attributes of mineral soil?

Answer 4

• Cooler
• Less OM
• Less microbial activity

Question 5

What are some variables that effect mineral soil?

Answer 5

Texture

• fine vs coarse
• fine = more water and low temperature
• coarse = less water

Question 6

What is Mycostasis

Answer 6

Inhibition of fungal growth.

Question 7

What are the 3 causes of mycostasis?

Answer 7

Antagonism - fungal warfare between species inhibits both
Competition - for water nutrients and energy
Harsh environment - Temperature and moisture conditions can arrest fungal development

Question 8

Where is mycostatis the most prominent?

Answer 8

in the LFH, because that is where most fungus are and the least resilient layer to environmental changes.

Question 9

What is the tea break fungus?

Answer 9

Heat from repeated fires sterilizes soil, except for a fungus known as the tea break fungus which can establish the sterilized soils and survive hot conditions. Kills surrounding trees.

Question 10

What are the 4 groups of root Fungi?

Answer 10

SOIL INHABITING (asco)
 -not host specific
 - lie dormant as spores awaiting young roots
 - primarily a nursery problem
MYCORRHIZAE (zygo, asco, basidio)
 - symbiotic
WILTS (asco)
 -typically very host specific
 -live in sapwood
 -transpiration issues kill tree
 -black stain + dutch elm
ROOT INHABITING DECAYS
 -host specific
 -similar to heartrot/ wood decays
 -cannot travel freely in soil (mycostasis)
 -Facultative saprophyte (Mainly a parasite)

Question 11

What is a facultative saprophyte?

Answer 11

Organism is primarily a parasite but can survive on dead wood

Question 12

How do root rots spread?

Answer 12

Root grafting

Question 13

List the root structure

Answer 13

Bark
 -outer bark
 -periderm
 -inner bark 
Cambium
Wood
 -sapwood
 -heartwood

Question 14

How to Roots decays initially infect hosts?

Answer 14

• Spores
• Vegetative (root contact)
• Moves quickly down outer bark and more slowly inside due to defenses.

Question 15

Why do rood inhabitors stay below LFH?

Answer 15

Mycostasis in LFH arrests upward rot development.

Question 16

What are some name examples of root inhabiotors

Answer 16

Annosus, Tomentosus, Phelinus (laminated root rot).

Question 17

What are the typical symptoms of root disease?

Answer 17

• Decreased growth (shortened leaders/stalled growth)
• Thinning/Chlorotic crown (Yellowing)
• Stress cone crop (High number of small cones typically on young tree)
• Windthrow/Break ( Throw Typical with phellinus. Natural broken hollow stump. Break typical with armillaria)
• Centres ( creates pockets/patches in stand due to mortality )
• Tree sweep on flat ground (compromised root structure)

Question 18

What does the term chimney refer to?

Answer 18

Hollow stump left behind after windbreak associated with armillaria.

Question 19

What is the code for Armillaria? What about Phellinus?

Answer 19

DRA
Disease Rot Armillaria

DRL
Disease rot laminated

Question 20

What is a term for fungi that can survive and travel in soil?

Answer 20

Rhizomorph

Question 21

What is DRL? Which species are at risk?

Answer 21

Phellinus weirii
P. sulphurescens
(Laminated root rot)

-Infects Fd (sulphurescens) and Cw (weirii).

Question 22

What is type of rot is the cedar form of DRL?

Answer 22

A butt rot

Question 23

What sections are the soil expressed in?

Answer 23

OM 
Litter
Fermentation
Humus - colloidal organic matter
A horizon 
B horizon
C horizon

Question 24

Define quiescent

Answer 24

In a state or period of inactivity/dormancy