Forest pathology

Forest pathology is the research of both biotic and abiotic maladies affecting the health of the a forest or tree, primarily fungal pathogens and their insect vectors. It is a subfield of forestry and plant pathology. Pathology is from Ancient Greek πάθος, pathos which may be translated into English as either "experience" or "suffering". and -λογία, -logia, "An account of" or "the study of".

Forest pathology is part of the broader approach of forest protection.

Abiotic factors

There a number of abiotic factors which affect the health of a forest such as moisture issues like drought, winter-drying, waterlogging or Precipitation such as hail, snow, storm.

Wind is also an important abiotic factor as Windthrow (the uprooting or breaking of trees due to high winds) causes an obvious and direct loss of stability to a forest or its trees.

Often, abiotic factors and biotic factors will affect a forest at the same time. For example, if wind speed is 80 km per hour then many trees which have root rot (caused by a pathogen) are likely to be thrown. Higher wind speeds are necessary to damage healthier trees (such as 125 km per hour).

Fire and related abiotic factors also affect the health of forest. Lightning. Nutrient imbalances: deficiencies, chemicals (toxic salts, herbicides, air pollutants). Temperature: low, high.

The effects of man often alter a forest's predisposition to damage from both abiotic and biotic effects. For example soil properties may be altered by heavy machinery.

Biotic factors

• Fungi: Ascomycota, Basidiomycota and fungi imperfecti
• Oomycota: Phytophthora.
• Bacteria.
• Phytoplasmas.
• Viruses.

Parasitic flowering plants

• Many plants can parasitize trees via root to root contact. Many of these parasitic plants originate in the tropical and subtropical climates.

Animals

Nematodes, insects especially bark beetles, mammals may browse. Browsing can be prevented with Tree shelters

Hazard trees

• The likelihood of property damage or personal injury due to tree failure. Hazard includes not only the tree's condition, but the potential target as well. Rating systems, procedures and guidelines have been developed for decision making but knowledge, judgement, and experience are an important part to the process.

Pathogens that affect trees

• Armillaria sp of which cause white rot root disease
• Ash dieback
• Cenangium
• Hymenoscyphus pseudoalbidus which causes as Ash Dieback
• Heterobasidion annosum which causes Annosum or red root rot
• Chestnut blight
• Rickettsia which causes possibly this citrus greening disease
• Spiroplasma
• Dutch elm disease
• Ink disease
• Emerald ash borer
• Olive tree pathology
• Witch's broom
• White Pine Blister Rust
• Phytophthora cinnamomi a root rot
• Polypore or Bracket fungus
• Sudden oak death
• Tinder conk

Signs and symptoms

Symptoms are a result of a pathogen:

• Blight
• Canker
• Chlorosis
• Drunken trees
• Forest dieback
• Gall
• Girdling
• Root rot
• Virescence
• Wilt disease

Signs are the visible presence of a part of a pathogen:

• Ascus is a part of an acomycota fungus.
• Conk_(fungi) is the fruiting body of a bracket fungus.
• Hypha are collectively called a mycelium
• Mycelial cord or rhizomorphs

Pathology detection

This can be done by dogs or machines smelling the trees. It is similar to noses used to find truffles. It can also be done by monitoring and identification can happen via tree clinics, experts such as arborists or even non-experts through citizen science.

See also

• Allelopathy
• Disease
• Etiology
• Disturbance (ecology)
• Forest IPM
• Inoculum
• Outline of forestry
• Pest (organism)
• Plant disease epidemiology
• Robert Hartig
• Forest Pathology (journal)
• Secondary forest

Further reading

• Tainter, Frank H., and Fred A. Baker . Principles of Forest Pathology. New York, NY: John Wiley & Sons, Inc., 1996.
• European Journal of Forest Pathology (Eur J Forest Pathol), Springer, ISSN 0300-1237 (printed), ISSN 1573-8469 (electronic), 1895–present, 5-Year Impact Factor: 2.054

External links

• Forest & Shade Tree Pathology
• Forest pathology team at INRA Nancy, France
• Hazard Trees