TS Forest Pathology

Forest pathology

Study of diseases in woody plants

CODIT

Compartmentalization of decay in trees

Reaction zone

Boundary that forms around the wound to resist the spread of infection at the time of the wound

Barrier zone

Very strong boundary zone that grows around the outside of the reaction zone

New wood

Normal wood outside reaction zone

Wall 1

Above and below, vertical vascular system, weakest wall

Wall 2

On the inside of the wound, last cells in each growth ring

Wall 3

Sides of the wound, discontinuous

Wall 4

On the outside, separates tissue at the time of wounding from the tissue that forms after, strongest wall

Allelopathy

Ability to produce biochemicals that affect the health of other organisms

Hydrojuglone

Non toxic but when exposed to air becomes juglone which is toxic

Tannins

Deactivate enzymes and cause cells to die

Alkaloids

Usually species specific, only few trees like coffee tree and coca plant

Thorns

Modified short branches (honey locust)

Spines

Modified leaves or parts of leaves (holly)

Prickles

Woody epidermal outgrowths (rose)

Hair

Long or short epidermal growths (red raspberry)

Hormonal disruptors

Mimic hormones and cause abnormal plant development (phytoestrogens)

Ascomycetes

Largest class of fungi, Asci is spore production organ, 8 spores called Ascospores, Asci grouped together are Ascocarps

Basidiomycetes

Tree disease pathogens and all wood destroying fungi, spores produced by Basidium, produces 4 external stalks called Sterigmata, each produces a Basidiospore

SO2 visible signs

From combustion of fossil fuels, yellowing of older needles, discolouration and defoliation on angiosperms

Fluoride visible signs

From metal mining/smelting, causes tip burn on current year’s growth and eventually death of needles

Ozone visible signs

Comes from cars, causes green/yellow mottling on needles, reddish brown flecks on leaves