Callus: the tissue that develops around a wound.
Conk: the spore-producing structure of some wood decay fungi; forms on the external surface of the host (see fruiting body).
Decay: the disintegration of plant tissue. The process by which sound wood is decomposed by the action of wood-destroying fungi and other micro-organisms.
Fruiting body: in higher fungi, the reproductive structure that bears the spores (see conk).
Fungi: a group of lower organisms that lacks chlorophyll and cannot produce its own food; therefore must depend on a host to produce its food.
Gouge: penetration into the sapwood of the tree or deeper.
Hazard: the degree to which the characteristics of a tree or stand make it vulnerable to damage. It is equivalent to susceptibility.
Heart rot: decay in the heartwood (centre) of the tree.
Incidence: the proportion of damaged or affected trees within a stand or area.
Inoculum: the amount of woody material infected with, or potentially able to be infected with, a decay fungus.
Injury: damage of a tree by a physical or chemical agent.
Mycelium: the vegetative portion of a fungus that penetrates the wood, grows on the bark and through the soil to spread the disease.
Pathogen: any agent, whether a living organism or non-living agent, that induces disease.
Risk: the probability and expected severity of damage determined by host susceptibility and suitable environmental conditions (both combined equate to hazard) plus pathogen proximity, abundance and virulence.
Saprophyte: an organism that commonly feeds on dead organic material (usually by decomposing and absorbing it, assisting in its decay) but that may in exceptional circumstances attack living hosts (e.g., those weakened by primary pathogens or stress).
Scar: a mark left after regrowth of damaged tissue following an injury.
Signs: visible portion of a decay, or its products, seen on or in the host plant.
Stain: discoloration in the wood, usually caused by wood decay fungi (incipient or early stage of decay where the wood has not yet started to break down).
Stand dynamics: the study of changes in forest stand structure over time, including stand behavior during and after disturbance.
Symptoms: visible reaction of the host plant to infection, disease or other pest attack.
Wound: an injury that removes a portion of the bark and cambium from the tree but does not penetrate into the sapwood. Wounds may serve as entry points for wood decay fungi.
Walkthrough: initial reconnaissance of an area, to make a preliminary assessment of site conditions and suitability for further surveys or activities.