Glossary - Mountain Pine Beetle in Alberta

 
     
 
 
 Aerial survey - Identifying suspected MPB killed trees from a fixed-wing plane or helicopter. Beetle killed trees are identified by the discoloration of the needles within the first year of attack
Age distribution - The range of tree ages in a forest stand

Age-class distribution - The distribution of different age classes within the population being examined (Dictionary of Natural Resource Management)

Baiting - The use of synthetic pheromone baits to detect the presence of MPB in a new area or to monitor changes in the population. It can also be used to attract the beetles to a given forested area that will be controlled.

Biological diversity (biodiversity) - The variety and variability within and between living organisms from all sources such as terrestrial, marine and other aquatic ecosystems, and the ecological complexes they are part of

Blue stain fungus - One of several fungi that has a symbiotic relationship with the MPB. The spores of the fungus are carried from tree to tree in the beetle's mouth pouches. The fungus spreads through the conductive tissue of the tree causing the wood to turn blue

Cambium - The living layer of the tree between the sapwood and inner bark that produces the new phloem and xylem

Climate change - Changes in climate (such as temperature, precipitation, wind) that differ significantly from previous average conditions and are seen to endure, bringing about corresponding changes in ecosystems and socioeconomic activity

Colonization - The establishment of a species in an area that is not currently occupied by that species (Dictionary of Natural Resource Management)

Cut and burn - A treatment option that includes the cutting and burning of either a single tree or small patches of trees that are currently infested

Cut and peel - A treatment option that includes hand falling and peeling (removing) the bark off either a single tree or small patches of trees that are currently infested. This method exposes the beetles to the elements, and they die from exposure

Declining population - The last stage in an epidemic cycle where population levels decrease to their normal or endemic, levels. This stage is caused by lack of suitable hosts and/or harsh climatic conditions that increase beetle mortality

Endemic population - The normal population common to the area which is kept in check by natural factors. It is the first phase of a mountain pine beetle epidemic cycle

Epidemic population - A population of an organism that is well above the endemic level. It is a temporary large-scale outbreak. In the case of MPB, the population has the ability to infest almost all of the mature pine trees in the forest stand. Natural factors are no longer effective in beetle control

Fire hazard - The level of risk for ignition and/or spread of fire in a forest. A general term to describe the potential fire behaviour, without regard to the stand of weather-influenced fuel moisture content, and/or resistance to fireguard construction for a given fuel type

Fire suppression - All activities concerned with controlling and extinguishing a fire following its detection

Forest stand - A group of trees in a given area that have similar characteristics (e.g. age or species) and can be uniquely distinguished from adjoining areas

Gallery - A tunnel carved into the inner bark of the tree by the adult mountain pine beetle to lay eggs or by larvae for food

Girdling - A term used to describe the damage done to the phloem layer (inner bark) around a tree. Girdled trees will often die because the flow of nutrients and water is broken between the needles and the other parts of the tree, such as the roots

Ground survey - A survey that involves walking into a forest and making forest health observations of a given area. If suspected MPB- killed trees are identified from an aerial survey, someone trained in MPB identification will head out to a site to confirm the presence of the MPB

Growing season - The length of time in a year in which trees are actively photosynthesizing. The frost-free part of any one year. (Dictionary of Natural Resource Management)

Habitat - The area in which an organism usually lives

Hazard - The condition of stands (susceptibility) and the prevailing environmental conditions (such as climate) that are conducive to a mountain pine beetle attack. Does not include the probability that this will occur

Hectare - An area 100m long by 100m wide - just under the size of two football fields

Host - The plant or animal on which an insect feeds

Host susceptibility - The lack of ability of a host species to withstand MPB colonization. Factors that could affect susceptibility would be tree age, tree diameter, tree species and tree stress

Incipient - A population of an organism that is on the rise due to a lack of at least one limiting factor

Infestation - A large-scale temporary increase in numbers in a given location, where the insect and its damage are noticeable

Larva - An immature life stage of an insect. It emerges from an egg. It the case of the MPB, this stage causes the most damage to the tree

Limiting factors - Any factor (biotic or abiotic) that inhibits the growth of a species population

Mortality - The death rate in a population of organisms

Mountain pine beetle - A native bark beetle species that feeds on the inner bark of pine trees of western North America.

Natural controls - Methods of controlling organism populations without human intervention

Natural enemies - The parasites, parasitoids, predators and pathogens associated in nature with a specific wild population of plants or animals. (Dictionary of Natural Resource Management)

Outbreak - A large-scale temporary increase in population causing severe damage over a large geographic area.

Parasite - An organism that benefits from a relationship while negatively affecting its host

Pesticide - A substance used to kill a pest in an area. Examples include insecticides (for unwanted insects) and herbicides (for unwanted plants)

Pheromones - A chemical hormone released by an organism for communication in the same species; e.g pheromones released by female beetles attract other female and male beetles to the tree

Phloem - The food-conducting tissue of the tree that forms the main component of the inner bark

Pitch tubes - Small blobs of pitch secreted by the host tree in its efforts to trap and prevent the MPB from entering the stem

Prescribed fire - Fire that is intentionally set by qualified fire management personnel according to predetermined objectives and burning conditions for a certain purpose. Examples of prescribed fire objectives might include controlling forest insects and exposing rich mineral soil for growing plants. (Canadian Interagency Forest Fire Centre glossary.)

Pupa - The stage of transition between larva and adult in an insect's life. It is inactive during this time

Risk - The probability of a MPB attack in a stand. The factors that could increase risk may include high susceptibility, high hazard, high potential of beetle movement into the stand and high beetle population levels close to the stand

Salvage harvesting - The harvesting of the beetle- killed timber before the wood quality degrades to a level below merchantability. The purpose of the harvest is maximizing the timber profit of beetle-killed timber and to remove the dead timber to allow for reforestation

Sanitation harvesting - A treatment option that involves harvesting then processing trees at a mill to reduce the beetle population and prevent its spread to healthy stands

Severe weather - Extreme weather events that result in unusually harsh weather, such as colder than normal temperatures, heavy winds, blizzards, and tornadoes

Sign visible - evidence of the presence of a specific insect or pathogen. For example, the presence of larvae and adults and the larval and egg gallery characteristic can be used to identify mountain pine beetle

Species diversity - The variety of species and their distribution and abundance in a habitat

Succession - The orderly process of change over time in an ecosystem where an early pioneering community is replaced by another until a stable 'climax' community is reached

Symbiosis - A relationship between two organisms in which both organisms benefit

Symptom - The visible reaction of a host tree to an attack by the mountain pine beetle. Pitch tubes are a good example of a symptom

Xylem - The main water- and nutrient-conducting tissues of the tree; the main component of sapwood

  
 
 
 
For more information about the content of this document, contact Devon Belanger.
This information published to the web on March 1, 2016.
Last Reviewed/Revised on February 21, 2018.