CURRENT ISSUE A: K2 '25 Flashcards

How is globalization contributing to the spread of invasives

Increased trade and transportation introduces invasives and can create corridors (e.g) highways, pipelines) for them to spread

Give 4 benefits of low-intensity fire

• clears thick understory vegetation, allowing light to reach the ground for new plants to grow and sequester carbon

• soil is enriched by ash, in which the seed bank can germinate

• tree roots are not damaged and continue holding soil in place

• reduces forest fuels and clears “vegetation ladders” to reduce chance of surface fires climbing up into the crown

give 5 detrimental effects of high-intensity fires

• hard for plants to regenerate due to destruction of seed bank in soil and/or too big of a burned area for seeds to reach open ground

• Lack of food for rodents due to stunted regrowth and scorching of seeds

• scorched soil is difficult for pines to grow in, so invasive species can take over

• Since tree roots scorched, ash and debris flows into streams, harming fish and frog habitat

• fragments habitat, as there is no cover in burned areas for species to hide

define native

species indigenous to Canada, with periodic outbreaks

define alien/exotic

a species recently introduced to Canada

define invasive

insects and diseases that spread beyond their usual range, whose numbers rise beyond an acceptable threshold

define pest

any insect/animal that destroys large tracts of commercially-viable forests or Canadian products for export

How is wildfire going to change in Alberta as climate change continues?

• forests get hotter and drier, making them more fire-prone, causing more severe and frequent wildfires

• greater occurance of short-interval reburns, which make it more difficult for trees to establish

• hotter, drier conditions unconducive to seedling germination

How will changes in wildfire affect Alberta’s forests?

• shift from old-growth Jack pine forests to forests dominated by early-successional aspen with lots of shrubby understory

• decreased carbon storage

Define drought

a shortage of precipitation for an extended period of time, usually a season or more, resulting in insufficient water avilability that adversely affects animals, vegetation, and people

List 3 impacts of increasing drought on Alberta’s forests

• failing regeneration

• stresses trees leading to stunted growth

• increased susceptibility to pests and diseases

What does CMI stand for and how is it calculated

Climate Moisture Index, = annual precipitation - expected amount of water evaporated

How will the prairie ecozone of Canada be affected by drought

the prairie will become drier and also expand north and eastward, replacing some boreal forest

Mountain pine beetle biology

• phloeophagous

• in late summer, female bores vertical galleries under bark and lays eggs. She carries in a sac spores of the blue stain fungus, which begins infecting tree and weakening it so it can’t stop beetles, then eventually blocking xylem and killing tree

• larvae overwinter inside tree, burrowing and eating phloem

• adults emerge in July-September, picking up fungal spores on the way out

Mountain pine beetle symptoms

• pitch tubes and sawdust

• woodpecker holes

• long vertical galleries made by adult and radiating branches by larvae

• 2-3 months after attack, foliage dries out and dulls

• the following spring after attack, foliage turns red

• blue staining working its way into the wood

Mountain pine beetle forest impacts

• in low populations, only attack stressed and weakened trees

• when lots of trees stressed, populations grow into outbreak and the beetle starts attacking healthy trees

• natural predators can’t control outbreak populations and lack of cold winters means winter doesn’t kill htem either

Mountain pine beetle invasivity

• native to BC lodgepole pines

• has begun acting invasively by expanding into Alberta’s Jack pine forests

Brown spruce longhorn beetle invasivity & host

native to europe, arrived in Nova Scotia in 1990s in wood packing material. Attacks red, white black, and norway spruce, but can also eat other conifers. Secondary pest in native range, but has been attacking healthy trees in NS

Brown spruce longhorn beetle biology & symptoms

• eggs laid singly in bark

• larvae bore into phloem, creating frass-filled galleries

• larvae overwinter in L-shaped pupal cells

• exit tree from small circular holes in spring, which an be seen with resin flowing down them

• adults can be found in 2 wk period from June-August

spruce budworm invasivity

native to southern canada up hugging rockies. Found to cycle, with outbreaks occuring every 30-40 years, lasting 8-10 years each.

spruce budworm biology

• eggs hatch at the end of august. New larvae don’t feed, but migrate to center of tree, spin silken hibernacula, and hibernate

• emerge in May. Eat new buds and current-year foliage from tip down, inwards

• in midsummer, larvae pupate and become moths

• moths do not feed. mate and lay eggs

Spruce budworm symptoms and damage

• defoliation of current year foliage in May. If outbreak levels, larvae may start to eat past year’s foliage

• in outbreaks, stands may turn rust-colored due to all the dead needles

• lots of silk

• often nonfatal first year, but can cause permanent damage or death after 5 years, especially in fir which is most susceptible

Forest tent caterpillar biology, symptoms

• in June, female deposits egg bands around twigs coated with sticky substance. The egg overwinters.

  • the egg bands can be easily seen and removed in the fall when leaves drop

• larvae emerge the following May and cause rapid defoliation, rarely fatal

• outbreaks controlled by the large flesh fly parasitoid

Emerald Ash Borer invasivity

• native to east Asia

• arrived in Michigan and Ontario in 2002

EAB biology & symptoms

• In mid summer, females lay eggs singly in bark crevices

• larvae hatch and tunnel into phloem, creating s-shaped galleries, girdling tree and killing 99% within 6 years

• beetles emerge through D-shaped holes and can be seen feeding on leaves

• visible tree decline: yellowing, sprouts

EAB control

• cannot move wood products out of infected areas

• harvest ash trees before an infestation to get some value out of the wood, then try to replace it with other species

ALB invasivity

native to China, arrived in US in 1996 and Ontario in 2003 (just after EAB), but has been successfully eradicated in Canada

ALB biology & symptoms

• In the summer, females chew grooves in bark and lay large eggs singly

• larvae tunnel first through phloem, then into heartwood, then pupate

• adults emerge from big holes, causing lots of sap drip and sawdust

What are the main three types of fungi that cause forest diseases

• deuteromycotina: reproduces asexually through conidia

• ascomycotina: reproduces both sexually or asexually via ascospores bundled into asci (sacs)

• basidiomycotina: reproduce mainly sexually via basidiospores on ends of basidia

Western gall rust biology

• native, basidiomycotina, affects lodgepole and Jack pine

• creates a popcorn-like gall encircling a branch, with white blisters under bark

• in Spring, releases orange spores that directly infect other pines

• gall dries out the tissue beneath it, killing bark and sometimes needles

• little harm to tree, especially mature trees. Can cause growth defects in seedlings

• spread in wave years when conditions are right

• control it by pruning gall before it bursts in the spring

Fir needle cast (Isthmiella faullii) biology and symptoms

• native, ascomycotina, affects firs

• 1st year: new shoots infected, no symptoms

• 2nd year: first fruiting bodies appear on top of needles

• 3rd year: ascospores form on the underside of leaves, look like black lines

• no way to control

Armillaria root root biology

• native, basidiomycota, affects all trees

• first, soil-dwelling fungi finds and extends into healthy roots

• spreads to root collar, then up into trunk

• kills tree by plugging xylem, or windthrow finishes the job

• establishes then radiates out from disease centers

Armillaria root rot symptoms

• Pine needles turn yellow then red, while spruces only turn green

• excessive sap flow

• chestnut brown mushroomy fruiting bodies at base of tree

• rotting inner wood first looks pale and wet, then spongy

Pine-aster rust aka needle rust of pine biology

native, basidiomycotina, affects Jack and lodgepole pine

1. pycnial stage: Needles infected in fall. The next spring, orange droplets form on needles

2. aecial stage: white columnar blisters form in summer, then rupture and infect alternate host: asters

3. uredial stage: in asters, produce spores and infect more asters

4. telial stage: develops on underside of asters

5. basidial stage: releases basidiospores which reinfect pines

rarely serious, mainly of aesthetic concern. Needles killed after growing season so not harmful