Lecture Midterm Flashcards
Describe as many indications of a healthy forest as you can
- Soil erosion minimal & stream banks should be stable
- Diverse & appropriate aquatic & wildlife species
- Clean water should flow from streams except for extraordinary run-off conditions
- Vigorous & healthy appearance of trees & understory plants
- Growth & mortality consistent with ecosystem type & age of dominant trees
- Vegetation diversity should be balanced between supply & demand of light, water + nutrients & growing space
- Species age class distribution & stand densities should be within historical ranges for the site
- Forests should be capable of tolerating & recovering from disturbances such as fire & wind
- Should be free of non-native insects & vegetation
- Insects, disease & fire frequencies should be within the normal range of the ecosystem
What are the 12 noted negative impacts of diseases & pests in forests & provide an example of each
- Tree mortality - defoliators, bark beetles, root disease
- Destruction of solid wood - wood boring insects, decay
- Growth reductions - decreased height and/or diamter growth = volume loss
- Delayed regeneration - Lost time and increased costs of establishing a new crop
- Stocking deficiencies - limits intensive stand treatment options, loss of growing space
- Longer rotations - years added to reach a given size
- Degeneration of species composition - mountain pine beetle disrupts harvesting of species profile
- Loss of tree species - spruce weevil, white pine blister rust
- Reduced tree or wood quality - deformity or decay @ entry wounds - terminal weevils, spruce budworm, stem decay, blue stain
- Disruption of harvest scheduling and planning
- Site degeneration - chronic growth loss, wildlife habitat loss aesthetics etc. - spruce weevil, mountain pine beetle
- Limits silviculture system planning
In brief, what are the main responsibilities of the Canadian Forest Service and the MFLNRO?
CFS:
research into: insect and disease mgmt
biological controls
biodiversity
biotechnology
genetic improvements
MFLNRO:
routine cruising/silviculture surveys
aerial surveys of outbreaks
ground surveys
What are the general characteristics of fungi?
Heterotrophic
- Lack chlorophyll
Cell walls of chitin
Hyphae, mycelium
Have sexual or asexual spores or both
Parasites or saprophytes (or both)
Secrete enzymes and acids, digest outside the hypha then absorb them
What are the distinguising characteristics of insects?
Body composed of 3 main divisions (head, thorax, abdomen)
Jointed legs
Antennae present
Wings USUALLY present
5 adaptive features of insects
- Flight - Disperse to colonize new habitat/leave unfavourable ones, escape predators
- High reproductive potential - Keeps numbers high, evolve quickly
- Small in size - tough to see, able to colonize small habitat
- Physiology - specialized structures (mouth, antennae, wings, hard skeleton)
- Exoskeleton - armouring, casing/attachments, low mas/weight, prevents moisture loss
Describe the 2 types of insect life cycles
Complete metamorphasis - egg (resting stage), larvae (feeding stage), pupae (transformation), adult (sexual stage)
Incomplete metamorphasis - egg, various instars (stage in process where insect is immature), sexual adult
Note: Bark beetles go through 4 instar larval stages
Give an example of each of these insect orders:
Lepidoptera
Coleoptera
Diptera
Hemiptera
Homoptera
Orthoptera
Hymenoptera
Lepidoptera - Butterflies, moths
Coleoptera - Beetles, weevils
Diptera - Flies, mosquitos, tabanids, midges
Hemiptera - True bugs (Stink bug)
Homoptera - Aphids, scale insects, cicadas
Orthoptera - Locust, preying mantis, cricket
Hymenoptera - Bees, wasps, ants
Identify the type of life cycle associated with each order insect order
Lepidoptera - Complete
Coleoptera - Complete
Diptera - Complete
Hemiptera - Incomplete
Homoptera - Incomplete —>although it more closely resembles complete
Orthoptera - Incomplete
Hymenoptera - Complete
What is the Phyllum and Class that insects belong to?
Phyllum - Arthropoda —> “jointed legs”
Class - Hexapoda —> “6 legs”
Define abiotic injury
Damage caused by non-living or chemical factors in the environment
Examples of things which might cause nutrient deficiencies in trees
- soil volume
- texture, permeability of soil
- soil alkalinity
one possible symptom of nutrient deficiency
chlorotic needles (lack of chlorophyll)
Examples of conditions that indicate symptoms of trees suffering from temperature extremes
- Birch dieback(water stress-higher temps, less moisture, increased dessication)
- Cedar Flagging(sunscald)
- Frost cracks/frost heaving
- Shoot/bud frost kill
Examples of conditions that indicate symptoms of trees suffering from water extremes
- pole blight
- red belt (warm, dry winds in day, cold air drainage at night mean no water from frozen soils, needles dried out from wind and cant draw out water)
- winterkill : trees killed above where snowline was
3 part definition of decline disease
- A slow, progressive deterioration in health and vigor
- Primarily affects a mature cohort of trees(group, similar age/ht/species) because they require the most nutrients and water
- Symptoms: initial symptoms are general, non specific, and non-diagnostic
3 causal factors of decline diseases
- Pre disposing factors: Long term(ie: climate, site, age, genetics)
example: drought-prone - Inciting factors : Short term
Example: drought conditions - Contributing factors: opportunistic fungi and insects like bark beetle. Finish off tree, but normally wouldn’t do so unless tree was declining
Example: leptographium fungus on pole blight, Armillaria, Birch Die Back
Decribe a decline disease on a specific tree species, briefly detail causal agents associated with tree’s evolution from healthy stem to mortality
Birch Die Back
Predisposing Factor: age and size class, problems most severe on drought-prone sites
Inciting factors: drought conditions
Contributing factors: birch die back combined with bronze birch borer(executioner) lead to stem death
Factors that produce windthrow risk
Biophysical hazard + Treatment Risk = Windthrow Risk
Biophysical hazard: topo exposure, soil characteristics, stand characteristics
Treatment Risk: assessment of the wind loading on remaining edge trees in larger openings, or assessment of wind loading in retention harvesting areas
Catastrophic winds
- infrequent
- unpredicatable
- local knowledge and historical perspective helpful with management
- tough to manage-volumes are significant
- salvaging these losses are important because: recovering economic losses, hard to clean up-need to allow for stand regen, fire, insects
Endemic Winds
- peak winds expected to reoccur annually
- somewhat more predictable than catastrophic winds (possible to assess risk)
- management activities can reduce risk to a degree
- aerial wind throw patterns need to be assessed at both the stand and landscape levels (look at bigger picture)
Characteristics of high hazard soils
- high coarse fragments
- shallow: watertable, root restricting layer, species rooting depth
- poor drainage
- finer textured soils
Characteristics of high hazard stands
- windfirmness of species (want it to be high) ex-Py, Fd, Lw, Cw, Pl
- uniform structure
- good height/dbh ratio (high ratio more susceptible)
- root disease/stem decay
Relative windfirmness of 13 tree species
HIGH: Py, Fd, Lw, Cw, Pl
MED: Bg, At, Ac, Ep
LOW: Sx, Bl
Treatment risk for group selection, patch cuts, clearcuts
high risk occurs when:
- downwind edge is perpendicular to damaging winds, equals susceptibility
- open funneling
- opening is greater than 5 tree lengths in windward direction
- cut block edges project into an opening-more abrupt the angle, greater the risk
Treatment risk for uniform retention cuts
- Greater than 50% stem removal(trees used to being protected)
- vets and healthy dominants (high grading)
- when the least windfirm species are left
Resistance to mechanical injury for species:
Lw, Cw, Bg, Pw, Fd, Cw, Bl, Sx, Pl, Hw
- VH: Lw, Py
- H: Fd
- M: Pw
- L: Bg, Bl, Sx, Pl, Hw
- VL: Cw
4 Mechanical injury wound factors
- Relation of stand entry to occurrence of decay( Greater the number of stand entries, high the probability of wound creation)
- Relation of wound height to percent stem removal (Fewer trees harvested result in more damage due to more obstacles and difficulty of using designated skid trails)
- RElation of wound height to occurrence of decay (frequency of infection decreases from ground up)
- Relation of wound size to occurrence of decay (Small scars less likely to result in decay)
Decay fungi and advanced regen
- Only when injured, younger trees generally susceptible to decay fungi (except for Cw with sweep in lower stem assoc with p.weirii)
- Advanced regen is more suspect and should be checked for decay
- Destructive sampling encouraged
10 Guidelines for reducing wounds in partial cuts
- Retention criteria should emphasize good form and vigour
- Target species with good resistance to mechanical injury
- Account for landing and processing needs with targeting residuals
- Restric operating season. Avoid spring and early summer if possible (flowing sap, loose bark)
- match the size and type of equipment to:
topography, piece size, residual spacing - Plan for “rub trees” when skidding
- Orient trails and skid directions to minimize sharp turns
- Adapt falling techniques to the stand in question
- Make objectives and priorities clear to operators
- Be prepared to make adaptations to harvest methods if things arent going according to plan
Explain why its important to avoid damage to residuals in partial cuts
- Scarring creates potential for decay entry in retained species
- Time is decay’s greatest ally so the younger the tree when it’s injured, the greater the potential for decay to reduce stem value
Describe nematodes
- worm-like, unsegmented animals
- live on soil, feed on roots
- Pinewood nematode-trees wilt and die
Describe viruses
- Can live only in other organisms
- disrupt cell functions
- Alter DNA
- symptom: yellowing, light green, or clear patches on leaves
- Also used to control defoliators
Describe bacteria
- simple one-celled organisms
- with respect to trees, only a few disease causing agents known
- Eg: fire blight on apple/pear trees or Defoliator controls (BTK)
6 factors used to ID animal damage:
- Geographic Area: many animals cause notable damage to trees within certain areas of the province but are not even present in others. (EG: hares only cause prolific damage in North and central interior of BC, but are all over BC)
- Season: Some animals only cause significant damage at certain times of year (porcupines in the winter)
- Tree Species attacked: many animals selective in type of tree, but not exclusionary. (EG: deer, elk and moose love Cw, but browsing can extend to all species)
- Age of tree this is damaged: Some animals only cause damge to trees of certain ages (EG: bears dont damage young seedlings)
- Animal signs and symptoms: droppings, tracks, trails, sheds, holes, quills, hair
- Type of Damage: Most reliable indicator
Types of damage by animal: deer/elk/moose
DEER, ELK,MOOSE:
Seedling and sapling browse
- Sapling, pole-sized andmature tree rubbing
bear damage
usually only attacks pole size or larger
all conifers susceptible (Fd,Lw preferred in interior)
Large sections of bark stripped from trees
Significant damage usually restricted to important habitat areas
Number of trees attacked is low compared to other animals but consequences are high
Porcupine damage
attacks all species and ages of conifers, but prefers saplings and larger
damage almost entirely restricted to winter (feed on inner bark)
bark is gnawed from trees rather than stripped
can see evidence of both vertical and diagonal tooth marks
cause scattered mortality over fairly extensive areas (treees die from lower stem being girdled)
if mortality doesnt occur, top kill and deformity still can
Vole damage
seedling damage most common
fuzzy patches of gnawed bark around base of tree
damage often extends below ground
runway holes are key ID feature
damage includes: mortality or reduced growth in young seedlings, scattered mortality in older seedlings if fully girdled, damage can be siginificant at height of 3-4 year population cycle
squirrel damage
attacks concentrated in central and southern interior
Pl most susceptible of conifers
sapling to pole size preferred
damage: cutting/pweeling of terminal shoots, removeal or hollowing out of buds
damage id’d by gnawed surfaces rel. smooth with indistinct toothmarks
reduced tree growth
hare damage
snowshoe hare and cottontail rabbit
damage only in north and central interior
pl preferred of conifers, Pl not covered by snow in winter hit the hardest
only trees less than 6cm dbh susceptible(distinguishes from squirrel damage)
shear, knife like cuts
bark gnawed in ragged patches around base of tree
Damage: small seedlings die from root collar feeding, larger seedlings suffer growth stunting and deformity, damage extent mimics the 9-11 year population life cycle
Main responsibilities of Canadian forest service and MFLNRO
CFS:
- insect collections
- research into: insects/disease management, biological controls, biodiversity, biotechnology, genetic improvement
MFLNRO
- cruising/silvicultural surveys
- aerial surveys of outbreaks
- ground surveys
