BIOL 3447- Exam Flashcards
(110 cards)
1
Q
what are the phases of silvicultural systems
A
- regeneration -> tending -> harvesting
- can be cyclical or as the interdependence of components
2
Q
types of management
A
- exploitation
- non declining even flow: continued access to resources
- balance structure: replenishment
- wise use: use in the present and continuous supply in the future
3
Q
exhaustible vs flow resources
A
exhaustible: resources of limited and finite amounts
flow: resources that are replenished to some degree
4
Q
single cohort system
A
- cohort establishment only at the beginning with replacement at rotation end
- single age class managed as one unit- homogenous stand conditions
- tending applied to promote development
- some harvest of immature trees to promote growth and generate revenue
5
Q
multi cohort system
A
- wide range of age classes- typically 3 cohorts at different stages of development
- tending and establishment of regeneration are concurrent
- return to stand at intervals to control structure and maintain cohorts
- periodic merchandising of logs to generate revenue
6
Q
describe the different levels of intensity of management
A
- wild: perfect alignment with ecological development, small amount of timber management if possible, may include protected areas or areas too remote for timber
- regulated: moderate alignment with ecological development, managed through ecological forestry, balance biological and commodity goals
- domesticated- managed through technological forestry, best conditions for growth, high levels of investment
7
Q
describe the factors affecting silvicultural decisions (5)
A
- accessibility (constructing roads)
- markets (is there a market to support the cost of growing timber)
- site quality (is the site of good enough quality to support growth)
- tree character and conditions (are the trees of good quality)
- ownership
8
Q
economic costs of silviculture
A
- access- can you get to and process the wood at a reasonable cost?
- interest- does anyone want the product and what price are they willing to pay?
- timing- how quickly can you get the product to market
9
Q
economic values of silviculture
A
- wood as a resource- easy to harvest, good insulating properties, strong and durable, can be harvested relatively endlessly
- stumpage- price on standing timber and the right to harvest it
- user fees- recreational opportunities, access to easement and conservation areas
10
Q
types of timber harvesting systems
A
- whole tree: removal of the entire tree (stem, branches, stump, roots) to the landing
- tree length: felling, topping, and delimbing trees in the forest, tree is bucked at the landing or mill
- cut-to-length: felling, topping, and delimbing the tree in the forest, tree is bucked in the forest
11
Q
describe some of the effects of silviculture on the ecosystem
A
- skid trails: temporary roads/trails used by logging equipment to remove logs
- machinery equipment may leave ruts or disturb soil
- increase in overland flow and mobility of debris and foreign chemicals
- removal of vegetation decreases shade and increases water temp
12
Q
best management practice
A
- optimal operating methods for preventing or reducing water pollution and protecting wetlands
- includes planning of transportation, appropriate retirement, planting landings, limiting how many roads can be in use at one time
13
Q
US clean water act (crown sustainability act)
A
- BMPs can be applied to landings, skid trails, truck roads, stream and wetland crossings, harvests by water
- includes installing water barres and culverts, leaving buffer strips, planning, seeding with stabilizing plants, controlling the season, controlling slash, periodic maintenance, retirement
14
Q
airborne laser scanning data
A
- digital surface model: elevation model that captures the environment’s natural and artificial features
- digital elevation model: representation of the bare ground (exclude surface objects)
- canopy height model: maps tree height as a continuous surface, DSM-DEM
15
Q
how can LiDAR be used to facilitate planning
A
- allows you to plan where best to do things:
- shut down skidding in saturated areas
- place landings on soft gradients
- prohibit machinery from stream side buffers
- make sure roads and trails are kept in good condition
- predict costs based on current surfaces
- detect ephemeral streams (important habitat features)
16
Q
how can water systems be protected
A
- riparian zone (interface between land and water) protection (maintain litter, reduce sedimentation, maintain shade)
- buffer strip: strips of vegetation that provide a physical barrier to slow the flow of water and reduce runoff
- filter strip: a narrow strip of vegetation that acts as a barrier to pollutants into the waterways
17
Q
describe the timeline of planning and implementing a harvest
A
- schedule operations to avoid critical times
- use machine operation strategies that minimize litter disturbance
- design trails/roads to keep the surface dry
- maintain landings to prevent erosion
- match equipment and practices to the needs and conditions
18
Q
fire triangle
A
- oxygen: fire is an oxidation reaction
- fuel: any combustible material, affected by moisture content and piece size
- heat: fire occurs when fuels are heated up beyond their ignition temperature, water is an effective fire suppressant because of its high heat capacity
19
Q
describe the different types of fires
A
- ground fire: burn below the surface, low frequency-high impact, long recovery, alters soil chemistry dramatically
- surface fire: burns lightweight fuels at the surface, moderate temperatures, high frequency- low impact, short recovery
- crown fire: high fuel loads with ladder fuels, low frequency- high impact, long recovery, resets the system for succession
20
Q
ignition
A
- requires activation energy to initiate the reaction
- most common forms of ignitions are lightning and humans
21
Q
what affects the spread of a fire (5)
A
fuel loads, landscape connectivity, topography, hydrology, wind
22
Q
general fire hypothesis
A
communities of plants have evolved with a fire regime and thus depend on fire
23
Q
what do forests require for fire to play a significant role (4)
A
- ignition sources
- appropriate fuel structures (type of fuel determines the type of fire)
- seasonality (at least one season with warm dry conditions)
- sufficient productivity
24
Q
describe the best fuels
A
- high SA:V (fine twigs)
- low moisture content
- high concentration of flammable compounds (terpenes)
- varied (encourages consistent fire)
25
fire adaptations (5)
- thick bark
- high foliage/self pruning
- sprouting (persistence adaptation)
- stimulate germination
- serotiny
26
describe the longleaf pine system
- seedlings germinate on mineral soil and have rapid growth
- grass stage- secondary needles and buds have protective resins, juvenile bank to survive fire
- mature trees have thick corky bark
- fire controls pests and competition
27
describe the clearcutting system
- even age forest of shade intolerant species
- emulates large disturbances
- emphasis on light penetration to support regeneration
- applied as a mosaic over the landscape
- cost efficient and simple
28
what does a successful clearcut require
- sufficient seed source
- receptive seed bed
- timely management of competition
29
types of clearcuts
- conventional (complete removal of overstory)
- clearcut with standards (veteran trees are retained)
- seed tree (trees of seed bearing age are retained and dispersed throughout the stand, maintains structural diversity)
30
clearcuts in Ontario
- retention of 10-36% of original stand
- minimum of 25 snags per ha
- variable sizes
- new clearcuts separated from older clearcuts
31
modified clearcuts
- patch clearcut: patches are harvested in various shapes and sizes reflecting the underlying forest mosaic
- strip clearcut: adjacent strips cut sequentially, strip size and orientation regulated by ecological conditions, eventual coverage of entire stand
32
describe the importance of seed sources
- harvest removes seed trees
- few species have a viable seed bank
- maximum widths are determined by the distance to adjacent seed sources
- site variation and advanced regeneration will influence regeneration sucesss
33
environmental effects of clearcuts
- increases surface and soil temps
- increases evaporation and decreases humidity
- increases soil moisture (reduced interception of precipitation, increased infiltration and percolation)
- greater overland flow
- faster decomposition
- nutrient release
- leaching
34
what microsite factors influence clearcuts
- slope- the steeper the slope the better draining the soil and more susceptible the site is to drought
- aspect- southern aspect is associated with a decline in regeneration
35
describe the different types of retention
- provides habitat refuge, travel corridors, legacies, visual appeals
- dispersed: retained trees are spread throughout the area
- aggregate: retained trees are concentrated into habitat island- possibly more attractive to different species, provides operational value
36
slash
provides temperature moderation, protection fro herbivores, more suitable microenvironment, slow release of nutrients
37
describe the changing face of clearcuts
- historically, clearcuts had straight edges, square corners, and retained trees were isolated to thin strips along streams
- total, patches or bands of trees are retained throughout the site, there may be a mixture of aggregate and dispersed retention, greater visual appeal, diffuse boundaries
38
free to grow status
stands that meet stocking, height, and/or height growth rate as specified in the ground rules and are judged to be healthy and essential free from competing vegetation
39
silvicultural success
- all standards contained in the silviculture ground rule applied to that stand have been met
- e.g. standards for target species, acceptable species, future forest condition, wildlife habitat
40
clearcut advantages
- high yields and low costs
- regeneration of shade intolerant species
- easy site prep and machine access
- pest control
41
clearcut disadvantages
- dependence on seed rain/bank and risk of failed regeneration
- intense competition
- reduced transpiration effects and high evaporative demand
- soil disturbance and erosion
- increased fire risk
- loss of habitat
42
shelterwood characteristics
- single cohort of mid-tolerant species
- emulates moderate disturbances
- primarily used with natural regeneration- new cohort develops under older trees
- sufficient canopy cover to mitigate change in microenvironment
43
phases of a shelterwood
- remove: removing trees to modify the light environment and benefit regeneration
- retain: retaining adequate cover to create seed and a positive environment for seedlings
- maintain: producing the regeneration niche of the species you're trying to regenerate
44
cuts in a shelterwood
- prep cut: removing inferior trees, allow more room for good trees, gives time for seed to be produced
- seed cut: opening the canopy to 50%, hope that trees drop seed, allow for regeneration
- removal cut: most of the shelterwood is taken off, a few residual stems are left
45
seed tree method
- appropriate number of individual trees are left across an open area to provide seed for production of the next crop of trees
- used for species that do well in open conditions but are limited by seed dispersal
46
seed tree
residual stem that is a source of seed for the regenerating cohort
47
characteristics of good seed trees
- upper canopy position (access to resources)
- thick stem relative to height
- well balanced symmetrical crown
- wind firm morphology
- large, medium dense crowns, tallness, and poor root anchorage makes trees more susceptible to wind
48
forest regeneration success
- height and durability of seed trees
- frequency of seed crops
- seed production (related to crown size and stem thickness)
- seedbed suitability
- seed viability and germination rates
49
shelterwood with reserves method
- individuals are selected and left to overtop the new cohort
- typically large diameter trees are retained at a low density
- rarely used in NA forestry
50
advantages and disadvantages of shelterwood with reserves method
- D: increased variability in light environment, slower growth rate, trees may become flat topped
- A: more growth on retained, more aesthetic, maintains certain habitat features
51
characteristics of reserve trees
- longevity (50-80 yrs)
- good form, no lean, dominant/codominant crown
- no dead/dying branches or epicormic branching
- species not prone to dieback
52
strip shelterwood method
- parallel strips of 1 tree length in width are cut in successive entries
- creates progressive canopy openings until a majority of the stand has mature age class removed
- even aged stand
- initiates regeneration and ensures everywhere is close to viable seed
53
group shelterwood method
- creates patches of regeneration dispersed throughout the site
patches are circular and approx 1 tree length in diameter
- cuttings expand patches until they coalesce
54
benefits of shelterwood
- vertical structure
- variation in environment/density
- legacy trees
- transition habitat
55
objectives of selection silviculture
- sustained and regular yields
- stable structure and forest conditions
- full site utilization- optimal stocking and production of quality timber
- regular replacement of mature trees
- habitat availability
56
characteristics of selection
- multiple cohorts
- high live crown ratios
- high vertical structure (foliage at all layers)
- wide range of diameters
- strong height:diamter relationship (based on vigour)
57
working cycle
forest under a particular work plan- the area where one silvicultural system is specified
58
balance
- each age/size class occupies the same amount of crown space (many small, few large)
- regulating densities in each cohort maximizes site occupancy
- negative correlation between crown size and density (lower density leads to larger crowns)
59
q factor
- describes the slope of the exponential curve relative density to diameter classes
- q= # of trees in class (n)/ n+1
60
problems with q type structure
- idealized ratio and not a realistic representation
- underestimation of ingrowth in spacing and pole size classes
- divergence of economic and biological effects
61
steps in the selection system
- inventory of stand composition and structure
- identify the diameter classes for cohorts
- determine the appropriate residual density and cutting cycle
- compare actual diameter distribution to desired structure
- write a marking prescription to remove excess trees from overstocked size classes
- mark and cut the stand
62
retention priorities
- target age class
- vigour, form, soundless, low risk
- species
- crow position
63
rehabilitating a degraded stand
- retain an appropriate residual density even if high risk or low vigour trees are retained
- plan for 2-3 cuts to upgrade the stand over time
- choose a lower residual density and extend the cutting cycle
- lower the max diameter and retain some suboptimal trees
64
regeneration in the selection system
- reduce the stocking of each diameter class
- removal of mature age class to release developing stand
- aim to propagate and promote the highest quality individuals int ehe and and allow them to replace inferior individuals
65
effects of selection post harvest
- high residual stand density
- small increase in soil moisture and nutrients
- increase in diffuse light in the understory
- short term increase in temp and decomp
66
variation in the light environment after selection harvesting
- increases depth of light penetration
- ground remains in partial shade
- saplings under gaps are stimulated
- germination and establishment of shade tolerant species is promoted
67
foliage height diversity
- proportion of total foliage at different height s
- low score is associated with foliage concentrated in a few layers
68
establishment
- important for revegetation a stand
- requires germination, shoot system penetration, and root system penetration
- requires net positive assimilation as soon as possible
69
site preparation
- deals with changes of conditions that favour the species you're trying to manage
- can be done before or after
- alters the physical environment or deals with competing vegetation
70
goals of site prep
- vegetation control
- litter removal/mixing
- promotes decomposition
- alters nutrient balance
- modifies habitat and enhances conditions
- reduces fuel
- facilities operations
71
passive site prep
- side effect of another activity- unpredictable
- often couple with natural regen
- skid trail mix soil, damage competing vegetation, and create a mineral seed bed
72
active site prep
- intervention to enhance the regeneration process
- varied in intensity and extend depending on the application
- controlled and more expensive
73
what are the types of site prep
- mechanical: altering the soil or litter, reducing competing vegetation, usually with machines
- chemical: application of fertilizer or herbicide
- fire: kill or reduce competition and reduce organic debris
74
extent of site prep
- broadcast: affects the entire stand
- strip: applied in narrow alternating bands
- spot: focused exclusively on the development of seedlings
75
types of mechanical site prep
- blading: bulldozers with blades that skim the surface
- bedding: elevating cultivated bed to promote drainage and aeration
- chopping/shearing: heavy rollers crush and separate debris (woody mulch)
- chaining: chain is dragged behind a bulldozer, promotes decomposition and aeration
76
advantages and disadvantages of mechanical site prep
- A: slash management, mulching, vegetation management, improving drainage, scarification
- D: erosion, compaction, weeds, sprouting, nutrient loss, temperature variation
77
chemical site prep applications
- individual stem
- broadcast: larger areas
- aerial: can treat hundreds of ha, only requires a few personnel, tightly restricted, must be applied at the correct time
- ground level: only practical with good access and practical quantity, more targeted, require more volume and people
78
advantages and disadvantages of chemical site prep
- A: wide spread efficacy, sprout prevention, lack of forest floor disturbance, cost effective
- D: off target damage, variation in efficacy, timing requirements, increased fuel loads, restrictions
79
prescribed burning
- controlled use of fire under conditions that permit its containment to a pre-determined area
- produces a specified intensity of heat and rate of spread to satisfy the planned objectives and provide the desired benefits with minimum damage at an acceptable cost
- a practical tool used in parks
- associated with the management of mid-tolerant species
80
fire weather index
- based on temperature, relative humidity, wind speed, and rain
- varies from 0-23 (cooler, wetter conditions have lower scores)
81
types of prescribed fire
- strip: light a protective back fire that consumes any fuel to prevent fire from burning past that point, then light a strip that slowly burns towards the back fire
- spot: similar to strip but uses patches
- ring: back fire is lit, perimeter of the burn area is lit and produces an updraft that causes rapid and intensive spread into the centre
82
advantages and disadvantages of prescribed burn
- A: slash and debris removal, nutrient release, vegetation and pest control, fuel reduction
- D: release of toxins, narrow range of conditions, risk of escape, temporary, erosion, nutrient leeching
83
12 points from the big meadow fire
- prescribed fires reduce hazardous fuel to restore forest structure and composition
- get fires back into the ecosystem
- reduces severity of future fires
- window of very specific conditions
- maintain fire resistant vegetation
- previous fire suppression
- fire knowledge has evolved
- limitation to when burns can occur, so burn whenever you can
- burn area is heterogenous
- regrowth involves different phases
- emergency response team investigates after
84
choosing a site prep treatment
- vegetation present/desired
- distribution of species/debris
- topography and substrate
- planned management
- anticipated costs and benefits
85
plantation
a forest community or stand established artificially by sowing or planting
86
reasons for tree planting
- lack of seed source
- establish tree cover in an altered enviro (e.g. abandoned agriculture field)
- control composition, spacing, arrangement
- narrow window of conditions for establishment
- problematic natural regen
87
objectives of tree planting
- products
- protective cover
- visual appeal
- animal food and cover
- windbreaks
- ecosystem restoration/rehabilitation
88
urban forestry
- urban grove: a small closed tree community in undeveloped part of a city, unplanted
- urban savannahs: strips of street side trees widely dispersed or in isolated clusters of small trees in open groves or parks, planted
- paving trees: widely dispersed individual trees
89
role of plantations in conservation
- mimics natural disturbance
- focus on native species
- conserves woody debris
- longer rotation
- early thinning
90
selecting the right species for artificial regen
- must consider the goal of the plantation
- cover, landuse history, climate, aspect, soil
91
translocation rules
- seed cannot be moved more than 161 km in distance or 150-300 m in elevation
- donor and recipient site should be similar
92
biological potential
rate of germination
93
cold stratification
the process of exposing seeds to cold and moist conditions to encourage germination
94
scarification
the process of altering the seed coat to allow for quicker water absorption and improve germination rate
95
sowing rate
the density of seed to spread in order to achieve a given stocking level (seeds/unit area)
96
seed certification
verification of the source of the seed and an assessment of the relevant properties of the seed lot
97
seed lot
- cohort of seed gathered from the same source during the same year
- seed may differ from year to year, so seed lot tell you about viability and germination rates
98
types of seed
- unclassified seed: no info on where it comes from or its quality
- source-identified seed: from good natural stands or plantations where the location is registered, no additional attributes but tells you if its from the right seed zone
- selected: seed from a specific genotypes
- certified orchard seed: the highest level, proven by progeny test, highest quality with specific attributes from the best genetic line
99
bareroot seedlings
- grown without pots or containers and shipped free of any medium around the roots
- must consider: temperature, soil moisture, and seedling activity
- spring is the best time to plant
100
limitations of bareroot seedlings
- seedlings must be lifted at an appropriate time for planting
- seedlings deteriorate quickly after lifting and most be stored properly or planted immediately
- seedlings must be handled with care
- difficult to plant
101
container stock
- grown in a receptacle filled with soil or other rooting medium and out planted with the rooting medium left undisturbed around the roots
- various containers and rooting media are used to maximize performance
102
advantages of container stock
- control of growing conditions
- shorter nursery rotations and faster early growth
- uniform size and condition
- higher survivor ship
- much easier to plant
103
limitations of container stock
- high production cost
- technical difficulties with production
- heavier than barefoot
- vulnerable to frost heave
104
intermediate treatments
- deliberate cutting used to thin out a stand to provide more resources to the retained trees
- improves spacing, composition, and vigour
- includes release treatments (sapling) and thinning (post sapling- pre commercial/commercial)
105
low thinning
- RC- lowest crown positions and overtopped trees
- R- upper canopy dominants, focusses growth on larger trees
- E- decreases vertical density, improves quality
106
crown thinning
- RC- dominant and codominant crown positions, poor vigour and quality
- R- upper canopy dominants, favours best growing stock, fillers and trainers
- E- inform spacing, improves diameter growth, maintains some vertical diversity
107
selection thinning
- RC- diameter limit, low quality/value species
- R- smaller trees, good growth form, promotes a certain species
- E- best genetic stock is removed, poor natural regeneration, decreased yield
108
free thinning
- RC- spacing out crop trees
- R- uniform spacing or strips in natural stands, rows in plantations
- E- higher volumes from thinning, little changes in vertical structure, variety of trees retained
109
how is a thinning method chosen
- present stand conditions
- species mixture
- stand age (time to rotation, self thinning)
- landowner objectives (product
- end use (market, non-timber values)
110
