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84 Cards in this Set

  • Front
  • Back
What is Ecological Resilience?
The capacity of natural systems to absorb distrubances and undergo change while maintaining its essential functions, structure
What are qualitative characteristics of ecological resilience?
1. State and spatial scale of system concidered.
2. Pertubation of interests.
3. temporal scale of interest.
What is a alternative stable state?
A stable state is a set of self perpetuating and mutually reinforcing structures and processes.
What do shifts between ecosystems depend on?
1. Frequency
2. Intensity
3. compounding disturbances
What is panarchy?
Ecosystems are a set of interacting adaptive cycles that occur at different spatial and temporal scales.
What are the four phases of adaptive cycles?
1. Rapid growth and exploration(r)
2. Conservation(K)
3. Release or collapse(sigma)
4. Renewal or reorganization(alpha)
What is release?
Release of accumulation of biomass and nutrients.
What is Silviculture?
The art of producing and tending forest stands by applying scientifically acquired knowledge to control forest establishment, growth, quality and health
Applying different treatments to make forests more productive or useful to landowners and society on a sustainable basis
What do manage in silviculture?
Stand density and spacing
Utilizing site productivity
What determines even-aged vs. uneven-aged form?
Height differences (crown class)
Diameter distributions (graphs)
Geometry and size of cut
Factors for choosing a regeneration method?
Desires of the owner
Biological considerations
What is Natural-Disturbance-Based Management (NDBM)
Forest management approaches based on the dominant natural disturbance regime will restore or maintain biodiversity and essential ecosystem functions by restoring or maintaining the full historical range of habitat heterogeneity observed at multiple scales in unmanaged forests.
What are the Stages of Stand Development
Stand Initiation Stage
Stem Exclusion Stage
Understory Reinitiation Stage
Complex or Old Growth Stage
What occurs during the stand initiation phase?
Accumulation of biomass
Begin vertical stratification of tree crowns
“BRUSHY” stage
Invasion continues until all growing space is occupied
Other things about stand initaition phase?
Follows major disturbances (wind, fire, clearcuts)
Regeneration of open space from seed, sprouts and advance regeneration
One cohort or age class
Stage ends when canopy becomes continuous and trees begin to compete each other for light and canopy space
Stand Initiation Stage Management Implications?
1Site preparation to favor a certain species
2Light tolerance
3Future species composition
4Regeneration mechanism advantage
Density --- too many or too few
What happens during the Stem Exclusion Stage
Canopy is too dense to allow new saplings to grow into the canopy
Canopy continues to have one cohort
Competition is intense and density-dependent self-thinning occurs
Crowns are small enough so that when one tree dies, the other trees are able to fill the vacated space in the canopy by expanding their crowns
Few, if any stems are added to the population of overstory trees
Mortality rates are high, especially in the intermediate and suppressed crown classes
Full utilization of growing space, possibility of stagnation
Characterized by growth, competition and mortality produced spatial adjustments
Species dominance in exclusion phase can be attained through:
Inherent faster growth than competitors
1Initially superior crown position
Stem Exclusion Stage Silvicultural Implications?
1Thinnings to shape desired future condition of the stand
2Species composition and stand structure/form
3Density/spacing arrangements
What happens during the Understory Reinitiation Phase?
Tree reproduction becomes re-established beneath the parent stand --- more than one cohort
This reproduction, more than likely, becomes a major component of the new stand that develops after the next stand initiating disturbance
Crowns of trees are now large enough so that when one tree dies, the surrounding trees can not fill the gap --- density independent mortality
Thus, new cohorts can eventually enter the canopy, diameter distribution becomes bimodal --- large and small peaks
Factors that influence species composition during the Understory Reinitiation Phase?
Light --- degree of shade tolerance
Soil moisture
What happens during Complex Stage (Old Growth)?
Natural mortality of large overstory trees produces irregular canopy gaps and accelerates the recruitment of reproduction and subcanopy trees into the overstory and main canopy. This stage marks the transition of an even-aged to an uneven-aged stand
Other on old growth?
Multi-aged population, reverse J-shape
Result of stand maturation (overmature?)
Gap formation and filling
Gaps become more numerous until the stand forms a mosaic of old trees and gaps filled with younger trees of various ages and species
As trees refill gaps, stand diameter frequency distributions change from:
bell-shaped to
irregular shaped to
reverse J-shaped
What happens during the Complex Stage?
Incomplete stand-scale disturbance
Eliminates only a portion of the overstory
Significant number of trees standing
Does not return to stand initiation stage
Events that cause mosaics of younger trees developing in large canopy openings interspersed with older trees
What is Crop Tree Management?
Crop tree release is the selection and release of desirable trees by removing adjacent competing trees in immature stands
What is the purpose of Crop tree mgmt?
increase diameter growth, improve stand composition and form
Application of crop tree mgmt?
Target 30-50 crop trees per acre
Use crown touching technique release on at least 2 and preferably 3 sides
Remove only trees interfering with horizontal crown expansion
Application of crop tree mgmt?
Apply in overstocked, young stands where form of butt log has been established after crown closure
Economic advantages of crop tree mgmt?
Growth rate is enhanced, rotation is shortened
Better trees, improved form & grade
Better sites
Primary Factor --- adjusts species composition. Higher valued species!
Factors that affect tree value?
What does crop tree mgmt improve?
Straight stems
Clear stems
Potential log height
Potential grade
Risks of crop tree mgmt include?
Epicormic branching --- factors include species, genetics, crown position, aspect, density, position on the bole
Logging damage --- size, season of year
Condition of tree --- respond to release?
Potential for damage from ice, wind, etc.
Mortality --- opportunity costs
What is thinning?
Cuttings made in immature stands for the purpose of utilizing material which otherwise might be lost before the rotation age is reached and/or redistributing the growth of the stand to fewer more desirable stems

Thinning --- reduce competition so that growth that does occur is on fewer stems that continue to grow at a good rate (given site conditions and tree age)
In thinning what factors effect what trees to remove?
Crown classification
vigor, health, and form of the trees and spacing between trees
How Does Thinning Do That?
Alter environment of remaining trees
Crowns and root system
Changes in sunlight received, carbon dioxide, temperature, crown space, root environment (moisture, nutrient, etc.)
What effect does thinning have on Stem Form?
Thinned stands --- increased DBH growth at base of stem
Unthinned stands --- increased DBH growth at base of crown
Impact on taper of stem --- form class --- gradual thinning, not a drastic cut
What Effects does thinning have on Height and Diameter?
Stand density has little effect on height growth
DBH growth, usually a good response, but depends on degree of overstocking before release, type of thinning, and age and crown class of tree
What effect does thinning have on DBH?
Drastic increases in diameter growth indicates that you have waited too long to thin and may not be desirable due to wood properties
Objective --- keep trees growing at a good, even rate
Appearance --- rings will decrease in width from the pith outward, but basal area growth remain almost constant
What are the rule of thumb guidelines for thinning?
Thin to a basal area (BA) that is equal to site index
Lighter thinning in older stands, i.e., BA remaining should increase as age increases
Rate of production is less on older trees, thus need higher BA to keep stand growth at a given rate
What is MAI?
Mean annual increment
What is PAI?
Periodic annual increment
What is the Basis for determining sustainable cut?
MAI is cumulative over a lifetime
MAI = PAI when MAI culminates at its maximum
What do we get from Peak MAI?
maximum production rate harvested annually
PIA is greater than MIA?
the stand has not reached culmination of MAI
Why thin?
merchantable or economic yield may be greatly increased
health of the stand, water yield, wildlife habitat, etc
HOW Thinnings Effects on Economic Yield?
Salvage of mortality
Increase in tree size and improvement in wood quality
Yields earlier income
Reduced investment in growing stock
Improve stand composition
May reduce cost of future operations
General Comments on Thinning
Intensity of thinning --- depends on objectives or product produced
Costs incurred --- spacing vs. thinning (density control)
Longer rotations vs. shorter rotations
Natural vs. Artificial regenerated stands
Considerations other than wood production?
a. forage production
b. wildlife habitat
c. aesthetics and recreation
d. water yield and quality
What is Low Thinning?
Removes trees of subordinate crown positions to favor those of upper crown classes, with little effect on main crown canopy for intensities of less than C-grade thinning from below.
What is Crown Thinning?
Favors the best trees of the upper-crown positions, removing competitors from the main crown canopy
What is the purpose of crown thinning?
provide space in canopy for crown expansion
Where do you use crown thinning?
developing selected crop trees
What is selection thinning?
Removes the largest trees in upper crown positions, uncovering smaller ones for future growth and develpoment
Where would you use selection thinning?
tolerant conifers!
very little in hardwoods
What is free thinning?
Combination of selection, low and crown thinnings.
What is the main concern for mechanical thinning?
What is row thinning?
Removing trees in designated rows w/o reducinig crowding among trees
What are the two types of mechanical thinning?
Row and Spacing
What are biological conciderations for thinning programs?
Decrease in live-crown ratio
Decrease in DBH
Stock conciderations
natural pruning
How often to thin?
What DBH growth rate begins to decrease
hard to determine
What do you thin?
Unwanted species
Poor form
Insects & disease
Slow growth
Spacing considerations
What is a release treatment?
Salvage a situation deemed untenable in light of ownership goals when stands have adequate regeneration but other vegetation threatens its long-term survival and development.
What does release treatment do?
Free young stands fo desirable trees, not past sapling stage.
What are reasons for release treatment?
Protect young trees from injuries and suppression by shrubs, vines, and other interfering plants
Improve the species and quality composition of trees in a young community
Reduce interference of mor rapidly develping or older trees along the margins of a stand
Reduce crowding of desirable species within densely stocked young growth
Enhance the growth and development of selected elite trees or those of a particular species.
What is the Cleaning type of release treatment?
Treatment during the sapling stage to free selected trees from competition of overtopping trees of comparable age and to favor the trees of better species and quality
Removing woody vines and shrubs that overtop or seem likely to suppress desirable trees not past sapling stage
What is the Weeding type of release treatment?
Treatment during the seedling stage to eliminate or suppress mainly herbaceous plants and shrubs that overtop or interfere with desirable young trees
What is a liberation cut?
Freeing tree not past sapling stage from competetion and overhead competetion.
What are types of herbicide vegetation control?
Killstop and roots
Kill on contact
Applied to soil
Hormone-type herbicides
What are the mechanisms for herbicide uptake?
What are things to concider in the timing of the application of herbicide?
Stage of plant development
Condition of leaves
Growth stage
Soil moisture
What are chemical techniques for herbicide spraying?
Foliar spray
Basal spray
Stump spray
Soil applied
Girdling & injection
What are onsite impacts of herbicides?
Non-target organisms
Soil health
Ecosystem recovery
What are offsite impacts of herbicides?
Landscape impacts
How do we apply herbicides?
Ground equipment
What are herbicides used for silviculture?
Invert emulsions
How do we make a prescription?
Define goals
Know you crop and site
Identify weeds
Know research results
Read the label and re-read the label
Read and heed the MSDS
Use correct volume and application
Use correct adjuvants
Follow up on efficacy
What are some chemical herbicides for pines?
What are the two types of disturbances?
Severe: landslides, fire, glacial melting
Releasing:Wind and pests
A seed only requires a microsite for establishment
If you require 2000 individuals per hectare
Need 2000 suitable microsites
If a microsite was only 10 sq centimeters

The area needed would be 0.005% of the hectare
What are conciderations for seedling enviroment?
Water loss from the soil surface by evaporation
Heat transfer from the soil surface
What are the 7 stages of the regeneration process?
1. Flowering
2. Seed supply
3. Seed dispersal
4. Storage
5. Germination
6. Succulent stage
7. Growth and establishment
Regeneration Method Advantages
Least expensive
Usually regenerates species and trees well adapted to the site
Direct control over the genotypes, species, and placement of trees in the new stand
Complete control over time of establishment and duration of the establishment period
Can repeat it to ensure success at difficult sites and circumstances
Regeneration Method Disadvantages
Often produces stands with some variation in species composition, stocking , and time of establishment
Limited to indigenous genotypes and species
Subject to natural forces of disaster
Depends on a good seed crop
Expensive with a long wait until revenues repay the investment
Impractical to use in remote areas, except at a high cost
Requires a major logistical support effort, especially for growing, shipping, and planting seedlings