Silviculture 101: Systems and Terminology Flashcards
Planned program of treatments over the entire life of the stand
Silvicultural Systems
What do silvicultural systems include?
- Regeneration treatments
- Tending operations
- Intermediate treatments
- Protection measures
What are the phases of silviculture and their equivalent stages of stand development?
- Regeneration = Stand initiation stage
- Tending = Stem Exclusion stage
- Harvest = Understory reinitiating stage
The procedure by which the stand is established and renewed
Regeneration methods
Silvicultural systems are named after what?
Regeneration method
An approach that combines regeneration methods in the same stand or harvest unit
Hybrid approaches
2 Classification of Silvicultural Systems
- Origin (Sources of regeneration)
2. Age class (Arrangement of cuttings in time)
Rely largely on vegetative regeneration from stump sprouts, root suckers, or layered branches
Low-forest Methods
Any type of cutting in which dependence is placed mainly on vegetative reproduction
Coppice Method
Regeneration of stands based on sexual reproduction (germinated seed)
High-forest methods
Entire community of mature trees is removed in one or more cuttings over a short interval of time to allocate growing space to a new, even-aged cohort
Even-age methods
3 Methods under Even-aged
- Clearcutting method
- Seed-tree method
- Shelterwood method
Removal of the entire stand in one cutting
Clearcutting method
In clearcutting method, regeneration occurs following ____, either through _____ or _______ after harvest
Harvest, artificial or seeds germinating after harvest
Removal of the old stand in one cutting, except for a small number of seed trees left singly or in small groups
Seed-tree method
Provide for establishment of advance regeneration
Seed trees
Removal of old stand in a series of cuttings extending over a relatively short portion of the rotation
Shelterwood Method
Shelterwood method encourages the establishment of ______ under the partial shelter of seed trees
advance regeneration
Seedlings or saplings that develop or are present in the understory.
advance regeneration
Most of the mature forest is removed, but widely spaced vigorous trees are left to grow above the new cohort
Two-aged (High forest) Methods
2 Methods under two-aged methods
- Shelterwood with reserves
2. Clearcut with reserves
Only some trees in a community have reached maturity and are removed over an extended time period to allocate space to a new age class
Uneven-aged methods
Occasional replacement of single trees or small groups of trees with regeneration from any source
Selection methods
2 types of selection
- Single-tree selection
2, Group selection
Intermediate treatments are applied to? (3)
- Improve the existing stand
- Regulate stand growth
- Provide early financial returns
Intermediate treatments are applied without any effort directed at _____
Regeneration
3 Methods under Release Treatments
- Weeding
- Cleaning
- Liberation cutting
At what stage is weeding done?
Seedling stage
What is the objective of weeding?
Eliminate or suppress herbaceous plants or shrubs before they overtop or interfere with desired trees
At what stage is cleaning done?
Sapling stage
What is the objective of cleaning?
To free selected trees of better species and quality from overtopping of trees of comparable age
What is the objective of liberation cutting
To free young trees not past the sapling stage from competition from older overtopping trees
Liberation cutting often corrects problems not addressed by ______
earlier site preparation
Removal of live trees from a stand with the intention of improving growing conditions on the site for the uncut or leave trees
Thinning
Thinning reduces what?
Competitive pressure
2 Types of Thinning Methods
- Pre-commercial thinning methods
2. Commercial thinning methods
Thinning before the cut trees have sufficient merchantable volume to yield adequate volume for commercial harvesting
Pre-commercial thinning
Pre-commercial thinning is an early investment to increase the _____ from the whole crop
net return
3 Types of Commercial Thinning Methods
- Based on how individual trees are chosen for removal
- Free thinning
- Variable Density Thinning
2 Criteria of Thinning Methods Based on how individual trees are chosen for removal
- Crown position in the canopy/Crown classes/Kraft classification
- Predetermined spacing or pattern of removal
3 Thinning Methods under the Kraft classification
- Low thinning
- Crown thinning
- Selection thinning
What does the low thinning method favor and what it eliminates?
Favor: Dominants and codominants
Eliminate: Lower crown classes
What does the low thinning method emulate?
Natural development processes
What does the crown thinning favor and what does it eliminate?
Favor: Best quality dominants and codominants
Eliminate: Other dominants and codominants
What does selection thinning favor and what does it eliminate?
Favor: \Lower crown classes
Eliminate: Dominant crown classes
Trees are removed in proportion to their occurrence (no crown class considerations)
Geometric thinning
What is the objective of geometric thinning?
To maintain a predetermined spacing among trees
Apply all other elements of thinning at once
Free thinning
What us the objective of free thinning?
To approve stand structure
Thinning regime in which thinning intensity and tree marking rules are varied within stand of interest
Variabble Density Thinning
Other term for variable density thinning?
Skips and gaps approach
What are skips?
Portions of stand that are left lightly or completely unthinned
What are gaps?
Portions of stand that are heavily harvested including removal of dominant trees.
2 characteristics of skips
- High stem density
2. Heavy shade
What does gaps increase?
understory development
Part of the stand that is often thinned to intermediate levels
Remaining matrix/thinned matrix
What does Variable Density Thinning increase?
Heterogeneity in stand density and cover
What does VDT emulate?
Natural variation in stand structure
2 results of VDT
- Competitive mortality
2. Small-scale canopy disturbance
