Transcript FOR 350 2016 What is..

FOR 350
Silviculture
What is silviculture?
The art and science of controlling the establishment,
composition, structure, and growth of a forest stand to
meet the landowners’ objectives on a sustainable basis
What is silviculture?
The art and science of controlling the establishment,
composition, structure, and growth of a forest stand to
meet the landowners’ objectives on a sustainable basis.
• Three parts to the definition
– Manipulative, objective driven, sustainable
• Silviculture builds on many other disciplines
– Ecology and silvics, physiology, soils, measurements,
economics, social science
• Silviculturists (not silviculturalists) operate in the realm of
the biologically possible
– Operate under social and economic constraints
• Only solutions that are simultaneously biologically
possible, economically feasible, and socially acceptable,
will be considered appropriate (and sustainable)
To know what is biological possible
• One must understand how the forest environment
influences individual trees and communities they form
To know what is biological possible
• One must understand how the forest environment
influences individual trees and communities they form
• Silvics is the study of the biological characteristics of tree
species and communities including how:
1) Trees reproduce, establish, and grow
2) Physical environment influences their physiology and character
3) Tree communities influence their physical environment and the
interaction between vegetation and physical environment as forests
change through time
Silviculture Is Objective Driven
• Silviculturists affect the direction of stand development,
but there is often the reality of ‘you can’t get there from
here’
Silviculture Is Objective Driven
• Silviculturists affect the direction of stand development,
but there is often the reality of ‘you can’t get there from
here’
• Even if you can get there from here (i.e. biological
feasible), you need a roadmap, a start and end point
Silviculture Is Objective Driven
• Silviculturists affect the direction of stand development, but
there is often the reality of ‘you can’t get there from here’
• Even if you can get there from here (i.e. biological
feasible), you need a roadmap, a start and end point
• Objectives and forest inventory data form basis for road
map
Silviculture Is Objective Driven
• Silviculturists affect the direction of stand development, but
there is often the reality of ‘you can’t get there from here’
• Even if you can get there from here (i.e. biological
feasible), you need a roadmap, a start and end point
• Objectives and forest inventory data form basis for road
map
• Inventory data gives you the starting point
• Objectives define where you are going
The Stand
• A stand is a contiguous group of trees sufficiently
uniform in age or size class distribution, composition,
structure, site quality and/or location to be a
distinguishable unit.
– Silviculture is practiced at the stand level
– Forest management is primarily concerned with the forest (or
tract), a collection of stands administered as an integrated unit
The Silvicultural System
• To meet landowner objectives, silviculturists alter the
forest environment by manipulating stand structure
• Required environment is influenced by:
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Species composition
Silvics of desired species and competitors
Stand structure
Age structure
Health and vigor
Potential damaging agents
The Silvicultural System
• A silvicultural system encompasses everything that is done
throughout a rotation
• In theory, it is unique for each stand
• The systems are named for their respective regeneration methods
(e.g., shelterwood system, single-tree selection system)
• Naming convention identifies the structural character of a stand
The Silvicultural System
• Each silvicultural system should:
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Sustain ecosystem health and productivity
Improve tree growth and quality
“Optimize” market and non-market benefits
Shorten investment period and contain costs
Categories of Silvicultural Systems
• Even-aged System
A planned sequence of treatments designed to maintain and regenerate a
stand with one age class. The range of tree ages is usually less than 20
percent of the rotation.
• Multiaged Systems
Sequence of silvicutlural practices designed to maintain and regenerate two or more
age classes in a given stand
– Uneven-aged
A planned sequence of treatments designed to maintain and
regenerate a stand with three or more age classes.
– Two-aged
A planned sequence of treatments designed to maintain and
regenerate a stand with two age classes.
An Example: Phases of an Even-Aged System
Establishment
Phases of an Even-Aged System
Intermediate Treatments
Benefits
• Reduce density
• Improve growth and quality
• Favor desired species
• Shorten rotation
Phases of an Even-Aged System
Site Preparation
Benefits
• Improve germination,
survival, and growth of desired
seedlings
• Removal of unwanted
vegetation and slash
Phases of an Even-Aged System
Regeneration Methods
Benefits
• Create conditions require to
establish new stand of
desired species
The Silvicultural System
• Modifications of a silvicultural method
– Type: apply different kinds of treatments
• e.g., burn vs. herbicide
– Intensity: change the intensity of application
• e.g., light vs. heavy thinning
– Timing: alter timing of application
• e.g., winter vs. summer burn
– Sequence: change the sequence of treatments over time
• e.g. control vines before or following harvest
The Silvicultural System
• Method of choice for stand depends on:
– Nature and requirements of an ownership (i.e., landowner
objectives)
– Stand character and condition
– Site quality
– Species silvics
– Range of treatments available for use
– Accessibility and terrain
– Type of and proximity to forest products markets
The Silvicultural System
• Modifications often implemented for non-timber
considerations:
– Size and distribution of regeneration area
– Rotation length
– Density, species, and condition of residual trees
• Seed production
• Light availability
• Habitat structure
• Species “life-boating”
– Coarse woody debris retention
– Best Management Practices (BMPs) relating to soil and water
quality