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: 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: 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.  Uneven-aged System A planned sequence of treatments designed to maintain and regenerate a stand with three or more age classes. Two-aged (Hybrid) System A planned sequence of treatments designed to maintain and regenerate a stand with two age classes.

Silvicultural Systems and Methods A silvicultural system is named based upon the regeneration method used Regeneration methods are classified as follows: Even-aged Clearcutting, seed-tree, shelterwood Uneven-aged Single-tree selection, group selection Two-aged (hybrid) Reserve shelterwood, reserve seed-tree, clearcutting with reserves

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 The choice of a method depends on: Landowners objective Existing plant community and silvics Stand conditions Range of treatments available for use

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 Modifications often implemented for non-timber considerations: Size and distribution of regeneration area Rotation length Nature of residual trees Species left on site Amount, kind, and frequency of seed production Amount of light to forest floor Coarse woody debris left on site (amount, size, and distribution) Implementation of Best Management Practices (BMPs)

Biologic and economic factors affecting silviculture Site quality Stand character and condition Nature and requirements of an ownership Accessibility and terrain Forest products markets