introduction to silviculture treatments, site...

Introduction to Silviculture Treatments, Site Preparation Learning Objectives • Know the nature and purpose of silviculture treatments • Know the biological, operational and administrative considerations in choosing treatments. • Understand how microsite conditions are manipulated through site preparation. • Understand the distinction between site preparation and site degradation.

Successful regeneration depends on: •Suitable genetic material •Viable seeds, seedlings, vegetative material •Suitable microsites and environmental conditions •Good initial establishment •Unencumbered growth

Silviculture Treatments

• The goal of silviculture treatments is to move the site/stand from its current condition towards the desired future condition.

• This includes modification of soils, vegetation, micro- and site-level climate.

• Treatments are selected based on biological, ecological, operational, economic and societal considerations.

Treatment phases include: • Site preparation • Regeneration • Stand tending (pre-commercial thinning,

fertilization, pruning • Commercial thinning • Harvesting Vegetation management and forest health

management occur throughout all phases.

Site prepare to modify: •Logging slash - amount, distribution, suitability for insects •Vegetation - amount, distribution, species composition, growth rate •Forest floor - depth, distribution •Mineral soil - temperature, drainage, bulk density

Categories of site preparation: •Prescribed fire •Mechanical •Herbicides

In choosing method and equipment consider: •Physical and biological effects on microsite properties, crop plants and non-crop organisms. •Operational requirements and constraints. •Social issues, administrative and legal requirements.

Effects of site preparation on seedling environment

Vegetation competition – light:

at 4 years

Soil temperature:

A B C

Which site prep treatment produces best conditions for growth?

… in boreal and cool temperate zones, air and soil temperatures are rarely warm enough for optimal growth:

Nutrients: mineralization of forest floor nutrients (primarily nitrogen) is greatest on mounds or plow berms. Scalping can reduce nutrients.

Soil bulk density and root growth:

Prescribed Fire What kind of planting spots can fire create? Operational considerations •Must maintain fire weather stations and records •Calculate fire weather and venting indices •Need to inform government agencies •Be prepared to take advantage of narrow burning windows •Effectiveness depends on fire severity (too severe or not enough) •Provide public information

Recovery of non-crop competitors varies with species. Favors fire adapted species.

A Spring, before leaf flush B Summer, after full leaf out C Fall, after leaf drop D A or C

The best time to burn is:

Spring and fall burns give better coverage, but plants resprout more. D

Mechanical Site Preparation

Operational considerations •Decide on optimal microsite and pattern •Match implement to desired microsite •Match prime mover to site and implement (tool) •Avoid site degradation •Need access to site and skilled operators

Mechanical site preparation enables different patterns of spots…

… and different kinds of spots:

raised

level lowered

soil material

A

B

C

Which spot is best for a wet rich site?

These spots have different properties and can be used to offset site growth limiting conditions:

Forwarder Excavator

Skidder

Crawler Human

Prime Movers: Prime mover

Push/Pull/ Lift

Speed Machine Size Ground Pressure

Terrain Conditions

Human Push, Pull, Lift

Slow Low ground pressure

Any

Crawler Push, Pull Slow Medium - Large; High ground pressure

Gentle to moderately steep <35%

Skidder Pull, (Push) Fast Large; High ground pressure

Gentle <15%

Forwarder Pull Fast Large; Moderate ground pressure

Gentle <35%

Excavator Lift Slow Small - large; Low - moderate ground pressure

gentle to steep <50%

(see line drawings on p. 157-161 of RBCF)

http://www.youtube.com/watch?v=e3luK2nkCp8

Brush rake

Slash rake

bucket

Rake

Mulching head

Prime mover/ Action

Implement Treatment Coverage

Crawler / Push Straight blade

move or pile slash; shear brush above ground

uniform or strip

Brush or Slash rake

move or pile slash; remove brush (tops and some roots), break up upper soil

uniform or strip

V-blade move slash; shear brush above ground

strip

Excavator/ Lift Mounding bucket

invert humus or mineral mounds

spot

Slash rake move or pile slash spot

Mulcher chop brush and slash, mix plant debris, humus and mineral

spot

Implements:

Plow Disk trencher

Ripper bar Scarifier/mounder

Bedding plow

Drag scarifier

Prime mover/ Action

Implement Treatment Coverage

Skidder, Forwarder, (Crawler)/ Pull

Plow break up hard soil, drain, create terraces and linearly inverted mounds

strip

Ripper break up hard soil strip

Disc trencher

scalp and invert forest floor along trench

strip

Patch scarifier

scalp and invert forest floor spot

Mounder invert humus or mineral mounds

spot

Bedding plow (discs)

mix humus and mineral uniform or strip

Drag scarifier

distribute cones, lightly scalp and mix organic and mineral

uniform or strip

Implements cont…

Which spot is best for this site?

A B C

Raised Neutral Lowered

What prime mover and implement would you use on this site?

A B C D

Skidder, disk trencher Crawler, blade Excavator, rake Human, shovel

Site degradation is damage to the productive capacity of a site. Avoid these kinds of impacts:

Site degradiation cont….

In Summary… Site prepare to: •Modify logging slash, vegetation, forest floor, and mineral soil •To improve microsite quality •To reduce fuel and pest hazards •To improve planter access

Match method to microsite type and pattern, and to site conditions. Don’t degrade site by burning or scalping too much forest floor, or by compaction.

Role Playing 1. Foresters: a) What information and instructions do you need to give a

site prep contractor who is going to prepare your SP site?

b) How will you ensure quality and avoid site degradation?

2. Contractors: a) What do you need to know if you are going to bid on

this project? b) What will motivate you to produce a quality job and

avoid site degradation?