Silviculture exam2

Site preparation

any treatment applied to slash, competing vegetation, forest floor or soils that modifies exisitng vegetative or physical site conditions to create a favorable environment for regeneration

Objectives of site prep.

(RRR) Remove, Reduce, Rearrange phsycial obstacles to human activies

• logging, slah, stumps, roots

• facilitates movement of planting crews + equipment

Seed bed prep: treatment of forest floor to expose mineral soil by burning or mechanical scarification

Treat competing vegetation: remove prexisting vegetation to minimize competing rengeration

Types of stie preparation treatments

Mechanical methods

chemical mehtods

Prescribed fire

(not restricted to clearcut areas)

mechanical methods - site prep

designed to alter soil or litter/reduce unwanted vegetation and debris

logging distrubance (passive site prep

• creates scarified seed bess (mix of humus + soil - ideal for paper/yellow birch, red/white pine)

  • <30% of soil is scarified

• reduces planting costs

• reduces competition from residual vegetation

• exposes or cultivates mineral soil 

Chemical methods - site prep

used to kill or deter interferring organisms (herbicides) or supplement soil nutrients

kill ground level vegetation to improve fuel conditions for prescribed burning 

(Apply in summer so leaves absorb chemicals down to roots)

Prescribed fire- site prep

Used to kill interferring vegetation or reduce organic debris

Side effects of mechanical site prep

• potential for compaction

• removal of organic soil horizon

  • reduced infiltration, nutrient stores in soil

• Change in surface topography

  • puddling in depressions

  • frost heaving + damage in depressions

• damage to residual stem

Chemical site prep methods

• Broadcast methods - spray herbicides over foliage/bark of existing communities or over stumps of cut trees/shrubs that might resprout

• selective application - individual stems/patches of vegetaition, labor intensive and more expensive (most common in VT)

Advantages of chemcial site prep

• effective at killing a broad array of weeds + other interferring plants

• does not disturb soil surface or affect inherent site potential

• cost effective

Disadvantages of chemical site prep

• chemicals may kill more than just targets species 

• often need to wait a year for woody plants to spout before application

• does not modify soil seed bed conditions

• removal of one species may imprvoe conditons for other competitors (secondary invaders)

• very controversial