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FW 404 Forest Stand Improvement [FSI] 9/11

Poor Vertical Structure and Plant Richness

  • Where quail go to die

  • Umstead is not natural. Used to be cotton fields, even if it’s not really managed today. Naturally regenerated maybe.

Use the baseball technique

  • Do quail go to die at this place?

    • Question: Can you see a ball from 10 feet away on the ground? If not, too little ground cover.

Pre-commercial thin (PCT)

  • Done early in stand development

    • when, or just before, crowns close

  • before trees commercial

    • cost to landowner

  • Concentrate growth on crop trees

    • shift composition

  • Prolong time to crown closure

    • increase plant richness and structure

  • $200+ per acre for pre-commercial thinning

  • Ultimate wildlife benefit: prolonging canopy closure to allow light over canopy to reach the ground

    • too dense: too much shade, nothing to eat for animals

    • too many trees cut: too much fuel potential, wildfire risk

Commercial Thinning

  • Concentrate growth on crop trees

  • Trees in marketable size class

  • More sunlight on the forest floor

  • Stocking charts for many species

  • Generally <70% canopy cover

    • < 70 ft per acre BA for wildlife in pines

    • < 50 ft per acre BA for northern bobwhite

    • Greater BA where site index is greater

      • Site index = the height of the dominant trees in an even-aged stand at a specific/base age

Improvement/Retention Cuts

  • Typically in older age stands

  • Often ecological over economical

  • Remove undesirable trees (girdled, sprayed, or cut) (girdle cuts off blood vessels from tree to kill it)

    • poorly formed individuals

    • non-commercial species

    • low wildlife value

  • Recover from high-grading

  • Variable retention replicates natural disturbances like tornadoes

Improvement cutting

Before/After Thinning

The trees are the same below but now different ages/heights

Long After Thinning without Fire

Looks like shelterwood. Intermediate light. Midstory hardwood encroachment: when hardwoods creep into midstory and compete for light. Managers should want to avoid this.

Thinning Effects on Vegetation

  • Open, diverse structure

  • Growth of understory woody and herbs

  • Benefits:

    • understory birds and quail

    • small mammals

    • white-tailed deer

    • wild turkey

    • woodland birds (like nuthatch)

      • good species for stewardship plan (brown-headed nuthatch)

    • some bats (less clutter for foraging)

      • more active in forests with trees spread apart, canopy more open

Prescribed Fire After Thinning

  • Clears leaf litter after germination

  • Limits midstory growth

  • Improves browse nutrition

  • Promotes desirable frobs

  • Stimulates fruiting

  • Woody shrubs fruit more prolifically 2-5 years after fire

Thin AND Burn!

  • Too little light and too much litter

  • Nothing can grow under litter layer in second photo

Restoration with Thinning (and Burning)

Mid-rotation Herbicide Release

  • Broadcast application

  • Controls mid-story hardwood in pine

  • Increase growth of crop trees

  • Increases shrub-herb in understory

    • Arsenal (Imazapur) releases legumes

  • Best if followed by prescribed fire

    • to get rid of leaf litter, which can’t be removed with herbicide

    • promotes growth of forbs

Crop Tree Management

  • Focus on individual trees, not stand

  • Choose trees based on:

    • species’ commercial value

    • species’ wildlife value

    • individual characteristics

      • straightness

      • crown size

      • mast production

      • leave cavity trees

girdling

Crop Tree Management

  • Inject or girdle competitors

  • Remove only crowns near crop trees

  • Use on best sites

Before/after C.T. M.

CTM Benefits to Wildlife

  • Favor desirable species

    • “wildlife thinning”

  • increase acorn/mast production

  • increase understory

  • generate snags

  • CTM increases crown size and therefore acorn production

    • some oaks not very good at making acorns

    • large crowns make more acorns

  • Control = acorn production increased due to being an up year vs down year

    • 2001 vs 2002

Fertilization

  • Success varies by soil, rate, etc

  • “More acorns”? “sweeter acorn”?

  • May decrease acorn production!

  • Crowns must have room to grow

  • CTR more efficient

Better FSI

  • Lower canopy cover and more sunlight

  • thin on frequent intervals

  • follow with prescribed fire

  • leave select mast trees

  • leave snags

  • don’t high grade