Rehabilitation and Regeneration of Degraded Forest Stands

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Rehabilitation and Regeneration of Degraded Forest Stands. Mary Ann Fajvan and Susan Stout USFS Northern Research Station Acknowledgements: Jeff Stringer, Wayne Clatterbuck , Andy Ezell. Silviculture : Manipulating Stand Structure and Growth.
Rehabilitation and Regeneration of Degraded Forest Stands Mary Ann Fajvan and Susan Stout USFS Northern Research Station Acknowledgements: Jeff Stringer, Wayne Clatterbuck, Andy Ezell Silviculture: Manipulating Stand Structure and Growth Landowner Intentions: Manage for sustained yield of wood products and other services. Prescribed Fire Herbicides Thinnings Shelterwood Two-age Management Group Selection Landowner Goals vs.Land use history
  • Grazing
  • Fire
  • Disease/Insects
  • Logging damage
  • Harvesting
  • Deer browsing
  • Invasive plants
  • Sprouting-rot, quality
  • Disturbance Interactions
  • Previous cutting, combined with other disturbances, can diminish the potential to sustain quality yields of timber
  • Single or repeated harvests where the majority or all of the desirable trees have been cut leaving a stand of undesirable species and low quality.
  • “High-grading” “Diameter-limit cutting” “Select Cut” “Exploitative Harvesting”
  • Effects of Partial Harvesting on Stand Structure: 1995 WV Assessment
  • Average diameter decreased 10.2” 9.4”
  • Total basal area decreased 75.5 52.9 ft2/a
  • Percent stocking decreased 65% 45%
  • Classification of Harvested Stands
  • Silvicultural treatment (4)
  • Nonsilvicultural treatment(23) Both will produce sawtimber in 10-15 years
  • Stand should be regenerated (31)
  • Regeneration has/should occur (16)
  • NS treatment, quality timber potential lost, fiber possible (25)
  • Fajvan et al. May 1998. Journal of Forestry FUTURE? Effects of Diameter-limit Cutting on Sustainability Acknowledgements:Aaron Graves, Shawn Grushecky, Karl Knipling, Brian Tift, Travis Deluca Stand Structure Preharvest: 1993 Postharvest: 1995 BA 12-inch limit: 10-37, AGS 16 ft2/a BA 16-inch limit: 34-76, AGS 37 ft2/a Average dbh: 8.7-9.6 “ Species removed: 89-96% yellow-poplar and red oak Stand damage 15-25 ft2/a
  • Age: 60
  • Average BA: 120 ft2/a
  • Average dbh: 11”
  • Species Composition
  • Yellow-poplar 50%
  • Red oak 30%
  • Red maple 10%
  • Black cherry 7%
  • White oak 3%
  • Effects of Residual Trees on Regeneration Development After Diameter-limit Cutting Residual Clump Gap Regeneration Diameter-limit CuttingSpecies Importance Values: 9 Years After Harvest Rehabilitate and Regenerate Diameter-limit Cutting Future Sawlog? Retain AGS and seed trees Black Cherry Create/maintain gaps Reduce shade on saplings; liberation Management Options* for Degraded Stands: Rehabilitate, Regenerate, or Combination? Total Stand Rehabilitation Requirements:
  • A manageable stand of crop trees must exist
  • Owner must be willing to perform TSI and long-term management *Ezell, A.W. 2004. Evaluating high-graded hardwood stands. Mississippi State University Extension Service. Publication 1834.
  • Adapting Stringer Guidelines to SILVAH System: Regenerate, or Combination?Rehabilitate, Regenerate, or Combination?
  • Dr. Jeff Stringer, U Ky, developed “SilviculturalPresriptions for Degraded Stands”
  • Based on doing the best you can with what you have
  • Adapted these guidelines to SILVAH variables and inventory processes
  • Appropriate for stands with < 35% stocking of Acceptable Growing Stock and low amounts of Seed Source UGS
  • Some new ideas and terminology Regenerate, or Combination?
  • Normally, we call trees with no potential to produce a sawlog “UGS” – Unacceptable Growing Stock
  • Caused by poor form
  • Caused by poor health
  • Caused by undesirable species
  • In degraded stand situation, we separate these into
  • SSUGS – Poor form, good health, desirable species – still Seed Source
  • UGS – Undesirable species, poor health, unlikely to survive to produce seed
  • Some new ideas and terminology Regenerate, or Combination?
  • Normally, we look at stand level totals and averages
  • % stocked with desirable regeneration
  • % stocked with interfering plants
  • In degraded stands, we’re interested in each patch as a potential lifeboat for the stand
  • % stocked with desirable regenandno interference – “free to grow desirable regen”
  • SILVAH & Degraded Regenerate, or Combination?Stands: Current Procedure
  • If relative density (stocking) of AGS falls below 35%, SILVAH recommends regenerating
  • If stand level seed source for desirable species is limiting, SILVAH recommends stand-wide artificial regeneration (planting)
  • When desirable seed source BA falls below 25 ft2/acre in Allegheny/Northern Hardwoods
  • Below 40 ft2/acrein mixed oak stands
  • These prescriptions are both costly and risky
  • They ignore any positives in degraded stands
  • Degraded Stand Inventory Procedure Regenerate, or Combination?
  • Identify and evaluate AGS (age, vigor, form species)
  • Identify Seed Source Unacceptable Growing Stock (SSUGS) especially for at risk species.
  • Assess regeneration potential for desirables (sprouting too)
  • Assess site quality
  • Determine spatial distribution of AGS, SSUGS, regeneration
  • Rehabilitation requirements: Regenerate, or Combination? Minimum Basal Area: 20-30 ft2/acre saplings 40-50 ft2/acre poles/saw Above C level, with at least 35% AGS/SSUGS Spatial distribution of desirable trees Uniform Scattered Clumped Regeneration Requirements: AGS/SSUGS < 35% stocking, Regeneration Patches/Sources > 70%).
  • Total Stand Regeneration:
  • There are insufficient/unsuitable crop trees; current rotation is over
  • Owner must be willing to harvest low value, perform release operations and long-term management
  • Spatial distribution of any advance regeneration
  • Age of regeneration (development since harvest)
  • Composition/shade tolerance of regeneration
  • Competitive status: Crown class
  • Leave 5 seed trees/a; consider culls of desirables
  • Midstory canopy density; site prep on good sites for oak
  • Consider Planting
  • Combined Regeneration Rehabilitation and Regeneration Situation: Sufficient AGS/SSUGS present but widely scattered or clumped. Regeneration potential spatially irregular. Oak sapling Combined Regeneration Rehabilitation and Regeneration Guidelines:
  • Maintain clumps of AGS
  • Keep/reduce BA <20 ft2/a in open areas
  • Retain seed trees (scattered or within clumps)
  • Maintain opening size 150’ diameter for oak; 1.25 ac for mixed species
  • Do the best with what you Regeneration have:
  • Use UGS of desirable spp. as seed source
  • Capitalize on ANY desirable advance regeneration
  • Practice a mix of releasing remaining AGS and regenerating where there are none (may include planting)
  • Likely to take many entries
  • As a forester, you need to feel good about each incremental improvement
  • Speed and effectiveness of rehabilitation depend upon
  • landowner’s willingness to invest (e.g. herbicide)
  • markets for small and/or poor quality material
  • Chart O: Degraded Stand Analysis & Rx Regeneration Are there enough AGS plus SSUGS to manage? YES NO SSUGS RD + AGSRD ≥ 35% and Seed Source BA ≥ 30 sq. ft./ac SSUGSRD + AGSRD < 35% or Seed Source BA < 30 sq. ft./ac Use traditional SILVAH charts for regeneration, retaining SSUGS and AGS for seed source Is desirable regeneration present? YES NO Any Des Regenand Any EstRegen No Deer > 0 Any Des Regenand Any Des Regen No Deer = 0 Release all Des Regen with 1 – 1.5 acre openings; work with AGS and SSUGS elsewhere; fence if needed YES Is Des Regen free to grow? Work with AGS and SSUGS to regenerate; supplement with art regen; fence if needed NO Treat interference to release Des Regen while creating 1 – 1.5 acre openings; work with AGS & SSUGS elsewhere; fence if needed Degraded conditions cannot be corrected in one treatment Regeneration Requires time, money, management skill and patience Best to PLAN BEFORE YOU CUT!
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