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 Our hardwood forest have complex structures due to many species, silvical properties and growth rates- stands are typically even-aged and tree size mostly determined by shade tolerance and competition/growth rate.

Landowner Intentions: Manage for sustained yield of wood products and other services. Prescribed Fire Herbicides Thinnings Shelterwood Two-age Management Group Selection Herbicide line

Landowner Goals vs. Land use history Grazing Fire Disease/Insects Logging damage Harvesting Deer browsing Invasive plants Sprouting-rot, quality Disturbance Interactions The ability of a woodlot to provide the benefits a landowner desires. health of a woodlot is determined by the type of disturbance that has occurred

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” Harvesting that was not related to any silvicutural prescription but to a short term goal.

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% Most of you are familiar with the 1995 assessment of harvests in Ny, WV and Pa where our goal was to classify the type of harvest, the structure of the residual stand and the future of the residual stand. Stands were left with very irregular distributions of residual trees

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 WV experiment monitoring long-term effects of d-limit Acknowledgements: Aaron Graves, Shawn Grushecky, Karl Knipling, Brian Tift, Travis Deluca

Stand Structure Preharvest: 1993 Postharvest: 1995 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% 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 12 “ Stands were classified as regeneration should occur and some of the 16” could be harvested again for low value products.

Effects of Residual Trees on Regeneration Development After Diameter-limit Cutting Residual Clump Gap One graduate student looked at the effects of residual trees on the development of the regeneration

Regeneration Species Importance Values: 9 Years After Harvest Oak and Poplar from 80% to <20. There was plenty of oak regen and it is still there but very short and not counted. Poplar was more prevalant after harvest in the gaps. What happened?

Don’t like cherry

Rehabilitate and Regenerate Future Sawlog? Retain AGS and seed trees Black Cherry Create/maintain gaps Point out black cherry sapling as the future in a gap but the residual trees are slowing down the development of the cohort that has resulted from the harvest in 1993. I think there would also have been an effect on height of poplar but the sample size was not very large. 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. Rehabilitation means you still have enough to work with in the current rotation even though value may be low, stocking is sufficient but improvement cutting necessary to ensure sustainability of new cohort.

Adapting Stringer Guidelines to SILVAH System: Rehabilitate, Regenerate, or Combination? Dr. Jeff Stringer, U Ky, developed “Silvicultural Presriptions 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 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 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 regen and no interference – “free to grow desirable regen”

SILVAH & Degraded 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/acre in mixed oak stands These prescriptions are both costly and risky They ignore any positives in degraded stands Modify current procedure

Degraded Stand Inventory Procedure 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 How to identify the positives and get a realistic picture of what you have to work with

Rehabilitation requirements: 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 Stand relative density should not be below 50% for rehabilitation, and at least 35% stocking should be Acceptable Growing Stock OR Seed Source Unacceptable Growing Stock. Below this level you regenerate at least parts of the stand, depending on the spatial distribution of AGS, SSUGS, and desirable regeneration. Spatial distribution of AGS also affects economics of harvesting.

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 Did a seed cut ? years ago. Some seedlings got established but the competing vegetation also flourished such as ferns . . AGS and SSUGS in overstory represent < 35% stocking, existing regeneration patches plus patches of adequate seed source represent at least 70% stocking for next stand.

Combined Rehabilitation and Regeneration Situation: Sufficient AGS/SSUGS present but widely scattered or clumped. Regeneration potential spatially irregular. Oak sapling

Combined 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 0.5 acre will regenerate a mix of species but patch will need to be expanded sooner than 1.25 acre.

Do the best with what you 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 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 Regen and Any Est Regen No Deer > 0 Any Des Regen and 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 So – we’re in a stand in which there are not enough plain AGS to manage, so we lower our standards. If AGS plus SSUGS give us enough to work with -- > 35% stocking – then we can use the standard SILVAH charts. If they don’t, we have to treat parts of the stand differently, developing either strong crop trees or regeneration potential into regeneration whereever we find it; fencing if deer are limiting, and only planting where there’s really nothing positive over the area of an acre or more. Is Des Regen free to grow? YES 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

Best to PLAN BEFORE YOU CUT! Degraded conditions cannot be corrected in one treatment Requires time, money, management skill and patience Best to PLAN BEFORE YOU CUT!