Forest Management & Regeneration All forest management has regeneration consequences in northeastern forests Susan L. Stout Research Silviculturist Northern Research Station USDA Forest Service, Irvine, PA

This is NOT a regeneration webinar We’ll discuss partial cutting practices –Principles –Benefits –Strategies And their implications for regeneration Linked to a later webinar on treating some problems partial cutting might cause

Scope Examples and data will be from naturally regenerated mixed northeastern hardwood forests, primarily in PA Emphasis on even-aged forests Principles apply more generally to mixed forests where natural regeneration methods are used

With a little help from my friends… Todd Ristau Dave Marquis Ben Roach Chris Nowak Jim Finley Ruth Yanai Mark Twery Ralph Nyland Dave Jackson and others

Principles of Silvicultural Partial Cutting Concentrate growth on the best trees Salvage mortality Reduce rotation Influence species composition These principles apply to both even- and uneven-age stands

Relative Density? Similar to “stocking” Relative to the basal area and # trees/acre found in unmanaged stands Expressed as a fraction of 100%

Open-Grown Trees Individual tree growth is at maximum level Widely spaced trees unable to “fully occupy” growing space georgiachronicles.files.wordpress.com/2009/03.

Basic Concept Above some threshold density of trees, a particular piece of land is going to produce a certain amount of wood per year The idea underlying thinning is that YOU can choose whether that wood is spread over a large number of small trees or a smaller number of soon-larger trees of your choice in species and quality

Moderate stand density Optimal trade-off between individual tree growth and stand growth Actual density considered moderate varies with species composition Economics vary with markets and large product premiums

Dense stands Mortality high among smallest stems Individual tree growth low Maximum control of understory light

Residual density is a COMPROMISE among Stand growth, tree growth, tree quality, and understory response

Promote stand development Enhance habitat for plants and animals Alter visual qualities Move toward old growth (big tree) conditions

Enhance habitat Openness in canopy, especially later in stand development, desirable for some wildlife species –Some bats –Some birds – e.g. Cerulean warblers Google Image

Alter Visual Qualities BeforeAfter

Accelerate development of “big tree” condition Thinning can promote faster tree growth regardless of management objective

When to thin The younger the stand, the more responsive it will be General recommendation is to make a first thinning as soon as it can be made commercially – that varies with markets, especially fiber (or biomass?) prices

How to thin after Nowak 1997

How to Thin II Primarily from below Pay attention to saplings – may need to treat them in young stands About 1/3 of cut in main crown canopy to favor best trees

Allegheny hardwoods Annual net growth after Nowak 1996 Highly variable, with maximum from ~70 to ~110 ft 3 / acre / yr In older stands, pattern is same but response is less The more cherry, the greater the growth

Mixed Oaks After Dale and Hilt 1989 Shows cumulative benefit of thinning SI 65 grows about 50 ft 3 / acre / yr

After Kimmins 1987, Oliver and Larson 1990 Stand development Stand Establishment Stem ExclusionUnderstory ReinitiationOld Growth

After Kimmins 1987, Oliver and Larson 1990 Stand development Stand Establishment Stem ExclusionUnderstory ReinitiationOld Growth

Regeneration Effects During Stem Exclusion Trees very responsive Canopy closure occurs quickly Overstory can maintain control of site If thinning leaves best trees and is not too heavy

Shade Tolerant, Slow Growing Species Grow extremely well in partial shade; resilient to deer browsing; shade out other regeneration

Hay-scented and NY Fern HS & NY fern have a dichotomous forking rhizome. In partially cut stands the rhizome grows faster and produces rhizome buds which grow out rapidly

Invasives An emerging problem associated with partial cutting – e.g. Ailanthus Very important to recognize and address invasives with every entry

Seed Source All partial cutting has potential to change species composition Important to retain seed source for all species desired in next stand, even in early thinnings

After Kimmins 1987, Oliver and Larson 1990 Stand development Stand Establishment Stem ExclusionUnderstory ReinitiationOld Growth

Understory Reinitiation Older trees less responsive Takes longer to regain crown closure Risk of creating or worsening understory problems is greater

Forest Management & Regeneration Many benefits associated with partial cutting in mixed hardwood forests All these benefits come with risks related to regeneration Careful practice – thin from below, don’t thin too much – reduce this risk Conserving desirable seed source also very important

But what if you end up with these problems anyway? Dave Jackson Webinar February 9 th Regenerating Hardwood Stands: Managing Competition, Deer, and Light

Bibliography Hyperlinks will take you to TreeSearch, a one-stop on-line source for research publications produced by US Forest Service scientists.TreeSearch Roach, Benjamin A A Stocking Guide for Allegheny Hardwoods and Its Use in Controlling Intermediate Cuttings. Res. Pap. NE-373. Upper Darby, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 30p.A Stocking Guide for Allegheny Hardwoods and Its Use in Controlling Intermediate Cuttings. Roach, Benjamin A.; Gingrich, Samuel F Even-aged silviculture for upland central hardwoods. Agric. Handb Washington, D.C.: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 39 p.Even-aged silviculture for upland central hardwoods. Stout, Susan Laurane; Nyland, Ralph D Role of species composition in relative density measurement in Allegheny hardwoods. Can. J. For. Res. 16:574 ‑ 579.

Bibliography (Cont.) Marquis, David A.; [Editor] Quantitative silviculture for hardwood forests of the Alleghenies : Thinning/Distribution/Marketing's/Principles/Summary. Gen. Tech. Rep. NE-183. Radnor, PA: U. S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station p.Quantitative silviculture for hardwood forests of the Alleghenies : Thinning/Distribution/Marketing's/Principles/Summary. Yanai, Ruth D.; Twery, Mark J.; Stout, Susan L Woody understory response to changes in overstory density: thinning in Allegheny hardwoods. Forest Ecology and Management. 102: Woody understory response to changes in overstory density: thinning in Allegheny hardwoods. Nowak, Christopher A.; Marquis, David A Distribution-of-cut guides for thinning in Allegheny hardwoods: a review. Res. Notes NE Radnor, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 7 p.Distribution-of-cut guides for thinning in Allegheny hardwoods: a review.

Bibliography (Cont.) Nowak, Christopher A Wood volume increment in thinned, 50- to 55-year-old, mixed-species Allegheny hardwoods. Canadian Journal of Forest Research 26: Wood volume increment in thinned, 50- to 55-year-old, mixed-species Allegheny hardwoods. Hilt, Donald E.; Dale, Martin E Thinning even-aged, upland oak stands. In: Hutchinson, Jay G., ed. Central hardwood notes. St. Paul, MN.: U.S. Dept. of Agriculture, Forest Service, North Central Forest Experiment Station Thinning even-aged, upland oak stands. Kimmins, J.P Forest ecology. New York. MacMillan. Oliver, Chadwick Dearing; Larson, Bruce C Forest stand dynamics. New York: McGraw-Hill. 467 p.