Forest Management Regeneration All forest management has regeneration

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 • Ruth Yanai • Dave Marquis • Mark Twery • Ben Roach • Ralph Nyland • Chris Nowak • Dave Jackson • Jim Finley • 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 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 Before After

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

Stand development Stand Establishment Stem Exclusion After Kimmins 1987, Oliver and Larson 1990 Understory Reinitiation Old Growth

Stand development Stand Establishment Stem Exclusion After Kimmins 1987, Oliver and Larson 1990 Understory Reinitiation Old 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

Stand development Stand Establishment Stem Exclusion After Kimmins 1987, Oliver and Larson 1990 Understory Reinitiation Old 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 Tree. Search, a one-stop on-line source for research publications produced by US Forest Service scientists. • Roach, Benjamin A. 1977. 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. 30 p. • Roach, Benjamin A. ; Gingrich, Samuel F. 1968. Even-aged silviculture for upland central hardwoods. Agric. Handb. 355. Washington, D. C. : U. S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 39 p. • Stout, Susan Laurane; Nyland, Ralph D. 1986. Role of species composition in relative density measurement in Allegheny hardwoods. Can. J. For. Res. 16: 574‑ 579.

Bibliography (Cont. ) • Marquis, David A. ; [Editor] 1994. 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. 247 -376 p. • Yanai, Ruth D. ; Twery, Mark J. ; Stout, Susan L. 1998. Woody understory response to changes in overstory density: thinning in Allegheny hardwoods. Forest Ecology and Management. 102: 45 -60. • Nowak, Christopher A. ; Marquis, David A. 1997. Distribution-of-cut guides for thinning in Allegheny hardwoods: a review. Res. Notes NE 362. Radnor, PA: U. S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 7 p.

Bibliography (Cont. ) • Nowak, Christopher A. 1996. Wood volume increment in thinned, 50 - to 55 -year-old, mixed-species Allegheny hardwoods. Canadian Journal of Forest Research 26: 819 -835. • Hilt, Donald E. ; Dale, Martin E. 1989. 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. 6. 06. • Kimmins, J. P. 1987. Forest ecology. New York. Mac. Millan. • Oliver, Chadwick Dearing; Larson, Bruce C. 1990. Forest stand dynamics. New York: Mc. Graw-Hill. 467 p.