Silviculture

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Silviculture is the practice of controlling the establishment, growth, composition, health, and quality of forests to meet diverse needs and values. The name comes from the Latin silvi- (forest) + culture (as in growing). The study of forests and woods is termed silvology. Silviculture also focuses on making sure that the treatment(s) of forest stands are used to preserve and to better their productivity.[1]

To some the distinction between forestry and silviculture is that silviculture is applied at the stand level and forestry is broader. For example John D. Matthews says "complete regimes for regenerating, tending, and harvesting forests" are called "silvicultural systems".[2]

So active management is required for silviculture, whereas forestry can be natural, conserved land without a stand level treatment being applied. A common taxonomy divides silviculture into regenerating, tending and harvesting techniques.

Regeneration[edit]

Forest regeneration is the act of renewing tree cover by establishing young trees, generally promptly after the previous stand or forest has been removed. The method, species, and density are chosen to meet the goal of the landowner.

It may be divided into natural regeneration:

"Human-assisted natural regeneration" means establishment of a forest age class from natural seeding or sprouting in an area after harvesting in that area through selection cutting, shelter (or seed-tree) harvest, soil preparation, or restricting the size of a clear-cut stand to secure natural regeneration from the surrounding trees.

The process of natural regeneration involves the renewal of forests by means of self-sown seeds, root suckers, or coppicing. In natural forests, conifers rely almost entirely on regeneration through seed. Most of the broadleaves, however, are able to regenerate by the means of emergence of shoots from stumps (coppice) and broken stems.[3]

and artificial regeneration.

Tree provenance is important in artificial regeneration. Good provenance takes into account suitable tree genetics and a good environmental fit for planted / seeded trees in a forest stand. The wrong genotype can lead to failed regeneration, or poor trees that are prone to pathogens and undesired outcomes.

Artificial regeneration has been a more common method involving planting because it is more dependable than natural regeneration. Planting can involve using seedlings (from a nursery), (un)rooted cuttings, or seeds.[4]

Whichever method is chosen it can be assisted by tending techniques also known as intermediate stand treatments.

Tending[edit]

Enrichment planting[edit]

A strategy for enhancing natural forests' economic value is to increase their concentration of economically important, indigenous tree species by planting seeds or seedlings for future harvest, which can be accomplished with enrichment planting (EP).[5] This means increasing the planting density (i.e., the numbers of plants per hectare) in an already growing forest stand."[6]

Release treatments[edit]

Thinning[edit]

Thinning is an operation that artificially reduces the number of trees growing in a stand with the aim of hastening the development of the remainder.[8] The goal of thinning is to control the amount and distribution of available growing space. By altering stand density, foresters can influence the growth, quality, and health of residual trees. It also provides an opportunity to capture mortality and cull the commercially less desirable, usually smaller and malformed, trees. Unlike regeneration treatments, thinnings are not intended to establish a new tree crop or create permanent canopy openings.

Common thinning methods:[9]

Previous studies have demonstrated that repeated thinnings over the course of a forest rotation increase carbon stores relative to stands that are clear-cut on short rotations and that the carbon benefits differ according to thinning method (e.g., thinning from above versus below).[10]

Ecological thinning is where the primary aim of forest thinning is to increase growth of selected trees, favoring development of wildlife habitat (such as hollows) rather than focusing on increased timber yields. Ecological thinning can be considered a new approach to landscape restoration for some types of eucalypt forests and woodlands in Australia.

Pruning[edit]

Pruning, as a silvicultural practice, refers to the removal of the lower branches of the young trees (also giving the shape to the tree) so clear knot-free wood can subsequently grow over the branch stubs. Clear knot-free lumber has a higher value. Pruning has been extensively carried out in the Radiata pine plantations of New Zealand and Chile, however the development of Finger joint technology in the production of lumber and mouldings has led to many forestry companies reconsidering their pruning practices. "Brashing" is an alternative name for the same process.[11] Pruning can be done to all trees, or more cost effectively to a limited number of trees. There are two types of pruning: natural or self-pruning and artificial pruning. Most cases of self-pruning happen when branches do not receive enough sunlight and die. Wind can also take part in natural pruning which can break branches.[12] Artificial pruning is where people are paid to come and cut the branches. Or it can be natural, where trees are planted close enough that the effect is to cause self-pruning of low branches as energy is put into growing up for light reasons and not branchiness.

Forest care[edit]

This may be reducing browsing. It can also be techniques for dealing with forest pathogens.

Common methods[edit]

Silvicultural regeneration methods combine both the harvest of the timber on the stand and re-establishment of the forest. The proper practice of sustainable forestry[13] should mitigate the potential negative impacts, but all harvest methods will have some impacts on the land and residual stand.[14] The practice of sustainable forestry limits the impacts such that the values of the forest are maintained in perpetuity. Silvicultural prescriptions are specific solutions to a specific set of circumstances and management objectives.[15] Following are some common methods:

"Uneven-aged and even-aged methods differ in the scale and intensity of disturbance. Uneven-aged methods maintain a mix of tree sizes or ages within a habitat patch by periodically harvesting individual or small groups of trees, Even-aged methods harvest most or all of the overstory and create a fairly uniform habitat patch dominated by trees of the same age".[27] Even-aged management systems have been the prime methods to use when studying the effects on birds.[28]

See also[edit]

Citations[edit]

  1. ^ Hawley, R.C. and D.M. Smith. The Practice of Silviculture. 6th edition. New York: John Wiley & Sons Inc., 1954. Print.
  2. ^ John D. Matthews, Silvicultural Systems. Oxford Science Publications. 1991, ISBN 9780198546702
  3. ^ Template:11 Huss,J. 2004;
  4. ^ Tappeiner, J.C., D.A. Maguire, and T.B. Harrington. Silviculture and Ecology of Western U.S. Forests. Corvallis: Oregon State University Press, 2007. Print.
  5. ^ Template:5 Keefe,K. 2012;
  6. ^ 'Fact Sheet 4.12. Forest Regeneration', IPCC Special Report on Land Use, Land-Use Change And Forestry
  7. ^ Daniel, Theodore, John Helms, and Frederick Baker. Principles of Silviculture. 2nd ed. New York: McGraw-Hill, 1979. Print.
  8. ^ Template:6 Savill,P.S. 2004;
  9. ^ Baker, Frederick. Theory and Practice of Silviculture. First Edition. New York: McGraw-Hill, 1934. Print.
  10. ^ Template:7 D’Amato,Anthony W. 2011;
  11. ^ The Dictionary of Forestry, The Society of American Foresters
  12. ^ Smith, D.M., B.C. Larson, M.J. Kelty, and P.M.S. Ashton. The Practice of Silviculture: Applied Forest Ecology. 9th edition. New York: John Wiley & Sons, Inc., 1997. Print.
  13. ^ Oregon State University Extension Service
  14. ^ RESIDUAL DAMAGE IN A CONIFER STAND THINNED WITH A CTL SYSTEM, University of Idaho
  15. ^ Template:8 Bauhus,Jürgen 2009;
  16. ^ Conservation Approaches for Woody, Early Successional Communities in the Eastern United States. Frank R. Thompson, III and Richard M. DeGraaf Wildlife Society Bulletin , Vol. 29, No. 2 (Summer, 2001), pp. 483-494. Web. 4 October 2013.
  17. ^ Effects of Group-Selection Opening Size on Breeding Bird Habitat Use in a Bottomland Forest. Christopher E. Moorman and David C. Guynn Jr. Ecological Applications , Vol. 11, No. 6 (Dec., 2001), pp. 1680-1691. Web. 4 Oct. 2013.
  18. ^ Template:9 Schulte,Benedict J. 1998;
  19. ^ Template:12 Gamborg,Christian 2003;
  20. ^ Template:3 Brose,Patrick H. 2008; 3 Brose,Patrick H. 2008;
  21. ^ Template:4 Holgén,Per 2000; 4 Holgén,Per 2000;
  22. ^ Survival and Growth of Under-Planted Trees: A Meta-Analysis across Four Biomes. Alain Paquette, André Bouchard and Alain Cogliastro Ecological Applications , Vol. 16, No. 4 (Aug., 2006), pp. 1575-1589
  23. ^ Template:4 Holgén,Per 2000;
  24. ^ Smith, D.M., B.C. Larson, M.J. Kelty, P.M.S. Ashton (1997) The Practice of Silviculture: Applied Forest Ecology, John Wiley & Sons, p. 340-46
  25. ^ Template:10 Harmer,R. 2004;
  26. ^ Kohm, K. A, and Franklin, J. F., Creating a forestry for the 21st century: the science of ecosystem management. Island Press. 1997, ISBN 978-1-55963-399-4
  27. ^ The Role of Disturbance in the Ecology and Conservation of Birds Jeffrey D. Brawn, Scott K. Robinson and Frank R. Thompson III Annual Review of Ecology and Systematics , Vol. 32, (2001), pp. 251-276. Web. 4 October 2013.
  28. ^ Effects of Selection Cutting on Bird Communities in Contiguous Eastern Hardwood Forests . Andrew P. Jobes, Erica Nol and Dennis R. Voigt The Journal of Wildlife Management , Vol. 68, No. 1 (Jan., 2004), pp. 51-60. Web. 4 October 2013.

References[edit]

  • Daniel, T. W., J. A. Helms, and F. S. Baker 1979. Principles of Silviculture, 2nd Edition. McGraw-Hill, New York. 521 pp. ISBN 0-07-015297-7
  • Evans, J. 1984. Silviculture of Broadleaved Woodland. Forestry Commission Bulletin 62. HMSO. London. 232 pp. ISBN 0-11-710154-0
  • Hart, C. 1995. Alternative Silvicultural Systems to Clear Cutting in Britain: A Review. Forestry Commission Bulletin 115. HMSO. London. 93 pp. ISBN 0-11-710334-9
  • Nyland, R. D. 1996. Silviculture, Concepts and Applications. The McGraw-Hill Companies, Inc. New York. 633 pp. ISBN 0-07-056999-1
  • Nyland, R. D. 2002 Silviculture: Concepts and Applications, 2nd Edition. The McGraw-Hill Companies, Inc. New York. 704 pp. ISBN 0-07-366190-2
  • Savill, P., Evans, J., Auclair, D., Falck, J. 1997. Plantation Silviculture in Europe. Oxford University Press, Oxford. 297 pp. ISBN 0-19-854909-1
  • Smith, D. M. 1986. The Practice of Silviculture, 8th edition. John Wiley & Sons, Inc., New York. 527 pp. ISBN 0-471-80020-1
  • Smith, D. M., B. C. Larson, M. J. Kelty, P. M. S. Ashton. 1997. The Practice of Silviculture: Applied Forest Ecology, 9th edition. John Wiley & Sons, New York. 560 pp. ISBN 0-471-10941-X
  • Reid, R. (2006) 'Management of Acacia melanoxylon in Plantations' [1]
  • Reid, R. (2002) 'The Principles and Practice of Pruning' [2]

External links[edit]