Should forest regeneration studies have more replications?

Should forest regeneration studies have more replications?

Authors

  • David B. South School of Forestry and Wildlife Science, Auburn University, AL 36849-5418
  • Curtis L. VanderSchaaf School of Agricultural Sciences and Forestry, Louisiana Tech University, Ruston, LA 71272

DOI:

https://doi.org/10.21750/REFOR.3.03.27

Keywords:

Experimental design, Hypothesis, Replication, Statistics, Survival

Abstract

When it comes to testing for differences in seedling survival, researchers sometimes make a Type II statistical error (i.e. failure to reject a false null hypothesis) due to the inherent variability associated with survival in tree planting studies. For example, in one trial (with five replications) first-year survival of seedlings planted in October (42%) was not significantly different (alpha = 0.05) from those planted in December (69%). Did planting in a dry October truly have no effect on survival? Authors who make a Type II error might not be aware that as seedling survival decreases (down to an overall average of 50% survival), statistical power declines. As a result, the ability to declare an 8% difference as “significant†is very difficult when survival averages 90% or less.  We estimate that about half of regeneration trials (average survival of pines <90%) cannot declare a 12% difference as statistically significant (alpha = 0.05).  When researchers realize their tree planting trials have low statistical power, they should consider using more replications.  Other ways to increase power include: (1) use a one-tailed test (2) use a potentially more powerful contrast test (instead of an overall treatment F-test) and (3) conduct survival trials under a roof.

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Author Biographies

David B. South, School of Forestry and Wildlife Science, Auburn University, AL 36849-5418

Emeritus Professor

Curtis L. VanderSchaaf, School of Agricultural Sciences and Forestry, Louisiana Tech University, Ruston, LA 71272

Assistant Professor

References

Amishev DV, Fox TR (2006) Impact of weed control and fertilization on growth of four species of pine in the Virginia Piedmont. In: Proceedings of the 13th biennial southern silvicultural research conference. US Forest Service. General Technical Report SRS-92. p. 121-123.

Blake JI, South DB (1991) Effects of plant growth regulators on loblolly pine seedling development and field performance. In: Proceedings of the 6th biennial southern silvicultural research conference. US Forest Service. General Technical Report SE-70. p. 100-107.

Boyer WD (1989) Response of planted longleaf pine bare-root and container stock to site preparation and release: fifth-year results. In: Proceedings of the 5th biennial southern silvicultural research conference. US Forest Service. General Technical Report SE-74. p. 165-168.

Clabo DC, Clatterbuck WK (2015) Sprouting capability of shortleaf pine seedlings following clipping and burning: first-year results. In: Proceedings of the 17th biennial southern silvicultural research conference. US Forest Service. General Technical Report SRS-203. p. 137-142.

Cram MM, Enebak SA, Fraedrich SW, Dwinell SW, Zarnoch SJ (2007) Evaluation of fumigants, EPTC herbicide, and Paenibacillus macerans in the production of loblolly pine seedlings. Forest Sci 53(1): 73-83.

Curtis CM, Aust WM, Seiler JR, Strahm BD (2015) Survival and growth of restored Piedmont riparian forests as affected by site preparation, planting stock and planting aids. In: Proceedings of the 17th biennial southern silvicultural research conference. US Forest Service. General Technical Report SRS-203. p. 431-436.

Dean TJ, Scott A, Holley AG (2013) Before and after comparisons of tree height in successive loblolly pine plantations with intervening machine, whole-tree harvesting. In: Proceedings of the 15th biennial southern silvicultural research conference. US Forest Service. General Technical Report SRS-175. p. 9-12.

de Souza DPL, Gallagher T, Mitchell D, McDonald T, Smidt M (2016) Determining the effects of felling method and season of year on the regeneration of short rotation coppice. International Journal of Forest Engineering 27(1): 53-65. https://doi.org/10.1080/14942119.2015.1135616 DOI: https://doi.org/10.1080/14942119.2015.1135616

DeWit JN, Terry TA (1983) Site preparation effects on early loblolly pine growth, hardwood competition, and soil physical properties. In: Proceedings of the 2nd biennial southern silvicultural research conference. US Forest Service. General Technical Report SE-24. p. 40-47.

Dong H, Burdett AN (1986) Chemical root pruning of Chinese pine seedlings raised in cupric sulfide impregnated paper containers. New Forest 1(1): 67-73. https://doi.org/10.1007/BF00028122 DOI: https://doi.org/10.1007/BF00028122

Ezell AW, Yeiser JL, Lauer DK, Quicke HE (2013) Effect of application timing on efficiency of site preparation treatments using Chopper ®Gen2TM In: Proceedings of the 15th biennial southern silvicultural research conference. US Forest Service. General Technical Report SRS-175. p. 219-221.

Foster JR (2001) Statistical power in forest monitoring. Forest Ecology and Management. 151: 211-222. https://doi.org/10.1016/S0378-1127(01)00591-6 DOI: https://doi.org/10.1016/S0378-1127(01)00591-6

Hassan AE, Silva C (1999) Effect of planting date on first-year survival of two pines. In: Proceedings of the 10th biennial southern silvicultural research conference. US Forest Service. General Technical Report SRS-30. p. 344-349.

Hay RL, Rennie JC (1983) Height growth of containerized white pine on the Cumberland plateau, Tennessee. In: Proceedings of the 2nd biennial southern silvicultural research conference. US Forest Service. General Technical Report SE-24. p. 128-133.

Haywood JD, Tiarks AE, Elliott-Smith ML (1998) Response of direct seeded Pinus palustris and herbaceous vegetation to fertilization, burning, and pine straw harvesting. Biomass Bioenerg 14(2): 157-167. https://doi.org/10.1016/S0961-9534(97)10029-0 DOI: https://doi.org/10.1016/S0961-9534(97)10029-0

Jackson DP, Enebak SA, South DB (2012) Survival of southern pine seedlings after inoculations with Pythium and cold storage in the presence of peat moss. Forest Pathol 42: 44-51. https://doi.org/10.1111/j.1439-0329.2011.00721.x DOI: https://doi.org/10.1111/j.1439-0329.2011.00721.x

Kamaluddin M, Chang SX, Curran MP, Zwiazek JJ (2005) Soil compaction and forest floor removal affect early growth and physiology of lodgepole pine and Douglas-fir in British Columbia. Forest Sci 51(5): 513-521.

Larsen HS, South DB, Williams HM, Boyer JN (1989) Survival and early growth of loblolly pine seedlings from six nurseries. In: Proceedings of the 5th biennial southern silvicultural research conference. US Forest Service. General Technical Report SO-74. p. 151-154.

Land SB, Roberts SD, Duzan HW (2004) Genetic and spacing effects on loblolly pine plantation development through age 17. In: Proceedings of the 12th biennial southern silvicultural research conference. US Forest Service. General Technical Report SRS-71. p. 413-419.

Mize CW, Schultz RC (1985) Comparing treatment means correctly and appropriately. Can J Forest Res 15: 1142-1148. https://doi.org/10.1139/x85-185 DOI: https://doi.org/10.1139/x85-185

Nemec AFL (1991) Power Analysis Handbook for the Design and Analysis of Forestry Trials. Biometrics Information Handbook 2. B.C. Ministry of Forests, Victoria. 26 p.

Paquette A, Girard JP, Walsh D (2011) Deep planting has no short- or long-term effect on the survival and growth of white spruce, black spruce, and jack pine. North J Appl For 28(3): 146-151. DOI: https://doi.org/10.1093/njaf/28.3.146

Park HM (2008) Hypothesis Testing and Statistical Power of a Test. Working Paper. The University Information Technology Services (UITS). Center for Statistical and Mathematical Computing. Indiana University. https://scholarworks.iu.edu/dspace/handle/2022/18738

Peterman RM (1990) The importance of reporting statistical power: the forest decline and acidic deposition example. Ecology 71(5): 2024-2027. https://doi.org/10.2307/1937612 DOI: https://doi.org/10.2307/1937612

Rowan SJ (1987) Nursery seedling quality affects growth and survival in outplantings. Georgia Forest Researach Paper 70, Research Division, Georgia Forestry Commission. 14 p.

Schoenholtz SH, Barber BL (1989) The impact of herbicides on loblolly pine plantation establishment in East Texas. In: Proceedings of the 5th biennial southern silvicultural research conference. US Forest Service. General Technical Report SO-74. p. 341-348.

Schubert MR, Rennie JC, Schlarbaum SE (2004) Four pine species grown at four spacings on the eastern highland rim, Tennessee, after 30 years. In: Proceedings of the 12th biennial southern silvicultural research conference. US Forest Service. General Technical Report SRS-71. p. 433-436.

Scott DA, Stagg DA (2013) Plant community responses to soil disturbance and herbicide treatments over 10 years on the Texas LTSP study. In: Proceedings of the 15th biennial southern silvicultural research conference. US Forest Service. General Technical Report SRS-175. p. 21-27.

Smith AE (1989) Interference with loblolly pine (Pinus taeda) seedling growth by three grass species. Weed Technol 3(4): 696-698. DOI: https://doi.org/10.1017/S0890037X00033066

South DB, Jackson DP, Starkey TE, Enebak SA (2012) Planting deep increases early survival and growth of Pinus echinata seedlings. The Open Forest Science Journal 5(1): 33-41. https://doi.org/10.2174/1874398601205010033 DOI: https://doi.org/10.2174/1874398601205010033

South DB, Miller JH (2007) Growth response analysis after early control of woody competition for 14 loblolly pine plantations in the U.S. Forest Ecol Manage 242 (2): 569–577. https://doi.org/10.1016/j.foreco.2007.01.070 DOI: https://doi.org/10.1016/j.foreco.2007.01.070

South DB, VanderSchaaf CL (2006) The statistical reason why some researchers say some silvicultural treatments "wash-out" over time. In: Proceedings of the 13th biennial southern silvicultural research conference. US Forest Service. General Technical Report SRS-92. p. 333-337.

VanderSchaaf CL, South DB, Doruska PF (2003) The power of statistical tests of herbicide trials in forest nurseries. Proc. Southern Weed Science Society. 56: 202-211.

Venator CR, Barnett JD (1985) Relating root growth potential to survival and growth of loblolly pine seedlings. In: Proceedings of the 3rd biennial southern silvicultural research conference. US Forest Service. General Technical Report SO-34. p. 20-24.

Venator CR, Mexal, J.G. (1981) The effect of wrenching and planting date on the survival of loblolly pine seedlings. In: Proceedings of the 1st biennial southern silvicultural research conference. US Forest Service. General Technical Report SO-54. p. 125-127.

Walker RF, West DC, McLaughlin SB (1981) Pisolithus tinctorius ectomycorrhizae enhance the survival and growth of Pinus taeda on a southern Appalachian Coal spoil. In: Proceedings of the 1st biennial southern silvicultural research conference. US Forest Service. General Technical Report SO-34. p. 329-33.

Walker RF, West DC, McLaughlin SB, Amudsen CC (1985) The performance of loblolly, Virginia, and shortleaf pine on a reclaimed surface mine as affected by Pisolithus tinctorius ectomycorrhizae and fertilization. In: Proceedings of the 3rd biennial southern silvicultural research conference. US Forest Service. General Technical Report SO-54. p. 410-416.

Warren WG (1986) On the presentation of statistical analysis: reason or ritual. Can J For Res 16(6): 1185-1191. https://doi.org/10.1139/x86-211 DOI: https://doi.org/10.1139/x86-211

Williams HM, South DB (1995) Root growth potential and field survival of container loblolly pine seedlings fall fertilized with nitrogen. In: Proceedings of the 12th biennial southern silvicultural research conference. US Forest Service. General Technical Report SRS-1. p. 357-363.

Xydias GK (1983) Factors influencing survival and early stocking trends in plantation of loblolly pine. In: Barnett, Proceedings of the 2nd biennial southern silvicultural research conference. US Forest Service. General Technical Report SE-24. p. 101-108.

Zedaker SM, Gregoire TG, Miller JH (1993) Sample-size needs for forestry herbicide trials. Can J For Res 23: 2153-2158. https://doi.org/10.1139/x93-268 DOI: https://doi.org/10.1139/x93-268

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Published

2017-07-01

How to Cite

South, David B., and Curtis L. VanderSchaaf. “Should Forest Regeneration Studies Have More Replications?”. REFORESTA, no. 3 (July 1, 2017): 19–30. Accessed March 28, 2024. https://journal.reforestationchallenges.org/index.php/REFOR/article/view/51.

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