Assessing Internal Hurricane Damage To Standing Pine Poletimber

Authors

  • Timothy D. Faust
  • Mark M. Fuller
  • Robert H. McAlister
  • Stanley J. Zarnoch

Keywords:

Storm damage, poletimber, toughness, tension strength, FIA damage class

Abstract

Two test methods were used to assess type, location, and degree of internal stem damage to standing pine poletimber (5.0-8.9 in. diameter at breast height, DBH) caused by Hurricane Hugo. A total of sixty trees [15 from each of the four Forest Inventory Analysis (FIA) damage classes] were taken from three sites in the Francis Marion National Forest. Internal damage was expected in the form of ring shake and compression failure. Five stem sections (A through E) were taken from each tree at different heights. From each section, specimens were cut from four quadrants (Tension, Compression, Left, and Right) relative to the wind direction during the storm for toughness and tension perpendicular to the grain testing. A total of 2,147 toughness specimens were tested. A total of 273 specimens were tested in tension perpendicular to the grain. The dependent variables analyzed were toughness, tension strength, and specific gravity with FIA damage class as the whole plot factor.

Although there was an increasing trend in toughness from Damage Class 1 through 4, analysis of variance showed damage class not to be a significant effect on toughness. Stem section and quadrant were found to be significant on toughness. Much of the variation in toughness due to stem section may be attributed to the effects of juvenile wood differences with tree height. Also a high occurrence of reaction wood in Quadrant C (side of the tree away from the wind) would contribute to lower toughness strength. Similarly, specific gravity (SG) values showed an overall increase from Damage Class 1 through 4. Specific gravity of Damage Classes 1 and 4 was found to be significantly different. Statistical analysis showed no apparent relationship between damage class and tension strength perpendicular to the grain.

The lack of evidence for internal damage is relatively unimportant compared to the evidence of change in the wood properties from the formation of reaction wood. In leaning stems (FIA Damage Classes 2, 3, 4), reaction wood should continue to form. In straight trees, reaction wood formed in the two growth seasons following the storm, but it is unclear whether it will continue to form. The results lead to the conclusion that stands with leaning stems should be harvested and replanted.

References

American Society For Testing Materials. Standard D143-93. 1993. Toughness and tension perpendicular to the grain procedures. Philadelphia, PA.nEhinger, L. H. 1990. Hurricane Hugo damage. Annual Conference of the International Society of Arboriculture, August 1990, in Toronto, Ontario.nFoster, D. R. 1988. Species and stand response to catastrophic wind in central New England, USA. J. Ecology 76:135-151.nMayer, H. 1988. Windthrow. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 1989, 324:1223, 267-281.nSheffield, R. M., and M. T. Thompson. 1992. Hurricane Hugo—Effects on South Carolina's forest resource. Southeastern Forest Experiment Station Research Paper SE-284.nStudholme, W. P. 1989. Windthrow on the Canterbury Plains. Workshop on wind damage in New Zealand exotic forests. FRI bulletin 146. Forest Research Institute, Ministry of Forestry, PV 3020, Rotorua, New Zealand.nSAS Institute, Inc. 1988. SAS/Stat Users Guide, Release 6.03 Edition, Cary, NC: SAS Institute, Inc. 1,028 pp.nUSDA Forest Products Laboratory. 1987. Wood handbook: Wood as an engineering material. Agric. Handbk. 72, Washington, D.C. 466 pp.nWebb, S. L. 1988. Windstorm damage and microsite colonization in two Minnesota forests. University of Minnesota, Department of Ecology and Behavioral Biology, Minneapolis, MN.n

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Published

2007-06-25

Issue

Number 4 / October 1994

Section

Research Contributions

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