MECHANICAL PROPERTY ASSESSMENT FOR ESTABLISHING DESIGN VALUES OF WESTERN JUNIPER

Authors

  • Byrne T. Miyamoto Oregon State University
  • Arijit Sinha Oregon State University
  • Scott Leavengood Oregon State University
  • Jeffrey Morrell Oregon State University
  • Donald DeVisser West Coast Lumber Inspection Bureau
  • Dylan Kruse Sustainable Northwest

Abstract

Western juniper (Juniperus occidentalis) is a conifer that is native to Oregon, California, Washington, Nevada, and Idaho. Juniper is highly decay resistant and, therefore, is a popular choice for fence posts and landscape timbers. Forest management practices over the past 100 yr have resulted in an immense population increase in western juniper stands, transforming the grasslands/sagebrush biome into juniper forests. Landowners have been encouraged to cut back western juniper to restore grassland habitat, but there is no major market associated with juniper lumber. This study assessed the mechanical properties of western juniper to develop its design values for inclusion in the National Design Specification. Small clear samples were prepared from juniper harvested from three locations in eastern Oregon, one location in northeast California, and one location in southwest Idaho according to ASTM D143 for compression, bending, and shear. Average strength values were calculated and compared with similar wood species. Most properties were similar to those of other species, but modulus of elasticity was significantly lower. Compressive properties of western juniper also differed, with compression parallel-to-grain being lower and compression perpendicular-to-grain being relatively higher. Differences between species might be attributed to cell wall structure and distribution of lignin in the cells. Design values for western juniper were calculated using the strength values to establish allowable properties for visually graded lumber.

Author Biographies

Byrne T. Miyamoto, Oregon State University

Department of Wood Science & Engineering

Graduate Research Assistant

Arijit Sinha, Oregon State University

Associate Professor

Department of Wood Science & Engineering

Scott Leavengood, Oregon State University

Department of Wood Science & Engineering

Associate Professor

Jeffrey Morrell, Oregon State University

Department of Wood Science & Engineering

Associate Professor

Donald DeVisser, West Coast Lumber Inspection Bureau

Executive Vice President

Dylan Kruse, Sustainable Northwest

Policy Director

References

Ali KH, Hussain T, Kamali A (2014) Compression perpendicular

to grain in timber—Bearing strength for a sill

plate. Master Thesis, Civil Engineering, Department of

Building Technology, University Linnsuniversitetet, Vaxjo,

Sweden.

ASTM D1990-14 (2014) Standard practice for establishing

allowable properties for visually-graded dimension lumber

from in-grade tests of full-size specimens. ASTM, West

Conshohocken, PA.

ASTM D143-14 (2014) Standard test methods for small clear

specimens of timber. ASTM, West Conshohocken, PA.

ASTM D198-15 (2015) Standard test methods of static tests of

lumber in structural sizes. ASTM,West Conshohocken, PA.

ASTM D2395-14e1 (2014) Standard test methods for density

and specific gravity of wood and wood-based materials.

ASTM, West Conshohocken, PA.

ASTM D245-06 (2011) Standard practice for establishing

structural grades and related allowable properties for visually

graded lumber. ASTM, West Conshohocken, PA

(Reapproved).

ASTM D4442-16 (2016) Standard test methods for direct

moisture content measurement of wood and wood-based

materials. ASTM, West Conshohocken, PA.

American Wood Protection Association (AWPA) (2016)

Standard E5 standard field test for evaluation of wood

preservatives to be used in marine applications (uc5a, uc5b,

uc5c); panel and block tests. AWPA E5-15 in AWPA

Annual Book Standards. AWPA, Birmingham, AL.

American Wood Protection Association (AWPA) (2016)

Standard E8 standard field test for evaluation of wood

preservatives to be used in ground contact (uc4a, uc4b,

uc4c); post test. AWPA E8-15 in AWPA Annual Book

Standards. AWPA, Birmingham, AL.

Bedell TE, Eddleman LE, Deboodt T, Jacks C (1993)

Western juniper—Its impact and management in Oregon

rangelands. EC 1417, Oregon State University Extension

Service, Corvallis, OR.

Burke EJ (2008) Interim report: Updated findings in the

determination of the mechanical properties of the wood of

western juniper (Juniperus occidentalis Hook.). Report of

, September 2008. University of Montana, Missoula, MT.

Unpublished report. 10 pp.

Drew DM, Allen K, Downes GM, Evans R, Battaglia M,

Baker P (2012) Wood properties in a long-lived conifer

reveal strong climate signals where ring-width series do

not. Tree Physiol 33(1):37-47.

Highley TL (1995) Comparative durability of untreated

wood in use above ground. Int. Biodeterior Biodegrad 35:

-419.

Kiaei M, Sadegh AN, Moya R (2013) Site variation of

tracheid features and static bending properties in Pinus

eldarica wood. Cellul Chem Technol 47(1-2):49-59.

Leavengood S (2008) Developing markets for lesser-known

species: The case of western juniper in Oregon. In Proc.

st International Convention of Society of Wood Science

and Technology, November 10-12, Concepcion, CHILE.

Miller RF, Bates JD, Svejcar TJ, Pierson FB, Eddleman LE

(2005) Biology, ecology, and management of western

juniper (Juniperus occidentalis). Oregon State University

Agricultural Experiment Station Technical Bulletin 152,

pp.

Morrell JJ, Miller DJ, Schneider PF (1999) Service life of

treated and untreated fence posts: 1996 post farm report.

Research contribution 26, Forest Research Laboratory,

Oregon State University. Corvallis, OR, 24 pp.

Myers CG, Weidenhoeft WM, Davis WM (1998) Basic fiber

and chemical properties of western juniper, Prepared by

the U.S. Forest Products Laboratory, Madison, WI. Unpublished

report. 3.

Shmulsky R, Jones PD (2011) Lumber, in Forest products

and wood Science An Introduction, Sixth Edition, Wiley-

Blackwell, Oxford, UK.

Siegel S, Castellan NJ (1988) Nonparametric statistics for

the behavioral sciences (2nd ed.) New York: McGraw-

Hill.

USDA (2010) Wood handbook—Wood as an engineering

material. General Technical Report FPL-GTR-190. U.S.

Department of Agriculture, Forest Service, Forest Products

Laboratory, Madison, WI. 508 pp

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Published

2018-04-18

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Section

Research Contributions