BASIC FIBER AND CHEMICAL PROPERTIES OF WESTERN JUNIPER

Gary C. Myers
Alex C. Wiedenhoeft (fiber length and diameter analysis)
Mark W. Davis (lignin and carbohydrate analysis)
USDA, Forest Service
Forest Products Laboratory

Madison, Wisconsin

INTRODUCTION

Western juniper (Juniperus occidentalis) has either never had basic fiber dimensions and chemical compositions measured, or these findings have never been published. Nothing was uncovered in a literature search, and this type of information is basic when searching for utilization options.

Log cross sections were obtained by Larry Swan, Resource Specialist, Winema National Forest, Klamath Falls, OR, and shipped to Forest Products Laboratory for this limited investigation. Samples were identified as Bonanza, Lost River, and Running Y.

PROCEDURES

Fiber (tracheids) length and diameter measurements
Two samples were taken from each log cross section; one from near the center between growth rings 5 and 10, and the other from within five growth rings of the bark. These samples were separated into individual fibers by standard maceration techniques using Jeffries solution. Fiber samples were placed on microscopic slides, and fiber lengths and diameters were measured using a procedure described by Quirk (J.T. Quirk, "Semiautomated Recording of Wood Cell Dimensions", Forest Science 27(2):336-338 (1981)).

Lignin and carbohydrate analysis
Two samples were also taken from each log cross section; one from near the center, and the other from near the bark. Each sample was Wiley milled to pass a 20-mesh screen and vacuum dried at 45 degrees C. Lignin content was determined using a procedure described by Effland (M.J. Effland, "Modified procedure to determine acid-insoluble lignin in wood and pulp", Tappi Journal 60(10):143-144 (1977)). Carbohydrate contents were determined by a procedure described by Davis (M.W. Davis, "Rapid modified method for compositional carbohydrate analysis of lignocellulosics by HPAEC/PAD", J Wood Chem & Technology, accepted for publication (1998)).

RESULTS

Fiber length of western juniper is about the same as other junipers. It is shorter than most softwoods and longer than most hardwoods, but closer to hardwoods than softwoods (see Table). Fiber diameters are smaller than most softwoods, and about the same as hardwoods.

Lignin content is much higher than all softwoods and hardwoods. Extractive content, hemicellulose content, and cellulose content are lower than most temperate softwoods and hardwoods.

CONCLUSIONS

Western juniper might be acceptable for hardboard, MDF, and other reconstituted panel products. The small fiber diameter and short fiber length might yield a pulp that produces a smoother paper surface, which is important for printing and writing papers. However, the short fiber length, high lignin content, and low cellulose content appear undesirable for chemical pulping and production of high strength papers.



Properties of Western Juniper vs. Other Common Species*
Species Density (lbs/ft3) Fiber/Vessel length (mm) Fiber dia. (mm) Alpha cellulose (%) lignin (%)
western juniper 31.0 1.60 0.012-0.031 38.6 35.5
eastern redcedar 32.9 2.15 0.020-0.030 ? ?
ponderosa pine 28.0 3.60 0.035-0.060 45.0(1) 25.1(1)
lodgepole pine 24.0 3.50 0.035-0.055 47.3(2) 25.9(2)
Douglas-fir (coastal) 34.0 4.50 0.035-0.055 52.6(3) 28.0(3)
white fir 22.0 3.50 0.035-0.050 49.1(4) 27.8(4)
western hemlock 24.0 4.00 0.030-0.050 50.0(5) 29.9(5)
red alder 25.0 1.20/ 0.85 ? 44.0(6) 24.1(6)
sugar maple 44.0 0.92/ 0.41 ? 49.2(7) 21.5(7)
Northern red oak 44.0 1.32/ 0.42 ? 46.0(8) 23.9(8)



Table created by Scott Leavengood, Oregon State University Extension Agent. Fiber length, diameter, cellulose, and lignin data for western juniper from G.C. Myers, A. Wiedenhoeft, and M.W. Davis, USDA Forest Service- Forest Products Laboratory. Density data for western juniper from Dr. Ed Burke, University of Montana.

Fiber length, diameter, cellulose, and lignin data for other species from Essentials of Pulping and Papermaking by C.J. Biermann, 1993, Academic Press publishers, San Diego, CA. Density data from The Wood Handbook: Wood as and Engineering Material, Ag Handbook #72, 1989, USDA Forest Service, Forest Products Laboratory, Madison, WI.


* all properties reported at 12% MC
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1. 4.9", 1.9% heartwood

2. Montana, sound, 7.4", little decay

3. Oakridge, OR, second-growth, residues

4. California

5. Washington

6. Washington, 7.8"

7. Michigan

8. Michigan, 5.9"
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