Final Report
Western Juniper Log Storage Project
December 31, 1996
Report Authors
Scott Leavengood, Oregon State University Extension Service
Larry Swan, U.S. Forest Service
Technical Coordinator
Larry Swan, U.S. Forest Service
Project Implementation
Bill Breedlove, Private Consultant
Project Administration
Klamath County Economic Development Association
The preparation of this report was funded in part with a grant from the Oregon State Lottery,
through the Regional Strategies Fund administered by the State of Oregon Economic
Development Department.
Regional Strategy Board Project Sponsors
South Central Region (Lead)
Baker-Malheur Region
North-Central Region
Financial Assistance and Other Contributions Are Gratefully Acknowledged
From the Following Companies and Organizations:
U.S. Forest Service, Pacific Northwest Region
Oregon State University Extension Service
High Desert Wood Products, Dairy, Oregon
Oregon State University, Forest Products Department
All Native Hardwoods, Roseburg, Oregon
Henderson Millworks, Klamath Falls, Oregon
Rainier Wood Products, Sweet Home, Oregon
Abstract
Western juniper (Juniperus occidentalis) product trials in 1992 and 1993 revealed a potential problem with
excessive end-splitting during drying and remanufacture. Splitting reduces raw material recovery and may
cause reductions in quality and value of finished products. It was theorized by academicians and
manufacturers that the problem might in part be caused by "raw material handling", e.g., excessive log
storage time and improper log storage methods.
Oregon lottery funding was obtained by the Western Juniper Commercialization Steering Committee to
study effects of differing log storage methods (end-coated vs. non end-coated) and storage duration on
product recovery and value. The sample set consisted of 25 logs: Eight were left as a control, 8 were end-coated on both ends, as well as all knots over 3 inches, and 9 were simply coated on both ends. All were
harvested in early October, 1995 from the same site and classified as "saw logs" by a local mill with
experience sawing juniper. A representative sample of the "green" logs was then sawn into lumber, dried,
and remanufactured into finger-joint blanks. The remaining logs were sawn, dried, and remanufactured
into finger-joint blocks after 250 days of storage.
Recovery figures for lumber and finger-joint blanks were calculated for both storage periods. Lumber
recovery(1) values were approximately 1.66 (i.e., the lumber recovered was 1.66 times the volume predicted
by the gross log scale) for logs stored 30 days. Lumber recovery for logs stored 250 days was
approximately 1.43. Lumber recovery was approximately 20 percent greater for logs stored for 30 days than
for logs stored for 250 days. Finished product recovery(1) in the form of finger-joint blanks was 53 percent
for lumber sawn from logs stored 30 days and 44.7 percent for lumber sawn from logs stored for 250 days.
This slight decrease in finished product recovery is likely insignificant.
Data were unable to be gathered comparing specific effects of log storage on end-coated versus uncoated material. It was impossible to distinguish end-coated versus uncoated logs after 250 days due to weathering. End-coating probably contributed to a better than expected lumber recovery, however, to what extent could not be determined.
Purpose
The purpose of this project was to compare results of different western juniper (Juniperus occidentalis) log
storage methods and storage duration on product recovery and value. Results will provide manufacturers
guidance about the effects of long-term log storage on product recovery and value, as well as log storage
methods to improve product recovery and value.
Need
Western juniper product trials in 1992 and 1993 indicated a potential problem with end-splitting. Observers
commented on the tendency for small end-splits in green lumber to continue propagating (in some instances
up to 12 inches or more) while the wood was in service. End-splitting is not an unusual problem for wood.
Western juniper, however, may split more easily and to a greater extent than other common commercial
species. The tensile strength perpendicular to grain in the radial direction (a key strength value related to
"ease of splitting") for western juniper at 12 percent moisture content is approximately 235 psi (Burke
1994). This value is quite low when compared to other common commercial woods such as Douglas-fir
(390 psi) and ponderosa pine (420 psi)(2) and therefore, there is reason to believe that western juniper may be
more susceptible to end-splitting and checking.
A separate project has been conducted to study drying techniques for western juniper to improve finished
product quality (Leavengood et al. 1996).
Background
This project was formulated and designed by members of the Western Juniper Commercialization Steering
Committee, a loosely-organized cooperative venture of the U.S. Forest Service, Wood Products
Competitiveness Corporation, Inc. (WPCC), and Oregon State University Extension Service. Steering
Committee membership is composed of wood products industry representatives (small, medium and large
companies), government agencies, non-profit economic development and environmental organizations, and
private landowners.
An Oregon Multi-Region Program grant proposal was prepared and submitted to the Governor of Oregon in
the fall of 1994, and was approved in April, 1995 (Swan 1996). Work began in the fall of 1995 and the
project was completed in the fall of 1996.
Prior Work
A literature review conducted prior to the project revealed no citations concerning the effects of log storage
method and storage duration on recovery and value of western juniper products. However, work has been
done on storage duration and methods for other species.
For example, Carpenter and Toole (1963, p.25) found that after 1 year of storage without water spray or end-coating, checking and staining were so severe in eastern cottonwood (a species with very low resistance to
staining and decay) that the logs were "...not worth sawing". Other researchers have reported the benefits of
water spray or water storage to reduce end-checking and staining due to fungi. Researchers have also shown
that end-coating reduces degrade in logs during storage providing the coatings are applied when logs are still
very green (Rosen and Miceli 1980; Rice 1995).
It is unlikely that western juniper manufacturers will use water spray or storage techniques because of high
capital investment and maintenance requirements, as well as increasing environmental restrictions. End-coating, on the other hand, requires far less capital outlay and appears economically and logistically
practical for most juniper manufacturers.
Current Practices
The vast majority of western juniper logs (approximately 80 to 90 percent) are unsuitable for sawing into
lumber because of large and numerous limbs, spiral grain, rapid taper, bark seams, and rot(3) (Swan personal
communication). It can take several months to accumulate a sufficient number of quality logs to be sawn
economically by mills which produce more than 10,000 board feet per day(4). Many small manufacturers
working with juniper, especially those operating portable mills, currently store logs for months before
processing and do not end-coat.
Western juniper, like other wood species, develops end-checks rapidly after harvest. Long storage periods
aggravate the problem. Use of end-coating helps retard moisture loss, and reduces checking and splitting.
End-coating is commonly practiced with higher value species, such as oak, which require lengthy "pre-drying" before being kiln dried. It is rarely used with softwoods in the Western United States due to the
availability of other storage methods, such as water spray and mill ponds, prompt drying of green lumber,
lack of perceived need, and the perception that processing costs would significantly increase, due to
additional labor and material.
Methodology
Twenty-five trees were harvested by High Desert Wood Products in early October, 1995, near Bonanza in
south central Oregon. All came from the same site and exposure, and were classified as "saw logs" by the
manufacturer, who has extensive experience processing juniper. Diameter at breast height (DBH) ranged
from 8 to 14 inches. Trimmed-out logs averaged 24 feet. There was very little butt rot and only 1 tree had a
slight spiral grain.
Eight logs were left as a control (uncoated), 8 were end-coated on both ends, as well as all knots over 3
inches, and 9 were simply coated on both ends(5). The logs were decked on a south-facing slope and oriented
with the prevailing wind toward the butt ends of the logs.
Phase I
In early November, 1995, approximately 30 days after harvest, 6 logs were bucked into segments 8½ feet in
length, resulting in a total of 18 segments. The average small- and large-end diameters for the segments
were 11 and 15 inches, respectively.
Four days later, the 18 segments were sawn by All Native Hardwoods (Roseburg, Oregon) into "full-sawn" 1
inch thick by 3 inches wide by 8½ foot long boards. A Wood Mizer portable horizontal bandmill was used
for this operation. Green lumber recovery based on actual board dimensions (versus nominal dimensions)
was recorded for each log segment. The lumber was then immediately covered and transported to Oregon
State University's (OSU) Forest Products Department for drying.
After drying, the material was transported to Henderson Millworks in Klamath Falls, Oregon, for
remanufacture into finger-joint blanks. Target rip width was 2¾ inches. Two "back-up rips" of 2½ and 2
inches were allowed. Material was graded as clear or tight-knot, and recovery was measured using an
"industry standard block tally" (volume of stacked blocks determined by multiplying width times length
times height, and converting to board feet).
Phase II
In mid-June, 1996, approximately 250 days after harvesting, the remaining logs were bucked into 35
segments, 8½ feet in length. Average small- and large-end diameters for the segments were 10 and 14
inches, respectively. The logs were sawn the next day at All Native Hardwoods in Roseburg, using the
same Wood Mizer portable horizontal bandmill and sawyer, but slightly different specifications: Logs were
manufactured into 1 inch thick lumber instead of 1-inch lumber as in Phase I. Width and length
specifications remained the same as in Phase I. Lumber recovery was recorded for each log segment.
After drying, the material was transported to Rainier Wood Products, Sweet Home, Oregon, for
remanufacture into finger-joint blanks. Target rip width was changed to 3 inches, from 2¾ inches, due to
market demand. Only one "back-up rip" width of 2 inches was allowed. As in Phase I, material was graded
as clear or tight-knot, and recovery measured using an "industry standard block tally".
Results
Gross log scale for the log segments in Phase I (logs stored approximately 30 days) was 780 board feet
using Scribner Decimal C tables. Total board feet of green lumber recovered was 1297 board feet (tallied
actual size). Total lumber recovery(1) was 1.66 (i.e., the lumber recovered was 1.66 times the volume
predicted by the gross log scale).
For the remanufacturing portion of Phase I, recovery was calculated as a percentage of lumber input (board
feet finger-joint blanks ÷ board feet lumber). Of the 1200 board feet of lumber which was remanufactured
(97 board feet were provided to interested parties for small product samples) 641 board feet or 53.4 percent
were recovered as finger-joint blanks. Recovery breakdown was:
(where RL is random length and BF is board feet)
(36 board feet were removed before tallying and used for product trials)
Gross log scale for the log segments in Phase II (logs stored approximately 250 days) was 1285 board feet
using Scribner Decimal C tables. Total board feet of green lumber recovered was 1840 board feet (tallied
actual size). Total lumber recovery was 1.43.
For the remanufacturing portion of Phase II, of the 1840 board feet of lumber remanufactured, 823 board
feet (44.7 percent) were recovered as finger-joint blanks. The recovery breakdown by grade was:
Discussion
Green Lumber Recovery
Total green lumber recovery (as a percentage of gross log scale) decreased nearly 20 percent for logs stored
for 250 days versus logs stored only 30 days. This is despite the fact that almost 70 percent of the logs in
this sample were end-coated.
It should be noted that raw material variability can significantly affect such a small sample. For example,
western juniper logs from the same site may differ from one another in terms of degree of taper, amount of
rot present, log size, degree of bark fluting, bark seams, and spiral grain. However, steps were taken to
avoid this problem: 1) All logs were harvested from the same stand of trees and the same exposure; and 2)
Average log diameters were maintained for both phases of the project.
Analysis of recovery data revealed that, even with the measures taken to assure log consistency, there was a
significant amount of variability in recovery between individual logs. However, statistical analysis of
lumber recovery data provided evidence of a difference in recovery between the two phases of the project
above and beyond what can be explained by inherent variability in log size or quality.
Finger-Joint Block and Grade Recovery
Total finger-joint block recovery (as a percentage of lumber tally) was approximately 53.4 percent and 44.7
percent for logs stored 30 days and 250 days, respectively. This amount of variability is likely insignificant.
It appears that while lumber recovery is adversely affected by long storage periods, finished product
recovery is not.
Value recovery, as evidenced by grade recovery of finger-joint blanks, was similar for the two phases: 26.8
percent clear material (as a percentage of lumber input) was recovered in Phase I and 22.3 percent in Phase
II. It is difficult to determine if duration of storage impacted value recovery, because variables such as
equipment operators and specifications were not controlled (for example, two backup rips were allowed in
Phase I, but only one backup rip was allowed in Phase II).
The ability to distinguish end-coated versus uncoated logs was lost during the project due to weathering. It
is impossible, therefore, to compare the long-term effect of end-coating on product recovery. Based on end-coating studies performed with other wood species, it is highly probable that the decrease in lumber
recovery observed in this project was due, at least in part, to end-checking on the uncoated logs. According
to Bill Breedlove, a clear difference in extent and depth of end-splitting between end-coated and uncoated
logs was observable after only 30 days (Breedlove personal communication).
Recommendations
To optimize lumber recovery, it is recommended that if juniper saw logs will not be processed within 30
days following harvest, they be end-coated immediately following falling. It is also recommended that log
storage time be minimized.
Literature Cited
Burke, E.J. 1994. Physical and Mechanical Properties of Western Juniper. Unpublished report, University
of Montana School of Forestry, Missoula, Montana. 20 pp.
Carpenter, B.E. and E.R. Toole. 1963. Sprinkling with Water Helps Protect Hardwood Logs in Storage.
Southern Lumberman, 207(2576):25-26.
Dealy, J.E. 1990. Western Juniper. In Silvics of North America, Volume 1, Conifers (R.M. Burns and
B.H., Honkala, Technical Coordinators). U. S. Department of Agriculture Handbook 654 (p. 113). U.S.
Government Printing Office, Washington, D.C.
Leavengood, S., L.R. Swan, and B. Breedlove. 1996. Drying Western Juniper. Final report submitted to
the Oregon Economic Development Department. 18 pp.
Rice, R.W. 1995. Transport Coefficients for Six Log and Lumber End Coatings. Forest Products Journal,
45(5):64-68.
Rosen, H.N. and C.M. Miceli. 1980. End Coating Effects on High-Temperature-Dried Yellow-Poplar.
Forest Products Journal. 30(4):47-50.
Scharpf, R.F. 1993. Diseases of Pacific Coast Conifers. U.S. Department of Agriculture Handbook 521 (p.
168). U.S. Forest Service, Pacific Southwest Research Station, Albany, California.
Swan, L.R. 1996. Regional Strategies Program - Proposal for Multi-Region Project: Western Juniper
Commercialization - Industry Development Facilitator and Alternative Fiber Markets. Unpublished grant
proposal. On file, Oregon Economic Development Department, Salem, Oregon.
Wood Handbook: Wood as an Engineering Material. Rev. 1987. USDA Forest Service Forest Products
Laboratory- Ag Handbook 72. 466 pp.
1. Lumber Recovery = BF Lumber/ BF Log Scale, Finished Product Recovery = BF Finger-joint Blocks/ BF Lumber, where BF = Board Foot Back to Abstract, Back to Results
2. Strength values from the Wood Handbook: Wood as an Engineering Material, 1987 Back
3. Juniper pocket rot (Pyrofomes demidoffii [Fomes juniperinus]) (Scharpf 1993), also
referred to as white trunk rot, attacks a large percentage of living trees. There is also an
unidentified brown cubicle rot (Dealy 1990). Back
4. For comparison, many portable mills, such as those commonly found in Eastern Oregon,
are hard-pressed to consistently saw more than 1,000 board feet per day (Swan personal
communication).Back
5. End-seal product used was: Anchor End Seal. Cost at the time of the project was about
$33 for five gallons. Supplier was Lacey-Harmer, Portland, Oregon (1-800-367-9992).Back