Grading Options for 

Western Hemlock 

“Pulpwood” Logs From 

Southeastern Alaska 

David W. Green 

Kent A. McDonald 

John Dramm 

Kenneth Kilborn 

United States

Department of 

Agriculture 

Forest Service 

Forest 

Products 

Laboratory 

Research 

Paper 

FPL–RP–583
Abstract 

Properties and grade yield are estimated for structural lumber 

produced from No. 3, No. 4, and low-end No. 2 grade western hemlock logs of the type previously used primarily for 

the production of pulp chips. Estimates are given for production in the Structural Framing, Machine Stress Rating, and 

Laminating Stock grading systems. The information shows 

that significant amounts of higher grade structural lumber can 

be produced from these lower grade logs. 

Keywords: western hemlock, grade yield, structural lumber, 

Alaska

Acknowledgments 

The authors acknowledge the cooperation of Viking Lumber, 

Klawock, Alaska, in conducting this study and the assistance 

of Cherilyn Hatfield of the Forest Products Laboratory in 

conducting the computer simulations of MSR yield determined in this study. We especially acknowledge the cooperation of William L. Galligan for many helpful comments on 

the draft and for writing the section on marketing considerations in Appendix B. 

May 2000 

Green, David W.; McDonald, Kent A.; Dramm, John; Kilborn, Kenneth. 

2000. Grading options for western hemlock “pulpwood” logs from southeastern Alaska. Res. Pap. FPL-RP-583. Madison, WI: U.S. Department of 

Agriculture, Forest Service, Forest Products Laboratory. 15 p. 

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Contents 

 Page

Introduction............................................................................1

Background............................................................................1

Forest Resources of Tongass National Forest...................1

Structural Grading Systems................................................2

Grade Yield Studies of Alaskan Hemlock .........................3

Summary............................................................................4

Materials and Methods...........................................................5

Sampling ............................................................................5

Grading and Processing .....................................................5

Testing ...............................................................................5

MSR Simulation.................................................................5

Results and Discussion...........................................................6

Structural Framing .............................................................6

Laminating Stock ...............................................................7

Machine-Stress-Rated Lumber...........................................9

Implications .....................................................................10

Conclusions..........................................................................11

Literature Cited ....................................................................11

Appendix A—Building Codes and Voluntary 

Products Standard PS–20.....................................................12

Building Codes and Product Standards............................12

Voluntary Product Standard PS–20 .................................12

Selected Contacts.............................................................13

Appendix B—Marketing Considerations.............................14

Technical Characteristics of a Case Study ......................14

Mill Optimization.............................................................14

Market Pricing .................................................................15
Research Highlights 

In southeastern Alaska, large high-quality logs of western 

hemlock (Tsuga heterophylla) have traditionally been cut 

into export cants, and lower quality logs have generally been 

chipped for pulp. Although pulp chips are still being exported, the demise of local pulping facilities has greatly 

reduced markets for these lower quality logs. Product recovery studies conducted in the 1970s and 1980s did not focus 

on current grading systems for engineered wood products, 

such as wooden trusses, I-joists, and glued-laminated timbers. The objective of the study reported here was to estimate 

the grade yield of structural dimension lumber that can be 

obtained from lower quality western hemlock “pulpwood” 

logs. 

A total of 409 logs were selected at random from inventory at 

a southeastern Alaska mill. The Puget Sound Log Scaling 

and Grading Bureau graded 89% of these logs as No. 3 or 

No. 4, 4% as No. 2, and 7% as “culls.” The culls could not 

be processed in a commercial sawmill. Small-end diameter of 

the 32-ft- (9.8 m-) long logs ranged from 5 to 36 in. (130 to 

910 mm); the small-end diameter of most of these logs was 

<12 in. (300 mm). The logs were sawn into nominal 2 by 4, 

2 by 6, and 2 by 10 lumber1

 and visually graded as structural 

lumber by a Quality Supervisor of the Western Wood Products Association. All lumber graded as at least No. 3 Structural Framing in the rough, green condition (72% of total 

number of pieces of lumber produced) was dried, surfaced, 

and shipped to the Forest Products Laboratory in Madison, 

Wisconsin, for testing. 

For dried and planed lumber, the results of this research 

indicate the following: 

• As Structural Framing, No. 2 and better lumber is suited 

for framing and truss production and No. 3 for general 

construction. Approximately 50% of the dressed, dry 

lumber was graded as No. 2 and better, and 67% as No. 3 

and better. 

• As lumber for the production of glued-laminated structural 

timbers, about 28% of pieces qualified as L1, 17% as L2, 

and 17% as L3. For lamstock, the amount that qualifies as 

Dense is critical; 85% to 95% of the lumber qualified as 

Dense. 

• Approximately 80% of machine-stress-rated (MSR) lumber is used in truss production and 20% for the production 

of wooden I-joists. Most trusses are made from 2 by 4 

lumber. Two important grades for truss lumber are 1650f 

and 1800f. Approximately 33% of the 2 by 4 lumber could 

 

1

Nominal 2- by 4-in. = standard 38- by 89-mm, 2- by 6-in. = 

38- by 140-mm, and 2- by 10-in. = 38- by 235-mm. Lumber 

hereafter referred to as 2 by 4, 2 by 6, and 2 by 10. 

qualify as 1800f and 35% as 1650f. For 2 by 4 lumber of 

the highest grades, the yield of MSR lumber was often 

much higher than that of visually graded lumber with 

equivalent properties. 

These results suggest the following conclusions: 

• This research establishes that a significant amount of 

higher quality structural lumber can be produced from 

Alaskan hemlock logs that were once used primarily for 

the production of pulp chips. 

• Most of this lumber would need to be kiln- or air-dried to 

be acceptable in the marketplace. This is especially true of 

MSR lumber and laminating stock. In this study, the yields 

of the higher grades of Structural Framing were improved 

by drying and surfacing. 

• This study only considered yields from lower quality 

“pulpwood” logs. It is unlikely that a modern productionoriented mill would be established just to process such 

logs. A study is needed to evaluate yields from hemlock 

sawn from higher grade sawlogs. 

• It is essential that markets be established for this lumber 

before production of a particular grade is considered. 

The next steps for Alaskan mills interested in producing 

structural lumber are as follows: 

1. Investigate potential markets and market requirements 

for specific types of lumber products. 

2. Conduct a yield study at the mill for products of interest, 

using locally available logs. 

3. Evaluate the economic feasibility of producing these 

specific lumber products. 

4. Arrange certification by a grading agency certified by 

the American Lumber Standards Committee. 

As is generally true with all the grading systems, markets are 

more easily found for higher grade lumber. The challenge is 

to find markets for the approximately 50% of the pieces that 

do not qualify as at least No. 2 Structural Framing and for the 

sawdust, bark, and slabs. 

Grading Options for Western 

Hemlock “Pulpwood” Logs 

From Southeastern Alaska 

David W. Green, Supervisory Research Engineer

Kent A. McDonald, Research Wood Scientist (retired)

John Dramm, Utilization Specialist

Forest Products Laboratory, Madison, Wisconsin

Kenneth Kilborn, Team Leader

Nothwest Research Station, Sitka, Alaska

Introduction 

In southeastern Alaska, large high-quality logs of western 

hemlock (Tsuga heterophylla) have traditionally been cut 

into export cants and lower quality logs have generally been 

chipped for pulp. While pulp chips may still be exported, the 

demise of local pulping facilities has greatly reduced markets 

for these lower quality logs. Although product recovery 

studies were conducted on Alaskan hemlock in the 1970s 

and 1980s, these studies either focused on logs <14 in. 

(<360 mm) in diameter, did not relate lumber grade to log 

grade, or did not include structural grades and grading systems currently used for engineered products and structures. 

From the information available, it is not possible to obtain 

accurate estimates of utilization options for hemlock cut from 

the lower end of the log quality range. The objective of this 

study was to estimate the grade yield of structural dimension 

lumber that can be obtained from lower quality western 

hemlock logs of the type that have traditionally been pulped 

in southeastern Alaska. The study evaluated both visual and 

mechanical grades for a variety of lumber widths currently 

sold in domestic and Pacific Rim markets. It did not evaluate 

potential yield of structural lumber from the larger “sawlogs” 

that would be traditionally used for production of dimension 

lumber. Mills that are currently producing structural lumber 

have access to information on lumber recovery from sawlogs. 

Mills that are not currently producing structural products 

should conduct a recovery study on sawlogs. 

Background 

Forest Resources of Tongass 

National Forest 

The Tongass National Forest covers an area of 

16.9 × 106

 acres (6.8 × 106 ha) in southeast Alaska. Of this, 

2.4 × 106

 acres (972 × 103 ha) have been tentatively judged 

suitable for timber production (Table 1) (USDA 1997). 

Because some of this area is being managed for other objectives, only approximately 576 × 103

 acres (233 × 103 ha) 

are available for harvest (USDA 1999). About 61% of the 

timber volume on this land is hemlock, 28% Sitka spruce 

(Picea sitchensis), 6% yellow-cedar (Chamaecyparis nootkatensis), and 5% western redcedar (Thuja plicata). The 

small-end diameter of about 60% of the sawlogs is less than 

29 in. (740 mm) and that of the remainder is larger than this 

dimension (Fig. 1). For spruce and hemlock, a significant 

proportion of these logs would grade as No. 2, No. 3, and 

Utility according to Forest Service “cruise” grades (Table 2). 

Table 1—Distribution of land types on Tongass 

National Foresta

Land type 

Area 

(×103

 acres (×103 ha)) 

Nonforest 6,949 (2,812) 

Forestland withdrawn 4,179 (1,691) 

Nonproductive forests 2,400 (971) 

Physically unsuited 524 (212) 

Inadequate information 429 (174) 

Tentatively suitable 2,400b (971) 

a

USDA 1997. Numbers reflect rounding. 

Figure 1—Size distribution of sawlogs on Tongass 

National Forest. 1 in. = 25.4 mm. 
2 

However, about 35% of the hemlock is graded as No. 3 and 

Utility. These lower quality hemlock logs have traditionally 

been pulped. With the closing of the last pulp mill in Alaska 

in March 1997, these lower quality hemlock logs represent 

the greatest opportunity to improved utilization. 

Because of an expected harvesting rotation of about 80 years, 

a significant amount of the younger growth (stands cut since 

1954) will not be available for 30 to 40 years (Fig. 2). However, this second-growth timber will have different species, 

size, and volume attributes than does the old-growth timber 

that is currently being harvested. 

Structural Grading Systems 

Several structural grading systems are used commercially for 

nominal 2-in.- (standard 38-mm-) thick dimension lumber 

(Forest Products Laboratory 1999).2

 Three visual grading 

systems and one mechanical grading system will be discussed 

here. In all three systems, western hemlock, including 

hemlock cut in Alaska, is sold in a marketing group called 

Hem–Fir. The Hem–Fir grouping includes western hemlock, 

California red fir, grand fir, noble fir, Pacific silver fir, and 

 

2

Nominal 2- by 4-in. = standard 38- by 89-mm, 2- by 6-in. = 

38- by 140-mm, and 2- by 10-in. = 38- by 235-mm. Lumber 

hereafter referred to as 2 by 4, 2 by 6, and 2 by 10. 

white fir. Of these, western hemlock and Pacific silver fir 

grow in southeastern Alaska (Viereck and Little 1972). 

These grading systems gain their legal authority through a 

system of model building codes and voluntary product standards used throughout Alaska, Hawaii, and the continental 

United States. This system is discussed for the full range of 

building products in Green and Hernandez (1998) and summarized for solid-sawn lumber in Appendix A. 

Visual grading, the oldest stress-grading method, is based on 

visual assessment of growth characteristics and defects. The 

Light Framing visual grading system is used primarily in the 

western United States for lumber of nominal 2- to 4-in. (standard 38- to 89-mm) thickness and 2- to 4-in. (38- to 89-mm) 

width. The Structural Framing visual grading system is used 

throughout the United States for the higher grades of 2 by 4 

lumber and for wider width lumber. The grade names used 

by these two systems are as follows: 

These grading systems have evolved over time. Prior to 1968 

nominal 6-in. (standard 140-mm) and wider lumber produced 

in the western United States was assigned to Construction, 

Standard, and Utility grades. After 1970, the current system 

of restricting these grades to lumber nominal ≤4 in. (standard 

≤89 mm) in width was adopted throughout the West. As will 

be described, the older yield studies on structural lumber 

from western species reported results for only Select Structural, Construction, Standard, and Utility grades, regardless 

of lumber width. Increasingly, however, Structural Framing 

lumber is being used in engineered structures such as 

wood trusses. 

The concept of “strength ratio” may be used to gain some 

appreciation of the differences between Light Framing and 

Structural Framing grades. A strength ratio is the theoretical 

ratio of the strength of a piece of lumber containing defects 

(such as a knot) to that of the same piece of lumber if no 

defects were present. Table 3 shows the minimum bending 

strength ratio associated with each grade in both systems. By 

current grade rules, the minimum strength ratio of Standard 

grade in the Light Framing system is less than that of No. 3 

in the Structural Framing system. Thus, older studies that 

report yields only as “Standard and better” provide little 

information about yields of the Structural Framing grades. 

Table 2—Distribution of log grades for suitable 

timberland on Tongass National Foresta

Distribution (% total)

Log grade Western hemlock Spruce 

Peeler, select, No. 1 7.0 4.9 

No. 2 26.6 16.3 

No. 3 18.2 6.1 

Utility 17.2 3.7 

a

Walk 1997.

Figure 2—Age distribution of young-growth trees on 

Tongass National Forest. 1 acre = 0.405 hectare. 

Light Framing Structural Framinga 

Construction Select Structural 

Standard No. 1 

Utility No. 2 

Stud No. 3 

a

Defined here as both Structural Light Framing 

and Structural Joist and Plank grades. 
3 

Mechanically graded lumber offers the engineer a greater 

degree of consistency and reliability in structural properties 

than does visually graded lumber. Mechanically graded 

lumber also offers unique combinations of mechanical properties not available through visual grading that may enable 

the engineer to make more efficient use of the available 

forest resource—especially a lower coefficient of variation 

(COV) on modulus of elasticity (MOE) (Winistorfer and 

Theilen 1997). The system for machine-stress-rated (MSR) 

lumber uses both visual assessment of defects and nondestructive determination of flexural MOE to sort lumber into 

grades (Galligan and McDonald 2000, Brown and others 

1997). Grade names for MSR lumber are a combination of 

the allowable bending stress (Fb) and the average allowable 

MOE (E) assigned to the grade. For example, a grade “name” 

of 1450f–1.3E is a grade assigned an allowable bending 

stress of 1,450 lb/in2 and MOE of 1.3 × 106

 lb/in2. Most 

MSR lumber is used in the production of metal-plate wood 

trusses, with perhaps 20% used in the production of wood 

I-joists. The MSR grade assignment for western species is a 

combination of visual limitations and specifications on MOE. 

In assigning grade, the importance of knots, holes, and distorted grain on the edge of the piece is stressed. The percentage of the net cross section of the member that these edge 

characteristics may occupy limits Fb assignment, as shown in 

Table 4. There are also restrictions on general slope of grain 

and other characteristics. 

A special set of visual grades is also available for lumber of 

western species to be used in glued-laminated timbers 

(glulam). Grade names for this system are L1, L2, and L3. 

Lumber meeting the visual requirements of L1 and L2 grades 

and having a specific gravity of 0.39 or higher at 12% moisture content may also qualify as “dense” (AITC 1993). The 

laminating grades of L1, L2, and L3 also limit the percentage 

of the cross section that a knot can occupy to the same visual 

quality levels as MSR. Laminating grades that combine 

visual characteristics with assessment of MOE are also produced. These “E-rated” grades would be required for higher 

strength glulam beams produced in the United States. 

Grade Yield Studies of 

Alaskan Hemlock 

Three previous Forest Service studies focused on grade yield 

of western hemlock logs from Alaska. Woodfin and Snellgrove (1976) sampled 30 logs at each of 12 locations in 

southeastern Alaska. At each location, the logs were chosen 

to represent the size and quality of timber available to any 

sawmill in that region, rather than the normal log mix at that 

mill. The logs were scaled according to rules of the Puget 

Sound Log Scaling and Grading Bureau. As might be expected, the majority of these logs were graded as No. 2 or 

No. 3 (Table 5). At the mill, the logs were cut into 10- to 

28-ft (3.0- to 8.5-m) lengths and sawn primarily for the production of nominal 4- by 4- in. (standard 89- by 89-mm) 

“babysquares.” From non-cull logs, recovery of green lumber 

was 48% of gross log volume. In contrast, recovery from cull 

Table 3—Assumed minimum bending strength 

ratios for visually graded structural lumber

 Strength ratio 

Lumber grade 

Structural 

Light Framing 

Light 

Framing 

Select Structural 0.65 — 

No. 1 0.55 — 

No. 2 0.45 — 

Construction — 0.34 

No. 3 and STUD 0.26 — 

Standard — 0.19 

Utility — 0.09 

Table 4—Visual quality levels for MSR lumber 

from western species

Visual quality 

level 

Edge knot displacement 

(% cross section) Fb

1 1/6 >2100 

2 1/4 1500–2050 

3 1/3 950–1450 

4 1/2 0–900 

Table 5—Distribution of log grades for western 

hemlocka

 Distribution (% total) 

Log grade Mill length Wood length 

Peeler 0.2 0.4 

No. 1 4.3 4.4 

No. 2 45.0 33.2 

No. 3 42.9 56.0 

Cull 7.6 5.9 

a

Woodfin and Snellgrove 1976. 

Table 6—Lumber grade yield from mill-length logsa 

 Yield (%) from various grades 

Lumber grade Peeler No. 1 No. 2 No. 3 

C & Btr Selectb

 45.8 39.2 15.0 1.1 

Select Structural 4.1 5.1 10.8 9.1 

Construction 20.6 17.1 25.4 29.8 

Standard 16.1 15.5 22.1 28.6 

Utility 8.5 16.1 20.5 24.7 

Economy 4.5 7.0 6.1 6.6 

a

Woodfin and Snellgrove 1976. 

b

Common & better Select. 
4 

logs was only 26%. Of the 335,400 board feet of lumber 

recovered, about 88% was nominal 4-in.- (standard 

89-mm-) thick material. This lumber was graded according to 

rules of the West Coast Lumber Inspection Bureau (WCLIB 

1956). The yield of sawn lumber by lumber and log grade is 

given in Table 6. The No. 2 and No. 3 logs yielded similar 

percentages of Construction, Standard, and Utility grades of 

lumber. Although this study provided good estimates of total 

product recovery from logs of all quality levels, it is not 

possible to estimate the yield of lumber in the Structural 

Framing, MSR, or glulam grading systems from these data. 

Fahey (1983) evaluated product recovery from 365 lower 

quality “pulpwood” logs processed through either a stud or 

dimension mill. The diameter of all the logs was ≤14 in. 

(≤356 mm). Because of the small diameter of the logs, no 

information was taken on log grade. Based on surface characteristics, Fahey (1983) stated that most logs would have 

met requirements for the No. 2 grade. The logs were sawn 

primarily for production of nominal 2-in.- (standard 

38-mm-) thick dimension lumber. For lumber sawn at a 

dimension mill, 53% of the log volume was recovered as 

dimension lumber. 

Product 

Log volume 

(%) 

Chips 40.6 

Sawdust 6.2 

Rough green lumber 53.2 

Dressed dry lumber 41.5 

Shavings and shrinkage 11.7 

At the dimension mill, about 68% of the lumber produced 

was 2 by 4 and 26%, 2 by 6 (Table 7). The grade name 1650f 

also appears in the results and seems unusual for visually 

graded lumber by current definitions. This is the allowable 

bending strength that was assigned to Select Structural Hem–

Fir in the early 1980s. At that time, western hemlock had an 

allowable strength of 1,800 lb/in2

. We are not sure why 

Fahey (1983) decided to call this lumber 1650f rather than 

Select Structural. 

A third study was conducted on the suitability of Sitka spruce 

and western hemlock logs recovered from beaches in southeastern Alaska for the production of lumber, pulp, and energy 

generation (Ernst and others 1986). Three classes of logs 

were evaluated: logs from live trees (control), from trees that 

had recently died (“recently dead”), and from trees that had 

been dead for a longer time (“older dead”). No information 

was presented on the grade of the logs. Logs were sawn at a 

dimension mill and a cant mill. No significant difference in 

percent yield (cubic recovery) was found between live and 

recently dead trees. For these classes, the recovery at the 

dimension mill averaged 62% and for the older dead trees, 

53%. For Sitka spruce, recovery averaged 61% for the live 

and recently dead trees. Insufficient logs were obtained for 

reliable estimates for older dead spruce. Standard and better 

lumber grade recovery averaged 65% for Sitka spruce 

(Table 8). For western hemlock, the recovery of Standard 

and better lumber averaged 60.5% for live and recently dead 

trees and 53.3% for older dead trees. 

Summary 

The information presented in this section indicates that the 

forest resource on the Tongass could sustain a supply of logs 

with diameters ≥29 in. (≥737 mm) for the next several decades. However, many of these logs are of lower grade and do 

not necessarily have an established market. It is also apparent 

that historical studies are of limited use in estimating the 

yield of structural grades of dimension lumber presently used 

for engineered wood products and structures. To help foster 

improved utilization of the forest resource in southeast 

Alaska, it is important to make estimates of grade yield for 

western hemlock logs from the lower end of the log quality 

range that formerly were pulped for chip production. 

Table 7—Recovery of nominal 2-in.- (standard 38-mm-) 

thick lumber from small-diameter hemlock logsa

 Recovery of mill dimension 

lumber (% log volume) 

Lumber grade 2 by 4 2 by 6 

Select Structural 1.3 0.3 

1650f 4.2 1.4 

Construction or No.1 12.9 4.4 

Standard or No. 2 23.1 11.4 

Utility or No. 3 20.3 6.7 

Economy 5.7 1.9 

a

Fahey 1983. Note: 2.3% logs were sawn as nominal 1- by 

 4-in. (standard 19- by 89-mm) lumber, 2.2% as 1- by 6-in. 

 (19- by 140-mm) lumber, and 1.9% as 2- by 3-in. (38- by 

 62-mm) lumber. 

Table 8—Grade yield for lumber cut from beached logsa

Yield (% log volume) 

 Western hemlock 

Lumber grade 

Sitka 

spruce 

Live and 

recently dead Older dead 

Clear 3.3 7.6 3.8 

Standard and better 65.0 60.5 53.3 

Utility 19.4 20.9 25.8 

Economy 12.3 11.0 17.1 

a

Ernst and others 1986. 
5 

Materials and Methods 

Sampling 

A common practice in southeast Alaska is to “woods sort” 

logs into sawlogs (high grade, larger logs) and pulpwood 

logs (lower grade, generally smaller logs). These tree-length 

logs are then inventoried separately at the sawmill. At a mill 

on Prince of Wales Island in southeastern Alaska, 409 western hemlock pulpwood logs were selected at random from 

inventory. The logs were of random length in the range of 

14 to 48 ft (4.3 to 14.6 m), with an average length of 32 ft 

(9.8 m). Small-end log diameter ranged from 5 to 36 in. 

(127 to 914 mm); for most logs, small-end diameter was 

≤12 in. (≤305 mm) (Fig. 3). The logs were graded and scaled 

using the Scribner scale by a representative of the Puget 

Sound Log Scaling and Grading Bureau (Gray’s Harbor 

1982). The net log volume was 20,920 board feet. The logs 

were graded as follows: low end of No. 2 grade, 3.7% 

(15 logs); No. 3, 38.9% (159 logs); No. 4, 49.9% (204 logs); 

and cull, 7.5% (31 logs). The cull logs were too decayed 

and deformed to process. 

Grading and Processing 

The woods-length logs were cut into 14-ft (4.3-m) lengths 

prior to sawing and physically sorted by log grade. This 

length was chosen for handling and shipping convenience. 

The approximately 400 mill-length logs were painted on the 

ends; different colors of paint were used for each log grade. 

The logs were then processed through the mill, one log grade 

at a time. Based on recommendation of trends for domestic 

and Japanese markets, the logs were sawn to maximize production of 2 by 4, 2 by 6, and 2 by 10 lumber. The rough, 

green lumber was graded as Structural Framing by a Quality 

Supervisor of the Western Wood Products Association 

(WWPA 1998). All lumber with a rough green grade of 

No. 3 or better was shipped to Seattle, Washington, and dried 

by a conventional schedule in a commercial dry kiln. The 

Economy grade lumber was left in Alaska to minimize shipping charges. The dry lumber was then shipped to the Forest 

Products Laboratory (FPL) in Madison, Wisconsin, where it 

was re-graded by the same WWPA Quality Supervisor who 

had graded the rough green lumber. Each piece of lumber 

was graded as Structural Framing, as Lamstock, or by the 

visual requirements of MSR. The lumber was then placed in 

a conditioning chamber to equilibrate to approximately 15% 

moisture content. 

Testing 

The primary objective of testing the lumber was to provide 

data with which to simulate MSR grades, not to assess the 

strength of lumber produced in any of the visual grading 

systems. To reduce the amount of testing, only those pieces 

with potential to qualify for an MSR grade were tested; that 

is, lumber with a visual quality level (VQL) of 4 or higher 

(Table 4). Potential effects of this type of sorting will be 

discussed in appropriate sections of the results. A flatwise 

dynamic MOE was determined for each piece selected for 

testing using transverse vibration procedures, MOEtv (Ross 

and others 1991). The pieces were then tested in edgewise 

bending using third-point loading and a span-to-depth ratio 

of 21:1 (ASTM D4761, ASTM 1996), with the apparent 

worst defect as close to the middle of the test span as possible but randomly located with respect to the edge to be 

stressed in tension. After testing, a cross section was cut from 

near the point of failure for determining oven-dry moisture 

content and specific gravity (ASTM D4442, D2395– 

Method A). 

MSR Simulation 

Simulations were conducted on selected MSR grades from 

1450f–1.3E to 2400f–2.0E. The same grades were simulated 

for both 2 by 4 and 2 by 6 lumber to help potential producers 

in assessing the resource quality with respect to MSR 

production. This does not imply that each of these grades is 

commonly produced in each of these widths, nor that it is 

undesirable to produce other grades. There was insufficient 

2 by 10 lumber to conduct a meaningful computer 

simulation. 

With MSR lumber, the grade yield for any one grade is 

affected by how many grades are being produced at the same 

time. Normally, at least two grades are produced at once. 

Producing more than three grades simultaneously is not 

common. To help judge the potential of the resource for the 

production of MSR lumber, we first simulated what the yield 

would be if only one MSR grade were produced at a time. 

This helped us to ascertain the highest grade useful to produce. One rule of thumb suggests that the yield of the highest 

grade should be at least 10% of the pieces graded. Following 

the initial simulations, additional simulations were done to 

illustrate the effect on yield of producing two grades 

Figure 3—Size distribution of hemlock pulpwood simultaneously. 

logs from Alaska. 
6 

Results and Discussion 

Structural Framing 

The grade yield for the rough, green lumber graded in Alaska 

is given in Table 9. Note that because all pieces were 14 ft 

(4.3 m) long, grade yield by piece and by lumber volume 

would be equal for a given lumber width. Overall, 52% of the 

lumber was graded as No. 2 or better and 73% as No. 3 or 

better relative to the total board foot volume of the lumber. 

Although no directly comparable values are available, these 

yields would appear to be good for structural lumber from 

such low quality logs. From the perspective of a mill, 27% of 

the lumber did not make No. 3 grade. Generally, a mill producing Structural Framing makes its profits on the amount of 

No. 3 and better lumber (Standard and better for 2 by 4’s), so 

finding a market for the lower 28% represents a real 

challenge. 

The yields of dressed, dry lumber are given in Table 10. Like 

the yield for Structural Framing lumber, the grade yield of 

No. 2 and better lumber was about 50%. The yield of No. 3 

and better was about 67%. It is generally noted that the number of pieces of lumber is higher in the upper grades for 

surfaced lumber compared to those for rough lumber. 

Because the same person graded all the lumber, this difference is believed to be primarily the result of the difficulty of 

seeing defects in rough lumber. As discussed previously, the 

pieces that graded lower than No. 3 based on rough, green 

dimensions were not taken to FPL for testing. The pieces that 

remained in Alaska, plus those pieces that were graded as 

Economy after arrival at FPL, are combined into the Economy grade in Table 10. Thus, we assumed that Economy 

pieces left in Alaska would not be given a higher grade after 

drying and surfacing. Although this assumption is not always 

correct, it should be conservative (that is, give a slightly 

lower yield in grades No. 3 or higher for dry lumber). Slight 

differences in the total number of pieces for a given size were 

the result of counting errors while at the mill and the loss of a 

few pieces in drying or shipping. The yield by log grade is 

shown in Table 11. Because of the limited number of pieces, 

a breakdown by log grade for 2 by 10’s would not be 

meaningful. 

For dressed, dry lumber, the yield of Construction grade 2 by 

4’s was 35 %. Because only those pieces that could make 

No. 3 grade were shipped to FPL, the yield of Standard grade 

2 by 4’s may not be meaningful (Table 3). This is because 

the No. 3 grade restricts knots on the edge of the wide face to 

a maximum of 1.75 in. (44.4 mm) whereas Standard allows a 

knot of up to 2 in. (51 mm) anywhere on the wide face.

Table 9—Grade yield of Structural Framing from rough, green lumbera

Number of pieces Percentage of pieces Percentage of volume Lumber 

grade 2 by 4 2 by 6 2 by 10 2 by 4 2 by 6 2 by 10 All 2 by 4 2 by 6 2 by 10 All 

SS 43 106 19 3.7 8.4 10.8 6.5 1.2 4.6 1.4 7.2 

No. 1 134 243 26 11.6 19.3 14.8 15.6 3.8 10.5 1.9 16.2 

No. 2 310 344 61 26.8 27.3 34.7 27.6 8.8 14.9 4.4 28.1 

No. 3 281 277 18 24.3 22.0 10.2 22.2 8.0 12.0 1.3 21.3 

Economy 388 289 52 33.6 23.0 29.5 28.1 11.1 12.5 3.7 27.2 

All 1,156 1,259 176 100 100 100 100 32.9 54.4 12.7 100 

a

SS denotes Select Structural. 

Table 10—Grade yield of Structural Framing from dressed, dry lumber

Number of pieces Percentage of pieces Percentage of volume Lumber 

grade 2 by 4 2 by 6 2 by 10 2 by 4 2 by 6 2 by 10 All 2 by 4 2 by 6 2 by 10 All 

SS 114 203 26 10.1 16.3 15.0 13.4 3.3 8.9 1.9 14.1 

No. 1 202 153 15 17.9 12.2 8.7 14.5 5.8 6.7 1.1 13.6 

No. 2 218 298 50 19.3 23.9 28.9 22.2 6.3 13.1 3.6 23.0 

No. 3 146 247 31 12.9 19.8 17.9 16.6 4.2 10.8 2.3 17.3 

Economy 451 348 51 39.8 27.8 29.5 33.3 13.1 15.2 3.7 32.0 

All 1,131 1,249 173 100 100 100 100 32.7 54.7 12.6 100 
7 

Likewise, the yield of Utility grade would be biased because 

the maximum size of a wide face knot is 2.5 in. (64 mm). 

Thus, some pieces that remained in Alaska might have made 

Standard or Utility grade. 

The properties of No. 2 and higher grades are summarized in 

Table 12. This information is provided to help the producer 

understand the quality of the resource. Because the normal 

range of log quality was not tested, the lumber properties are 

not directly comparable to data obtained in the U.S. in-grade 

testing program (Evans and Green 1987). For 2 by 4 and 2 by 

6 lumber, only those pieces were tested that had a sufficiently 

high visual quality level (VQL 4 or better) to potentially 

qualify for MSR grades. This had little effect on the number 

of samples for a given grade except for No. 3. About half the 

No. 3 lumber would not qualify for MSR. For this reason, 

results for the No. 3 grade are not included in Table 12. The 

2 by 10 lumber was not tested because there was not enough 

lumber to compare properties. 

Laminating Stock 

Another traditional use of hemlock is for the production of 

glulam beams. Table 13 shows the yield of the laminated 

grades obtained by visual grading (lam-grades) based on 

dressed, dry lumber. About 28% of all pieces was graded as 

L1, approximately 17% as L2, and 17% as L3. Again, this 

would appear to be a good yield of high quality lumber from 

logs that would have previously been used only for pulp 

production. The properties of this lumber are summarized in 

Table 14. Only those pieces that were tested for MOR, 

MOE by transverse vibration (MOEtv), and specific gravity 

were included in this table. Thus, the sample sizes are somewhat lower than those shown in Table 10. Of the 2 by 4 

lumber, 90% of L1 pieces and 84% of L2 pieces had a 

specific gravity of 0.39 or higher and would qualify as 

Dense. For 2 by 6 lumber, 94% of L1 pieces and 90% of 

the L2 pieces would qualify as Dense. 

As mentioned previously, higher strength glulam beam must 

be produced using E-rated laminations. Table 15 provides 

Table 11—Grade yield of Structural Framing by log grade for dry Alaskan hemlock

 Number of pieces of dry lumber from individual log gradesa

 2 by 4 2 by 6 

Lumber grade No. 2 No. 3 No. 4 No. 2 No. 3 No. 4 

SS 12 52 50 32 129 42 

No. 1 15 97 90 7 96 50 

No. 2 25 116 77 28 173 96 

No. 3 23 71 52 27 150 69 

Economy 20 284 147 28 245 75 

a

Insufficient volume of 2 by 10’s by log grade to make valid comparisons. 

Table 12—Flexural properties of hemlock Structural Framing lumbera

MOEb (×106

 lb/in2 (GPa)) MOR (×103 lb/in2 (MPa)) Lumber 

grade 

Pieces 

(no.) 

MC 

(%) 

SG 

(OD/OD) Mean SD Mean SD 5th percentile 

2 by 4 

 SS 110 14.1 0.477 1.756 (12.108) 0.330 (2.275) 7.827 (53.967) 1.913 (13.190) 4.796 (33.068) 

 No. 1 197 13.9 0.467 1.649 (11.370) 0.390 (2.689) 6.836 (47.134) 2.473 (17.051) 3.184 (21.954) 

 No. 2 202 13.7 0.468 1.508 (10.398) 0.428 (2.951) 6.156 (42.446) 2.447 (16.872) 2.358 (16.258) 

2 by 6 

 SS 203 13.5 0.476 1.998 (13.776) 0.354 (2.441) 7.216 (49.754) 2.113 (14.569) 3.759 (25.918) 

 No. 1 152 13.3 0.462 1.841 (12.694) 0.356 (2.455) 5.272 (36.345) 1.926 (13.280) 2.316 (15.969) 

 No. 2 291 13.1 0.460 1.819 (12.542) 0.419 (2.889) 5.127 (35.351) 2.051 (14.142) 2.174 (14.990) 

a

MC is moisture content, OD ovendry, SG specific gravity, and SD standard deviation.

b

MOE for edgewise orientation by static test. 
8 

Table 13—Grade yield of Lamstock from dressed, dry lumber

Number of pieces Percentage of pieces Percentage of lumber volume 

Grade 2 by 4 2 by 6 2 by 10 2 by 4 2 by 6 2 by 10 All 2 by 4 2 by 6 2 by 10 All 

L1 300 347 64 26.5 27.8 37.0 27.8 8.7 15.1 4.7 28.5 

L2 169 225 28 15.0 18.0 16.2 16.6 4.9 9.9 2.0 16.8 

L3 161 239 21 14.2 19.1 12.1 16.5 4.6 10.5 1.5 16.6 

Economy 501 438 60 44.3 35.1 34.7 39.1 14.5 19.2 4.4 38.1 

All 1,131 1,249 173 100 100 100 100 32.7 54.7 12.6 100 

Table 14—Properties of Alaskan western hemlock by Lamstock gradea

MOEtv (×106 lb/in2 (GPa)) MOR (×103 lb/in2 (MPa)) 

Size Gradeb Pieces 

(no.) 

MC 

(%) 

SG 

(OD/test) Mean SD Mean SD 5th percentile 

2 by 4 L1 272 13.9 0.443 1.681 (11.590) 0.303 (2.089) 7.580 (52.264) 2.294 (15.817) 3.371 (28.243) 

 L1 Dense 245 13.9 0.451 1.712 (11.804) 0.292 (2.013) 7.769 (53.567) 2.240 (15.445) 3.548 (24.463) 

 L2 155 13.8 0.436 1.584 (10.922) 0.289 (1.993) 6.163 (42.494) 2.382 (16.424) 2.870 (19.789) 

 L2 Dense 131 13.5 0.447 1.610 (11.101) 0.287 (1.979) 6.382 (44.004) 2.409 (16.610) 2.913 (20.085) 

 L3 121 13.8 0.432 1.583 (10.915) 0.319 (2.200) 5.193 (35.806) 2.271 (15.659) 2.032 (14.011) 

2 by 6 L1 323 13.5 0.445 1.782 (12.287) 0.287 (1.979) 6.760 (46.610) 2.222 (15.321) 3.217 (22.181) 

 L1 Dense 303 13.5 0.450 1.800 (12.411) 0.282 (1.944) 6.878 (47.424) 2.197 (15.148) 3.423 (23.602) 

 L2 203 13.3 0.434 1.658 (11.432) 0.249 (1.717) 4.936 (34.034) 1.767 (12.183) 2.295 (15.824) 

 L2 Dense 182 13.1 0.442 1.686 11.625) 0.239 (1.648) 5.098 (35.151) 1.687 (11.632) 2.667 (18.389) 

 L3 214 13.0 0.428 1.577 (10.873) 0.259 (1.786) 4.234 (29.193) 1.861 (12.832) 1.706 (11.763) 

a

MOEtv denotes MOE by flatwise transverse vibration. 

b

Note that the Dense pieces are a subset of the L grades. 

Table 15—Distribution of flatwise MOE values by transverse vibration for dressed, dry Alaskan 

hemlock by visual quality level

Distribution of MOE by visual quality level 

MOE 2 by 4 2 by 6 tv group 

(×106

 lb/in2 (GPa)) 1/6 1/4 1/3 1/2 1/6 1/4 1/3 1/2 

 Pieces (no.) 

0.7 (4.8) 0 1 0 0 0 0 0 0 

0.8 (5.5) 2 0 2 0 0 1 1 0 

0.9 (6.2) 3 2 1 2 1 0 0 0 

1.0 (6.9) 7 7 1 2 2 2 3 1 

1.1 (7.6) 6 6 7 8 9 3 2 5 

1.2 (8.3) 15 16 6 6 11 8 7 7 

1.3 (9.0) 15 12 3 6 16 16 4 11 

1.4 (9.7) 27 19 6 6 30 13 16 10 

1.5 (10.3) 36 15 8 7 45 19 11 11 

1.6 (11.0) 41 19 6 7 59 22 12 6 

1.7 (11.7) 35 23 2 3 69 21 8 12 

1.8 (12.4) 30 19 4 1 53 17 10 2 

1.9 (13.1) 25 7 4 4 59 9 5 2 

2.0 (13.8) 28 8 1 1 31 9 0 3 

2.1 (14.5) 11 3 1 0 17 6 1 1 

2.2 (15.2) 4 2 0 0 11 1 1 1 

2.3 (15.9) 4 0 0 0 6 1 0 0 

2.4 (16.5) 1 0 0 0 2 0 1 0 

2.5 (17.2) 0 0 0 0 1 0 0 0 

2.6 (17.9) 0 0 0 0 2 0 0 0 

Mean MOEtv 

(×106

 lb/in2 (GPa)) 

1.68 

(11.59) 

1.58 

(10.89) 

1.48 

(10.20) 

1.44 

(9.93) 

1.75 

(12.07) 

1.65 

(11.38) 

1.57 

(10.83) 

1.54 

(10.62) 

COV (%) 18.2 19.0 20.5 19.0 15.5 16.6 17.3 17.0 
9 

the distribution of MOEtv values within a given edge knot 

class and the average MOEtv for each class. This information 

could be used to make initial estimates of the yield of E-rated 

Hem–Fir for various glulam layups (AITC 1993). 

Machine-Stress-Rated Lumber 

Table 16 shows the number of pieces for selected MSR 

grades from the computer simulation. The percentage grade 

yield is shown in Table 17. According to current American 

Lumber Standards Committee guidelines, any lumber that 

fails to make an MSR grade (called falldowns) may be sold 

Table 16—Simulated grade yields of MSR lumber from Alaskan hemlock pulpwood logs 

based on pieces graded as No. 3 and bettera

 Pieces from visual falldowns from MSR 

Size MSR grade 

Pieces of 

MSR SS No. 1 No. 2 No. 3 VQL 5 

Total 

number 

of pieces 

Sorting one MSR grade at once

2 by 4 2400f-2.0E 104 74 151 180 46 548 1,103 

 2100f-1.8E 207 40 120 143 45 548 1,103 

 1800f-1.6E 368 0 59 90 38 548 1,103 

 1650f-1.5E 388 0 47 84 36 548 1,103 

 1450f-1.3E 461 0 0 66 28 548 1,103 

2 by 6 2400f-2.0E 105 144 142 253 93 502 1,239 

 2100f-1.8E 146 124 132 242 93 502 1,239 

 1800f-1.6E 240 0 197 213 87 502 1,239 

 1650f-1.5E 297 0 161 194 85 502 1,239 

 1450f-1.3E 461 0 82 117 77 502 1,239 

Sorting two MSR grades at once

2 by 4 and 2100f-1.8E 

1650f-1.5E 

207 

169 

0 

0 

0 

52 

0 

88 

0 

39 

0 

548 

—b

 

1,103 

2 by 6 and 2100f-1.8E 146 0 0 0 0 0 —b 

 1450f-1.3E 309 0 87 118 77 502 1,239 

a

Note that when grades are sorted one at a time, the number of pieces in lower MSR 

 grades includes the pieces from a higher grade. 

b

Falldowns. 

Table 17—Estimated percentage grade yields of Alaskan hemlock sorted as MSR lumber, 

from Table 16a

Yield from visual falldowns of MSR (%) 

Size MSR grade 

MSR yield 

(%) SS No. 1 No. 2 No. 3 VQL 5 All 

Sorting one MSR grade at once

2 by 4 2400f-2.0E 9.4 6.7 13.7 16.3 4.2 49.7 100 

 2100f-1.8E 18.8 0 14.5 13.0 4.0 49.7 100 

 1800f-1.6E 33.4 0 5.3 8.2 3.4 49.7 100 

 1650f-1.5E 35.2 0 4.3 7.6 3.2 49.7 100 

 1450f-1.3E 41.8 0 0 6.0 2.5 49.7 100 

2 by 6 2400f-2.0E 8.5 11.6 11.5 20.4 7.4 40.6 100 

 2100f-1.8E 11.8 10.0 10.6 19.6 7.4 40.6 100 

 1800f-1.6E 19.4 0 15.9 17.2 6.9 40.6 100 

 1650f-1.5E 24.0 0 13.0 15.7 6.7 40.6 100 

 1450f-1.3E 37.2 0 6.6 9.4 6.2 40.6 100 

Sorting two MSR grades at once

2 by 4 and 2100f-1.8E 18.8 0 0 0 0 0 — 

 1650f-1.5E 15.3 0 4.7 8.0 3.5 49.7 100 

2 by 6 and 2100f-1.8E 11.8 0 0 0 0 0 — 

 1450f-1.3E 24.9 0 7.0 9.5 6.2 40.6 100 

a

Note that when grades are sorted one at a time, the number of pieces in lower 

 MSR grades includes the pieces in a higher grade. 
10 

as visually graded lumber provided that the assigned allowable bending strength Fb for the visual grade is less than that 

of the MSR grade for which the lumber failed to qualify. For 

each MSR grade, or grade combination, Tables 16 and 17 

also give the yield of falldowns by visual grade. The top 

section of each table shows simulated yields if only one MSR 

grade is produced at a time. For 2 by 4 lumber, approximately 19% of the lumber qualified as 2100f–1.8E MSR 

(Table 17). For 2 by 6 lumber, the grade must be dropped to 

1800f to obtain about the same yield. The observation that 

yield of a given grade will drop with increasing lumber width 

will generally be true for MSR lumber and is a reflection of 

the effect of size on lumber strength. With visually graded 

lumber, allowable properties are adjusted to lower values as 

width increases (ASTM D1990, ASTM 1996). To simplify 

specification of MSR lumber, allowable properties for MSR 

grades traditionally have not been adjusted for width. 

As already mentioned, producing two MSR grades simultaneously would affect the yield of the lower grade. For example, producing 2100f–1.8E 2 by 4 lumber in combination 

with 1650f–1.5E would not affect the yield of 2100f, but it 

would reduce the yield of 1650f from 35.2% to 15.4% (bottom section of Table 17). In addition, it would also affect the 

amount of falldowns available for sale as visually graded 

lumber. 

However, the two grading systems cannot be easily compared 

on the basis of assigned properties. Table 18 shows the 

allowable properties for visually graded Hem–Fir lumber and 

the MSR grades simulated in this report. The grades for MSR 

lumber are determined by market demand, and they do not 

necessarily match those of visually graded lumber. For some 

customers (or some uses), lumber strength Fb may be the 

primary property of interest; for others, MOE. The last two 

columns of Table 18 “match” the MSR grades used in this 

report to the properties of the visual grades by Fb and then 

by E. 

Suppose that a mill was approached by a customer who 

wanted primarily 2 by 4 lumber with a bending strength Fb of 

2100f. For visually graded lumber, this would require Select 

Structural grade. From Table 10, we would estimate the yield 

at 10.1% for visually graded lumber. For MSR 2 by 4 lumber, the top grade could be set at 2100f–1.8E, with an estimated yield of 18.8%% (Table 17). However, if the customer 

were using No. 1 and better (No. 1 & Btr) as the top grade, 

an MSR grade of 1650f–1.5E would give an estimated yield 

of 35.2%, compared to a yield of 28.0% for visually graded 

No. 1 & Btr (add yields of No. 1 and Select Structural in 

Table 10). 

If an MOE value of 1.8E were specified by the customer, this 

high a value cannot be achieved with traditional visually 

graded lumber (Table 18). If an MOE of 1.6 × 106

 lb/in2

were the primary selection criterion, then the estimated yield 

of 1800f–1.6E MSR would be 33.4% as compared to 10.1% 

for visually graded Select Structural lumber. Additional 

comparisons could be made for other grades of 2 by 4’s and 

2 by 6’s by using Tables 10, 17, and 18. For a discussion of 

the technical advantages of MSR lumber, see Winistorfer and 

Theilen (1997). 

Implications 

This study presents information on the anticipated yields of 

structurally graded lumber for western hemlock produced 

from Alaskan pulpwood logs. It is not likely that a commercial mill could profitably process only this type of log; however, this material could supplement lumber cut from higher 

quality sawlogs. Production of the lumber is of no use unless 

markets can be found and the lumber can be produced at a 

profit. Mills interested in producing a particular lumber 

product should first establish potential markets for their 

material. Then, they should conduct a yield study at their mill 

using available timber resources and the grades of lumber 

that are in demand. Only then will the mills have adequate 

information on which to make marketing decisions. As with 

all grading systems, it is generally easier to find markets for 

higher grade lumber. The challenge is to find markets for the 

approximately 50% of the pieces that did not make at least 

No. 2 grade, plus the sawdust, bark, and sawdust. 

Conducting a market analysis using yield data such as given 

in this report is a tricky business, best left to companies or 

mills that intend to market the product. For example, this 

study presents information about grade yield for a wide range 

of grades and sizes. However, an individual mill must focus 

Table 18—Comparison of visual and selected MSR 

grades of Hem–Fir by bending strength (Fb) or MOE

Visually graded MSR matcheda

Size Grade Properties by Fb by E

2 by 4 

 2400f-2.0E 

 2400f-2.0E 2100f-1.8E 

 SS 2100f-1.6E 2100f-1.8E 1800f-1.6E 

 1800f-1.6E 

 No. 1&Btr 1650f-1.5E 1650f-1.5E 1650f-1.5E 

 No. 1 1460f-1.5E 1450f-1.3E 1650f-1.5E 

 No. 2 1275f-1.3E 1450f-1.3E 

 No. 3 750f-1.2E 

2 by 6 

 2400f-2.0E 

 2100f-1.8E 

 SS 1820f-1.6E 1800f-1.6E 1800f-1.6E 

 1650f-1.5E 

 No. 1&Btr 1430f-1.5E 1450f-1.3E 1650f-1.5E 

 No. 1 1260f-1.5E 1650f-1.5E 

 No. 2 1100f-1.3E 1450f-1.3E 

 No. 3 650f-1.2E 

a

MSR grades other than those used in this report are 

 available from WWPA (1998). 
11 

on those grades and sizes for which they can find customers. 

Deciding to produce lumber using two grading systems, a 

common situation, is further complicated because the grades 

produced in one system affect the yield of grades produced in 

the other system. Also, general trends in pricing for a product 

may not reflect what a particular mill can get for its product. 

A small mill can sometimes find a niche market that supports 

an activity that would not be profitable for a big mill. To aid 

mills in conducting their own market analysis, Appendix B 

outlines some considerations needed to extend the results 

presented in this report, or similar reports, to an analysis of 

market potential. 

Conclusions 

• This research establishes that a significant amount of 

higher quality structural lumber can be produced from 

Alaskan hemlock logs that were once used primarily for 

the production of pulp chips. 

• Most of this lumber would need to be kiln- or air-dried 

to be acceptable in the marketplace. This is especially 

true of MSR lumber and laminating stock. In this study, 

the yields of the higher grades of Structural Framing 

were improved by drying and surfacing. 

• This study only considered yields from lower quality 

“pulpwood” logs. It is unlikely that a modern production-oriented mill would be established just to process 

such logs. A study is needed to evaluate yields from 

hemlock sawn from higher grade sawlogs. 

• It is essential that markets be established for this lumber 

before production of a particular grade is considered. 

Literature Cited 

AITC. 1993. Manufacturing standard specifications for 

structural glued laminated timber of softwood species. AITC 

177–93. Englewood, CA: American Institute of Timber 

Construction. 

ASTM. 1996. Annual book of standards. Vol. 04.09, Wood. 

Philadelphia, PA: American Society for Testing and 

Materials. 

ASTM D1990. Standard practice for establishing allowable properties for visually-graded dimension lumber from 

in-grade tests of full-sized specimens. 

ASTM D2395. Standard test methods for specific 

gravity of wood and wood-based materials. 

ASTM D4442. Standard test methods for direct moisture 

content measurement of wood and wood-based 

materials. 

ASTM D4761. Standard test methods for mechanical 

properties of lumber and wood based structural material. 

Brown, L.S.; DeVisser, D.A.; Tuvey, R.S.; Rozek, A.K. 

1997. Mechanically graded lumber: the grading agency 

perspective. Wood Design Focus. 8(2): 3–7. 

Ernst, S.; Plank, M.E.; Fahey, D.J. 1986. Sitka spruce and 

western hemlock beach logs in southeast Alaska: suitability 

lumber, pulp, and energy. Res. Pap. PNW–352. Portland, 

OR: U.S. Department of Agriculture, Forest Service, Pacific 

Northwest Forest and Range Experiment Station. 

Evans, J.W.; Green, D.W. 1987. Mechanical properties of 

visually graded lumber: Vol. 3, Hem–Fir. Springfield, VA: 

National Technical Information Service. 

Fahey, T.D. 1983. Product recovery from hemlock “pulpwood’’ from Alaska. Res. Pap. PNW–303. Portland, OR: 

U.S. Department of Agriculture, Forest Service, Pacific 

Northwest Forest and Range Experiment Station. 

Forest Products Laboratory. 1999. Wood handbook—

wood as an engineering material. Gen. Tech. Rep. FPL–

GTR–113. Madison, WI: U.S. Department of Agriculture, 

Forest Service, Forest Products Laboratory. 

Galligan, W.L.; McDonald, K.A. 2000. Machine grading: 

practical concerns for lumber producers. Gen. Tech. Rep. 

FPL-GTR–7, Madison, WI. U.S. Department of Agriculture, 

Forest Service, Forest Products Laboratory. 

Gray’s Harbor. 1982. Official log scaling and grading rules. 

Tacoma, WA: Gray’s Harbor Log Scaling and Grading 

Bureau, Hoquiam, Washington. 

Green, D.W.; Evans, J.W. 1989. Moisture content and the 

mechanical properties of lumber: decisions for the future. In: 

Green, D.W.; Shelley, B.E.; Vokey, H.P., eds. Proceedings, 

workshop on in-grade testing of structural lumber; 1988, 

April; Forest Products Laboratory, Madison, WI. Proceedings 47363. Madison, WI: Forest Products Society: 44–55. 

Green, D.W.; Hernandez, R. 1998. Standards for structural 

wood products and their use in the United States. Wood 

Design Focus. 9(3): 3–12. 

Ross, R.J.; Geske, E.A.; Larson, G.H.; Murphy, J.F.

1991. Transverse vibration nondestructive testing using a 

personal computer. Res. Pap. FPL–RP–502. Madison, WI: 

U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. 

USDA. 1997. Tongass land management plan revision—final 

environmental impact statement. RID–MB–3386 (January). 

Juneau, AK: U.S. Department of Agriculture, Forest Service, 

Region 10. 

USDA. 1999. Record of decision. Tongass National Forest 

land and resource management plan (April). Juneau, AK: 

U.S. Department of Agriculture, Forest Service, Region 10. 

Viereck, L.A.; Little, E.L. 1972. Alaska trees and shrubs. 

Agric. Handb. 410. Washington, DC: U.S. Department of 

Agriculture, Forest Service. Reprinted by University of 

Alaska Press, Fairbanks, AK. 265 p. 
12 

Walk, F. 1997. Timber resources of the Tongass national 

forest. In: Dramm, J.;. Smyrski, R., eds. Proceedings: workshops on opportunities for forest products in southeastern 

Alaska. Unnumbered rep. Madison, WI: U.S. Department of 

Agriculture, Forest Service, Forest Products Laboratory: 7–8. 

WCLIB. 1956. Standard grading and dressing rules for 

Douglas-fir, west coast hemlock, Sitka spruce, and western 

redcedar. Rep. 15. Portland, OR: West Coast Lumber Inspection Bureau. 

WWPA.1998. Western lumber grading rules 98. Portland, 

OR: Western Wood Products Association. 

Winistorfer, P.E.; Theilen, R.D. 1997. Machine-graded 

lumber–design implications. Wood Design Focus. 

8(2): 14–20. 

Woodfin, R.O., Jr.; Snellgrove, T.A. 1976. Western hemlock in southeast Alaska–utilization, lumber recovery, and 

chip yield. Res. Pap. PNW–208. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest 

and Range Experiment Station. 

Appendix A—Building Codes 

and Voluntary Products 

Standard PS–20 

The system of model building codes and voluntary product 

standards for lumber in use throughout the United States 

ensures that the quality of these products is well established 

and reliable. However, this system can appear complicated 

and confusing to those new to the system. This appendix will 

briefly summarize the system as applied to structural lumber. 

A more detailed discussion, including the full range of structural wood products, may be found in Green and Hernandez 

(1998). 

Building Codes and Product Standards 

The regulation of building construction in the United States 

is accomplished through a document called a building code. 

A building code is a collection of laws, regulations, ordinances, or other statutory requirements adopted under the 

legislative authority of State or local governments. The code 

specifies the minimum acceptable construction requirements 

to protect public health and safety. Because of the complexity of issues faced by State and local governments in writing 

building codes, so called “model” building codes began to be 

developed early in the 20th century. These codes are intended 

to be the foundation upon which a legislative body can create 

its own regulations. 

Currently, the three organizations in the United States that 

write model building codes are the 

• International Conference of Building Officials (ICBO), 

• Building Officials & Code Administrators International, 

Inc. (BOCA), and 

• Southern Building Code Congress International 

(SBCCI). 

Each is a non-profit organization owned and operated by 

voting members composed of representatives of city, county, 

and State governments who have adopted that organization’s 

model code, plus representatives from the Federal government. The Uniform Building Code of ICBO has been 

adopted by most States west of the Mississippi River, including Alaska (Fig. 4). In establishing comprehensive regulations for all types of building construction, model building 

codes excerpt or directly reference numerous standards 

promulgated by a variety of nationally recognized technical 

and trade organizations. The text of the building code describes how each referenced standard is to be used for regulation purposes. Organizations producing voluntary consensus 

standards for wood-based materials referenced by model 

building codes include the 

• American Forest and Paper Association, 

• American Society of Civil Engineers, 

• American Society for Testing and Materials, and 

• Department of Commerce. 

Voluntary Product Standard PS–20 

Standard PS–20 establishes nationally recognized requirements for the grading of lumber. This standard was 

developed by the American Lumber Standards Committee 

(ALSC) in accordance with procedures of the U.S. Department of Commerce and is administered by the National 

Figure 4—Current areas of model building code use in 

United States. 
13 

Institute of Standards and Technology (NIST). Members of 

ALSC are appointed by the Secretary of Commerce to constitute an independent consensus body. The ALSC consists of 

representatives from 

• each agency that participates in the program and publishes and maintains grading rules and inspection facilities covering various species (rules-writing agencies), 

• each lumber inspection agency participating in the program that does not publish grading rules (non-ruleswriting agencies), and 

• the construction community, including architects, engineers, general contractors, home builders, wood-using 

industries, millwork manufacturers, lumber wholesalers 

and retailers, and consumers. 

The ALSC operates as an independent body with defined 

functions with regard to maintaining, implementing, and 

enforcing PS–20. The ALSC established the National Grading Rules Committee (NGRC) as an autonomous body 

charged with establishing and maintaining nomenclature and 

descriptions of lumber grades (Fig. 5). The NGRC is composed of members of rules-writing and non-rules-writing 

grading agencies, BOCA, ICBO, SBCCI, the American 

Society of Civil Engineers, the American Institute of Architects, consumer and distributor organizations, the Federal 

Highway Administration, the Defense Logistics Agency, 

NIST, and the Forest Products Laboratory. 

The ALSC also established a Board of Review as an independent body composed of three elected members (Fig. 5b). 

The function of the Board is certification and accreditation of 

grade rules and allowable properties established by the 

NGRC and of agencies that wish to grade lumber under 

PS–20 provisions. PS–20 states that design values contained 

in grading rules shall be developed in accordance with appropriate standards of the American Society of Testing and 

Materials and other technically sound criteria. NIST, with the 

advice and council of the Forest Products Laboratory, is the 

final authority in regard to the appropriateness of such standards and criteria. Once grade marks are approved, Boardapproved quality inspectors conduct periodic inspections to 

verify that grading agencies are following ALSC-approved 

procedures. Model building code for solid-sawn structural 

lumber is generally approved through recognition of the 

American Forest and Paper Association (AF&PA) National 

Design Specifications for Wood Construction. 

Selected Contacts 

American Lumber Standards Committee 

Board of Review 

P.O. Box 210 

Germantown, MD 20875–0210 

Phone: 301–972–1700 

USDA Forest Service 

Forest Products Laboratory 

One Gifford Pinchot Drive 

Madison, WI 53705–2398 

Phone: 608–231–9200 

West Coast Lumber Inspection Bureau 

Box 23145 

6980 SW Varns Road 

Portland, OR 97223 

Phone: 503–684–8928 

Western Wood Products Association 

Executive Office 

522 SW Fifth Avenue, Suite 500 

Portland, OR 97204–2122 

Phone: 503–224–3930 

Alaskan Office 

Michael J. McGuigan 

Alaskan Regional Manager of Quality Standards 

P.O. Box 770590 

Eagle River, AK 99577 

Phone: 906–694–3544 Fax: 906–694–3543 

Figure 5—Relationship of American Lumber Standards 

Committee to other entities: (a) process for writing and 

implementing standards, (b) Board of Review. FPL is 

Forest Products Laboratory. 
14 

Appendix B—Marketing 

Considerations 

This appendix provides basic data from which a marketing 

analysis can proceed.3

 It does not provide an analysis as such 

because many variables that are essential to such an analysis 

must be addressed by individual companies or, in some 

cases, by individual production facilities. In addition, there 

are technical characteristics in any “case-study” type of 

analysis that must be recognized and interpreted by the end 

user as part of the market analysis. This appendix briefly 

outlines, in a general way, some considerations needed to 

extend the results presented in a yield study, such as this one, 

to an analysis of market potential. 

Technical Characteristics 

 of a Case Study 

Sampling 

Yield studies are necessarily based on samples of a larger 

population about which inferences are to be made. The limitations of sampling should be considered. All samples are 

estimates; however, if the size of the original sample was 

quite small or limited in any way as a result of practical 

limitations, the yield values obtained from the study may 

need to be adjusted by judgment prior to setting market 

targets. 

Grades 

The grades used in the yield study were selected to represent 

the range of quality expected in the sample. This allowed 

inferences about the effect of the grading system variables on 

grade yield. The selection was not intended to represent the 

actual grade mix that might ultimately be chosen for the 

market. Consequently, the results of the yield sample must be 

further adjusted to meet current or anticipated market needs. 

Here are some examples. 

“And better” grades—One example of an “and better” 

(&Btr) grade is 2 by 4 No. 1&Btr under the American Lumber Standard system of stress grades for Structural Light 

Framing. This is a grade that includes both No. 1 and Select 

Structural grades, but the lumber may be grade stamped 

No. 1&Btr with no distinction between the constituent 

grades. In a yield study, both No. 1 and Select Structural may 

be identified to illustrate the amount of “and better” in the 

sample, but the yields will likely be merged by marketing 

personnel to 

forecast sales yields. 

 

3

 Source of information: William L. Galligan, Consultant, 

5223 Verda Lane, NE, Salem, OR 53705–2398. 

Another example is the Light Framing grade of 2 by 4 Standard and Better (Std&Btr). If a mill chooses not to grade 

Construction grade lumber separately, the mill is permitted to 

include this grade in the mix and stamp all pieces in the 

category as Std&Btr. Clearly, it is important that the study 

identify the amount of Construction-grade lumber; however, 

for sales purposes, Construction lumber may be grouped with 

Standard lumber and not separately identified. 

 “And better” market mixes—For lumber in the wider 

widths, sales are commonly based on grouping No. 1 and 

No. 2 lumber as No. 2&btr. As opposed to the No. 1&Btr 

grade that can be stamped on a combination of two grades 

(as previously discussed), both No. 1 and No. 2 lumber must 

be individually grade stamped even if commonly placed 

together in a bundle for sales. This is a case where sample 

yields of both No. 1 and No. 2 lumber are essential in a grade 

yield study so that the marketing expectations for the percentage of “No. 1” in the sales mix (called No. 2&btr) can be 

estimated. This market expectation can have significant price 

sensitivity. 

Grading categories—In dimension lumber, the categories 

Light Framing and Structural Light Framing overlap in the 

characteristics permitted. In the West, Light Framing is 

commonly used for 2 by 4 and Structural Light Framing 

lumber for the higher grades of 2 by 4’s. Structural Light 

Framing is used for all grades of wider width. To simplify a 

yield study, the grade analysis may be limited to the Structural Light Framing grades, or some grades of each category 

may be left out of the grade yield study. For example, the 

lower grade of Structural Light Framing (No. 3) is seldom 

sold in western species. As a result, the market analysis based 

on a yield sample that included No. 3 must convert the 

amount of No. 3 to Utility and Standard—perhaps in a side 

study, if the amount of No. 3 is significant. Clearly, the need 

for this type of refinement depends on the overall market 

potential of the study and the percentages of the grades in the 

study. Another example is measuring the amount of Select 

Structural lumber even if the mill has no intent of marketing 

that grade. 

Mill Optimization 

No sooner does a yield study arrive on the mill manager’s 

desk than the mill begins to explore ways to further extend 

the “good news” and minimize the “bad news.” If the study 

suggests promising results and the sample is judged by the 

mill to be adequate and representative, the “half life” of the 

results as accurate predictions can be very short; the insights 

of the study often immediately influence changes in mill 

practice even if the study recommendations are not followed. 

Log Bucking and Breakdown 

If the study suggests grade yields that can be improved by an 

adjustment in log bucking or breakdown, these adjustments 
15 

will be addressed by the mill. In addition, the price of the end 

product is likely to be a function of length, which will be 

addressed in log breakdown and subsequent trimming. This 

will include market insights not included in the basic study, 

which is usually based on a limited number of lumber 

lengths. These insights include the inelasticity of the market 

for some lengths and the premiums for others. 

Edging—Grades are often sensitive to width; that is, the 

yield may vary between widths because of the quality of the 

wood included in the piece—where it comes from in the log, 

the mill edging practice, and, consequently, the amount and 

quality of material incorporated in the piece. Mill studies on 

the effect of changing the edger settings for grade are not 

usually considered in initial yield studies. Furthermore, socalled “optimizing” edgers optimize primarily on volume, not 

grade, except as influenced by some grade characteristics 

such as wane. 

Trimming—Grade can usually be significantly affected by 

trimming “for grade” in the mill. The mill will employ a 

“trim list” with price-related rules on the amount to trim a 

piece based on the potential up-grade (+) and loss of trim (−). 

This may be an automated operation. Yield studies can incorporate this information but seldom do because of the 

complication in data collection and analysis. 

Grading—As carefully as a grading system is analyzed in a 

typical yield study, further scrutiny of the grading system will 

often generate more information needed for market analysis. 

This is because the grading system (or systems, because 

many mills are actually using more than one system simultaneously) is a family of grades—change one grade or introduce a new one and the grade yield of the adjacent grades 

shifts. It is even more significant when two of the grading 

systems employed are machine grading and visual grading 

because there are specifications on the grades permitted in 

simultaneous operation of the two systems. Market analysis 

should consider the entire spectrum of grades the mill can 

produce and should include mill insights on yield interactions 

that are anticipated because of mill experience. 

Market Pricing 

Any feasibility study is contingent upon the values assigned 

to the manufacturing costs and the market pricing. These are 

subject to both short- and long-term variation. A mill must 

make the assumptions most relevant to the operation and 

conduct sensitivity analysis on the results to include the 

effects of variability and uncertainty. 

Availability of Pricing Data 

Often no data are publicly available on grades such as those 

developed in machine grading or that are included within the 

“and better” market combinations. This makes it difficult to 

conduct a study of the impact of adding manufacturing efficiency to generate more product if the mill has no market 

experience in that product area. In some product areas, such 

as laminating lumber, grades are almost always sold in combinations, with re-grading taking place at secondary manufacture sites. In this instance, no prices are publicly reported; 

therefore, pricing of component grades requires networking 

with other companies or experience in the industry. 

Relevance of Public Price Data 

A word of caution is always needed in the use of published 

price data obtained from surveys. Commonly, this reflects 

some aspect of an average or consensus. These data may not 

represent the mill-specific product. Issues that may “shade” 

the published price include quality components, experience 

in the market, quantity available, reputation of the company, 

and conditions of sale. 

Niche Markets 

Pricing relevant to niche markets must be carefully evaluated 

to include the stability of the market, competition, actual enduse requirements, and mode of sale, including delivery. 

Niche markets are often based on company-to-company 

communication, and pricing can be linked to mutually 

acceptable measures of performance.