ABSTRACT- Seed was collected in 1964 from 100 wind­ pollinated Douglas-fir (Pseudotsuga menziesii (Mirb.)
Franco) parent trees from four sites, two near Corvallis,
Oregon, and two near Shelton, Washington. By 1974, eight commercial Christmas tree growers in Oregon and Wash­ ington had cultured, harvested, and marketed progenies grown in designed tests. Financial returns on progenies of the 10 best parents showed discounted gains of 18 percent in selling price but net returns were increased 58 percent be­ cau.se rapid growth was a major factor in profitability. Up­ right branching and dense, dark foliage contributed most to upgrading the trees. Seedlings from top-ranking parents are in commercial production, and second-generation breeding has begun.
Recent distribution to Christmas tree growers in the
Pacific Northwest of one-third of a million Douglas-fir seedlings originating from proven gen~tically superior parents represented a major landmark for the
Douglas-fir Christmas tree industry, as well as having major forestry implications. The seedlings were prog­ enies of top selections among 100 parent trees that had undergone a full cycle or rotation of testing between
1964 and 1974.
The work began when the senior author proposed a lo·w-cost genetic testing program whereby wind­ pollinated seed from 100 randomly selected trees would be sown in designed tests planted and main­ tained by growers. Low cost was an essential of the plan, for the industry in Washington and Oregon is small, having neither the organization nor the finances for a conventional seed-orchard approach. The test could be short, because Christmas trees are marketed in 7 to 10 years. And, when the results were in, com­ merical quantities of seed could be collected from 10 to
25 of the best parents. The risky question was whether genetic differences from only the female parents would provide enough gain.
The Study
In the autumn of 1964, we collected wind-pollinated seed from 60 parents in each state, to assure that 50 parents might yield sufficient seedlings for testing. In
Oregon, collections were made at Corvallis at 250-foot elevation on the west side of the Willamette Valley and at Lacomb on the east side of the valley in the same latitude but at 900-foot elevation. Washington trees were collected near Shelton, the "Christmas tree capi­ tal " at 500-foot elevation and near McCleary, 17 miies southwest, at 600 feet. Oregon source seedlings were grown during 1965 and 1966 at the U.S. Forest
Service's Forestry Sciences Laboratory, Corvallis.
Washington source seedlings were grown concurrently at the Webster Nursery, Olympia. The assumption, later shown to be partially incorrect, was that any nur­ sery differences would be unimportant at harvest age.
In the spring of 1967, arrangements were made (by
Bernard S. Douglass, USDA Fores.t Service, and
Gary Sanders, extension forester for Oregon State
University) for eight growers of the Northwest
Christmas Tree Association to culture the progeny to harvest age. The eight sites were near Shelton, Olym­ pia, and Chehalis, Washington, and Oregon City,
Salem, Corvallis, Springfield, and Roseburg, Oregon
(figs. rand 2); they provided a good sampling of the main commerical growing area for Christmas trees in the two states.
Each grower planted the trees according to the study design. Each was given 9 labeled seedlings represent­ ing each ofthe 100 parent trees for a total of 900. These
900 trees were divided into 3 replications of 300 seed­ lings, in which 3 seedlings of each parent were plant~d as a row at 5by 5-foot spacing. The family plots m every planting were individually randomized. The growers were free to use their usual cultural and maintenance techniques if they exceeded minimum practices, which included planting on plowed ground, yearly control of grass, and shearing. When shearing started in 1969, however, growers were asked to fol­ low the common procedure of shearing crowns to a
50-percent taper (half as wide as tree height), with leaders cut to a maximum of 24 inches in 1969, 18 inches in 1970, 12 inches in 1971, and usually shorter thereafter. All trees were sheared.
On all eight plantations, total heights were measured yearly until shearing began in 1969. At harvest, USDA grades and sheared heights in one-half-foot increments were recorded on each tree. In addition, notes on foliage characteristics, disease susceptibility, and other grade-oriented traits were made.
THE AUTHORS- Roy R. Silen is principal plant geneticist, For­ estry Sciences Laboratory, Pacific Northwest Forest. and Range
Experiment Station, USDA Forest Service, Corvallis, Oregon.
Boyd C. Wilson is forest geneticist, Department of Natural Re­ sources, State of Washington, Olympia.
May 1977/JOURNAL OF FORESTRY/255 ­

Olympio
~
1\l\
~ f\
0 Chehalis / ' \ / \
...____ '/\wASHINGTON
Corvallis•
0 l~ oSalem
OOregon City A
0
~
Springfield
ORoseburg
1\1\
1\1\
/\A
---
Figure 1. Parent tree locations (0) and study test sites(.).
Harvest began in 1971. Plantations near Corvallis,
Oregon City, and Chehalis, which averaged in the 6- to
8-foot range, were ready for final harvest by 1972. At
Roseburg, trees had encountered damaging frosts; they averaged about 4.5 feet in height, and few were harvestable by 1974. The Roseburg cost-and-return record is not included in this report. Plantations near
Shelton, Springfield, and Salem were harvestable in
1973 and 1974. That at Olympia ranked second in growth rate in 1969, then was so severely decimated by an unidentifiable root fungus that no trees were ready for harvest until 1974.
For the seven sites with cost data, 1974 values were computed for each tree on the basis of grade and height. Selling price per foot of height was 65, 55, and
40 cents for grades Premium, No. 1, and No. 2, re­ spectively. Grades depend upon number of sides of a
Christmas tree with unblemished foliage, the premium tree having a perfect top and four unblemished sides ..
Cost figures were supplied by Oregon State Univer­ sity Extension Service from studies of growers in the northern Willamette Valley. 1 These data provided broad average costs of each activity by year from nur­ sery through harvest; these costs were applied to all of the plantations. Since individual trees were harvested at different years in every plantation, average costs per year were accumulated for each tree until harvest, then converted to a common 1974 value by applying an interest rate of 8 percent on all costs and returns. This realistic rate also properly depresses returns for slow­ developing trees.
Observations on Traits
Initially, the predominant notion was that the best combination of traits might be slow growth to give good form and numerous internodal buds and long needles to provide dense foliage. This view proved largely erroneous.
Growth. -The value of rapid growth when com­ bined with shaping by shearing became apparent early.
1 Cost data obtained and calculated by Don Waldron, county agent, and Stanley D. Miles, farm management technologist.
Figure 2. One of eight sites containing 900
Douglas-fir Christmas trees originating from
100 wind-pollinated parent trees. After a complete rotation, the top parentage provided gains of over 20 percent in gross value.
256/JOURNAL OF FORESTRY/May
1977

' '
-,.......
~
'
/
. - -, ·.' ~ · ._r: ~ ~-.,:: " '. .;, ~ ; ,_·
• ' • r:-­
!·.·_,.,
'I'he fastest~growing plantations were producing the most marketable trees. Also, families with the fastest inherent growth were usually those with high ratings.
Figure 3, in which all 100 progeny families are ranked by l%9 height Gust before shearing began), shows that most of the top families in value at harvest were above average growth in each source locality. As a group, the top 10 families in value average 7.8 percent above the
OREGON PA/lENTS
10 lecom b . Ote on
6&
50
46
40 1
10
41
4G eo
65
50
45
40
D ua~~uu~~-~UU~LL
11
11 H 11 44~21 4 t40 23 33 41 u 50 4e 31 3e
RANK BY VALUE
42 38
47 n
43
37
15
28
32
4&
WASHINGTON PARENTS
10
Mt:Ouf)' . w.,h i nglon
51
41 a11 4
15
4 o31lllij7
2 4
12aa
RANK BY VALUE
Shelton . Wesl'ling\On
41 a ~~~~~~~ uu~La&&
~,.22~ 41 <Dmt:> 18 ~ 1 26~2 34 1e
41 n&o•3JgV•424a4423 3812 13
RANK BY VALUE
Figure 3. ·Height ranking at 5 years by seed source ofthe 100 parents (bars) and overall ranking in net value at harvest
(numbers). The most valued parent trees were among the better growers. The top 10 parents in each state are circled. study mean in height growth. Despite shearing, how­ ever, the very fastest growing families sometimes rated low because of foliage gaps at some whorls.
Branching. The trait of next highest value was acute-angle branching. Missing foliage on any side of the tree reduced grade; even more important, any openness, irregularity, or spiking in the top 12 inches reduced grade despite perfection of the tree in general.
Upright branching tended to cover these top defects better than did flatter branching.
Sufficient internodal branching became important in the years soon after shearing began. Numerous inter- · nodal buds, although lessening the crown . ir­ regularities, did not rate as important as upright branching. On some trees, most buds between whorls developed only into short shoots.
Foliage.- Foliage density was of '}.ext importance.
Trees with medium-length needles were more attrac­ tive than trees with long ones, especially if a profusion of twigs developed after shearing. Dark foliage color, particularly deep green or a blue cast, was preferred.
Frost resistance. Damage from spring frost was extensive only at the Roseburg site, where records were made on a 3-class rating in both 1969 and 1972.
Exceedingly early bursting of the Corvallis race caused it to suffer greatest damage. Much less frost damage was recorded for the later-bursting Lacomb race, and practically none for either of the late­ bursting races from Washington. Correlation of ratings between the 100 families for 2 years (r = 0.76, p <
0.01) indicated that degree of damage sustained by the individual families tended to be the same from year to year. Two of the best parent trees in the study ranked highest in frost resistance, but the top group of parents also.jncluded several moderately susceptible families.
Needle retention. -Sampling of 10 families at two sites by R. D. Stevens 2 showed that the loss of needles from cut branches when stored 5 weeks at room tem­ perature varied fivefold between families, but not sig­ nificantly within families. The same data indicated a. twofold difference in needle loss between branches from the sites sampled, but not a significant variation between replications within planting site.
Financial Returns
All s1tes.- Computed roadside selling price for the average study tree was $3 .06. Deducting an average cost of $2.10 resulted in an average net return of $0.96.
Comparing value with returns for the best and poorest parentages provides interesting steps in an array of possible genetic gains (table 1).
Net returns indicate a levering effect over gross re­
2 Stevens, R. D. 1974. Needle retention variation in the 100­ parent-tree study. Northwest Lookout, N. W. Christmas Tree Assn.,
Corvallas, Ore. 7(1):5-8.
Table 1. Value gains from best and poorest Christmas tree families.
Family
Gross Gross Net Net Gain for 1,500 value gain value gain trees per acre
Best
Best 10
Best 50
Average
Poorest
Dollars Percent Dollars Percent Dollars
3.88 26 1.78 85 1,230
3.62
3.35
18
9
1.52
1.25
58
30
840
465
3.06
2.57
0
-16
.96
.47
0
-52
0
-735
May 1977/JOURNAL OF FORESTRY/257

turns of better grades and earlier harvest possible with good families. For example, trees sold in 1971 gained about 26 percent more value from the 8-percent inter­ est and incurred costs for three years less than those harvested in 1974.
Such gains, if achievable in commerical production, compound the justification for genetic improvement.
Individual sites.Average parentage differences in net return between the poorest and the top family ranged from $0.47 to $1.78 per progeny tree (Washing­ ton No. 50 and Oregon No.1). The range on individual sites (table 2) was much greater, from -$1.52 to $3.66
(Oregon No. 50 at Olympia and Oregon No.4 at Cor­ vallis). Some parentage proved to be exceptionally good on all sites, providing net returns from 22 percent to 920 percent over average plantation values (Oregon
No. 1). A few, like the top Oregon parent, ranked among the top 10 on all sites. The top 5 of each state were, with few exceptions, better than average on all sites, but occasional divergent performance raises the potential of a much restricted use for some top par­ ents. Seed of such parents can be pooled into lots par­ ticularly suitable for either Oregon or Washington sites.
Two further observations are notable (table 2). The first, ironically, is that whereas increased profit from the greatest percentage-gains (up to 1,520 percent) on least profitable sites. The second is that whereas the
Oregon sources performed slightly better in this test, primarily a holdover of nursery differences, the Wash­ ington sources averaged more profit on the two most northerly Washington sites. Without exception, a
Washington parent proved to be the most profitable on each Washington plantation and an Oregon tree on the
Oregon plantations, evidence that any genetic screen­ ing of parentage should first explore the local seed source.
Grades and Parent Relationships
All desirable foliage and growth traits are reflected at harvest time in the proportion of Premium and No. 1 grades. A listing of the top 10 parent trees reveals the large differences in quality (table 3).
The average parent produced a combined 18.4 of 60 trees, or nearly one-third, in these grades. The top 10 produced 27.6, or nearly half; the top parent produced
60 percent in these grades and nearly four times the average number in the Premium grade.
Various traits such as relative .growth, needle length, branch angle, number of limbs per whorl, and
Table 2. Net return comparisons per Christmas tree of five best, two poorest, and average parent tree from each state. Listed cost per tree at each site permhs calculation of gross and net return comparison as shown for overall average.
Family rank c
2 a;
.s::. en
Ill
E
>-
5
.!!
iii
.s::.
Gl
.s::.
0
Planting site
~
0 c
0
01
!
0
E
Gl
-~
~ iii
~
0
0
"0
~ c;, c
·;::
Q. en
Overall average return
Gross Net
Increase over site mean
----,----------Dollars--------------~------
5
•
•
•
49
Washington seed sources:
1 1.54
2
3
4
.14
.42
.35
.65
50
Average
.25
.24
.53
4
5
•
•
•
49
Oregon seed sources:
1 .75
2
3
1.45
.81
.14
.71
50
Average
.08
-.04
.37
Cost per tree 1.79
1.43
2.41.
1.27
1.58
1.93
-1.15
-.70
.42
1.02
1.62
.27
1.38
.79
.15
-1.52
.10
1.95
0.71
2.22
.87
.81
.73
.74
.61
.44
1.36
.90
.95
1.12
1.08
.07
.96
.69
2.67
2.92
2.09
2.08
.71
.72
1.22
1.16
1.37
3.42
1.70
3.28
2.54
2.53
1.58
1.98
2.02
1.86
1.17
1.12
1.60
1.29
1.31
.84
.45
1.04
1.83
1.59
1.63
2.15
1.45
1.04
1.14
1.28
1.76
2.80.
3.12
3.39
2.95
3.05
2.13
2.44
2.87
3.61
3.63
3.53
3.66
3.19
2.73
2.64
2.96
1.70
0.21
.86
.38
1.07
.44
- .34
.95
- .47
.58
1.26
1.18
- .35
.52
-1.36
-1.16
.31
2.94
3.64
3.55
3.41
3.34
3.25
2.62
2.57
2.99
3.88
3.83
3.77
3.61
3.56
2.68
2.67
3.12
1.54
1.45
1.31
1.24
1.15
.52
.47
.89
1.78
1.73
1.67
1.51
1.46
.58
.57
1.02
2.10
Percent
74
70
64
48
43
73
63
47
39
29
-42
-47
0
-43
-44
0
258/JoURNAL OF FORESTRY/May 1977
I' r'

foliage/color recorded on the parent-tree record were analyzed for relationships with relative value of the progeny. Results were disappointing. Relationships with foliage color and number of limbs per whorl were the only ones that approached significance.
Improved Seedlings
The operational potential of the study was demon­ strated when the authors collected a sample of seed from 18 of the best parent trees that bore cones in the bumper year 1971. A total of 14 pounds, or about
560,000 seeds, was collected. This seed was sown at the Webster Nursery in Olympia, and has since pro­
'duced about 376,000 1-2 seedlings. For a lot made up of the six parents suitable for planting at low elevation in both states, the gross value gain averaged 18.2 per­ cent. An additional 12 parents showing good perfor­ mance either in Washington or in Oregon were com­ bined into .other lots that averaged 9 percent in gain.
Distribution of the very limited supply of elite seed­ lings was turned over to the U.S. Forest Service's
Division of State and Private Forestry in Portland,
·Oregon. The Division provided each of the original eight cooperating growers with 4,000 seedlings and dis­ tributed the remainder by lottery to other applicants.
A Developing Breeding Program
The best parents in both the Oregon and Washing­ ton groups were crossed in 1971. In Oregon, crosses of
11 pollens of top-performing trees on 6 parent trees were completely successful, providing 60 full-sib fami­ lies (plus 6 self-pollinated families). Washington crosses, which included some Oregon pollens as well, were partially successful. Seed from nearly 100 full-sib families was thus produced for a second generation of breeding. Seed from the 66 Oregon families was sown in 1972 for a breeding archive near Corvallis. In 1976 a distribution was made of full-sib seedlings for testing by four growers.
Forestry Implications
The.study furnishes a clear example of benefits from control of grass. All eight growers followed the study recommendation of complete cultivation before plant­ ing, but only six used the recommended atrazine
Table 3. Premium and No. 1 grade trees produced by the top-ranking parents.
..
7
6
8
9
5
10
1
2
3
4
Study rank in overall net value
Parent ranking 1
0-1
0-2
W-1
0-3
W-2
0-4
0-5
0-6
W-3
0-7
Average of top 10 families
Average of 100 families
Number by grade
Premium No.1
15
12
7
10
11
9
2
7
3
5
8.1
4.1
19.5
14.3
21
18
15
27
14
21
19
23
17
19
1 Parent ranking is for each state. Thus, W-3 Is the third-ranking tree among the Washington parents in Table 1 but ranks ninth overall. Tree numbers by grade are on the basis of 60 trees per fainily. grass-control measures the first year. Some also culti­ vated their sites following planting. The six that did had overall survival percentages of 94, 93, 93, 89, 83, and 83. The two that did not experienced a rapid rein­ vasion of grass and a seedling mortality, primarily from drought, of 46 percent and 54 percent. Even among the six, differences in grass competition for moisture developed by onset of summer drought and were reflected in seedling mortality percentages. The smaller seedlings of the Washington source displayed a decreasing survival percent over the Oregon source, as seen when the survivals of the two sources are ar­ rayed:
Plantations ranked by survival
4
5
6
7
8
I
2
3
Oregon sources
Washington sources
- - - - P e r c e n t - - - ­
94.9 92.4
95.6 90.0
93.8
90.0
91.3
88.7
87.3
87.6
74.2
56.4
79.1
78.9
33.1
32.0
With good grass control on the four best cultivated plantations, the difference in survival averaged only 3 percent, whereas with the poorest two the difference was nearly 33 percent.
Much more detailed genetic information could be presented from our analysis of variance, but only a few statistics and observations are pertinent in this article.
Figure 3 shows the range in family mean heights at 5 years. The statistics from the four populations are:
Seed origin
No. of Average height on parents sites at 5 years Range SD SE
----------Inches---------­
Oregon
Corvallis 31
Lacomb 19
Washington
Shelton 32
McCleary 18
46.6
52.2
44.4
48.8
54.7-40.9
56.9-46.6
48.7-40.5
57.9-43.1
3.8
3.1
2.3
3.8
0.6
.7
.4
.9
Population family means are significantly different, as are the race means between the two Oregon as well as between the two Washington plantations. Such dis­ tinctly different population growth on opposite sides of the Willamette Valley is noteworthy, especially as there are no barriers to pollen exchange. That distinct populations should occur between Shelton and
McCleary, separated only 17 miles by continuous young stands, is even more notewortf1y.
The main forestry benefit of the study, however, was a conceptual one. The entire method of using wind-pollinated seed for genetic testing, coupled with commerical collections from tested parent trees, is now being applied to· Douglas-fir for timber produc­ tion.
3 Virtually the same initial program has been adopted on much commerical forest ·land of the
Douglas-fir region as an alternative to grafted seed or­ chards. •
3 Silen, R. R. 1966. A simple, progressive, tree improvement pro­ gram for Douglas-fir. USDA For. Serv. Res. Note PNW45, 13 p.
Pac. Northwest For. and Range Exp. Stn., Portland, Oreg.
May 1977/JOURNAL OF FORESTRY/259