Page 7
BURNT WOODS COOPERATIVE--MAPPING GEOGRAPHIC GENETIC VARIATION
Roy Silen,
PNW
Following methods of marping geographic genetic variation developed i
1978-1979
for the Vernoni
. a and Molalla Cooperatives, a
similar map of the Burnt Woods
Cooperative area was mate from recent 10-year progeny . height data.
The Burnt Woods Cooperative is
a 70,000 acre forest area west of Corvallis owned
.
by Starker Forest and State of Oregon.
The 10-year progeny measurements apply
to families from 161 parent trees allotted among 5 sets of 31 to 33 families tested
on 8 sites.
Progeny av raged about 16 feet in height.
The top 20 percent were
7.5 percent taller than mc·an height and an estimated 17 percent greater in volume
as shown in Table l.
In the earlier analyses we used computer programs to produce a response surface,
then drew in i.soheight
heights
: ines to make the maps
of progeny wen
(see IFA TIN 1138).
Expected average
plotted for parents located within 500 meter square areas.
One program produced an equation by a stepwise regression for a predicted height
at the la itude, longit11de.,
and elevation of the parent.
smoothing technique called Krieging,
The other program uses a
in which mean heights of one 500 meter square
area was averaged with a weighting of mean values in adjacent 500 meter squares.
Isoheight contours from hoth methods produced maps that are interpretable in _erms
of influence of topographic features.
The smoothing method produced a clearer map
Of geogra;1hic genetic variation in height within the breeding zone.
This map is
shown in Figure 1.
Fastest inherent growth was associated with parents from low ridges, and slowest
with parents in the rain shadow of Little Grass Mountain, the highest ridge in the
ownership.
Like the Vernonia and Molalla geographic variation maps, this map supports
the suggestion that adaptation to a locale is precise.
Progeny height, range,
Table 1. Burnt _ Woods Trf'e Improvement 10-J'.ear height data.
shown by set and by overall average.
average, and percent dif fererh:e from average are
Set I
TI3iI1 Set 2
Set 3
Set 4
Set 5
(3
(31)
(32)
(32)
x
536
Tallest
529
54 7
512
529
542
Top 20%
523
537
521
533
531
529
Average
494
501
485
95
487
492
Shortest
395
454
437
435
450
434
% difference -in ht.
5.9
7.1
7.4
7.7
9.0
7.5
I 3.5
J6 1
16.8
17.2
20.4
16.8
from top 20% -in vol.
'!:./
.
l/
Number of families in the set. '!:./
Estimated from Vernonia Tree Improvement Cooperative 10-year data. Page 8
MAP OF GE.NE'r1c VARIA7i10N
5"1°011-i£i.J
C f'?O,/\/
7" I"'
s-10
) ... - ..
ye,.,,-::
/NC;) F He NT
8vR.Nr Wooos CooP£ A7" Y£"
-­
·­
·
.,,
·
-
•
•
•
•
Isoheight contour map of inherent growth rate for Burnt Woods Tree
Figure l.
Contours display 10 cm differences in growth of
Improvement Cooperative area.
progeny (about 3.5 percent differences} in period between 5 and 10 years.
Small figures are
Lines are solid within ownership area and dashed between.
coding of periodic height growth in 10 cm intervals from 250 cm (1) to 310 cm
(7) for the 500 meter squares in which parent trees are represented.