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Patterns of tree resistance were surveyed in December 1989; numbers of pitch streamers indicating unsuccessful fir
engraver attacks were classified as 0, < 5, 5-10, and > 10 on stems of all live trees.
Distributions of trees classified by status (live, dead) and number of pitch streamers were compared among provenances
by Chi-square Contingency Test (SAS Institute Inc. 1988). Data from the two replicates of each type of plantation
(geographic range, elevational transect) were similar and were pooled for analysis. In the geographic range plantations,
provenances were combined according to Hamrick and Libby (1972) as modified by Libby et al. (1980). The latter authors
divided white fir in the western part of its range into five major geographic groups based primarily on needle morphology:
(1)"Northern"--central Oregon and northwestern California; (2) "Central"-- south-central Oregon, central and northeastern
California; (3) "Southern California"; (4) "Interior South"m Arizona; and (5) "Interior North"-- eastern Nevada and western
Utah.
RESULTS
Of the 1,127 firs alive in all four plantations in 1987, 393 (35%) were killed by the fir engraver by 1993. Most (253)
of the mortality resulted from the attack season of 1987, with an additional 121 resulting from the 1988 attack season.
Relatively few (29) were killed by attack in 1989-1993. Only a few (10) trees were topkilled, two of which were killed in
subsequent years. Firs on the outside edges of the plantations were infrequently killed (4/97 or 4%).
Through 1993, cumulative mortality in the elevational transect plantations (256 of 578 total trees, or 44%) was almost
twice that in the geographic range plantations (137/549, or 25%). The associated Chi-square (adjusted for continuity) was
45.505, p < 0.0001 at 1 dr.
In the geographic range plantations, mortality differed among major geographic groups of Hamrick and Libby (1972)
and Libby et al. (1980). In both plantations, provenances of the Northern and Central groups had sustained the highest
mortality, while very few of the firs of the Interior South and Interior North groups were killed (Table 1). Low levels (1 1
percent) of mortality occurred in southern California firs. The Chi-square associated with among-group variation was
40.631, p < 0.0001 at 4 df. Among individual provenances, the one from nearest Camino (AK; Omo Ranch; 32 km distant)
had the highest mortality in both plantations.
Table 1.--Mortality of white fir provenances caused by fir engravers in the
geographic range plantations t at Camino, CA I987-1993
Group 2 Plantation 1 Plantation 3
Total Dead Pctdead Total Dead Pctdead
Northern 55 12 22 84 33 39
Central 106 22 21 124 55 44
Southern Calif. 40 3 8 47 7 15
Interior South 28 0 0 31 4 13
Interior North !4 0 0 20 1 5
1Each plantation contained 39 provenances from the western portion of white fir's
geographic range.
ZProvenances combined by major morphological groups of Hamrick and Libby
(1972).
In the elevational transect plantations, mortality in the two lower- elevation westside provenances nearest Camino
(AK, AL) averaged more than one-third greater than that in the two upper-elevation eastside provenances (AM, AN), which
are only about 50 km more distant (Table 2). The among-provenance Chi-square was 24.757, p < 0.0001 at 3 df.
Analysis of the distribution of pitch streamers on boles of surviving firs revealed that in the elevational transect
plantations, virtually all surviving firs had been attacked, and many heavily so (>10 streamers). In the geographic range
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