Seedlings from 25 provenances of Abies grandis and Abies
concolor were studied at two plantations, 12 at Philomath, Oregon,
and 13 at Camino, California. Native seedlings were studied at four
of the provenances' field sites. Stomatal infiltration pressure
measurements and plant moisture stress measurements were made
throughout one summer on the plantation seedlings to identify their
patterns of stomatal response to moisture stress. Stomatal distribution
on the needle surface was used to determine the degree of
resemblance of each provenance to the two Abies species. Seedlings
from four provenances were also studied during December to determine
which seedlings would retain the freshest Christmas tree characteristics
after being cut, transported, stored and displayed, and whether
'heir response could be predicted from stomatal behavior.
Three aspects of the stomatal response patterns differed from
one provenance to another: (1) occurrence of daily stomatal closure
or nonclosure, (2) time of closure and (3) degree of closure. The
stomata of the Abies grandis provenances tended to close daily while
the stomata of Abies concolor-influenced provenances remained open
during the day. The Abies grandis stomata also tended to close
earlier in the day than those in provenances mildly influenced by
Abies concolor, which did close daily to some degree. The provenances
represented at Camino could be grouped as to their degree
of stomatal closure. The members of each group were generally
morphologically similar, indicating genetic relationship. The
stomatal response data suggest that some genetic control of stomatal
response to moisture stress does exist. These genetically controlled
responses conceivably could affect the establishment of seedlings of
certain genotypes in particular habitats.
The Christmas tree keepability experiment resulted in one provenance,
20, retaining its favorable characteristics relatively well,
certainly better than the other provenances. Provenance 20 seedlings
are, therefore, recommended to be used as Christmas trees due to
their ability to retain fresh Christmas tree characteristics. Keepability
was not predictable from the summer stomatal response, but
was correlated with moisture stresses during display of the trees
