White Spruce Populations Research Articles

Isoenzyme Identification of Picea glauca, P. sitchensis, and P. lutzii Populations

Electrophoretic techniques were used to identify stands of pure Sitka spruce Picea sitchensis (Bong.) Carr. and pure white spruce P. glauca (Moench) Voss and spruce stands in which introgressive hybridization between the white and Sitka spruce had occurred. Thirteen heteromorphic isoenzymes of LAP, GDH, and TO were the criteria for stand identification. Estimates of likeness or similarity between seed-source areas were made from D determinations. Introgressed hybrid stands had isoenzyme frequencies that were intermediate between the two pure species, but the seedlings were somewhat more like white spruce than like Sitka spruce. Much of the west side of the Kenai Peninsula appeared to be a hybrid swarm area, with stands containing both Sitka and white spruce genes. The presence of white spruce genes in Sitka spruce populations was most easily detected by the presence of TO activity at Rm 52. White spruce showed activity at that position in 79% of its germinants; only 1% of the pure sitka spruce germinants had similar activity. Isoenzyme variation between stands of pure Sitka spruce was less variable than that between interior white spruce stands (mean distinction values were 0.11 for Sitka and 0.32 for white spruce). Cluster analysis showed all six pure Sitka spruce populations to be similar at .93, whereas pure white spruce populations were not similar until .69.

The Silvicultural Significance of Geographic Variation in the White Engelmann Spruce Complex in British Columbia

One hundred and sixty-two spruce provenances, representing allopatric and sympatric populations of white, Engelmann, and Sitka spruce in British Columbia were sown in a coastal nursery. Twelve of these provenances were randomized in four replications, two of which were of regular nursery soil and two of an artificial soil mix. One hundred and fifty were randomized in six replications, all of which were of the artificial soil mix. In the second nursery year a plastic greenhouse was placed over two replications of the 12 provenances.An assessment of the growth behavior of all provenances showed a strong correlation between time of entering dormancy and geographic origin. A high correlation between time of entering dormancy and total growth is also demonstrated. The dormancy curve is shown to characterize a provenance with some accuracy.High-elevation provenances, which were the first to enter dormancy, were stunted in growth and exhibited a "rosette" appearance as a result of decreased internode length, while certain low-elevation provenances from the interior of British Columbia grew as well as Sitka spruce.On the basis of these results, recommendations are made in regard to the propagation of interior spruce in coastal nurseries, both in the open and in plastic greenhouses, and in regard to the displacement of spruce provenances in the interior of British Columbia. It is emphasized that these recommendations are tentative and will be modified as information accumulates concerning the genecology of white and Engelmann spruce in British Columbia. A major source of new information in this respect will be the long-term field trials that followed the study reported here.

A GENECOLOGICAL STUDY OF THE GENUS PICEA IN BRITISH COLUMBIA*

SummaryThe study is divided into two parts. Part A is an investigation of geographic variation in immature spruce populations and refers to the growth behaviour of 150 spruce populations grown in a relatively uniform environment. The seed, which was collected throughout the white, Engelmann and Sitka spruce complex in British Columbia, was sown in a coastal nursery on Vancouver Island. Detailed measurements were made on these populations during two growing seasons. In the laboratory seed samples of the same populations were X‐rayed to determine embryo development, and subsequently germinated at 25° C, Part B is a study of geographic variation in mature spruce populations and refers to a biometrical assessment of variation in cone scale morphology which was carried out on a mass collection of spruce cones collected in 157 areas throughout the range of spruce in British Columbia. This collection, therefore, embraces all four spruce species of the province. These are Sitka spruce (Picea sitchensis (Bong,) Carr.), black spruce (P. mariana (Mill,) B,S,P,), white spruce (P. glauca (Nlotnc) Voss subsp, glauca) and Engelmann spruce (P. glauca (Moench) Voss subsp, engelmannii). All measurements were subjected to statistical analysis in order to determine the relation between the variation observed and factors of the environment at place of origin. The results of both studies testify to the overwhelming influence of environmental pressures associated with altitude with respect to variation in the white‐Engelmann complex. In regard to the white‐Sitka complex both studies indicate the extent and effect of the penetration of Sitka spruce populations into populations of white spruce. Zones of hybridization between spruce species are characterized. The ecological significance of photoperiodic adaptation in spruce, and the relative importance of flushing and dormancy in the microevolution of the species are considered. The bearing of the results on the taxonomic status of the species in British Columbia is discussed, and recommendations are made in regard to the silviculture of the species in this province.