Based on 15-year-old spruce (Picea mariana) trees of 40 open-pollinated families grown in New Brunswick, this study examined the genetic variation and inheritance of wood density, and its relationship with growth trait (tree diameter, tree height and bole volume). Implications of these genetic parameters for wood quality improvement were discussed. Although wood density, earlywood density and latewood density show smaller phenotypic variation than growth traits, a larger part of the variation in these traits is due to families. These traits are under strong genetic control (h~ ranges from 0.60 to 0.86, and h~ ranges from 0.56 to 0.68). Wood density has a strong genetic correlation with earlywood density and latewood density (+0.72 and -0.73, respectively), but earlywood density and latewood density are strongly related to each other. As a result, wood density components have little value in improving the efficiency of selection for overall wood density. Overall wood density shows negative genetic correlations with growth traits (ranging from -0.34 to -0.41). To achieve optimal genetic gains, therefore, index selection for multiple traits is essential. This study reveals that selection for dry mass weight would result in remarkably higher genetic gain in gross fibre yield than selection for bole volume alone (+ 14.15% and +9.28%, respectively). Furthermore, selection for dry mass weight would result in less reduction in wood density, and while holding wood density at zero change, it is still possible to obtain huge genetic gain in gross fibre yield.

A clonally replicated field test of full-sib black spruce (Piceamariana (Mill.) B.S.P.) progeny was established at four locations in Nova Scotia. Estimated variance components for 5-year height growth and survival were interpreted according to an additive–dominance–epistasis genetic model and used to derive estimates of gain from various selection and deployment strategies. Five years after striking, 64% of the total genetic variance for height growth was due to additive variance. Virtually all of the remaining nonadditive variance was composed of epistatic variances; dominance variance was negligible. Narrow-sense heritability for 5-year height growth was low at 0.059. Substantial nonadditive variance contributed to a somewhat higher estimate of broad-sense heritability at 0.093. Family-mean heritabilities were much higher: 0.823 and 0.697 for half-sib and full-sib family means, respectively. Comparable heritabilities for survival were estimated with high standard errors and were considered unreliable. Results from this study indicate that clonal selection may provide large increases in genetic gain by capturing (i) genetic variance due to epistasis and (ii) a greater portion of the additive variance. Genetic gains for 5-year height growth in the order of 22.6% might be achieved using the best 1% of tested clones for operational planting. Clonal propagation may also be a preferred method to capture substantial genetic gain (about 11%) from selection at the family level, resulting in simplified management of breeding populations while reducing costs associated with conventional soil-based orchards.

Field experiments of the range-wide black spruce (Piceamariana (Mill.) B.S.P.) provenance study were established between 1973 and 1977 through the cooperation of several organizations in the United States and Canada from the Atlantic Coast to Alberta. This study evaluates performance at 11 or 15 years from seed in 29 locations divided into 8 regional clusters of 2 to 10 experiments each. Analytical methods include correlations of height and survival with geographic and climatic variables, analyses of variance, and polynomial regressions followed by contour plotting. Best height was obtained in the Great Lakes States and in other temperate regions, and best survival in Newfoundland and some temperate regions with long growing seasons. Correlations between height and survival were positive and significant only in 10 locations, 8 of which were located in temperate regions. In many locations in boreal regions, correlations with latitude or climatic variables at the place of seed origin and height have opposite signs of correlations with survival, indicating difficulties when simultaneously selecting for good height and high survival in cold climates. Contour plots from the regressions demonstrate a similar trend by showing good pattern overlap of height and survival primarily in mild coastal (Newfoundland) or temperate continental climates (southern Quebec and Ontario, Great Lakes States). There is evidence that provenance differences are still developing and changes in rank are taking place, and therefore additional assessments are required in the future.

Initiation and cessation of growth and total height of seedlings at ages 2 and 3 years were measured in a nursery experiment with 100 seed sources of Piceamariana (Mill.) B.S.P. from natural stands sampled across the range from the Atlantic Coast to Alaska. Correlations with climatic and geographic factors were calculated and principal component, variance, and regression analyses made. The results showed that photoperiod and temperature were major factors of natural selection and that a clinal variation pattern is predominant. Since south–north trends of photoperiod and temperature are closely related to latitude, the regression of phenological variables and of height on latitude of origin gave an indication of response gradients. Total height changed by 2 to 11% from the experimental mean if a seed source was moved 1° of latitude north or south from its native area to a new site. The consequences for seed movement and breeding programs are discussed.

Foresters are among the first professionals that developed principles for sustainability. The need for sustainable forests was first expressed in Germany by H.K. von Carlowitz in 1713. Since about 1800 methods to achieve sustainability based on wood volume, forest area, or growing stock have been introduced in all jurisdictions in Germany and Austria. The general acceptance of the sustainability principle, improved education and professionalism of foresters, and the reform of forest administrations have all contributed to the success of forestry in central Europe. In Canada, forest conservation and sustainable management have been discussed since 1907 when university education in forestry was initiated, and sustainability is now firmly established in all provinces. Key words: history of forestry, forest inventory, forest regulation, forest management, G.L. Hartig, H. Cotta, J.C. Hundeshagen, B.E. Fernow