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UBC Theses and Dissertations

Relationship of cone production to wood traits of lodgepole pine Robertson, Donna L.

Abstract

In order to examine the relationship between cone production and wood traits, wood samples were taken from a clonal seed orchard of 15-year-old lodgepole pine (Pinus contorta Dougl.) and analyzed using X-ray densitometry. The relative density of each tree at breast height (1.38 m above ground), per-year volume and per-year bolewood biomass were calculated. In addition, cone counts were recorded from the seed orchard over a period of several years. The earlywood, latewood, and total-year components of volume, biomass, and relative density were regressed against cone counts for each tree over several years. In addition, the densitometer data were combined with May-July weather data for multiple regressions to discover which other variables were influencing wood traits. Analyses of variance showed a strong annual effect, which reflected the growth trends of the orchard trees. In addition, there was a strong clonal effect in the analysis of cone count and relative density. Regression results showed that ramet age was the most important factor in predicting the volume and biomass increment each year. There was a small effect on wood traits from cone bearing, temperature, and precipitation. Heavy conebearing had a negative relationship with wood density, but a positive relationship with volume and biomass increment. The positive relationship with volume and biomass was unexpected and may be the result of the strong effect of ramet age. Progeny data showed a uniformly negative relationship between wood traits and family fecundity. This may imply that unless there is selection against high fecundity, future plantations may experience decreases in wood density.

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